Make your own free website on Tripod.com
Thermal Energy Worksheet

Honors Physical Science

Show “K-U-E-S” on your own paper where necessary. Otherwise answer completely on your own paper.

1.A 10.0 g piece of copper wire, sitting in the sun reaches a temperature of 80.0°C.How many Joules are released when the copper cools to 40.0°C?The specific heat of copper is 0.377 J/g°C.

2.The specific heat of water is 4.184 J/g°C.How much thermal energy is required to change the temperature of 700.0 g of water from 25°C to 75°C?

3.How much thermal energy is released when a 200 g piece of blown glass at an initial temperature of 150°C is cooled to 25°C?The specific heat of glass is 0.837 J/g°C.

4.If 2077 J are released to change the temperature of a block of ice initially at a temperature of –20°C to 0°C, find the mass of the ice. Ice has a specific heat of 2.077 J/g°C.

5.Mercury has a specific heat of 0.139 J/g°C.How many Joules are required to change the temperature of a 50.0 g sample of Mercury from 20.7°C to 100.4°C.

6. A balloon is filled with 0.5 g of air, which has a specific heat of 1.046 J/g°C.How many Joules are required to change the temperature from 20°C to 30°C?

7.A 25 g block of sugar requires 781 Joules to change the temperature from 25°C to 50°C.What is the specific heat of sugar?

8.When a 400.0 g of ammonia is cooled from a temperature of 25°C to 10°C; 13,054 Joules of thermal energy are released?Find the specific heat of ammonia.

9.How much thermal energy is necessary to melt 500.0 g of ice at its freezing point?

10.How much thermal energy is necessary to vaporize 36.00 g of water at its boiling point?

11.If 5,100 Joules are released when a sample of water freezes, what is the mass of the water?

12.If 57,500 Joules are given off when a sample of steam condenses on a 454.5 g bowl, what is the new mass of the bowl with the condensation?

13. Why are there negative numbers on the Celsius temperature scale but no negative numbers on the Kelvin temperature scale?

14. When you touch a cold surface, does cold travel from the surface to your hand or does thermal energy travel from your hand to the surface? Explain.

15. Does a substance that heats up quickly have a high or a low specific heat capacity? Does a substance that cools down quickly have a high or a low specific heat capacity? Explain both.

16. Why can’t you determine if you are running a high temperature by touching your own forehead?

17.Which has a greater amount of internal energy, a titanic iceberg or a cup of hot tea? Explain.

18. What is temperature a measure of?

19. Why will a watermelon stay cool for a longer time than sandwiches when both are removed from the same cooler on a hot day?

20. The desert sand is very hot during the day and very cool at night. What does this tell you about the sand’s specific heat?

21. If 70oF air feels comfortable to us, why does 70oF water feel cool when we swim in it?

22. You can bring water to boil in a paper cup by placing it over a hot flame. Why doesn’t the paper cup burn while the water is boiling?

23. Why is it that you can safely hold your bare hand in a hot oven for a few seconds, but if you momentarily touch the metal insides you’ll burn yourself?

24. Turn an incandescent lamp on and off quickly while you are standing near it. You feel its heat but find that when you touch the bulb, it is not hot. Explain why you felt the heat from it.

25. If the composition of the upper atmosphere were changed so that it permitted a greater amount of terrestrial radiation to escape, what effect would it have on the earth’s climate? How about if the atmosphere reduced the escape of terrestrial radiation?

26. When you step out of a swimming pool on a hot, dry day in the Southwest, you feel quite chilly, while you don’t feel as chilly here in the humid Southeast. Why? 

27. Give two reasons why pouring a cup of hot coffee into a saucer results in faster cooling?

28. If all the particles in a sample of water had the same speed, and some were able to evaporate, would the remaining water have a lower temperature? Explain.

29. The human body can maintain its customary temperature of 37 oC on a day when the temperature is above 40 oC. How is this done? more detailed than just “sweat”

30. A great amount of water vapor changes state to become liquid water droplets in the clouds that form a thunderstorm. Is this a release of energy or absorbing of energy?

31. Why does the boiling temperature of water increase when the water is under increased pressure?

32. Water will boil spontaneously in a vacuum (empty space) – on the moon for example. Could you cook an egg in this boiling water?

33. Why does the water in a radiator often boil explosively when the radiator cap is removed? Think about the process of evaporation.

34. Melting ice causes the temperature of the surrounding air to ____________? Explain how your answer can be true.

35. Why does ice form at the surface of a body of water instead of at the bottom?

36. Heat cannot readily escape a thermos bottle, so hot things inside stay hot. Will cold things inside a thermos bottle likewise stay cold? Explain.

37. Your friend is holding the bottom of a large test tube filled with water. Strangely, your friend decides to place the top half of the test tube over a flame and boil the water in the top half of the tube. Why should you not be real worried about your friend’s hand being burnt?