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Energy & Chapter 2 Study Guide
ANSWERS
1. What is Matter?
Anything with mass and takes up space
2. What is a pure substance? What are 3 examples of pure substances? What are 3 examples of items that
are not pure substances?
Any single kind of matter. Table salt, sugar, baking soda. Not pure substances are cookies,
butter, milk
3. Compare the terms: Physical Property and Chemical Property
Physical property: characteristic that can be observed without changing the substance.
Chemical property: characteristic that describes its ability to change into different substances.
4. What are 3 examples of physical properties? What are 3 examples of chemical properties?
Physical: color, density, melting point, texture, flexibility.
Chemical: flammability, ability to react
5. Compare the terms: Elements and Compounds.
Elements are the simplest substances. Made of one type of atom.
Compounds: two or more elements chemically combined.
6. What are atoms? What kind of atoms make up the element Oxygen?
The basic unit of an element. Oxygen atoms make up Oxygen.
7. Why do different elements have different properties?
They are made of different atoms.
8. Compare the terms: Compounds and Molecules.
Compounds are when two or more different atoms of element chemically combine.
Molecules are when two more of the same atoms combine. For example O2, or H2
9. What is a Mixture? What is a solution?
Mixture is when two or more substances are mixed together but not chemically combined. Salad,
trail mix, etc. A solution is a mixture where the substances are so well mixed that they look like
one and they aren’t easily separated…but they still aren’t chemically combined. Salt water,
pancake batter, lotion.
10. Compare Homogenous Mixture and Heterogenous Mixture. What are 3 examples of each?
Homogeneous: Mixed so evenly that you can’t see the parts. Same as a solution.
Sugar water, salt water, brass, lotion
Heterogeneous: You can see the different parts.
Salad, chex party mix, popcorn mixed with chocolate chips!!, trail mix.
11. How do scientists separate mixtures?
Filtration, distillation, magnetic attraction, evaporation
12. Compare the terms Physical Change and Chemical Change?
Physical: looks different but still the same substance.
Chemical: changes makes a new substance.
13. What are 3 examples of a physical change and 3 examples of a chemical change?
Physical: breaking, blending, chopping, melting
Chemical: burning, rusting, tarnishing
14. Identify three different kinds of physical changes that could happen to a plastic spoon?
Bending it, breaking it, melting it
15. What evidence would you look for to determine whether a chemical change has occurred?
New substance made, such as tarnish, rust or patina. Or bubbles form, which can mean CO2 gas.
16. Why is melting an ice cube an example of a physical change?
Its still water! H2O
17. What is the Law of Conservation of Matter?
Matter is never created or destroyed.
18. What is energy? What is the SI unit for energy?
Ability to do work or cause change. Joule.
19. Compare the terms: Temperature and Thermal Energy?
Temperature is a measurement of the average kinetic energy of the molecules.
Thermal energy is the total kinetic energy of the molecules in a substance.
20. What is Kinetic Energy and what is the equation?
Kinetic energy is energy of motion. When you are running, you have kinetic energy. A football
flying through the air has kinetic energy. KE=1/2 mass x speed squared
Mass must be in kg
21. What is Potential Energy and what is the equation?
GPE is based on height and weight.
GPE= height x weight or GPE= mass x 9.8 x height.
Height must be in meters, mass must be in kg
22. Define and provide examples of renewable resources?
Renewable resource is on that has unlimited supply. To be considered renewable, a resource must
be supplied faster that it is used up
Examples: wind, tidal, hydroelectric, solar energy
23. Define and provide examples of nonrenewable resources?
Nonrenewable resource is one that has limited supply. Once it is used there is no more of it
Example: Fossil fuels
24. Compare the terms conduction and insulation. Provide an example of a good conductor and a bad
conductor.
Conductors transmit energy very well/easily. Substances with molecules closely packed together
are good conductors. Substances with molecules spread far apart are bad conductors. Copper
and other metals are good conductors, gases are bad conductors.
Insulators stop or slow down the transmission of energy.
25. What is an Endothermic Change? What is an example?
Endothermic is when energy enters. Ice melting
26. What is an Exothermic Change? What is an example?
Exothermic is when enter exits or leaves. Burning fire.
27. What are the 4 forms of energy?
Thermal, Chemical, Electromagnetic, Electrical.
Also, kinetic and potential.
28. What physical and chemical changes occurred during the “Dancing Spaghetti lab”?
Physical: water turned murky
Chemical: bubbles! CO2 gas formed
29. What was evidence of a chemical change during the “Dancing Spaghetti lab?”
Bubbles which indicates that CO2 gas formed.
30. What did you learn during the “Just Add Water Lab”? How does thermal energy transfer? From hot to
cold matter, or from cold to hot matter?
Thermal energy transferred from the hot water to the cold. The temp of the hot water decreased
and the temp of the cold water increased.