What is the heat in calories required to raise the temperature of 0.05 kg of water from 0 degrees C to 100 degrees C?

1. Belinda adds 20 g of sugar (carbon) at 25 °C to a 150 g cup of coffee (water) at 80 °C. What is the final temperature of the insulated mixture? (ccarbon = 0.12 cal/g* °C)

T = 79.1 C

2. David takes a container holding 3 kg of water at 25 °C and adds one kilogram of ice at 0 °C. What is the the final temperature and composition (water and ice) of the mixture?

All the ice will not be melted so the final mixture will be 3.95 kg of water and 0.05 kg of ice all at 0 degrees Celcius. There will be no further het transfer because both the water and the ice are at the same temperature.

3. If Chris has the same container of water as David does in problem two but adds only 0.50 kg of ice, what is the final temperature of the composition?

T = 10 C

4. Dewayne goes over to Cassie's house for tea. Her power goes out so, he decides to heat the tea pot with a camping stove. Being a physicist, Dewayne remembers that the specific heat of copper is 0.992 cal/g* C. He then weighs the tea pot and finds it to be 1.8 kg and contains 2.0 kg of water. The water is 20 C and must be heated to 100 C. How much heat is required to heat the tea? If the stove states that it can produce 700,000 J of heat, will he be able to get the tea to boiling?

Q = 1.73 x 10*5 cal. No, the total heat required is 728,000 J.

5. Dan takes 40.0 g of some mysterious substance from his laboratory and finds it condenses from a vapor at 61.6 °C to a liquid at 61.6 °C. It liberates 9870 J of heat. What is the heat of vaporization of this substance?

2.47 x 10*5 J/kg

6. Amanda takes one of Chris's CD's and tries to melt it. Chris grabs the CD which is 100 °C and drops it into 2.00 x 10*2 g of water at 20 °C. The mass of the CD is 1.00 X 10*2 g. The water and CD reach equilibrium at 21.6 °C. What is the specific heat of the CD?

171 J/kg*K

7. Aklilu once again takes his 750 kg car going at 23 m/s and hits his brakes coming to a stop. The brakes contain about 15 kg of iron which absorbs the energy. What is the increase in temperature of the brakes?

29 degrees Celsius

8. Belinda drinks 375 ml of a soda which generates 1.7 kJ/100 ml. She decides to burn off this food energy by climbing up the stairs. How high would Belinda have to climb if she has a mass of 65.0 kg?

1.0 x 10*1 m (about 3 flights of stairs)

9. A 4.2 g lead bullet moving at 275 m/s strikes a steel plate and stops. If all its kinetic energy is converted to thermal energy and none leaves the bullet, what is its temperature change?

290 degrees Celsius

10. How much heat is added to 10.0 g of ice at -20 °C to convert to steam at 120.0 °C?

3.09 x 10*4 J

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Text Solution

Solution : Given : m=5 kg, c=1 kcal/`kg^@C` Change in temperature `(DeltaT)`=100-20 =`80^@C` To Find : Heat energy needed to raise the temperature Solution :Energy to be supplied to water = energy gained by water = mass of water x specific heat of water change in temperature of water = `mxxcxxDeltaT` = 5 x 1 x 80 = 400 kcal Hence, the heat energy necessary to raise the temperature of water is 400 kcal.

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