Did anyone have a "Hardest Question"?
Let's all say what our hardest questions were in the comments... I think it will help us study for the exam, He doesn't tend to pick the longest questions, but does like the "hardest questions"
Post below!
NOTE: Chart for specific Heat and Latent Heat at bottom of page
1. The temperature of a gold bar rises by 10.0°C when it absorbs 0.677 kJ of energy by heat. THe mass of the bar is 525 g. Determine the specific heat of gold from these data.
_______ kJ/kg · °C
(Don't forget to click "like")
2. Lake Erie contains roughly 4.00 x 1011 m3 of water.
a) How much energy is required to raise the temperature of that volume of water from 11.0°C to 14.0°C?
______ J
b) How many years would it take to supply this amount of energy by using the 850-MW exhaust energy of an electric power plant?
_____ yr
(Don't forget to click "like")
3. A certain steel railroad is 13 yd in lenght and weighs 56.3 lb/yd. How much thermal energy is required to increase the length of such a rail by 3.0 mm? Note: Assume the steel has the same specific heat as iron.
______ J
NOTE: Click here for Coefficient of Thermal Expansion Chart
(Don't forget to click "like")
4. What mass of water at 27°C must be allowed to come to thermal equilibrium with a 1.86-kg cube of aluminum initially at 1.50 x 102°C to lower the temperature of the aluminum to 59.3°C? Assume any water turned to steam subsequently recondenses.
_______ kg
(Don't forget to click "like")
5. An aluminum cup contains 225 g of water and a 40-g copper stirrer, all at 27°C. A 420-g sample of silver at an initial temperature of 87°C is placed in the water. The stirrer is used to stir the mixture gently until it reaches its final equilibrium temperature of 32°C. Calculate the mass of the aluminum cup.
______ g
(Don't forget to click "like")
6. A 100 g aluminum calorimeter contains 250 g of water. The two substances are in thermal equilibrium at 10°C. Two metallic blocks are placed in the water. One is a 50 g piece of copper at 76°C. The other sample has a mass of 68 g and is originally at a temperature of 100°C. The entire system stabilizes at a final temperature of 20°C. Determine the specific heat of the unknown second sample.
_______ J/kg·°C
(Don't forget to click "like")
7. A student drops two metallic objects into a 120-g steel container holding 150 g of water at 25°C. One object is a 160-g cube of copper that is initially at 75°C, and the other is a chunk of aluminum that is initially at 5.0°C. To the surprise of the student, the water reaches a final temperature of 25°C, precisely where it started. What is the mass of the aluminum chunk?
_______ g
(Don't forget to click "like")
8. A 90-g ice cube at 0°C is placed in 910 g of water at 22°C. What is the final temperature of the mixture?
______ °C
(Don't forget to click "like")
9. A 74-g ice cube at 0°C is heated until 66g has become water at 100°C and 8.0g has become steam at 100°C. How much energy was added to accomplish the transformation?
______ J
(Don't forget to click "like")
10. A 40- g block of ice is cooled to -76°C and is then added to 600 g of water in a 80-g copper calorimeter at a temperature of 27°C. Determine the final temperature of the system consisting of the ice, water, and calorimeter. (If not all the ice metls, determine how much ice is left.) Remember that the ice must first warm to 0°C, melt, and then continue warming as water. (The specific heat of ice is 0.500 cal/g · °C = 2,090 J/kg · °C.)
Tf = ______ °C
mice final = ______g
(Don't forget to click "like")
11. A glass windowpane in a home is 0.62 cm thick and has dimensions of 1.14 m x 1.78 m. On a certain day, the indoor temperature is 26°C and the outdoor temperature is 0°C. (Assume the thermal conductivity of the glass is 0.8 J/s · m · °C.)
a) What is the rate at which energy is transferred by heat through the glass?
______ W
b) How much energy is lost through the window in one day, assuming the temperatures inside and outside remain constant?
______ J
(Don't forget to click "like")
12. A styrofoam box has a surface area of 0.79 m2 and a wall thickness of 2.0 cm. The temperature of the inner surface is 5.0°C, and the outside temperature is 26°C. If it takes 8.5 h for 5.0 kg of ice to melt in the container, determine the thermal conductivity of the styrofoam.
______ W/m · K
(Don't forget to click "like")
Let's all say what our hardest questions were in the comments... I think it will help us study for the exam, He doesn't tend to pick the longest questions, but does like the "hardest questions"
Post below!
NOTE: Chart for specific Heat and Latent Heat at bottom of page
1. The temperature of a gold bar rises by 10.0°C when it absorbs 0.677 kJ of energy by heat. THe mass of the bar is 525 g. Determine the specific heat of gold from these data.
_______ kJ/kg · °C
(Don't forget to click "like")
2. Lake Erie contains roughly 4.00 x 1011 m3 of water.
a) How much energy is required to raise the temperature of that volume of water from 11.0°C to 14.0°C?
______ J
b) How many years would it take to supply this amount of energy by using the 850-MW exhaust energy of an electric power plant?
_____ yr
(Don't forget to click "like")
3. A certain steel railroad is 13 yd in lenght and weighs 56.3 lb/yd. How much thermal energy is required to increase the length of such a rail by 3.0 mm? Note: Assume the steel has the same specific heat as iron.
______ J
NOTE: Click here for Coefficient of Thermal Expansion Chart
(Don't forget to click "like")
4. What mass of water at 27°C must be allowed to come to thermal equilibrium with a 1.86-kg cube of aluminum initially at 1.50 x 102°C to lower the temperature of the aluminum to 59.3°C? Assume any water turned to steam subsequently recondenses.
_______ kg
(Don't forget to click "like")
5. An aluminum cup contains 225 g of water and a 40-g copper stirrer, all at 27°C. A 420-g sample of silver at an initial temperature of 87°C is placed in the water. The stirrer is used to stir the mixture gently until it reaches its final equilibrium temperature of 32°C. Calculate the mass of the aluminum cup.
______ g
(Don't forget to click "like")
6. A 100 g aluminum calorimeter contains 250 g of water. The two substances are in thermal equilibrium at 10°C. Two metallic blocks are placed in the water. One is a 50 g piece of copper at 76°C. The other sample has a mass of 68 g and is originally at a temperature of 100°C. The entire system stabilizes at a final temperature of 20°C. Determine the specific heat of the unknown second sample.
_______ J/kg·°C
(Don't forget to click "like")
7. A student drops two metallic objects into a 120-g steel container holding 150 g of water at 25°C. One object is a 160-g cube of copper that is initially at 75°C, and the other is a chunk of aluminum that is initially at 5.0°C. To the surprise of the student, the water reaches a final temperature of 25°C, precisely where it started. What is the mass of the aluminum chunk?
_______ g
(Don't forget to click "like")
8. A 90-g ice cube at 0°C is placed in 910 g of water at 22°C. What is the final temperature of the mixture?
______ °C
(Don't forget to click "like")
9. A 74-g ice cube at 0°C is heated until 66g has become water at 100°C and 8.0g has become steam at 100°C. How much energy was added to accomplish the transformation?
______ J
(Don't forget to click "like")
10. A 40- g block of ice is cooled to -76°C and is then added to 600 g of water in a 80-g copper calorimeter at a temperature of 27°C. Determine the final temperature of the system consisting of the ice, water, and calorimeter. (If not all the ice metls, determine how much ice is left.) Remember that the ice must first warm to 0°C, melt, and then continue warming as water. (The specific heat of ice is 0.500 cal/g · °C = 2,090 J/kg · °C.)
Tf = ______ °C
mice final = ______g
(Don't forget to click "like")
11. A glass windowpane in a home is 0.62 cm thick and has dimensions of 1.14 m x 1.78 m. On a certain day, the indoor temperature is 26°C and the outdoor temperature is 0°C. (Assume the thermal conductivity of the glass is 0.8 J/s · m · °C.)
a) What is the rate at which energy is transferred by heat through the glass?
______ W
b) How much energy is lost through the window in one day, assuming the temperatures inside and outside remain constant?
______ J
(Don't forget to click "like")
12. A styrofoam box has a surface area of 0.79 m2 and a wall thickness of 2.0 cm. The temperature of the inner surface is 5.0°C, and the outside temperature is 26°C. If it takes 8.5 h for 5.0 kg of ice to melt in the container, determine the thermal conductivity of the styrofoam.
______ W/m · K
(Don't forget to click "like")
Specific Heats at atmospheric pressure:
Substance
|
J/kg ∙
°C
|
Cal/g ∙
°C
|
Aluminum
|
900
|
0.215
|
Beryllium
|
1820
|
0.436
|
Cadmium
|
230
|
0.055
|
Copper
|
387
|
0.0924
|
Ethyl Alcohol
|
2430
|
0.581
|
Germainium
|
322
|
0.077
|
Glass
|
837
|
0.200
|
Gold
|
129
|
0.0308
|
Human tissue
|
3470
|
0.829
|
Ice
|
2090
|
0.500
|
Iron
|
448
|
0.107
|
Lead
|
128
|
0.0305
|
Mercury
|
138
|
0.033
|
Silicon
|
703
|
0.168
|
Silver
|
234
|
0.056
|
Steam
|
2010
|
0.480
|
Tin
|
227
|
0.0542
|
Water
|
4186
|
1.00
|
Ice (H2O)
|
2090
|
0.500
|
Latent Heats of Fusion and Vaporization for some materials
Substance
|
Melting point
(°C) |
Latent Heat Fusion (J/kg)
|
Boiling Point (°C)
|
Latent Heat Vaporization (J/kg)
|
Helium
|
-269.65
|
5.23 x 103
|
-268.93
|
2.09 x 104
|
Nitrogen
|
-209.97
|
2.55 x 104
|
-195.81
|
2.01 x 105
|
Oxygen
|
-218.79
|
1.38 x 104
|
-182.97
|
2.13 x 105
|
Ethyl alcohol
|
-114
|
1.04 x 105
|
78
|
8.54 x 105
|
Water
|
0.00
|
3.33 x 105
|
100.00
|
2.26 x 106
|
Sulfur
|
119
|
3.81 x 104
|
444.60
|
3.26 x 105
|
Lead
|
327.3
|
2.45 x 104
|
1750
|
8.70 x 105
|
Aluminum
|
660
|
3.97 x 105
|
2450
|
1.14 x 107
|
Silver
|
960.80
|
8.82 x 104
|
2193
|
2.33 x 106
|
Gold
|
1063.00
|
6.44 x 104
|
2660
|
1.58 x 106
|
Copper
|
1083
|
1.34 x 105
|
1187
|
5.06 x 106
|
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