Matter and Energy Homework Problems

Transcription

1 Matter and Energy Homework Problems 1. For each of the following, determine if E is positive, negative, or zero. a. Energy is released b. Energy is consumed c. Water absorbs heat. d. The velocity of an argon atom increases. 2. Calculate the kinetic energy of each of the following particles. Report your answer in Joules a. A proton at rest. b. An electron traveling at the speed of light (2.998 x 10 8 m/s) c. A helium atom (mass = x kg) traveling at the speed of sound ( m/s) d x Argon atoms (6.63 x kg per atom) traveling at the speed of sound. e. A Hummer H2 (8614 pounds) traveling at 65 miles per hour. 3. Calculate the change in energy ( E) when: a. An electron traveling at the speed of light slows to the speed of sound. b. A helium atom at the speed of sound speeds up to the speed of light c. A Hummer H2 increases its speed from 65 to 75 mph. 4. It takes 6.51 kj of energy to convert x argon atoms from liquid to a gas. a. What kind of intermolecular force is keeping these argon atoms in the liquid phase? b. What is E for the vaporization of these atoms? c. What is E for the reverse of this process? d. How much energy per atom is necessary to carry out this process? e. Would you expect vaporization of x atoms of krypton to take more or less energy to vaporize? f. How much more energy would be needed for each atom of argon to be travelling at the speed of sound after the liquid gas transition? Assume that all atoms are at rest in the liquid phase. g. What is E for the whole process (vaporization + energy to move the atom). 5. Under standard conditions, Cl 2 is a gas, Br 2 is a liquid, and I 2 is a solid. Explain this trend. 6. Arrange the following in order of increasing kinetic energy. a. Steam at 100 ºC b. Ice at -100 ºC c. Liquid water at 100 ºC d. Liquid water at 0 ºC e. Steam at 101 ºC f. Ice at 0 ºC 1a. negative 1b. positive 1c. positive 1d. positive 2a. 0 J 2b x J 2c x J 2d J 2e J 3a x10-14 J 3b x J 3c J 4b kj 4c kj 4d. 1.08x10-23 kj 4f J 4g kj

2 Energy and Temperature Homework Problems 1. In your own words, what is the difference between specific heat and heat capacity? 2. Calculate the heat capacity for each of the following. Refer to the Physical Values Table that can be downloaded from the course website. a kg of Bismuth. b g of F2 gas c g of Silicon. d g of Silver e. 864 mg of Br2 liquid. 3. Calculate the change in energy ( E) when: a kg of Bismuth is heated from 12 ºC to 14 ºC. b g of Fluorine gas is cooled from 0 ºC to its boiling point. c g of Silicon at 25 ºC is heated to its melting point. d g of Silver at its melting point is cooled to 25 ºC. e. 864 mg of Br2 at its melting point is heated to its boiling point. 4. Determine the mass of each substance that it required for each process. a. 36 J of energy is absorbed when Bismuth is heated from 120 ºC to 250 ºC. b. F2 gas heats up by 250 ºC when 860 kj of energy is absorbed. c. 364 J of energy is released by Br2 at its boiling point as it cools to its melting point. d. Silver is heated from 0 ºC to its melting point when it absorbs MJ of energy. 5. What is wrong with the following statements? a. Fluorine gas releases 14 J of energy as its temperature is increased by 45 ºC. b. It takes 16.6 kj of energy to convert solid silicon at 1300 ºC to a liquid at 1534 ºC. 2a J/ C 2b. 4.64x10-5 J/ C 2c J/ C 2d J/ C 2e J/ C 3a J 3b x10-3 J 3c x 10 6 J 3d x10 5 J 3e J 4a x 10-3 kg 4b kg 4c x 10-3 kg 4d kg

3 Thermal Equilibrium Homework Problems 1. What does the term thermal equilibrium mean? 2. Examine the drawing. a. What is true about E 1 and E 2? b. The same statement cannot be made about T 1 and T 2. Why? c. If T 1 = - T 2, what must be true about the two substances? 3. Recalling that the specific heat of liquid water is J/(g ºC) and has a density of 1 g/ml, calculate the final temperature of the water: a kg of Bismuth at 12 ºC is dropped in 1 L of water at 94 ºC. b g of Silicon at 25 ºC is dropped in 500 ml of water at 1 ºC. c. 864 mg of Silver at its melting point is dropped in 150 ml of liquid water at its freezing point. 4. Determine the mass of each substance that it required for each process. a. How much silver at its melting point would be required to heat 150 ml of liquid water from 0 ºC to 100 ºC? b. How much Silicon at 25 ºC would be required to cool 500 ml of liquid water from 100 ºC to 50 ºC? c. How much water at 25 ºC would be required to cool 1500 g of Bismuth from its melting point to ºC? 5. Consider the following to answer 5a and 5b. An Argon atom (6.63 x kg) travelling at the speed of sound ( m/s) bumps into a Helium atom (6.42 x kg) traveling at 5 times the speed of sound. a. What is the maximum amount of kinetic energy that can be transferred to the argon atom? b. If the maximum amount of kinetic energy is transferred to the argon atom, what velocity would it be travelling at after the collision? What would the velocity of the Helium atom be? 3a ᵒC 3b ᵒC 3c ᵒC 4a kg 4b kg 4c. 100 g 5a x J 5b. Helium = 0 m/s Argon = m/s

4 Phase Change Energy Homework Problems 1. For each of the following, determine the sign of E. Solidification condensation fusion vaporization sublimation Use the following data for ethyl alcohol to answer the remaining problems. T b ( C) T m ( C) H fusion (J/g) H vaporization (J/g) C (solid) C (liquid) C (gas) J / (g C) J / (g C) J / (g C) g of liquid ethyl alcohol is cooled from the melting point to -120 C. Determine the heat released by this process g of ethyl alcohol is cooled from 92 C to a solid at -117 C. Determine E. 4. When a sample of ethyl alcohol is heated from -120 C to 78.2 C, 1000 J of energy is consumed. What is the mass of this sample? J of energy is given to 100 g of ethyl alcohol at 50 C. What is the final temperature? J of energy is given to 100 g of ethyl alcohol at 50 C. What is the final temperature? J of energy is given to 100 g of ethyl alcohol at 50 C. What is the final temperature? 2. E = J, so J are released 3. E = J g C C C

5 Matter and Energy Homework Problems 1. For each of the following, determine if E is positive, negative, or zero. a. Energy is released b. Energy is consumed c. Water absorbs heat. d. The velocity of an argon atom increases. 2. Calculate the kinetic energy of each of the following particles. Report your answer in Joules a. A proton at rest. b. An electron traveling at the speed of light (2.998 x 10 8 m/s) c. A helium atom (mass = x kg) traveling at the speed of sound ( m/s) d x Argon atoms (6.63 x kg) traveling at the speed of sound. e. A Hummer H2 (8614 pounds) traveling at 65 miles per hour. 3. Calculate the change in energy ( E) when: a. An electron traveling at the speed of light slows to the speed of sound. b. A helium nucleus at the speed of sound speeds up to the speed of light c. A Hummer H2 increases its speed from 65 to 75 mph. 4. It takes 6.51 kj of energy to convert x argon atoms from liquid to a gas. a. What kind of intermolecular force is keeping these argon atoms in the liquid phase? b. What is E for the vaporization of these atoms? c. What is E for the reverse of this process? d. How much energy per atom is necessary to carry out this process? e. Would you expect vaporization of x atoms of krypton to take more or less energy to vaporize? f. How much more energy would be needed for each atom of argon to be travelling at the speed of sound after the liquid gas transition? Assume that all atoms are at rest in the liquid phase. g. What is E for the whole process (vaporization + energy to move the atom). 5. Under standard conditions, Cl 2 is a gas, Br 2 is a liquid, and I 2 is a solid. Explain this trend. 6. Arrange the following in order of increasing kinetic energy. a. Steam at 100 ºC b. Ice at -100 ºC c. Liquid water at 100 ºC d. Liquid water at 0 ºC e. Steam at 101 ºC f. Ice at 0 ºC

6

7

8

9

10 Thermal Equilibrium Homework Problems 1. What does the term thermal equilibrium mean? 2. Examine the drawing. a. What is true about E 1 and E 2? b. The same statement cannot be made about T 1 and T 2. Why? c. If T 1 = - T 2, what must be true about the two substances? 3. Recalling that the specific heat of liquid water is J/(g ºC) and has a density of 1 g/ml, calculate the final temperature of the water: a kg of Bismuth at 12 ºC is dropped in 1 L of water at 94 ºC. b g of Silicon at 25 ºC is dropped in 500 ml of water at 1 ºC. c. 864 mg of Silver at its melting point is dropped in 150 ml of liquid water at its freezing point. 4. Determine the mass of each substance that it required for each process. a. How much silver at its melting point would be required to heat 150 ml of liquid water from 0 ºC to 100 ºC? b. How much Silicon at 25 ºC would be required to cool 500 ml of liquid water from 100 ºC to 50 ºC? c. How much water at 25 ºC would be required to cool 1500 g of Bismuth from its melting point to ºC? 5. Consider the following to answer 5a and 5b. An Argon atom (6.63 x kg) travelling at the speed of sound ( m/s) bumps into a Helium atom (6.42 x kg) traveling at 5 times the speed of sound. a. What is the maximum amount of kinetic energy that can be transferred to the argon atom? b. If the maximum amount of kinetic energy is transferred to the argon atom, what velocity would it be travelling at after the collision? What would the velocity of the Helium atom be? 3a ᵒC 3b ᵒC 3c ᵒC 4a kg 4b kg 4c. 100 g 5a x J 5b. Helium = 0 m/s Argon = m/s

11

12

13

14

15 Energy and Temperature Homework Problems 1. In your own words, what is the difference between specific heat and heat capacity? 2. Calculate the heat capacity for each of the following. Refer to the Physical Values Table that can be downloaded from the course website. a kg of Bismuth. b g of F 2 gas c g of Silicon. d g of Silver e. 864 mg of Br 2 liquid. 3. Calculate the change in energy ( E) when: a kg of Bismuth is heated from 12 ºC to 14 ºC. b g of Fluorine gas is cooled from 0 ºC to its boiling point. c g of Silicon at 25 ºC is heated to its melting point. d g of Silver at its melting point is cooled to 25 ºC. e. 864 mg of Br 2 at its melting point is heated to its boiling point. 4. Determine the mass of each substance that it required for each process. a. 36 J of energy is released when Bismuth is heated from 120 ºC to 250 ºC. b. F 2 gas heats up by 250 ºC when 860 kj of energy is absorbed. c. 364 J of energy is released by Br 2 at its boiling point as it cools to its melting point. d. Silver is heated from 0 ºC to its melting point when it absorbs MJ of energy. 5. What is wrong with the following statements? a. Fluorine gas releases 14 J of energy as its temperature is increased by 45 ºC. b. It takes 16.6 kj of energy to convert solid silicon at 1300 ºC to a liquid at 1534 ºC.

16

17

18

19 Phase Change Energy Homework Problems 1. For each of the following, determine the sign of E. Solidification condensation fusion vaporization sublimation Use the following data for ethyl alcohol to answer the remaining problems. T b ( C) T m ( C) H fusion (J/g) H vaporization (J/g) C (solid) C (liquid) C (gas) J / (g C) J / (g C) J / (g C) g of liquid ethyl alcohol is cooled from the melting point to -120 C. Determine the heat released by this process g of ethyl alcohol is cooled from 92 C to a solid at -117 C. Determine E. 4. When a sample of ethyl alcohol is heated from -120 C to 78.2 C, 1000 J of energy is consumed. What is the mass of this sample? J of energy is given to 100 g of ethyl alcohol at 50 C. What is the final temperature? J of energy is given to 100 g of ethyl alcohol at 50 C. What is the final temperature? J of energy is given to 100 g of ethyl alcohol at 50 C. What is the final temperature? 2. E = J, so J are released 3. E = J g C C C

20

21

22