Chapter 10 Study Guide Answer Key

Mrs. Malcolm’s 7th Grade Science

#1 and #2

• 1. ALL VOCABULARY! As usual, vocabulary will make an appearance in either matching, multiple choice, or short answer questions.

• 2. Key Questions! These are a great way to review, and there are only 6 in this chapter!

#3

• 3. What does the Law of Conservation of Energy state?

#3 Answer

• That energy is neither lost nor created during an transformation.

#4

• 4. The total energy of all the particles in a substance is called __________________________.

#4

• The total energy of all the particles in a substance is called Thermal Energy.

#5

• 5. What is temperature? What is heat?

#5 Answer

• Temperature: A measure of how hot or cold something is compared to a reference point; also the measure of the total amount of kinetic energy.

• Heat: the transfer of thermal energy from a warm object to a cooler object.

#6

• 6. What is a solid? A liquid? A gas? Give an example of each.

#6

• Solid: Definite shape and volume; desk, rocks, wall, baseball, carbon…

• Liquid: A definite volume but no definite shape; water, juice, soda….

• Gas: Has neither a definite shape nor definite volume; oxygen, air, nitrogen…

#7

• 7. In a system, when energy is transformed from one form to another, the total energy is ____________________________.

#7 Answer

• 7. In a system, when energy is transformed from one form to another, the total energy is conserved.

#8

• 8. In a flashlight, ______________________ energy in the batteries is transformed into electrical energy.

#8 Answer

• In a flashlight, chemical energy in the batteries is transformed into electrical energy.

#9

• 9. What is nuclear energy?

#9 Answer

• The energy that is stored in the nucleus of an atom.

#10

• 10. What is friction? How does it confirm the Law of Conservation of Energy?

#10 Answer

• The force that one surface exerts on another surface when two surfaces rub against each other. The heat produced by friction is evidence that energy is conserved. See page 354!

#11

• 11. What are three factors that determine an objects thermal energy?

#11 Answer

• 1. Temperature• 2. Number of particles• 3. How the particles are arranged

#12 and #13 Beaker 1 Beaker 2 Beaker 3

Mass of substance (g)

30 30 60

Temperature in C

200 100 200

Use the following table to answer questions 12 and 13 about thermal energy.12. Which beaker has the highest amount of thermal energy? ________________Explain your answer:

13. Which beakers contain the substance with the same average kinetic energy?

#12 and #13 Answers12. Which beaker has the highest amount of thermal energy? Beaker 3!

Explain your answer:

Beaker 3 has the most particles (highest mass) and the higher temperature.

13. Which beakers contain the substance with the same average kinetic energy?This is just like saying, “which two beakers have the same temperature?” Because average kinetic energy means temperature. So Beakers 1 and 3.

#14

• 14. If heat is transferred from a hot cup of coffee to the surrounding cooler air, the temperature of the coffee will (increase / decrease).

#14 Answer

• If heat is transferred from a hot cup of coffee to the surrounding cooler air, the temperature of the coffee will decrease.

#15

• 15. Suppose you leave a glass of ice-cold soda on a table in a warm room. In what direction(s) will heat be transferred in this system? When does heat transfer stop?

#15 Answer• Think back to page 359

and the BBQ dinner. This ice-cold soda is a lot like the iced tea.

• Heat will be transferred from the table and surrounding air into the colder soda.

• It will continue to transfer till the soda, air, and table are the same temperature.

#16

• 16. Heat transfer occurs in what direction?

#16 Answer

• Heat always transfers from the warmer object to the cooler object.

#17

• 17. What are the three main ways that heat is transferred? Define them.

• a. • b. • c.

#17 Answer

• A. Convection: a type of heat transfer that occurs only in fluids such as water and air.

• B. radiation: the transfer of energy by electromagnetic waves.

• C. Conduction: transfers het from one particle of matter to another within an object or between two objects.

#18

• 18. What is absolute zero?

#18 Answer

• The temperature at which no more energy can be removed from matter.

#19

• 19. Describe how a convection current works?

#19 Answer

• When air is heated, the particles spread out and the air becomes less dense. This allows the air to rise. When it gets away from the heat source, the air cools and sinks. This creates a current.

#20• 20. What heat transfer is occurring in C?

Where else in the picture is it occurring?

#20 Answer

• C is conduction. This is happening throughout the pan as the particles within the pan are transferring energy to one another. Also, you could say it is happening between the heating element and the pan.

#21

• 21. You need to be able to identify the different types of heat transfer!

If you don’t study….