CHEMISTRY: Chapter 10 Prep-Test

Transcription

1 CHEMISTRY: Chapter 10 Prep-Test Matching Match each item with the correct statement below. a. calorimeter d. temperature b. calorie e. specific heat c. joule f. heat 1. quantity of heat needed to raise the temperature of 1 g of water by 1 C 2. SI unit of energy 3. energy transferred between 2 objects because of temperature difference 4. device used to measure the heat absorbed or released during a chemical or physical process 5. a measure of the random motions of the components of a substance 6. quantity of heat needed to change the temperature of 1 g of a substance by 1 C Multiple Choice Identify the choice that best completes the statement or answers the question. 7. What happens to the energy produced by burning gasoline in a car engine? a. The energy is lost as heat in the exhaust. b. The energy is transformed into work to move the car. c. The energy heats the parts of the engine. d. all of the above 8. How does a calorie compare to a joule? a. A calorie is smaller than a joule. c. A calorie is equal to a joule. b. A calorie is larger than a joule. d. The relationship cannot be determined. 9. If heat is released by a chemical system, an equal amount of heat will be. a. absorbed by the surroundings c. released by the surroundings b. absorbed by the universe d. released by the universe 10. In an exothermic reaction, the energy stored in the chemical bonds of the reactants is. a. equal to the energy stored in the bonds of the products b. greater than the energy stored in the bonds of the products c. less than the energy stored in the bonds of the products d. less than the heat released 11. The quantity of heat required to change the temperature of 1 g of a substance by 1 C is defined as. a. a joule c. a calorie b. specific heat d. density 12. How many calories are in 642 joules? (1 cal = 4.18 J) a c. 154 b d How many joules are in 148 calories? (1 cal = 4.18 J) a J c. 148 J b J d. 619 J 1

2 Name: J 14. The specific heat of silver is How many joules of energy are needed to warm 4.37 g of silver from g C 25.0 C to 27.5 C? a J c J b J d J 15. On what principle does calorimetry depend? a. the principle of hotness c. law of dynamics b. law of conservation of energy d. law of multiple proportions 16. Two metals of equal mass with different heat capacities are subjected to the same amount of heat. Which undergoes the smallest change in temperature? a. The metal with the higher heat capacity. b. The metal with the lower heat capacity. c. Both undergo the same change in temperature. d. You need to know the initial temperatures of the metals. e. You need to know which metals you have. 17. What is the specific heat capacity of gold if it requires 48.8 J to raise the temperature of 15 grams of gold 25 o C? a. 29 J/g o C c. 79 J/g o C b J/g o C d J/g o C 18. When solid KBr is dissoved in water, the solution gets colder. This is an example of a(n) reaction. a. endothermic c. thermal nuclear b. exothermic d. exdothermic 19. Natural gas (CH 4 ) is burned in a furnace a. endothermic c. thermal nuclear b. exothermic d. exdothermic 20. The energy transferred between samples of matter because of a difference in their temperatures is called a. heat. c. chemical kinetics. b. thermochemistry. d. temperature. 21. Which expression defines specific heat? a. heat mass temperature change c. b. heat mass temperature change d. heat mass temperature change temperature change heat mass 22. The Greek letter stands for a. "heat stored in." c. "rate of." b. "mass of." d. "change in." 23. The study of all energy changes is called a. thermodynamics. c. entropy. b. enthalpy. d. temperature. 24. Temperature is a. associated with the sensation of hot and cold. b. proportional to the average kinetic energy of molecules. c. measured with thermometers. d. all of the above 2

3 Name: 25. According to the first law of thermodynamics, a. there is no such thing as a perpetual motion machine. b. the energy of a system is constant. c. the total energy used in any process is conserved. d. in any process there is a decrease in potential energy. 26. Which of the following statements is true? a. Energy as heat flows from a lower temperature to a higher temperature. b. Energy as heat flows from a higher temperature to a lower temperature. c. The amount of heat in a closed system is a constant. d. Energy as heat flowing into an object is determined by the amount of work done on the object. 27. In a calorimeter, the energy content of a substance is calculated from measurement of the temperature change in a known mass of a. iron. c. water. b. air. d. steel. 28. What units are used to measure heat? a. joules/mole or kilojoules/mole c. joules or kilojoules b. kelvins or degrees Celsius d. None of the above 3

4 Name: 29. Which experiment above illustrates how different amounts of energy result in different temperature changes when the mass of water is constant? a. Experiment 1 c. Experiment 3 b. Experiment 2 d. None of them True/False Indicate whether the statement is true or false. 30. The quantity of energy is increased as energy is used. 31. Endothermic reactions release heat to the surroundings. 32. In a calorimetry experiment, the system is thermally isolated from the surroundings. 33. If a person tries to lift a heavy box for 5 seconds and can't make it budge, the work done on the box is equal to the amount of energy the person uses. 34. In all cooling systems, energy as heat is transferred from one substance to another, leaving the first substance with less energy and with a lower temperature. 4

5 Name: 35. It takes more energy as heat to raise the temperature of water by one degree than to raise the temperature of steam by the same amount. 36. When a substance evaporates it adds energy as heat to its surroundings. 5