Kinetic Theory and First Law of Thermodynamics MCQs

Question 1

If k is 1.38 10^-23 J/K and NA is 6.02 10^23 mol^-1, then R is:

Accepted Answer

8.31 J mol^-1 K^-1

Answer

1.0

Answer

4.36 10^46

Answer

2.29 10^-47

Question 2

A graph of p against 1V at constant temperature is:

Accepted Answer

a straight line through the origin

Answer

a parabola

Answer

a hyperbola

Answer

a horizontal line

Question 3

A gas in a cylinder is compressed by 400 J of work while losing no heat. Its internal energy:

Accepted Answer

increases by 400 J

Answer

decreases by 400 J

Answer

increases by 800 J

Answer

is unchanged

Question 4

A gas expands from 1 L to 3 L at 100 kPa. The work done by the gas is:

Accepted Answer

200 J

Answer

2 10^5 J

Answer

300 J

Answer

100 J

Question 5

2 mol of an ideal gas is heated at constant volume and its internal energy rises by 500 J. The heat supplied is:

Accepted Answer

500 J

Answer

250 J

Answer

0 J

Answer

1000 J

Question 6

In an expansion at constant pressure, the p–V graph is:

Accepted Answer

a horizontal straight line

Answer

a circle

Answer

a hyperbola

Answer

a vertical line

Question 7

The time a molecule spends in a collision is assumed to be:

Accepted Answer

negligible compared with the time between collisions

Answer

infinite

Answer

equal to the time between collisions

Answer

longer than the time between collisions

Question 8

A gas at constant pressure 1 10^5 Pa changes volume from 0.002 m^3 to 0.005 m^3. The work done by the gas is:

Accepted Answer

300 J

Answer

30 J

Answer

3000 J

Answer

-300 J

Question 9

A machine that produces work without any energy input would violate:

Accepted Answer

the first law of thermodynamics

Answer

the zeroth law

Answer

Newton's first law

Answer

the second law only

Question 10

When water at 100 °C turns to steam at 100 °C, the molecules' average kinetic energy:

Accepted Answer

stays the same, while their potential energy increases

Answer

becomes zero

Answer

decreases

Answer

increases

Question 11

A 2 kg body of specific heat capacity 4200 J kg^-1 K^-1 is warmed by 10 K (no work done). The increase in its internal energy is:

Accepted Answer

84,000 J

Answer

42,000 J

Answer

1.68 10^5 J

Answer

8400 J

Question 12

At constant temperature, a gas at 200 kPa expands until its pressure is 50 kPa. Its volume:

Accepted Answer

becomes 4 times as large

Answer

becomes one quarter

Answer

halves

Answer

doubles

Question 13

Molecules of an ideal gas have no potential energy because:

Accepted Answer

there are no intermolecular forces (except during collisions)

Answer

they have no mass

Answer

they are at rest

Answer

they are very hot

Question 14

The pressure law states that at constant volume:

Accepted Answer

p propto T

Answer

V propto T

Answer

p propto 1T

Answer

p propto V

Question 15

NA is the number of particles in:

Accepted Answer

one mole of a substance

Answer

one gram of any substance

Answer

one kilogram

Answer

one cubic metre

Question 16

On a p–V graph, the work done by a gas is:

Accepted Answer

the area under the curve

Answer

zero always

Answer

the gradient

Answer

the intercept

Question 17

The Avogadro constant NA is about:

Accepted Answer

6.02 10^23 mol^-1

Answer

8.31 mol^-1

Answer

1.38 10^-23 mol^-1

Answer

3 10^8 mol^-1

Question 18

2 mol of an ideal gas is heated at constant pressure so its temperature rises by 50 K. The work done by the gas is:

Accepted Answer

831 J

Answer

416 J

Answer

1250 J

Answer

1660 J

Question 19

k is a fundamental constant whose value is:

Accepted Answer

the same for all gases

Answer

zero for ideal gases

Answer

different for each gas

Answer

dependent on pressure

Question 20

A gas expands from 2 L to 5 L at 1 atm (10^5 Pa). The work done ON the gas is:

Accepted Answer

-300 J

Answer

+300 J

Answer

+700 J

Answer

-500 J

Question 21

Temperature is the property that determines whether a body:

Accepted Answer

is in thermal equilibrium with other bodies

Answer

is a conductor

Answer

will float

Answer

has mass

Question 22

When the temperature of a gas rises, its internal energy:

Accepted Answer

increases, because the molecules move faster

Answer

stays the same

Answer

decreases

Answer

becomes zero

Question 23

A sealed can explodes when thrown into a fire because:

Accepted Answer

the gas pressure rises as its temperature rises at constant volume

Answer

the can melts first

Answer

the gas cools

Answer

the volume increases

Question 24

A real gas behaves most like an ideal gas at:

Accepted Answer

high temperature and low pressure

Answer

high pressure and high density

Answer

low temperature and high pressure

Answer

low temperature and low pressure only

Question 25

A gas absorbs 500 J of heat and does 200 J of work. The change in its internal energy is: (Use Q = Delta U + W, where Q = heat supplied to the gas and W = work done by the gas.)

Accepted Answer

300 J

Answer

150 J

Answer

600 J

Answer

3000 J

Kinetic Theory and First Law of Thermodynamics MCQs — Physics (page 6)

126. If k is 1.38 10^-23 J/K and NA is 6.02 10^23 mol^-1, then R is:

127. A graph of p against 1V at constant temperature is:

128. A gas in a cylinder is compressed by 400 J of work while losing no heat. Its internal energy:

129. A gas expands from 1 L to 3 L at 100 kPa. The work done by the gas is:

130. 2 mol of an ideal gas is heated at constant volume and its internal energy rises by 500 J. The heat supplied is:

131. In an expansion at constant pressure, the p–V graph is:

132. The time a molecule spends in a collision is assumed to be:

133. A gas at constant pressure 1 10^5 Pa changes volume from 0.002 m^3 to 0.005 m^3. The work done by the gas is:

134. A machine that produces work without any energy input would violate:

135. When water at 100 °C turns to steam at 100 °C, the molecules' average kinetic energy:

136. A 2 kg body of specific heat capacity 4200 J kg^-1 K^-1 is warmed by 10 K (no work done). The increase in its internal energy is:

137. At constant temperature, a gas at 200 kPa expands until its pressure is 50 kPa. Its volume:

138. Molecules of an ideal gas have no potential energy because:

139. The pressure law states that at constant volume:

140. NA is the number of particles in:

141. On a p–V graph, the work done by a gas is:

142. The Avogadro constant NA is about:

143. 2 mol of an ideal gas is heated at constant pressure so its temperature rises by 50 K. The work done by the gas is:

144. k is a fundamental constant whose value is:

145. A gas expands from 2 L to 5 L at 1 atm (10^5 Pa). The work done ON the gas is:

146. Temperature is the property that determines whether a body:

147. When the temperature of a gas rises, its internal energy:

148. A sealed can explodes when thrown into a fire because:

149. A real gas behaves most like an ideal gas at:

150. A gas absorbs 500 J of heat and does 200 J of work. The change in its internal energy is: (Use Q = Delta U + W, where Q = heat supplied to the gas and W = work done by the gas.)

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