Kinetic Theory and First Law of Thermodynamics MCQs

Question 1

Using R = 8.31 and NA = 6.02 10^23, k works out to:

Accepted Answer

1.38 10^-23 J/K

Answer

5.00 10^24 J/K

Answer

1.38 10^23 J/K

Answer

7.24 10^22 J/K

Question 2

The molar gas constant R has the unit:

Accepted Answer

J mol^-1 K^-1

Answer

N m^-2

Answer

J K^-1

Answer

J mol^-1

Question 3

1 mol of an ideal gas at 273 K occupies 0.0224 m^3. Its pressure is (R = 8.31 J mol^-1 K^-1):

Accepted Answer

1.01 10^5 Pa

Answer

10,100 Pa

Answer

1.01 10^6 Pa

Answer

2.03 10^5 Pa

Question 4

Boyle's law states that at constant temperature:

Accepted Answer

p propto 1V

Answer

p propto T

Answer

V propto T

Answer

p propto V

Question 5

Charles's law states that at constant pressure:

Accepted Answer

V propto T

Answer

p propto V

Answer

pV = 0

Answer

V propto 1T

Question 6

1 mol of an ideal gas is heated at constant pressure so its temperature rises by 100 K. The work done by the gas is:

Accepted Answer

831 J

Answer

416 J

Answer

1660 J

Answer

1250 J

Question 7

The internal energy of a gas decreases by 60 J while it does 40 J of work. The heat supplied to it is: (Use Q = Delta U + W, where Q = heat supplied to the gas and W = work done by the gas.)

Accepted Answer

-20 J

Answer

-200 J

Answer

-10 J

Answer

-40 J

Question 8

Kinetic theory assumes that between collisions the molecules:

Accepted Answer

move in straight lines at constant speed (no intermolecular forces)

Answer

are at rest

Answer

move in circles

Answer

attract each other

Question 9

A balloon taken from a warm room into a cold freezer:

Accepted Answer

shrinks

Answer

keeps the same size

Answer

expands

Answer

bursts

Question 10

Gas pressure is explained by kinetic theory as:

Accepted Answer

the force per unit area from molecules colliding with the walls

Answer

heat flow

Answer

the attraction between molecules

Answer

the weight of the gas

Question 11

In the equivalent form Delta U = Q + Won, the term Won is:

Accepted Answer

the work done on the system

Answer

the work done by the system

Answer

the heat lost

Answer

the change in temperature

Question 12

A gas expands at a constant pressure of 10^5 Pa from 2 L to 6 L while absorbing 1000 J of heat. Its internal energy increases by:

Accepted Answer

600 J

Answer

1400 J

Answer

400 J

Answer

1000 J

Question 13

Ideal gas behaviour is a good approximation for a gas of:

Accepted Answer

low density

Answer

very low temperature near liquefaction

Answer

high density

Answer

solid particles

Question 14

At constant pressure, a gas expands when heated because:

Accepted Answer

faster molecules need more space to keep the same collision rate per unit area

Answer

the container shrinks

Answer

gravity weakens

Answer

the molecules grow

Question 15

When the volume of a gas does not change, the work done by it is:

Accepted Answer

zero

Answer

nRT

Answer

maximum

Answer

pV

Question 16

Rubbing your hands raises their temperature because:

Accepted Answer

work done against friction increases internal energy

Answer

blood cools

Answer

heat flows from the air

Answer

the hands lose mass

Question 17

The kinetic theory assumes the number of molecules is:

Accepted Answer

very large, so statistical averages can be used

Answer

zero

Answer

very small

Answer

exactly one

Question 18

In a cyclic process (gas returns to its initial state):

Accepted Answer

net heat absorbed = net work done

Answer

net heat is always zero

Answer

net work is always zero

Answer

internal energy increases

Question 19

A fixed mass of gas at 1.5 10^5 Pa occupies 4 L. At constant temperature it is changed to 6 L. The new pressure is:

Accepted Answer

1 10^5 Pa

Answer

2 10^5 Pa

Answer

50,000 Pa

Answer

2.25 10^5 Pa

Question 20

The average translational kinetic energy of a gas molecule at 300 K is (k = 1.38 10^-23 J/K):

Accepted Answer

6.21 10^-21 J

Answer

1.24 10^-20 J

Answer

4.14 10^-21 J

Answer

1.86 10^-20 J

Question 21

Two identical blocks, one at 20 °C and one at 60 °C. The block with greater internal energy is:

Accepted Answer

the block at 60 °C

Answer

impossible to say even though they are identical

Answer

the block at 20 °C

Answer

they are equal

Question 22

Which gas is closest to ideal at room conditions?

Accepted Answer

helium

Answer

water vapour near boiling

Answer

ammonia near liquefaction

Answer

carbon dioxide at high pressure

Question 23

The first law of thermodynamics is a form of the law of conservation of:

Accepted Answer

energy

Answer

momentum

Answer

charge

Answer

mass

Question 24

In Q = Delta U + W, Q is the heat supplied to the gas and W is:

Accepted Answer

the work done by the gas

Answer

the power

Answer

the weight

Answer

the work done on the gas

Question 25

When a gas expands against a piston, work is done:

Accepted Answer

by the gas on the surroundings

Answer

by nobody

Answer

on the gas by the surroundings

Answer

only on the container walls

Kinetic Theory and First Law of Thermodynamics MCQs — Physics (page 3)

51. Using R = 8.31 and NA = 6.02 10^23, k works out to:

52. The molar gas constant R has the unit:

53. 1 mol of an ideal gas at 273 K occupies 0.0224 m^3. Its pressure is (R = 8.31 J mol^-1 K^-1):

54. Boyle's law states that at constant temperature:

55. Charles's law states that at constant pressure:

56. 1 mol of an ideal gas is heated at constant pressure so its temperature rises by 100 K. The work done by the gas is:

57. The internal energy of a gas decreases by 60 J while it does 40 J of work. The heat supplied to it is: (Use Q = Delta U + W, where Q = heat supplied to the gas and W = work done by the gas.)

58. Kinetic theory assumes that between collisions the molecules:

59. A balloon taken from a warm room into a cold freezer:

60. Gas pressure is explained by kinetic theory as:

61. In the equivalent form Delta U = Q + Won, the term Won is:

62. A gas expands at a constant pressure of 10^5 Pa from 2 L to 6 L while absorbing 1000 J of heat. Its internal energy increases by:

63. Ideal gas behaviour is a good approximation for a gas of:

64. At constant pressure, a gas expands when heated because:

65. When the volume of a gas does not change, the work done by it is:

66. Rubbing your hands raises their temperature because:

67. The kinetic theory assumes the number of molecules is:

68. In a cyclic process (gas returns to its initial state):

69. A fixed mass of gas at 1.5 10^5 Pa occupies 4 L. At constant temperature it is changed to 6 L. The new pressure is:

70. The average translational kinetic energy of a gas molecule at 300 K is (k = 1.38 10^-23 J/K):

71. Two identical blocks, one at 20 °C and one at 60 °C. The block with greater internal energy is:

72. Which gas is closest to ideal at room conditions?

73. The first law of thermodynamics is a form of the law of conservation of:

74. In Q = Delta U + W, Q is the heat supplied to the gas and W is:

75. When a gas expands against a piston, work is done:

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