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1.

Brownian motion was first observed in 1827 for:

smoke in air

pollen grains suspended in water

mercury drops

dust on a table

2.

Brownian motion gives evidence that molecules of a gas:

are at rest

move randomly and continuously

attract each other strongly

have no mass

3.

The random motion of smoke particles is due to:

gravity

collisions with air molecules

the light of the microscope

electric forces only

4.

Ammonia and hydrogen chloride gases mix and form a white cloud of NH₄Cl. This experiment shows:

gas molecules are attracted to each other

the existence of intermolecular spaces

that gases have no mass

that gases are solid

5.

Gases are easily compressed because:

their molecules are very large

the spaces between molecules are large

they have no pressure

they are heavy

6.

To study the relation between two variables of a gas (V, P, T), which must be kept constant?

The shape of the container only

The third variable and the mass of the gas

Nothing; all may change

The two variables being studied

7.

Boyle's law relates the volume and pressure of a fixed mass of gas at constant:

volume

pressure

temperature

density

8.

When the pressure on a fixed mass of gas is increased to four times (constant temperature), its volume:

quadruples

is halved

becomes one quarter

is unchanged

9.

A gas occupies 200 cm³ at 1 atm. At constant temperature, its volume at 0.5 atm is:

100 cm³

200 cm³

400 cm³

800 cm³

10.

In Boyle's experiment, the graph that is a straight line through the origin is:

V against P

V against 1/P

P against V

PV against V

11.

A gas is slowly compressed to half its volume at constant temperature. Its pressure:

halves

doubles

is unchanged

quadruples

12.

When a fixed mass of gas is compressed slowly to half its volume at constant temperature, its density:

halves

is unchanged

doubles

quadruples

13.

In Boyle's apparatus, the pressure of the trapped air when the movable tube is raised so that its mercury level is h cm above that in the other tube is:

Pa − h

Pa + h

h

Pa/h

14.

The coefficient of volume expansion of any gas at constant pressure is:

1/100 per °C

1/273 per °C

1/373 per °C

273 per °C

15.

Charles's law: at constant pressure, the volume of a fixed mass of gas is directly proportional to its:

Celsius temperature

Kelvin temperature

pressure

density

16.

A gas at 0 °C has a volume of 300 cm³. At 91 °C (constant pressure) its volume is:

300 cm³

364 cm³

400 cm³

573 cm³

17.

If the Kelvin temperature of a gas doubles at constant pressure, its volume:

halves

doubles

is unchanged

quadruples

18.

2 litres of a gas at 27 °C are heated at constant pressure to 127 °C. The new volume is about:

1.5 L

2.0 L

2.67 L

8.5 L

19.

At constant pressure, a gas at 273 K is heated until its volume doubles. The final temperature is:

273 °C

546 °C

136.5 °C

100 °C

20.

In Charles's experiment, the length of the trapped air column is a measure of its volume because:

the tube has a uniform cross-section

the pressure changes

the temperature is constant

the tube is open

21.

The pressure law states that, at constant volume, the pressure of a fixed mass of gas is directly proportional to its:

Celsius temperature

Kelvin temperature

volume

mass only

22.

The coefficient of pressure increase at constant volume for all gases is:

1/373 K⁻¹

1/100 K⁻¹

1/273 K⁻¹

273 K⁻¹

23.

A gas at 1 atm and 27 °C is heated to 127 °C at constant volume. The final pressure is about:

1.0 atm

1.33 atm

4.7 atm

0.75 atm

24.

Jolly's apparatus is used to find the:

coefficient of volume expansion at constant pressure

coefficient of pressure increase at constant volume

atmospheric pressure

density of a gas

25.

Mercury is placed in the bulb of Jolly's apparatus so as to fill about 1/7 of it in order to:

keep the volume of the remaining air practically constant

increase the pressure

cool the air

reduce the temperature

26.

At constant volume, the pressure of a gas at 27 °C will double when it is heated to:

54 °C

327 °C

600 °C

573 °C

27.

Absolute zero corresponds to:

0 °C

−100 °C

−273 °C

273 °C

28.

The temperature of the human body (37 °C) on the Kelvin scale is about:

37 K

100 K

310 K

373 K

29.

100 K corresponds to:

−173 °C

173 °C

−373 °C

373 °C

30.

An ideal gas is one whose:

volume is always zero

volume at constant pressure (or pressure at constant volume) would vanish at absolute zero

molecules never move

density is constant

31.

A graph of pressure against Kelvin temperature at constant volume is:

a horizontal line

a hyperbola

a straight line through the origin

a vertical line

32.

Real gases do not obey the gas laws near absolute zero because:

they become hotter

they liquefy or solidify

their mass increases

the pressure becomes infinite

33.

The general gas law for a fixed mass of gas is:

P₁T₁/V₁ = P₂T₂/V₂

P₁V₁/T₁ = P₂V₂/T₂

P₁V₁T₁ = P₂V₂T₂

P₁/V₁ = P₂/V₂

34.

STP means:

0 °C and 76 cm Hg

20 °C and 1 atm

100 °C and 76 cm Hg

0 K and 1 atm

35.

A gas has P = 2 atm, V = 1 L, T = 300 K. If the pressure becomes 1 atm and V = 2 L, the temperature is:

75 K

150 K

300 K

600 K

36.

An open flask is heated from 7 °C to 147 °C. The fraction of the original air that escapes is:

1/4

1/3

1/2

2/3

37.

The value of the universal gas constant is about:

0.0821 J/(mol·K)

8.31 J/(mol·K)

83.1 J/(mol·K)

1.013 J/(mol·K)

38.

The mass of one mole of oxygen gas (O₂) is:

16 g

28 g

32 g

44 g

39.

Two gases are mixed (constant temperature) in a container. The pressure of the mixture is equal to:

the larger of the two partial pressures

the mean of the two

the sum of the pressures each gas would have alone in the container

their difference

40.

A helium balloon rises in the sky. Its volume:

decreases because pressure falls

increases because the surrounding pressure decreases

stays constant

becomes zero

Curriculum

Physics — Second Secondary

Physics — Second Secondary

Physics — Second Secondary 2026/2027

Question bank: Chapter 6: Gas Laws

Quiz finished, well done