## Homework Helpers: Physics

## 9 Heat and Thermodynamics

### Chapter 9 Examination

**Part I—Matching**

Match the following terms to the definitions that follow.

a. absolute zero

b. kelvin

c. Celsius

d. Boyle”s law

e. Charles”s law

f. convection

g. temperature

h. pressure

i. specific heat

_______1.__ The temperature scale based on absolute zero.

_______2.__ States that the pressure and volume of an ideal gas at constant temperature are inversely proportional to each other.

_______3.__ The amount of energy required to increase the temperature of one gram of a substance by one degree Celsius.

_______4.__ Theoretically, the lowest temperature that an object can reach.

_______5.__ The amount of force exerted per unit of area.

**Part II—Multiple Choice**

For each of the following questions, select the best answer.

__6.__ What would happen to the pressure of a sample of neon gas if the volume remains constant as the temperature is increased from 30.0 K to 60.0 K?

a) The pressure would increase by 30.0 Pa.

b) The pressure would increase by a factor of three.

c) The pressure would decrease by a factor of three.

d) The pressure would decrease by 30.0 Pa.

__7.__ In an isometric process, which of the following quantities remain constant?

a) pressure

b) temperature

c) heat

d) volume

__8.__ The sun warming Earth is an example of which form of heat transfer?

a) radiation

b) convection

c) conduction

d) grounding

**Part III—Calculations**

Perform the following calculations.

__9.__ A system absorbs 235 J of heat from its surroundings, and the surroundings does 80 J of work on the system. Find the change in its internal energy.

__10.__ Calculate the specific heat capacity of an unknown material if it takes 16,700 J of energy to raise the temperature of a 1.13 kg sample of the substance by 22°C.

__11.__ What temperature in Fahrenheit is equivalent to 31.0°C?

__12.__ What temperature in Celsius is equivalent to 431 K?

__13.__ A 2.61 kg sample of water with an initial temperature of 4.00°C absorbs 6,570 calories of heat from its surroundings. What is the final temperature of the water?

__14.__ Brass has a coefficient of linear expansion of approximately 1.9 × 10^{–5} °C^{–1}. If a bar of brass has an initial length of 1.922 m at 3.00°C, what will be the length of the bar at 121.0°C?

__15.__ The pressure of an ideal gas is maintained at 1.55 × 10^{5} Pa while its volume increases by 0.1777 m^{3}. How much work does the gas do on its surroundings?

__16.__ A 7.50-L sample of hydrogen gas exerts a pressure of 1.25 × 10^{5} Pa at 299 K. If the temperature remains the same, as the gas is compressed to 2.00 L, what pressure will the sample of hydrogen exert?

__17.__ A sample of argon gas occupies 157 cm^{3} at 311 K. At what temperature would this sample of gas occupy 101 cm^{3}? (Assume pressure is constant.)

__18.__ How many moles of neon gas would occupy 1.75 dm^{3} at 51.0°C and 1.50 atm of pressure?

__19.__ The molecular mass of nitrogen is 28.0 g/mol. How fast do nitrogen molecules in a gas sample with a temperature of 57.0°C travel?

__20.__ How much heat is lost when a 2.50 kg sample of water cools from 85.0°C to 20.0°C?