Plant Systems: Energy Production

The process in which plants convert light energy into chemical energy is called Solution

1. Sequestration
2. Deposition
3. Respiration
4. Photosynthesis
5. Cellular Grouping

Photosynthesis is how plants store their energy.

Creative Commons Credit: CC BY-SA 3.0, Kristian Peters, 2006

Plant Systems: Energy Production

Which of the following gases is a by-product of cellular respiration in plants? Solution

1. Oxygen
2. Ozone
3. Hydrogen
4. Nitrogen
5. Carbon Dioxide

Cellular respiration should not be confused with photosynthesis! Yes plants can respire also, like we humans can.

Plant Systems: Energy Production

In plants, which of the following occurs during both the day and at night? Solution

1. Carbon dioxide production
2. Photosynthesis
3. Photosynthesis and cellular respiration
4. Cellular respiration
5. None of the above

Photosynthesis cannot occur at night, leaving only cellular respiration.

Plant Systems: Energy Production

What molecule does a plant use to store its energy? Solution

1. Sugar (Glucose)
2. Chloroplast
3. ATP (Phosphate)
4. Oxygen
5. CO₂

Photosynthesis creates the sugar out of sunlight, water, and carbon dioxide.

Soil Composition

Leaching of organic and inorganic fertilizers or pesticides into water systems can damage the watersheds. How do farmers minimize this risk? Solution

1. Using bricks of fertilizers or pesticides that don't dissolve.
2. Moving farms away from important waterways.
3. Using carbonate and calcium, rather than nitrate and phosphate chemicals.
4. Using bean and seed legume-crops to enrich the soil.
5. None of the above.

Legumes contain natural fertilizers, like nitrogen.

Soil Quality

Eutrophication is the when runoff leaks high amounts of nutrients into the aquatic ecosystem, causing an increase in the amount of carbon dioxide in the water. Solution

1. True
2. False

Runoff like sewage or fertilizers add unusually high levels of nutrients to the water. The most significant impact - rather than growth of algae - is the decrease in oxygen dissolved in the water. This is due to several factors including the decomposition of high amounts of biomass.

Characteristics of Ecosystems

Within the terrestrial ecosystem, trees are considered to be Solution

1. Biotic
2. Abiotic
3. Biotic and abiotic
4. Non-living
5. None of the above

Biotic

Ecology

Grass is a(n): Solution

1. Producer (Autotroph)
2. Consumer (Heterotroph)
3. Omnivore
4. Decomposer
5. Herbivore

Autotrophs store energy by making nutritional organic substances like sugars.

Biomass

The second level on the Biomass pyramid contains the Solution

1. Tertiary Consumers
2. Primary Consumers
3. Secondary Consumers
4. Primary Producers
5. Secondary Predators

Biomass

The trophic level with the largest biomass is Tertiary consumers. Solution

1. True
2. False

The trophic level with the largest biomass is Primary producers.
E.g.) Plants, algae, trees, grass, etc...

Biosystems

The process of building up toxins in larger animals is known as Solution

1. Toxification
2. Malnourishment
3. Unsustainability
4. Poisoning
5. Bioaccumulation

Bioaccumulation

In which of the following species would the highest concentration of fat-soluble toxins be found? Solution

1. Wolf
2. Grass
3. Mouse
4. Fox
5. Bear

Highest in the tertiary consumers at the top of the food web. The species at the top of the food web amongst these given examples is the bear.

Biosystems

A dramatic increase in the number of a certain species will: Solution

1. Always cause a permanent change in the balance of species
2. Have no affect on the number of other species
3. Lead to an extinction of the animals lower down the food web
4. Stress the carrying capacity of the system and increase predation, and sometimes the balance of species is restored
5. Change the sustainability of the ecosystem permanently.

While this has the chance of changing the sustainability of the ecosystem, it does not necessarily mean the system is ruined. Sometimes this is used intentionally to help restore a balance. Predators have more food and eat more, thriving and increasing the number of predators. Carrying capacity: the competition amongst the increased species' population will further reduce their numbers because of the limited nutrient resources.

Biosystems

In a forest ecosystem foxes are the predators of rats, and rats prey on smaller mice. If a municipality with unusually high numbers of rats were to collect them all and dump them in the forest outside of the city what would likely happen? Solution

1. The number of mice would increase
2. The number of foxes would decrease
3. The mice will always become extinct
4. The number of mice would stay the same
5. The number of foxes would increase

Many different things could happen, one of which could be an increase in the consumers as the food supply increases. (An other thing that could happen is the competition of the food supply between the rats, leading to reduction.)

Invasive Species

Zebra mussels and the goby fish are two examples of invasive species that have Solution

1. Restored the balance of aquatic ecosystems
2. Caused a decrease in the diversity of the ecosystem
3. Improved water quality
4. Caused an increase in the overall population of aquatic species
5. Managed to continually evolve and climb up the food web

These species have out-competed native species and this has caused a reduction in diversity.

Threats to Sustainability

As a researcher, what's one way to verify that overhunting or overfishing is actually happening? Solution

1. Set up cameras to take pictures of the hunters, fishers, and the species
2. Interview the people who hunt and fish to ask them to estimate the number of species left
3. Catch or tag the animals to estimate the number of species per square unit of area to determine the overall population
4. Count the number of times a species encounters a certain location over the period of a week
5. Leave out food and see how much gets eaten

These methods are currently used to monitor the populations of many different at-risk species.

Human Activity and Ecosystems

A rapidly-growing city requires a new energy source to provide power to the increasing number of residents. A nearby mass of water would provide an effective location for a hydroelectric dam, which creates power from the movement of flowing water. Describe how creating a massive artificial lake might affect the ecosystem. [2] Solution

Hint Clear Info

Incorrect Attempts:

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Hint Unavailable

Flooding upstream. (Maybe same amount of water downstream) although if diverted then lack of water would cause animals to move to another area with water. Animals lost habitat upstream, must move...

(Answers may vary... Add more possible answers...)

Mixtures and Solutions

There are two types of mixtures, mechanical mixtures and solutions. Which of the following is a solution? Solution Video

1. Pasta sauce
2. A mixture of jellybeans
3. Cereal with milk
4. Fresh orange juice with pulp
5. Air

Can you visually distinguish the particles as a heterogeneous mixture? If yes, then it is a mechanical mixture. If no, then it is a homogenous (solution) mixture.

A mechanical mixture contains more than one type of visible particles like pasta sauce, jellybean mixtures, cereal with milk, and the pulp in orange juice. Mechanical mixtures are heterogeneous mixtures.

A solution contains more than one type of particle that are not visible or distinguishable, like the different gases in air (nitrogen, oxygen, argon, carbon dioxide...) Solutions are a homogeneous mixture.

Provide an example of a typical solution that consists of ions. [1] Solution Video

Hint Clear Info

Incorrect Attempts:

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Hint Unavailable

Juices, sports drinks (like Gatorade, etc) contain ions like sodium Na⁺, calcium Ca²⁺, ...

(Answers may vary...)

Provide an example of a solution that consists of a pure liquid mixed with another pure liquid at room temperature. Solution

This is a bit difficult because most liquids students will say are unpure, aqueous solutions like juices, milks, etc... It is easier to understand a solution between one liquid (water) and any aqueous stuff, like the things mentioned previously.

Pure liquids don't have anything dissolved in them, for example:

• Water
• Ethanol
• Mercury
• Hexane hydrocarbon
• Benzene hydrocarbon

Accept any mixture of pure elements or compounds that are not visiblly distinguishable...
(Note that students do not yet understand polarity, so this could be tricky)

Solution mixtures can only be liquids or gases. Solution

1. True
2. False

Solutions can be a mixture between any of the following:

• liquids — liquids
• gases — gases
• gases — liquids
• solids — solids
• aqueous — liquids

Which of the following mixtures is an alloy? Solution Video

1. Sodium and Chlorine
2. Titanium and Bromine
3. Iron and Oxygen
4. Aluminum and Sulfur
5. Titanium and Gold

An alloy is a solid solution mixture of 2 metals. The metals are mixed by melting the metals into the liquid state and mixing as a solution. Once cooled to a solid they are in the form you may be familiar with, like brass or stainless steel. Titanium and Gold are the only two mixtures of metals listed in the answer choices.

Pure Substances

Explain how pure water, made up of hydrogen (H) and oxygen (O) is considered a pure substance. [1] Solution Video

Hint Clear Info

Incorrect Attempts:

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Hint Unavailable

Pure substances contain only 1 type of particle. The H₂O molecule is considered as one particle, and any number of these same particles is considered pure.

(If the hydrogen and oxygen were separated, then it would not be considered a pure substance because there would be different H₂ and O₂ particles).

Which of the following is a 'pure substance'? Solution Video

1. A coin, like a quarter
2. Paper
3. Wood
4. A bar of soap
5. Ice

Only ice is made up of just 1 type of molecule/particle.

The rest of these things contain 2 or more different particles. Coins are now made of a combination of different metal elements. Paper contains cells that contain millions of different kinds of particles. Wood is made of cells that contain millions of different kinds of particles. Soap contains many different kinds of particles.

• Coin: alloy solution mixture of 2 or more metal elements
• Paper: contains cells with many elements (proteins, organelles, DNA, RNA, ions), also chemicals in processing
• Wood: contains cells with many elements (proteins, organelles, DNA, RNA, ions)
• Soap: many different ingredients, glycerol, oils, fragrances...
• Ice: is PURE WATER H₂O and is the pure substance.

Physical State and Volume

Which of the following substances would contain particles the furthest distance apart, at a given temperature? Solution Video

1. Liquid nitrogen
2. Solid sulfur
3. Gaseous oxygen
4. Powdered phosphorus
5. None of the above

Gases particles are farthest apart because the heat and kinetic energy overcomes the forces of attraction between the particles.

Differentiate Physical and Chemical Changes or Properties

You should learn the difference between chemical changes and physical changes (or chemical properties and physical properties).

A chemical change has occurred when bonds are broken, and new bonds and substances are formed. Solution

1. True
2. False

A chemical change is when the atoms/bonds rearrange in some way.

The observational evidence that a chemical change has occurred includes: release (or absorption) of heat or light, odour, release of gas or bubbles, a change in colour, or formation of a new solid or liquid.

Which of the following is a chemical change? Solution

1. A puddle of water evaporating in the hot sun
2. Wet paint drying on a wall
3. Iron turning into rust a metal toy car left outside
4. Molten, liquid metal solidifying to form a brick of metal
5. Cheese melting in a pot on the stovetop

Remember that rusting is a chemical reaction/change because new bonds are formed as the molecules are rearranged.

Here are some examples of chemical changes:

• Combustion: $CH_4 + O_2 \xrightarrow{} CO_2 + H_2O$
• Dissolving: $NaCl_{(s)} \longleftrightarrow Na^{+}_{(aq)} + Cl^{-}_{(aq)}$
• Rust: $4Fe + 3O_2 \xrightarrow{} Fe_2O_3$

Burning is an example of a chemical change. Solution

1. True
2. False

Burning (combustion) changes the arrangement of the atoms to break or form new bonds. For example with methane gas, $CH_4 + O_2 \xrightarrow{} CO_2 + H_2O$

Check the two examples of physical changes/properties. Solution

1. Salt (Na⁺Cl^-) dissolving in water
2. Cellular respiration creating CO₂
3. Ice cream melting
4. Sugar burning
5. Water boiling

Melting and boiling are physical changes because only a phase change occurs, without rearranging any bonds between atoms.

Dissolving a sugar is a physical change, not a chemical change because no bonds are breaking when the sugar dissolves in water. The sugar changes from a solid to aqueous phase.

Dissolving a salt is a chemical change because bonds are rearranged when the ionic compound breaks apart from a solid into aqueous ions in the water.

Explain why dissolving sodium chloride into water is an example of a chemical change, while dissolving glucose (sugar) into water is a physical change. [2] Solution

Hint Clear Info

Incorrect Attempts:

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Hint Unavailable

Sodium chloride NaCl_(s) is a salt, and the ionic bonds between the 'Na' cation and 'Cl' anion are broken apart when they dissociate in the solution. Chemical changes change the bonding of the molecules, while physical changes do not change the bonding. $NaCl_{(s)} \longleftrightarrow Na^{+}_{(aq)} + Cl^{-}_{(aq)}$ See the difference between the two reaction equations... Only one breaks apart.

The sugar molecule C₆H₁₂O_{6 (s)} has covalent bonds so does not break apart when it is dissolved (solvated) into water. Physical changes only change the phase state of a compound without rearranging/changing any bonding, e.g. just solid to aqueous, or gas to a liquid. $C_6H_{12}O_{6 (s)} \longleftrightarrow C_6H_{12}O_{6 (aq)}$

Which two of the following cause a chemical change when dissolved in water? Solution

1. Sodium
2. Oxygen
3. HCl
4. Sugar
5. NaCl

Chemical changes are a change in the chemical bonding in a substance.

When ionic compounds dissolve in water, they separate into their aqueous (aq) ions (positive cation, and negative anion) and this is considered a chemical change.
H⁺Cl^- and Na⁺Cl^- are both ionic compounds.

A student is mixing some chemicals in a safe, controlled laboratory. Two liquids are mixed without heating or cooling. Which of the following is not evidence that a chemical reaction has occurred, or is occurring? Solution

1. Bubbles are coming out when liquids are mixed
2. The colour of the chemical changes
3. A sound is heard
4. A solid substance forms at the bottom of the container
5. The substance evaporates leaving behind a solid substance

Evaporation is a physical phase change from a liquid to a gas, therefore it is not a chemical reaction...

Other evidence a chemical reaction has occurred: change in temperature, production of light, or even odor...

Sort the following chemical and physical changes and properties. Solution

Melting

Color

Rusts

Covalent compound dissolves in water

Ionic compound dissolves in water

Solid, liquid, or gas phase

Combustible

Taste

Malleability or ductility

Burns

Density, mass, volume

Powder, or crystals

Chemical Change/Property

Physical Change/Property

Chemical Properties (based on reactions)

• Rusts
• Ionic compound dissolves in water
• Combustible
• Burns
• Density, mass, volume
• ...

Physical Properties (based on the senses)

• Melting
• Color
• Covalent compound dissolves in water
• Solid, liquid, or gas phase
• Taste
• Malleability or ductility
• Powder, or crystals
• ...

Physical States of Matter: Fluids

Which of the following are considered fluids? Solution

1. Solid
2. Liquid
3. Gas

1. II only
2. I, II, and III
3. II and III
4. III only

Fluids expand to fill their container and have no fixed shape... this can be either a liquid or a gas... Many people don't realize gases are fluids (maybe because they confuse with the word liquid).

Density Intro

Density is calculated as:

A material floats when it has a lower density than the fluid. Solution

1. True
2. False

Materials with higher densities than the fluid density, will sink to the bottom because of gravity.

A 450 g object is dropped into a fluid that has a density of 6.5 g/cm³. If the object has dimensions 5 cm × 4 cm × 3 cm, then determine what will happen. (Show your work in your own notes.) Solution

1. The object will float
2. The object will sink
3. The object has the same density as the fluid
4. Its cannot be calculated with the given information

First calculate the volume: $\begin{align} volume & = 5 cm × 4 cm × 3 cm \\ \\ & = 60 cm^3 \\ \\ \end{align}$ Then calculate density: $\begin{align} density & = \dfrac{mass}{volume} \\ \\ & = \dfrac{450g}{60cm^3} \\ \\ & = 7.5 g/cm^3 \\ \\ \end{align}$ Since the density of the object is higher than the fluid, then the object will sink.

When does something sink and when does it float? Solution

Creative Commons Credit: Kelvinsong, 2013

(Don't accept mass or volume).
Objects sink when its density is greater than the density of the fluid... And visa versa...

Shown in the diagram from top to bottom...

• Yellow: Oil
• Red: Wine alcohol
• Blue: Water with dye
• Green: Dish soap
• Brown: Maple syrup

The Unusual Density of Water

Water is most dense when it is: Solution

1. Solid ice
2. Liquid and cold
3. Liquid and hot
4. Gaseous vapor
5. The density of water is the same in all phases

Water is one of the few substances in the universe that is more dense as a liquid than as a solid.

Density Calculations

A 100 kg dinosaur bone is found in the desert.

Calculate the density, given the volume is 20 m³ Solution

1. 5 kg/m³
2. 2 kg/m³
3. 50 kg/m³
4. 10 kg/m³

$\begin{align} density & = \dfrac{mass}{volume} \\ \\ density & = \dfrac{100\ kg}{20\ m^3} \\ \\ & = 5kg/m^3 \\ \\ \end{align}$

Using your calculation of density, much would 4.25 m³ of this bone weigh? Solution

Hint Clear Info

Incorrect Attempts:

CHECK

kg

Hint Unavailable

Density, $\begin{align} density & = \dfrac{mass}{volume} \\ \\ density & = \dfrac{100\ kg}{20\ m^3} \\ \\ & = 5kg/m^3 \\ \\ \end{align}$ Use density to calculate mass, given the volume, $\begin{align} density & = \dfrac{mass}{volume} \\ \\ 5\ kg/m^3 & = \dfrac{mass}{4.25\ m^3} \\ \\ (5\ kg/m^3)(4.25\ m^3) & = mass \\ \\ mass & = (5kg/\cancel{m^3})(4.25\cancel{m^3}) \\ \\ mass & = 21.25\ kg \\ \\ \end{align}$

The Periodic Table

The periodic table is organized according to: Solution

1. Atomic mass
2. Number of electrons
3. Atomic number
4. The atomic symbol name
5. Melting point

Atomic number, the number of protons!

A row on the periodic table is called a group. Solution

1. True
2. False

A row on the periodic table is called a period. A column is a group.

Elements in the same group tend to share similar physical and chemical properties. Solution

1. True
2. False

Elements that share a group are in the same chemical family and share physical properties because they have the same number of valence electrons. The chemical property is based on the number of valence electrons that elements in a certain group have.

Which of the following elements would have similar physical and chemical properties to Neon (Ne)? Solution

1. Lithium
2. Magnesium
3. Nitrogen
4. Hydrogen
5. Argon

Because elements in the same group tend to share similar physical and chemical properties. Both Neon and Argon are in group 18.

Which collection of atomic numbers of elements is likely to share the same physical and chemical properties? Solution

1. 3, 4, 5, 6
2. 1, 3, 11, 19
3. 11, 15, 17, 18
4. 4, 8, 10, 12
5. 1, 3, 5, 7

Elements in the same group tend to share similar physical and chemical properties. Elements with atomic numbers 1, 3, 11, 19 are in the same group, group 1.

All these elements in the same group 1 would react to lose 1 electron to form +1 charged cations. For example: H⁺¹, Li⁺¹, Na⁺¹, K⁺¹

The Chemical (Group) Family on the Periodic Table

You can use a periodic table for the following...

Alkali earth metals are located in group: Solution Video

1. 8
2. 7
3. 2
4. 1
5. 3

The main names are: alkali earth metals (group 1: Li, Na, K...), alkaline earth metals (group 2: Be, Mg, Ca...), ..., halogens (group 17: F, Cl, Br...), and noble gases (group 18: He, Ne, Ar...).

Alkali earth metals are located in group 1.

Determine the different group numbers that each of the following chemical families are in: Alkali earth metals, Alkaline earth metals, Halogens, and Noble gases. Solution

Alkali earth metals: Group 1
Alkaline earth metals: Group 2
Halogens: Group 17 (or 7A)
Noble gases: Group 18 (or 8A)

The following elements belong to which chemical family (group)? Solution

Public Domain

Be, Mg, Ca

1. Alkali earth metals
2. Alkaline earth metals
3. Transition metals
4. Halogens
5. Noble gases

Alkaline earth metals

The elements of which chemical family (group) are most reactive in water? Solution

1. Alkali earth metals
2. Alkaline earth metals
3. Transition metals
4. Halogens
5. Noble gases

Alkali earth metals are most reactive in water. This is called a physical property.

The elements of which chemical family (group) are inert, and tend not to react chemically? Solution

1. Alkali earth metals
2. Alkaline earth metals
3. Transition metals
4. Halogens
5. Noble gases

Noble gases are considered inert, mostly.

Chlorine (Cl) is a gas at room temperature and has a green-yellow colour. Which chemical family (group) does chlorine belong to? Solution

1. Alkali earth metals
2. Alkaline earth metals
3. Transition metals
4. Halogens
5. Noble gases

Halogens

Classify the following 7 elements... Solution B, Si, Ge, As, Sb, Te, Po

1. Metals
2. Non-metals
3. Transition metals
4. Metalloids
5. Gases

These are the 7 Metalloids. Metalloids are special elements that have a mixture of properties of metals and non-metals. They are located on a step-ladder (staircase) on the periodic table between the metals and the non-metals.

Metals have a shiny luster, are malleable, ductile, and tend to conduct electricity and heat... But metalloids only have some combinations of these properties. For example Silicon (Si) has a shiny luster, but is not malleable, is brittle, and is a poor conductor of electricity...

Atomic Structure and the Periodic Table

Copy the table below and fill in the spaces with the atomic structures showing the following things. Solution

1. Number of protons and neutrons in the nucleus
2. The electrons on each ring (energy level), including the valence

On the periodic table, going across a period (left-to-right) increases the number of ________(I)________, and going down a group (top-to-bottom) increases the number of ________(II)________. [Not referring to protons or neutrons] Solution

Hint Clear Info

I =
II =

Incorrect Attempts:

CHECK

Hint Unavailable

On the periodic table, going across a period (left-to-right) increases the number of valence electrons on the outer orbit, and going down a group (top-to-bottom) increases the number of energy levels or orbits/rings.

Atomic Number and Atomic Mass

The number of neutrons always equals the number of protons in an atom. Solution

1. True
2. False

The number of neutrons is calculated with: Atomic Mass - Atomic Number

The atomic number always equals the number of protons in an atom. Solution

1. True
2. False

True

It is possible for the atomic mass to be smaller than the atomic number. Solution

1. True
2. False

The atomic mass is always higher than the atomic number. The atomic mass equals the number of protons + neutrons. The atomic number equals only the number of protons.

A Carbon atom has the following quantities: atomic number = 6, atomic mass = 12. Determine the number of neutrons in one Carbon atom. Solution Video

1. 6
2. 12
3. 2
4. 18
5. 10

A Silicon atom has 14 neutrons, 14 electrons, and 14 protons. What is the atomic mass of Silicon? Solution Video

1. 14
2. 28
3. 42
4. 21
5. 7

Atomic mass = Number of Protons + Number of Neutrons

Atomic mass = 14 + 14

Atomic mass = 28

Given the neutral (uncharged) element from the periodic table for Potassium (K), determine the number of protons, electrons, and neutrons, respectively. Solution $^{19}_{39}K$

1. 19 protons, 19 electrons, 19 neutrons
2. 39 protons, 39 electrons, 39 neutrons
3. 19 protons, 20 electrons, 39 neutrons
4. 39 protons, 39 electrons, 20 neutrons
5. 19 protons, 19 electrons, 20 neutrons

19 = atomic number = number of protons

39 = atomic mass = number of protons + neutrons

$\begin{align} \text{number of neutrons}\ & = \text{atomic mass}\ - \text{atomic number} \\ \\ & = 39 - 19 \\ \\ & = 20\ \\ \\ \end{align}$ A neutral (uncharged) element has: number of protons = number of electrons = 19

Which element would have a half-full second energy level? Solution

1. Carbon, C
2. Hydrogen, H
3. Helium, He
4. Beryllium, Be
5. Nitrogen, N

The second energy level can hold up to 8 electrons. Carbon has 4 electrons in the second energy level, the electrons on this outer shell are also known as valence electrons.

An isotope of an atom has: Solution Video

1. The same number of electrons and a different number of protons
2. The same number of protons and a different number of electrons
3. The same number of neutrons and a different number of electrons
4. The same number of neutrons and a different number of protons
5. The same number of protons and a different number of neutrons

The atomic number (number of protons) of an atom can never change - otherwise we would be able to convert one element into another, like convert iron into gold!

These two elements are the exact same in every way, except for one thing... Isotopes have a different number of neutrons. (But a different number of electrons is called an ion, rather than an isotope.)

The Thompson Model of an Atom

The Thompson model of an atom consists of a positively charged sphere with negatively charged electrons distributed evenly throughout the sphere. Solution

1. True
2. False

Yes this was how Thompson thought the atom was made. Thompson's model spaced the negatively charged particles evenly throughout a positively charged substance in the atom, like a "plum pudding", or chocolate chips in a cookie. (But he was eventually proven wrong about this atomic model)...

Geiger–Marsden (Rutherford's) Gold Foil Experiment

Rutherford's gold foil experiment demonstrated that Solution

1. Electrons are located at the edge of an atom on energy levels
2. Protons are positively charged and have a greater mass than negatively charged electrons
3. Atoms contain subatomic particles called protons, neutrons, and electrons
4. Atoms contain a cluster of positively charged protons located at the center
5. None of the above

Atoms contain a cluster of positively charged protons located at the center. (He was right, and Thompson was wrong)...

Rutherford shot particles (in the form of alpha particles with a mass) at gold foil, what he noticed was the particles were not all traveling through the gold atoms evenly.

Sometimes the particles were being reflected backwards. Therefore there must have been something inside the atom with a significant mass, and this they later found was the nucleus (so they discovered that atoms have a nucleus). The electrons don't have enough mass to reflect the alpha particles.

Bohr-Rutherford Model of an Atom

In an atom, electrons are located: Solution

1. At the sphere
2. Between the rings
3. Inside the nucleus
4. Below the surface
5. On energy levels or orbits

Draw a Bohr-Rutherford model of a Calcium (Ca) atom. (In your own notes) Solution

[Not shown.] Your diagram should include the central charges (20 p⁺, and 20n) and four rings of electrons with 2 unpaired on the inner, 8 (4 pairs) on the second, 8 (4 pairs) on the third, and 2 unpaired electrons on the outer/valence orbit.

Applications of The Bohr-Rutherford Model of an Atom

The innermost orbit of an atom can contain up to 8 electrons. Solution Video

1. True
2. False

The innermost orbit on an atom can contain up to 2 electrons.

Bohr-Rutherford models of the elements in the halogen group would have which of the following in common? Solution

1. Number of orbits (rings)
2. Number of protons and neutrons
3. Atomic number
4. Total number of electrons
5. Number of electrons on the outer ring

Number of electrons on the outer ring

Which element would have the same number of orbits (rings) as Sodium, Na? Solution

1. Hydrogen (H)
2. Lithium (Li)
3. Nitrogen (N)
4. Chlorine (Cl)
5. Calcium (Ca)

Elements in the same period (row) have the same number of orbits.

An element with an atomic number of 12 has what numbers of electrons on each orbit, ordered from inside to outside? Solution

1. 2, 8, 2
2. 2, 10
3. 8, 2, 2
4. 8, 4
5. 4, 8

The element with atomic number 12 is Magnesium (Mg). This is in the 3^rd period (row), which means there are 3 energy levels...

= 2, 8, 2

Atoms

The electrical conductivity of metals depends on which part of an atom? Solution

1. Protons
2. Neutrons
3. Mostly empty space in an atom
4. Electrons
5. Isotopes

Electrical conductivity is based on the movement of electrons.

Ions

What is an ion? [1] Solution

Hint Clear Info

Incorrect Attempts:

CHECK

Hint Unavailable

An ion is a charged particle that forms from a neutral element when electrons are removed or added. Elements that lose electrons form positive cations. Elements that gain electrons form negative anions.

If a Calcium (Ca) ion has a charge of 2+, determine the total number of electrons, given the atomic number of Calcium is 20. Solution

1. 18 electrons
2. 20 electrons
3. 22 electrons
4. 12 electrons
5. 8 electrons

18 electrons

Which of the following is an ion? Solution

1. N₂
2. NaCl
3. Mg
4. Cl^-
5. O₃

An ion has a charge, either as a positive cation, or a negative anion.

Which of the following elements will form an anion? Solution

1. Hydrogen (H)
2. Potassium (K)
3. Argon (Ar)
4. Aluminum (Al)
5. Oxygen (O)

Non-metals that gain electrons form negatively charged anions. These elements are located on the upper-left side of the periodic table. O^2- (Hydrogen, potassium, and aluminum form cations. Argon does not form an ion because noble gases are inert).

Determine the number of electrons that Magnesium will lose when a Magnesium cation is formed, and that Sulfur will gain when a Sulfur anion is formed. Solution

Hint Clear Info

Magnesium loses:
Sulfur gains:

Incorrect Attempts:

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electrons

Hint Unavailable

When Magnesium loses electrons to form its cation form... It will lose all the electrons in the outer valence orbit (energy level). Magnesium has 2 electrons in the valence that it will lose because it is in group 2.

When Sulfur gains electrons to form its anion form... It will gain all the electrons it needs to fill the outer valence orbit (energy level) up to 8 electrons. Sulfur starts with 6 electrons in the valence because it is in group 6A (or 16), so it needs to gain 2 more electrons.

Explain why Chlorine has a -1 charge when it forms an ion. [1] Solution

Hint Clear Info

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Hint Unavailable

The -1 charge comes from the difference in protons and electrons in the chloride ion.

Chlorine starts with 17 protons and 17 electrons. When the chloride ion gains 1 electron, it then has 17 positively charged protons and 18 negatively charged electrons. One more electron makes the charge -1.

Neutral, uncharged Lithium (Li) has an atomic number of 3 and a mass number of 7. For the Lithium ion, determine the number of protons, electrons, and neutrons, respectively. Solution $^{3}_{7}\text{Li}$

1. 3 protons, 7 electrons, 1 neutrons
2. 4 protons, 7 electrons, 3 neutrons
3. 3 protons, 3 electrons, 1 neutrons
4. 4 protons, 3 electrons, 1 neutrons
5. 3 protons, 2 electrons, 4 neutrons

3 = atomic number = number of protons

7 = atomic mass = number of protons + neutrons $\begin{align} \text{number of neutrons}\ & = \text{atomic mass}\ - \text{atomic number} \\ \\ & = 7 - 3 \\ \\ & = 4\ \\ \\ \end{align}$ A neutral (uncharged) element has: number of protons = number of electrons = 3

But the Lithium ion is in group 1 so it will lose 1 electron to get a +1 charge. A positively charged element has:
number of electrons = number of electrons - number electrons lost
= 3 - 1
= 2 electrons.

Characteristics of Common Elements and Compounds

CHCl₃ is an atom. Solution

1. True
2. False

CHCl₃ is a molecule or compound consisting of five atoms: one carbon, one hydrogen, and three chlorine atoms.

Which of the following is not a chemical compound? Solution

1. Carbon dioxide
2. Potassium
3. Water
4. Sugar
5. Salt

A compound is composed of two or more elements. A compound is not found on the periodic table. Potassium is the only single element listed, i.e. not a compound.

The Seven Diatomic Molecules

Which of the following does not form a diatomic molecule? Solution

1. Nitrogen
2. Oxygen
3. Helium
4. Chlorine
5. Iodine

(Note that diatomic molecules are not considered compounds.) The seven diatomic molecules you need to know are, "HOFBRINCL": H₂, O₂, F₂, Br₂, I₂, N₂, Cl₂.

Covalent Compounds

Two non-metals combine to form a covalent compound. Solution

1. True
2. False

True

Glucose is a simple sugar with the chemical formula, C₆H₁₂O₆. How many non-metal atoms are in one molecule of glucose? Solution

1. 1
2. 3
3. 24
4. 48

6 Carbons + 12 Hydrogens + 6 Oxygens = 24 atoms

Predict which of the following elements will form a covalent compound when combined. Solution

1. Hydrogen and Oxygen
2. Sodium and Sulfur
3. Aluminum and Fluorine
4. Lithium and Fluorine
5. None of the above

Covalent compounds are formed when two non-metals combine and share electrons.

(An exception is like hydrogen ion plus chlorine ion).

Ionic Compounds

An ionic compound consists of the combination of one neutral atom, plus one charged atom (anion or cation). Solution

1. True
2. False

Ionic compounds consist of a positively charged ion (cation), combined with a negatively charged ion (anion). The cation loses one or more electrons to the anion.

Determine the correct statement regarding the ionic compound, MgCl₂. Solution

1. Magnesium is a non-metal
2. Chlorine is a metal
3. Magnesium is an anion
4. The compound contains three elements
5. The compound contains three atoms

Magnesium is a metal.
Chlorine is a non-metal.
The compound contains three atoms and two different elements.

Which of the following is an ionic compound? Solution

1. C₃H₆
2. H₂O
3. Br₂
4. Be²⁺F^1-₂
5. O₃

An ionic compound is always made up of charged atoms, or ions. Usually an ionic compound consists of a metal cation, and a non-metal anion.

An ionic compound called aluminum trioxide is formed when two aluminum atoms combine with three oxygen atoms. Show the chemical formula for one molecule of aluminum trioxide. Determine which atom is the cation. [2] Solution

⁰

¹

²

³

⁴

⁵

⁶

⁷

⁸

⁹

⁻

⁺

⁽

⁾

₀

₁

₂

₃

₄

₅

₆

₇

₈

₉

₋

₊

₍

₎

Incorrect Attempts:

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Hint Unavailable

Al₂O₃

The positively charged Aluminum metal ion is the cation, and the negatively charged Oxygen non-metal ion is the anion.

The cation is always written first, and the anion last, in the chemical formula of an ionic compound.

Distinguishing Ionic and Covalent Compounds

A white chalky powder is left over in a lab from a chemical reaction. A curious chemist wants to quickly see if the compound is ionic or covalent. Determine based on the evidence below, whether the compound is ionic or covalent. Solution

• The chemist heats the compound over very high heat at 300˚C and the compound does not burn or melt.
• The chemist then mixes the compound with water and it dissolves easily.

Hint Clear Info

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Hint Unavailable

Ionic compounds have a high melting point and are mostly soluble in water. Covalent compounds have a low melting point, and are often insoluble in water. Covalent compounds will burn at lower temperatures, since the compound did not melt or burn, then it is most likely ionic.

Moon

The Earth is the only planet in our solar system that has a moon. Solution

1. True
2. False

The Earth only has one moon.

Jupiter has 63 moons!

Other planets have moons too, Saturn has 62 moons, Mars has 2 moons, ... and more...

Moon

The same side of Earth's Moon always faces Earth because... Solution

1. The Moon does not rotate on it's axis as it rotates around the Earth
2. The Moon does not orbit around the Earth as it is fixed in the same space over Earth
3. The Earth rotates around the Moon and the Sun
4. The Moon rotates on its axis in the same time it takes for the Moon to orbit the Earth

The Moon does rotate on its axis, and it does orbit the Earth.

The time it takes the Moon to orbit the Earth (the orbital period) is the same amount of time it takes for the Moon to rotate on its axis.

Therefore we always see the same side of the moon, even though the Moon is rotating on its axis. (BTW, the Moon's orbital period, and rotation period is 27.3 days).

Inner Earth Core

The center of the Earth (core) is almost as hot as the surface of the Sun. Solution

1. True
2. False

(This fact is slightly less known by students.) The core of the Earth is molten metal and rock because it is so hot. The temperature of the core of the Earth is close to the temperature of the surface of the Sun, around 5,430 °C. (Of course the core of the sun is many, many times hotter!)

Moon Terminology

The moon is classified as a type of... Solution

1. Planet
2. Star
3. Satellite
4. None of the above

A satellite travels around a planet.

Solar System Order

The Milky Way is our solar system. Solution

1. True
2. False

The Milky Way is our galaxy, which contains our solar system (the Sun + 8 planets).

Asteroids and Meteoroids

What is the main difference between an asteroid and a meteoroid? Solution

1. Location in space
2. Size
3. Material composition
4. Speed

Meteoroids are smaller than asteroids. Asteroids are like tiny planets, which also orbit the Sun like meteoroids. Meteoroids are debris formed from the collision of larger asteroids, or planets, etc. (Both terms are used for the presence in space, and are made of rock and metal)

Meteoroids

As a meteoroid falls from space to the Earth, which is the correct order of the name as it falls from space, to the ground? Solution

1. Meteorite, Meteoroid, Meteor
2. Meteoroid, Meteor, Meteorite
3. Meteor, Meteoroid, Meteorite
4. Meteoroid, Meteorite, Meteor

meteoroid (in space)
↓
meteor (in sky/atmosphere)
↓
meteorite (on ground)



(A 'shooting star' in the sky is a meteor).

Comets

What is a comet? [2] Solution

Hint Clear Info

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Hint Unavailable

Comets are clumps of ice, dust, and rock that orbit the Sun.

Bodies

Meteoroids, asteroids, and comets all orbit the Sun. Solution

1. True
2. False

True.

Celestial Bodies

Determine what is wrong with the following statement. [1] Solution The terrestrial planets are the 4 inner planets, and the gaseous planets are the 5 outer planets.

Hint Clear Info

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Hint Unavailable

The inner 4 planets are terrestrial (rock-based), while the outer 4 are gaseous based.

(There are only 8 planets that orbit the Sun).

Celestial Bodies

State one similarity and one difference between gaseous planets and terrestrial planets. [2] Solution

Hint Clear Info

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Hint Unavailable

(Answers may vary...)

Both have gravity and spherical in shape.

Gaseous planets made of gas, and terrestrial is sold rock/metal based.

Light Year

One light year (ly) is equal to approximately, 9.5 × 10¹² km.

One ly is also equal to 9.5 × 10¹⁵ m Solution

1. True
2. False

There are 1,000 m (10³ m) in 1 km... So 9.5 × 10¹² km => 9.5 × 10^{12 + 3} m => 9.5 × 10¹⁵ m

If the distance from Earth to the center of our Milky Way galaxy is 2.47 × 10¹⁵ km, calculate the distance in light years. Solution

1. 2.6 × 10⁴ km
2. 1.6 × 10⁴ km
3. 2.3 × 10⁴ km
4. 2.2 × 10⁴ km

1 ly = 9.5 × 10¹² km $\begin{align} \dfrac{1\ ly}{9.5 × 10^{12}\ km} & = \dfrac{1}{1} \\ \\ & = 1 \\ \\ \end{align}$ $\begin{align} & 2.47 × 10^{17}\ km \\ \\ & = 2.47 × 10^{17}\ km \ × \ \dfrac{1}{1} \\ \\ & = 2.47 × 10^{17}\ \cancel{km} × \ \dfrac{1\ ly}{9.5 × 10^{12}\ \cancel{km}} \\ \\ & = \dfrac{2.47 × 10^{17} \ × \ 1\ ly}{9.5 × 10^{12}} \\ \\ & = 0.26 × 10^{17 - 12}\ ly \\ \\ & = 0.26 × 10^{5}\ ly \\ \\ & = 2.6 × 10^{4}\ ly \\ \\ \end{align}$

Orbital Radius

The orbital radius is the Solution

1. Distance from the Sun to the Earth
2. Circumference of the Earth
3. Circumference of the orbit of the Earth around the Sun
4. Radius of the Earth

The radius of the orbit of the Earth around the Sun is the distance from the Sun to the Earth.

Orbit

What causes the orbit of planets around the Sun? Solution

1. The tilt of a planet's rotational axis
2. The spin of the planet
3. Gravity
4. None of the above

Gravity from the Sun prevents the planets in our solar system from going off in a straight path.

The Sun

The temperature of the surface of the Sun is ~6,000 ˚C while the core temperature is ~15 million ˚C. Solution

1. True
2. False

The surface of the Sun is, relatively, much cooler than its core. Nuclear fusion occurs in the core of the Sun, making it really hot [equivalent in energy to detonating 400 billion megaton nuclear bombs, every second]. But the surface of the Sun is actually nearly the same temperature of the core of the Earth.

The Sun could fit (approximately) how many Earths inside of it? Solution

1. 1,000
2. 10,000
3. 100,000
4. 1,000,000
5. 10,000,000

Approximately 1.3 million Earths would fit inside the Sun.

Explain the cause of Northern Lights (Aurora Borealis). [2] Solution

Hint Clear Info

Incorrect Attempts:

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Hint Unavailable

Charged particles (ions) escape from the surface of the Sun, traveling towards Earth. These particles are affected by the magnetic field and enter the atmosphere near the poles. The ions interact with atoms in the atmosphere, and this creates the photons of light that we see as the Northern Lights (Aurora Borealis).

The main source of energy in the Sun is... Solution

1. Fusion
2. Fission
3. Convection
4. Radiation
5. The amounts of all of the above are approximately equivalent

The main source of energy is nuclear fusion, of Hydrogen gas into Helium gas, occurring in the core at 15 million Kelvin. 600 - 700 million tons of Hydrogen is converted into helium, each second!

The mass of the Sun, is mainly due to... Solution

1. The heavier metals produced in the core.
2. The vast amount of Hydrogen gas
3. The vast amount of Helium gas
4. Unknown solids
5. Unknown liquids

The mass of the Sun is largely due to Hydrogen. By mass, the Sun is 75 percent Hydrogen, and 25 percent Helium. Metals make up less than 0.1 percent of the mass of the Sun.

Sun and Moon, Rise and Set

The Sun rises in the east and sets in the west, while the Moon rises in the west and sets in the east. Solution

1. True
2. False

Both the Sun and the Moon rise in the east and set in the west. (This is lesser known by students)

Models of the Universe

The current model of the universe is called the Geocentric model. Solution

1. True
2. False

The current model of the universe is called the Heliocentric model, in which the sun is at the center of the solar system.

The Axis of the Earth, Application

If the Earth was not tilted as it revolves on a 23.5˚ axis, then which of the following features would no longer occur? Solution

1. Sunrise and sunset
2. Seasonal light and temperature differences
3. The lunar cycle
4. The tidal movement in the oceans

The difference seasons are due to the tilt of the Earth, causing the North and South hemispheres to receive differing amounts of light in summer and winter during Earth's orbit.

Lunar Eclipse

A lunar eclipse occurs when... Solution

1. The Earth is between the Moon and the Sun
2. The Sun is between the Earth and the Moon
3. The Moon is between the Earth and the Sun
4. None of the above

During a lunar eclipse, the Earth blocks the light rays coming from the Sun - the Moon is in Earth's shadow.

(Also note that a solar eclipse occurs when the Moon is between the Earth and the Sun - the moon blocks the light coming from the Sun).

Gravity

Gravity is caused by celestial bodies with large volumes. Solution

1. True
2. False

Gravity is caused by large masses. Objects with high volumes do not always have high masses (this is low density).

Gravity depends on the mass.

Constellations

Stars, as seen in the sky, are not moving in space. Solution

1. True
2. False

Technically, the stars are moving because the universe is expanding. However, the movement cannot be noticed when you see the stars in the sky. The difference would be noticeable to the eye over 10,000 years. This is not to be confused with the 'apparent motion of the stars due to the movement (rotational, translational) of the earth.'

North Star

Which is the North Star? Solution

1. Polaris
2. Sirius
3. Betelgeuse
4. Mars

Polaris is the North Star. It is significant because it is located above the north pole in the northern hemisphere, and stays in one place.

NASA, ESA, N. Evans (Harvard-Smithsonian CFA), and H. Bond (STScl)

Satellites

The Moon is a satellite. Solution

1. True
2. False

A satellite is a body orbiting a planet. There are natural satellites such as the Moon, and artificial satellites, such as GPS and radio broadcasters.

Satellites Orbit

Which of the following factors affect the orbit of a satellite? Solution

1. Mass only
2. Speed only
3. Mass and speed
4. None of the above

Mass and speed

Orbits

Which of the following orbits is fixed in place over the Earth? Solution

1. The International Space Station in lower Earth orbit
2. Satellite systems in medium Earth orbit
3. Satellite systems in a geosynchronous (upper Earth) orbit
4. None of the above

Objects in a geosynchronous orbit stay in one spot in the sky, relative to a position on the Earth.

If you have a satellite television network, next time think that your signal is broadcast up 38,000km and back down 38,000 km for a total distance of about 76,000 km.

Retrograde Motion

What causes retrograde motion? Solution

1. The diameter of planets
2. The spin of planets on their axis
3. The speed of planets
4. The different compositions and brightness of planets

The speed of planets

Star Temperatures and Color

Order star color from hottest to coolest (top to bottom) Solution

White

Blue

Red

Yellow

From hottest to coolest: Blue, White, Yellow, Red Blue is about 40,000˚C, Red is about 3,000˚C.

Star Energy

A star's luminescence is the glow of gases due to very high temperatures that heat the gases on the surface of the star. What creates the energy in a star that makes the high temperature? Solution

1. Fission
2. Convection
3. Fusion
4. Radiation

Nuclear fusion is when hydrogen (H) atoms are pressed together under high pressure at the center of gravity of the star to form new atoms of Helium (He) and others. Very high amounts of energy are released from the center of stars as new atoms form. This travels outwards to create a glowing surface, with the difference colors based on the gases and the temperature.

Apparent and Absolute Magnitudes of Luminosity

Two different light sources, a very bright lamp, and a dim flashlight are held different distances from someone who can see the different brightness of the sources. The perceived brightness of a light source is luminosity.

It is possible for the dimmer flashlight to appear brighter than the lamp, depending on the distance to the observer. Solution

1. True
2. False

True

Which statement is correct about apparent magnitude and absolute magnitude ? Solution

1. Absolute magnitude is the strength of the light source, and apparent magnitude is how bright it appears to the observer
2. Absolute magnitude and apparent magnitude are the same
3. Apparent magnitude is the strength of the light source, and absolute magnitude is how bright it appears to the observer
4. Absolute magnitude depends on how close the source is to the observer

Absolute magnitude is the strength of the light source, and apparent magnitude is how bright it appears to the observer

Explain how apparent magnitude and absolute magnitude describes the luminosity of stars at different distances. Solution

• Apparent magnitude is
• Absolute magnitude is constant for a star and is related to its energy emitted.

It is possible for a star with a higher absolute magnitude to have a lower luminosity than a star with a low absolute magnitude. How? --> If the star with a low absolute magnitude is significantly closer to the observer...

Hertzsprung-Russell Diagram

Hertzsprung-Russell diagrams plot: Solution

1. Distance over planet size
2. Temperature over distance
3. Absolute luminosity over temperature
4. Position of constellations of stars in space

CC Credit: Hipparcos Catalogue from the Gliese Catalogue of Nearby Stars

Life Cycle of Stars

What is the next phase of life of a red giant star? Solution

Main sequence →→ Red Giant →→ White Dwarf →→ Nebula

Main sequence →→ Blue/Red Supergiant →→ Supernova →→ Nebula →→ Neutron Star

Nebula

Nebulas form new stars Solution

1. True
2. False

Nebula provides the gas matter to make stars. (Nebulas are also formed at the end of the life cycle of a star.) And they look pretty awesome:

NASA, via Antony McAulay

Life Cycle of Stars

Describe how new elements are formed in a star. [2] Solution

Hint Clear Info

Incorrect Attempts:

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Hint Unavailable

Fusion of Hydrogen and Helium. When the supply of Hydrogen (H) is used up, then the Helium (He) is used for fusion. Helium results in heavier atoms with more protons, like Carbon (C), Nitrogen (N), Oxygen (O), ...

(As an aside, the heavier elements in stars have high gravity, which causes supernovas, which forms nebulas).

The Big Bang

Based on the big bang theory, which of the following facts can be deduced? Solution

1. The planets are slowing down
2. The universe in continually expanding
3. Light travels faster in the empty vacuum of space
4. The Sun is cooling down

The universe was created in a big explosion in which all matter originated from the center of the universe and continues to move outwards from that center.

The universe continues to expand.

All matter is moving outwards in the universe.

The Big Bang

The universe was created approximately how many years ago? Solution

1. 14,000,000,000,000 years
2. 14,000,000,000 years
3. 14,000,000 years
4. 14,000 years

Approximately 14 billion (actually ~13.79 billion)

The Big Bang

Which of the following is not evidence for the big bang theory? Solution

1. Galaxies are moving away from eachother
2. Light elements were created first in the big bang and there is an abundance of these elements in the universe
3. The widespread presence of cosmic background radiation that is a remnant of the high heat of the big bang
4. The presence of black holes in the universe

The presence of black holes in the universe is not evidence for the big bang theory

The Big Bang & Absorption Spectrum Information

Edwin Hubble's evidence that the universe is expanding is shown by the absorption spectrum emitted by different galaxies. For galaxies moving away from our galaxy, the absorption spectrum shifts: Solution

1. Towards the green wavelengths of light
2. Towards the red wavelengths of light
3. Towards the blue wavelengths of light
4. Towards the violet wavelengths of light

This is absorption spectrum reading is called a red shift and indicates the light is originally from a galaxy that is moving away.

Information has been collected that shows galaxies are moving farther apart from one another and that the universe is expanding.

(Side note: the universe is not just expanding, it is accelerating farther apart).

Space Technologies

Which technology was developed by a space program? Solution

1. Fire resistant coatings
2. Memory foam
3. Freeze drying of foods
4. LEDs
5. All of the above were developed through space programs

All of the above were developed through space programs

Particles in Atoms (Background Review)

Which of the following is located outside of the atom's nucleus? Solution

1. Electron
2. Proton
3. Neutron
4. All of the above are inside the nucleus

Electron orbit the nucleus while protons and neutrons are inside (make up) the nucleus.

What subatomic particle has a positive charge? Solution

1. Neutron
2. Proton
3. Electron
4. Atom

Protons are positive.

Neutrons are neutral.

Electrons are negative

An atom with 3 protons and 4 electrons will have what charge? Solution

1. + 4
2. + 3
3. - 4
4. - 1

Protons are positive and electrons are negative. + 3 - 4 = - 1

Which of the following is incorrect? Solution

1. Protons can be removed from atoms
2. Electrons can be added to atoms
3. The number of an element can be different
4. Electrons can be removed from atoms

Basically everything can change except for the number of protons.

Think about it this way, if scientists could change the number of protons, then they would be able to turn iron into gold!

Charged Objects

A positively-charged object contains electrons. Solution

1. True
2. False

An object is charged when there are more particles of one type than the other type.

A positively charged object has:
(number of positive charges) > (number of negative charges).

E.g.) A positively charged object could have 100 positive charges and 99 electrons.

Neutral objects can become positively charged by transferring positive charges from a material. Solution

1. True
2. False

Positive charges cannot move. The only way to give a neutral object positive is to take away some of its electrons.

The Electrostatic Series and Friction

When copper is rubbed against fur, what will happen? Solution

Attraction of Electrons	Material
High attraction	Copper
↕	Ebonite
↕	Plastic
↕	Fur
↕	Glass
Low attraction	Acetate

1. Protons will move to the fur
2. Electrons will move to the fur
3. Protons will move to the copper
4. Electrons will move to the copper

Flow of electrons only.

Charge Methods

Which of the following is not a way to charge an object Solution

1. Heat
2. Induction
3. Friction
4. Conduction contact

Heat

Ground

Describe the flow of charges when a negatively-charged object is brought in contact to a grounded object. [1] Solution

Hint Clear Info

Incorrect Attempts:

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Hint Unavailable

The grounded object is connected to Earth, which acts as an infinite absorber or source of electrons.

When a negatively-charged object contacts a grounded object, the excess negative electrons are conducted through the grounding into the Earth.

Induction

What is induction? Solution

1. The flow of electrons between two materials in contact
2. The charging of an object from proximity without contact
3. The conduction of electrons in a metal
4. None of the above

The charging of an object from proximity without contact

Symbols for Resistance, Current, and Potential Difference

What are the correct units to use for resistance, current, and potential difference, respectively? Solution

1.   I
2.   A
3.   R
4.   V
5.   Ω

1. V, II, and IV
2. III, I, and V
3. III, II, and I
4. I, II, and IV

V, II, and IV

Circuit Parts

Which of the following is a load? Solution

1. Switch
2. Battery
3. Resistor
4. Wire

A load converts electrical energy into other forms of energy like light and heat in a lightbulb, or kinetic energy in a motor, or just heat in a resistor.

A Battery

Which of the following statements about a battery is incorrect? Solution

1. Batteries are made of cells
2. Batteries do not contain electrolytes
3. Electron current is the flow of negative charges
4. Conventional current is the flow of positive charges

The electrolyte in a battery creates current.

In a circuit the real particles moving are electrons, which flow from the negative to the positive terminals.

However, due to history, the direction of current is the flow of positive charges (which we know doesn't actually happen).

AC and DC

Electrical generators only produce alternating current (AC). Solution

1. True
2. False

Electrical generators do produce alternating current (AC), but they can also produce direct current (DC).

AC and DC

Why is alternating current (AC) typically used to transfer electrical energy long distances from power generation stations to consumers? Solution

1. Direct current (DC) cannot be produced at generating stations
2. Alternating current (AC) is stronger and more powerful
3. Alternating current (AC) can be transferred in more efficiently
4. Direct current (DC) is cannot be used to power homes

Alternating current (AC) can be transferred in more efficiently

Conventional Current

Which direction does conventional current flow in the circuit: Solution

1. Left
2. Down
3. Clockwise
4. Counterclockwise

Conventional current is the flow of positive charges. The longer side of the cell is positive and the positive charges flow from the positive terminal, to the negative terminal.

Series and Parallel

Adding a load in series to a battery and an original load will... Solution

1. Decrease the current in the original load
2. Decrease the potential difference in the original load
3. Increase the resistance in the original load
4. None of the above

The electromotive force (emf) of the source is constant. Potential difference in series is the sum of each load. Adding loads in series will decrease the potential difference in the existing loads. Current is constant for loads in series.

Series and Parallel

Adding a load in parallel would... Solution

1. Increase the total resistance in the circuit
2. Decrease the total resistance in the circuit
3. Decrease the potential difference
4. Increase the potential difference

Decrease the total resistance in the circuit... Resistances added in parallel decrease the total resistance.

Potential difference is unchanged in parallel.

Meters

Different instruments are used to measure current, potential difference, and resistance.

Which of the following measures current only? Solution

1. Voltmeter
2. Multimeter
3. Ammeter
4. Ohmmeter

Ammeter... (Multimeters measure current, resistance, and potential difference)

A voltmeter should be connected Solution

1. In series to a load
2. In parallel to a load
3. Any way
4. None of the above

Voltmeters measure voltage.

Parallel paths share the same voltage.

An ammeter should be connected Solution

1. In series to a load
2. In parallel to a load
3. Any way
4. None of the above

Ammeters measure current.

Loads on paths in series share the same current.

Fuses

A fuse will blow (go out) when which of the following quantities is too high? Solution

1. Electromotive force
2. Potential difference
3. Current
4. Resistance

Current is the flow of charges (electrons) over time. If the flow of current is too high, then this could be dangerous and a protective fuse will disconnect the circuit to stop the flow of current.

Electrical Resistance

Resistance in a circuit depends on each of the following except: Solution

1. Length of material
2. Material type
3. Strength of current
4. Temperature
5. Cross-sectional area

E.g.) each of the following would increase resistance:

A resistive material,
A long wire,
High temperature,
Thin cross-sectional area.

Electrical Resistance

Which of the following would have the lowest resistance? Solution

1. Cold metal that is long and thin
2. Warm plastic that is short and wide
3. Cold metal that is short and wide
4. Warm plastic that is short and thin

Cold metal that is short and wide (in the path of travel of current)...

Resistance

Three resistors are added in parallel: 2Ω, 3Ω, and 4Ω. Calculate the total resistance. Solution

R_T =

Hint Clear Info

Incorrect Attempts:

CHECK

Ω

Hint Unavailable

$\begin{align} \dfrac{1}{R_T} & = \dfrac{1}{R_1} + \dfrac{1}{R_2} + \dfrac{1}{R_3} \\ \\ \dfrac{1}{R_T} & = \dfrac{1}{2Ω} + \dfrac{1}{3Ω} + \dfrac{1}{4Ω} \\ \\ \dfrac{1}{R_T} & = \dfrac{6}{12}Ω + \dfrac{4}{12}Ω + \dfrac{3}{12}Ω \\ \\ \dfrac{1}{R_T} & = \dfrac{13}{12}Ω \\ \\ \dfrac{R_T}{1} & = \dfrac{12}{13}Ω \\ \\ R_T & = 0.92\ Ω \\ \\ \end{align}$

Calculations with V = IR

Answer the questions using the relationship with potential difference (V), current (I), and resistance (R) below.

When the electromotive force (emf) in a circuit is increased with a constant resistor, the current increases. Solution

1. True
2. False

Electromotive force (emf) is the volts in the source, like a battery. If V increases and R stays the same, then this means I increases.

A circuit has one resistor connected to a battery with a 5.0 V emf and a 0.5 A current. Calculate the value of the resistor. Solution

1. 5 Ω
2. 10 Ω
3. 1 Ω
4. 2 Ω

$\begin{align} V & = I R \\ \\ R & = \dfrac{V}{I} \\ \\ & = \dfrac{5.0\ V}{0.5\ A} \\ \\ & = 10.0\ Ω \\ \\ \end{align}$

A new circuit has two 4.0 Ω resistors connected in series, shown below. If the total electromotive force in the circuit is 8.0 V, calculate the current in each resistor. Solution

I =

Hint Clear Info

Incorrect Attempts:

CHECK

A

Hint Unavailable

For resistors in series, current is the same in each.

Calculate the current (I) in just one of the resistors: $\begin{align} V & = I R \\ \\ I & = \dfrac{V}{R} \\ \\ & = \dfrac{8\ V}{4\ Ω} \\ \\ & = 2\ A \\ \\ \end{align}$ Therefore the current in each resistor is 2 Amps.

Electrical Calculations

A 2 Amp motor is run over 3 minutes and has a total resistance of 10Ω. Solve for the total Energy, given the equations below. Solution V = I · R P = I · V E = P · t

E =

Hint Clear Info

Incorrect Attempts:

CHECK

J

Hint Unavailable

Current = I = Amps = A
Resistance = R = Ohms = Ω
Voltage = Volts = V
Energy = Joules = J
Power = Watts = W
(Time is in seconds) First calculate the voltage, V (potential difference): $\begin{align} V & = I · R \\ \\ & = (2A)(10Ω) \\ \\ & = 20V \\ \\ \end{align}$ Second calculate the power, P: $\begin{align} P & = I · V \\ \\ & = (2A)(20V) \\ \\ & = 40W \\ \\ \end{align}$ Third calculate the energy, E: $\begin{align} E & = P · t \\ \\ & = (40W)(180seconds) \\ \\ & = 7,200 \ J \\ \\ \end{align}$

Electricity Generation

All of the following are commonly used to generate electricity except which one? Solution

1. Water Dams and Tides
2. Nuclear
3. Fossil Fuels
4. Wind
5. Light
6. Geothermal
7. Sound

Sound

Electricity Generation

Which one is a non-renewable energy resource? Solution

1. Geothermal
2. Wind
3. Light
4. Nuclear

Nuclear

Power

The units of power are Solution

1. Watts, W
2. Joules, J
3. Amps, A
4. Volts, V

Watts, W

Power

When electricity is consumed, it is often called "power". The units for power are kilowatt·hour

One kilowatt·hour equals one kilowatt multiplied by one hour. Solution

1. True
2. False

True

How many watts (W) are in 1 kilowatt (kW)? Solution

1. 1
2. 10
3. 100
4. 1000

1 kilowatt (kW) = 1000 watts (W)

Calculate the efficiency of a dishwasher if it uses 2000 kW·h when a total of 2600 kW·h is input. Solution $\% \ Effienciey = \dfrac{Power_{used}}{Total\ Power_{input}} × 100\%$

1. 130 %
2. 33 %
3. 77 %
4. 23 %

$\begin{align} \% \ Effienciey & = \dfrac{Power_{used}}{Total\ Power_{input}} × 100\ \\ \\ & = \dfrac{2000\ kW·h}{2600\ kW·h} × 100\ \\ \\ & = 77\% \\ \\ \end{align}$

If the price of electricity is 10 ¢/kW·h, calculate the cost to run a 1000 W appliance for an hour and a half. Solution Cost = Rate × Power Use

It should make sense that the cost is the rate times the power usage in kW·h

Rate = 10 ¢/kW·h

! 1000 W = 1 kW

Power Use = (1 kW)(1.5 hr) = 1.5 kW·h $\begin{align} Cost & = Rate × Power\ Use \\ \\ & = (10\ ¢/kW·h) \ × \ (1.5\ kW·h) \\ \\ & = 15\ ¢ \\ \\ \end{align}$

The Relationship Between Scientific Ideas, Hypothesis, and Data

Which of the following would be an effective way to help show the occurrence of global warming? Solution

1. Measure the outside air temperature in the summer and winter.
2. Graph and average of the daily temperature data around the world for the past 100 years.
3. Observe the presence of icebergs in the ocean.
4. Measure levels of current greenhouse gases.

A good study will use the data over many years like the graph of average of the daily temperature data around the world for the past 100 years. This is a visual representation of the numeric data collected over as long a time span as possible for reliable data collection. The more data the better. Also a combination of many of the other data collections would be useful.

Formulating a Hypothesis Vs. Facts and Issues

Which of the following would be a hypothesis for the issue regarding: the use of solar and wind energy, instead of burning fossil fuels (oil, gas, etc.)? Solution

1. Solar panels can only be used during the daytime. Where would the energy come from to power the things we need at night?
2. The average wind turbine costs approximately $3.5 million to build and install (in 2012 dollars).
3. Many things require fossil fuels and it would be very difficult to convert the systems that we already have to make them run on alternative energy because it would be costly and difficult to organize.
4. People prefer to use energy from wind and solar, rather than fossil fuels, and this will make it easy to switch.

A hypothesis is a proposition or explanation made without knowing the truth of it yet. This is posed as a statement (rather than as a question) and forms the basis for the research or questions that will be the scientific investigation to follow.

Selecting Appropriate Equipment and Materials for Scientific Inquires

A student wishes to measure the effects of acid rain on their local pond near a field. What item would be most necessary to include in this student's toolkit in the field? Solution

1. A graduated cylinder beaker
2. A magnifying glass
3. pH paper
4. A thermometer

The student must first check if the pond is acidic or not. This is done with pH paper.

Workplace Hazardous Materials Information System (WHMIS)

Which of the following is WHMIS not used for? Solution

1. Phone book for companies
2. Toxicological information
3. First aid treatments
4. Proper handling and protective equipment procedures
5. WHMIS is used for all of the above

The WHMIS book contains information on:

• Product information, including manufacturer and contact information
• Hazards, toxicology, and safety data
• Physical properties
• Etc...

Appropriate Handling and Disposal Techniques

At the end of a classroom experiment in which several different chemicals were combined into a cool bubbly-foamy reaction, there are some extra chemicals left over. What should be done with these extra leftover chemicals? Solution

1. Pour each one back into the correct container or the locker.
2. Make sure the sink is clear and pour them down the sink drain making sure not to splash.
3. Put them in the garbage.
4. None of the above.

As a general guideline,

• Don't put unused chemicals back into their original container. (Unless specifically instructed to do so by your teacher.)
• Don't pour chemicals down the sink drain. (Unless specifically instructed to do so by your teacher.)
• Don't put chemicals in the garbage. (Unless specifically instructed to do so by your teacher.)

Safety Equipment

Which of the following pieces of safety equipment is not considered necessary? Solution

1. Goggles
2. Gloves
3. Lab coat and protective shoes
4. All of the above are necessary

Be careful! Always wear all your safety stuff in the chemistry lab! Gloves, Goggles, Protective clothing and shoes are the main protective methods in a lab. Sometimes even more protection is used depending on the experiment.

Gathering Data in a Lab

A student wants to compare how higher temperature allows more salt to dissolve in water. To record and organize the temperature and amount of salt properly, the student should Solution

Creative Commons Credit: Michel32nl, nl.wikipedia, 2004

1. Make sure to be neat and use a mechanical pencil and draw lines with a ruler.
2. Do the entire procedure at least three times and record data separately for each.
3. Use graph paper and not the other kinds of paper that are used in other subjects.
4. Make sure to use a calculator when writing down the numbers.

It is important to record more than one data point for each test, then these can be averaged to reduce error.

Controlling Variables

A controlled experiment changes two or more variables at a time to determine a change in a dependent variable. Solution

1. True
2. False

A controlled experiment only changes one independent variable at a time, and measures the change or effect on the dependent variable.

Dependent and Independent Variables

A dependent variable is one which Solution

1. Is changed during an experiment in order to measure the effect it has on another variable.
2. Is kept constant during an experiment in order to make sure any outcomes in an experiment are from other specific, known, and intended changes.
3. Changes due to the change in another variable.
4. Might be changed if the circumstances are right.

A dependent variable changes due to the change in another variable, which is known as the independent variable. For example time is the independent variable and concentration of a chemical is the dependent variable. On an x-y graph, the 'y' values is dependent on the 'x' value.

Qualitative and Quantitative Data

Which of the following is not a quantitative observation? Solution

1. Time it takes to melt an ice cube.
2. Colour the water turns after a colourful substance changes.
3. A measure of how wide a colony of bacteria has grown in an incubator.
4. The average height of the students in class 9A compared to 9B and 9C.

Qualitative Observations

Qualitative observations are based on descriptions from sensory information like: sight, smell, texture, colour, values like good or bad, etc.


Quantitative Observations

Quantitative observations are based on numerical data that can be measured like: length, weight, volume, time, area, speed, temperature, number, etc...

Qualitative and Quantitative Data

Size is a qualitative measurement and not a quantitative measurement. Solution

1. True
2. False

Size (small, medium, large) is an observation so it is a qualitative measurement. While mass (g, kg) or volume (mL, L, cm³) are quantitative values because they are measured.

Possible Sources of Bias

Which of the following scenarios could be biased? (More than one answer: check all that apply) Solution

1. An environmental report published by an oil company.
2. A study comparing the health benefits of coffee versus tea, paid for by The United Coffee Union
3. A salesman of The Fetching Car Company talking about the benefits of the cars they sell.
4. None of the above

Prejudice is present in three of the above answers.

Identifying Sources of Error/Uncertainty

Three students are measuring the speed of the fastest person in their school, Fastie McSpeedy. Each of the three students is given a stopwatch. They each record the time when McSpeedy crosses the finish line. The recordings are 14.50s, 14.97s, and 12.33s. What could be an explanation for the third student measuring a slower time? Solution

1. The surface of the running track.
2. Their own reaction time or their stopwatch.
3. The runner.
4. The lighting conditions during the run.

There are many possibilities for error in measurements. This is why it is important to take many repeated measurements and to average them together to reduce error.

Appropriate Units of Measurement (S.I. Units)

What is the most appropriate scientific unit of measurement for the mass of a Turkey? Solution

1. Pounds
2. Ounces
3. Grams
4. Grains

The most accepted unit in science is generally based on the metric system. Kilograms are SI units, so grams is the closest and most appropriate.