Q: If 120 g of H$$_2O is $$cooled from 95 °C to 45 °C, how much heat is released? (Specific heat capacity of H$$_2O = 4.184 J/g$$·°C)

$$q = 120 \times 4.184 \times (45 - 95) = -25,104 J$$

Q: A student heats 100 g of ethanol (specific heat capacity = 2.44 J/g·°C) from 20 °C to 50 °C. How much heat is required?

$$q = 100 \times 2.44 \times (50 - 20) = 7,320 J$$

Q: If 250 g of wood (specific heat capacity = 1.76 J/g·°C) absorbs 500 J of heat, what is the temperature change?

$$\Delta T = \frac{500}{250 \times 1.76} = 1.14$$ °C

Q: A metal sample requires 150 J of heat to increase its temperature by 10 °C. If its mass is 30 g, what is its specific heat capacity?

$$c = \frac{150}{30 \times 10} = 0.5 J/g$$·°C

Q: If a 200 g sample of a substance with a specific heat capacity of 0.900 J/g·°C is heated from 20 °C to 70 °C, how much heat is absorbed?

$$q = 200 \times 0.900 \times (70 - 20) = 9,000 J$$

Question 1

Which of the following best describes the relationship between heat added to an object and its temperature change?

Accepted Answer

Heat added is directly proportional to temperature change.

Question 2

If the temperature of a water sample goes from 25 °C to 50 °C, what happens to the amount of heat required?

Accepted Answer

It will double.

Question 3

Which formula correctly expresses the relationship between heat ($$q$$), mass ($$m$$), specific heat capacity ($$c$$), and temperature change ($$\Delta T$$)?

Accepted Answer

$$q = m c \Delta T$$

Question 4

A sample of copper absorbs 3.3 kJ of heat, which increases its temperature by 25 °C. If the specific heat capacity of copper is 0.385 J/g·°C, what is the mass of the copper sample in kg?

Accepted Answer

0.73 kg

Question 5

Which of the following substances will show the greatest temperature change upon absorbing 25.0 J of heat, based on their specific heat capacities?

Accepted Answer

250.0 g Ag

Question 6

What is the definition of specific heat capacity?

Accepted Answer

The amount of heat required to change the temperature of 1 g of a substance by 1 °C.

Question 7

If 120 g of H$$_2O is $$cooled from 95 °C to 45 °C, how much heat is released? (Specific heat capacity of H$$_2O = 4.184 J/g$$·°C)

Accepted Answer

$$q = 120 	imes 4.184 	imes (45 - 95) = -25,104 J$$

Question 8

A 50.0 g piece of heated metal is placed in 62.5 g of water at 20.0 °C. If the metal gives 14.5 J of energy to the water, what is the final temperature of the water? (Specific heat capacity of water = 4.184 J/g·°C)

Accepted Answer

61.08 °C

Question 9

Which of the following statements about molar heat capacity is correct?

Accepted Answer

It is the amount of heat required to change the temperature of 1 mole of a substance by 1 °C.

Question 10

Which equation would you use to calculate the amount of heat absorbed by a substance if you know its mass, specific heat capacity, and temperature change?

Accepted Answer

$$q = m c \Delta T$$

Question 11

A student heats 100 g of ethanol (specific heat capacity = 2.44 J/g·°C) from 20 °C to 50 °C. How much heat is required?

Accepted Answer

$$q = 100 	imes 2.44 	imes (50 - 20) = 7,320 J$$

Question 12

Why does water have a smaller temperature change than silver when both absorb the same amount of heat?

Accepted Answer

Water has a higher specific heat capacity than silver.

Question 13

Which of the following is a real-world application of specific heat capacity?

Accepted Answer

Designing climate control systems in buildings.

Question 14

If 250 g of wood (specific heat capacity = 1.76 J/g·°C) absorbs 500 J of heat, what is the temperature change?

Accepted Answer

$$\Delta T = \frac{500}{250 	imes 1.76} = 1.14$$ °C

Question 15

A metal sample requires 150 J of heat to increase its temperature by 10 °C. If its mass is 30 g, what is its specific heat capacity?

Accepted Answer

$$c = \frac{150}{30 	imes 10} = 0.5 J/g$$·°C

Question 16

Which of the following would require the most heat to increase its temperature by 1 °C?

Accepted Answer

1 mole of water

Question 17

If a 200 g sample of a substance with a specific heat capacity of 0.900 J/g·°C is heated from 20 °C to 70 °C, how much heat is absorbed?

Accepted Answer

$$q = 200 	imes 0.900 	imes (70 - 20) = 9,000 J$$

Heat Capacity and Specific Heat: Study Notes for Introduction to Chemistry

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