Thermal Energy and Specific Heat Problems

Formulas/Conversions

1 Calorie = 4.185 J

Celsius to Fahrenheit Conversion°F = (9/5 °C) + 32

Fahrenheit to Celsius Conversion°C = 5/9 (°F -32)

Celsius to Kelvin ConversionK = °C + 273

Q = (m) ( T)(C)Δ C = (Q) / (m T)Δ

Thermal Energy and Specific Heat Problems

1. A 15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature

changes from 25°C to 175°C. Calculate the specific heat capacity of iron in J/g°C.

2. How many joules of heat are needed to raise the temperature of 10.0 g of aluminum

from 22°C to 55°C, if the specific heat of aluminum is 0.90 J/g°C?

3. To what temperature will a 50.0 g piece of glass raise if it absorbs 5275 joules of heat

and its specific heat capacity is 0.50 J/g°C? The initial temperature of the glass is 20.0°C.

4. Calculate the specific heat capacity of a piece of wood if 1500.0 g of the wood absorbs

6.75×104 joules of heat, and its temperature changes from 32°C to 57°C.

5. 25.0 g of mercury is heated from 25°C to 155°C, and absorbs 455 joules of heat in the

process. Calculate the specific heat capacity of mercury in J/g°C.

6. What is the specific heat capacity of silver metal if 55.00 g of the metal absorbs 47.3

calories of heat and the temperature rises 15.0°C?

7. Octane, a substance found in petroleum, boils at 126°C and is a liquid over a range of

183 Celsius degrees. What is the melting point of octane in kelvins?

Thermal Energy and Specific Heat Problems

8. A 120g sample of an unknown substance was heated from 15oC to 30oC. The substance absorbed 458 joules of energy. What is the specific heat of this substance?

9. A 2.0-kg slab of concrete requires 11 kJ to raise its temperature from 23°C to 29°C.

What is the specific heat of concrete in J/g°C?

10. If the temperature of 28 g of ethanol increases from 15oC to 65.5 oC, how much heat was absorbed by the ethanol? (Specific heat ethanol = 2.44 J/goC)

Convert the following temperatures to both °F and Kelvin

11. -257.87 °C       °F       K

12. -40.0 °C       °F       K

13. 1064°C       °F       K

14. How much energy is needed to increase the temperature of 755 g of iron from 283 K to 403 K (CIron = 0.46 J/g°C)?      

15. If the specific heat of water is 4.185 J/g°C , how much energy must a refrigerator

absorb from 225 g of water to freeze the water if the initial temperature is 35 °C?      

16. What mass of water is required to absorb 4.7 x 105 J of energy from a car engine when

the temperature increases 57 °C?      

17. A vanadium bolt gives up 1124 J of energy as its temperature drops 25 K. If the bolt’s

mass is 0.093 kg, what is the specific heat J/g°C?      

18. Determine the change in energy if 550 g of copper (C = 0.39 J/g°C) is heated from 318

K to 24 °C.      

19. The temperature of deep space is thought to be around 3 K. What is this temperature

in °F?      

Thermal Energy and Specific Heat Problems

20. Determine the amount of energy needed to raise the temperature of a silver necklace

(specific heat = 0.23 J/g°C) with a mass of 22.5 g from 77 °F to 37 °C.