Gas Laws Test

Result

Gas Laws Test - 6

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Which of the following changes occurs when a constant volume of gas is heated?

A
Pressure decreases and average kinetic energy increases.

B
Pressure increases and average kinetic energy decreases.

C
Pressure and average kinetic energy both increase.

D
Pressure and average kinetic energy both decrease.

Solution

According to kinetic theory, on heating a constant volume of gas, average kinetic energy of molecules and pressure will increase.
Both pressure and kinetic energy are a function of temperature:
P T
This is Gay Lussac's law.
At constant 'V',

Also K.E =
Question 2
1 / -0

Which of the following is in accordance with Boyle's law for a given mass of dry gas at constant temperature?

A
If the pressure is halved, the volume is reduced to one-third of the original.

B
If the pressure is tripled, the volume is reduced to one-third of the original.

C
If the pressure is doubled, the volume is reduced to one-fourth of the original.

D
If the pressure is reduced to one-third, the volume is doubled.

Solution

Hence, when the pressure is tripled, the volume reduces to one-third.
Question 3
1 / -0

A gas occupies 600 cm³ at 900 mm Hg pressure. At what pressure will the gas occupy 450 cm³? (Assume that temperature remains constant.)

A
1200 cm Hg

B
120 cm Hg

C
120 mm Hg

D
12000 mm Hg

Solution

At a constant temperature:
P₁V₁ = P₂V₂ (Boyle's law)
600 900 = P₂ 450
P₂ = 600 2
P₂ = 1200 mm Hg
1200 mm Hg = 120 cm Hg
∴ P₂ = 120 cm Hg
Question 4
1 / -0

A gas occupies 800 cm³ under a pressure of 760 mm Hg. Under what pressure will the volume of the gas be reduced by 20% of its original volume? (Temperature remains constant.)

A
3800 mm Hg

B
950 mm Hg

C
980 mm Hg

D
1900 mm Hg

Solution

× 800 = 160
New volume V₂= 800 – 160 = 640 cm³
At a constant temperature:
P₁V₁ = P₂V₂(Boyle's law)
800 760 = P₂640
P₂ = 950 mm Hg
Question 5
1 / -0

Two cylinders containing carbon dioxide are connected together by a tube fitted with a tap. The capacity of one cylinder is 3 dm³ and that of the other cylinder is 2 dm³; the pressure of the first cylinder is 550 mm Hg and that of the second cylinder is 800 mm Hg. What will be the final pressure in the cylinders on opening the tap? (Temperature remains constant.)

A
330 mm Hg

B
320 mm Hg

C
650 mm Hg

D
450 mm Hg

Solution

New volume = 2 + 3 = 5 times
For the gas in the 1^st cylinder,
PV = P'V'
550 3 = P' 5
P' = 330 mm Hg
For the gas in the 2^nd cylinder,
PV = P'V'
800 2 = P'5
P'= 320 mm Hg
Final pressure in the two cylinders = 320 + 330 = 650 mm Hg
Question 6
1 / -0

At what temperature will the volume of a gas at 0°C be tripled? (Pressure remains constant.)

A
546°C

B
819°C

C
273°C

D
1082°C

Solution

At a constant pressure:
(Charles' Law)
0°C = 273 K

T₂ = 273 3
T₂ = 819
819 = °C + 273 = 546°C
Question 7
1 / -0

What will be the change in volume of a gas when it is heated from 0°C to 819°C under constant pressure?

A
Twice

B
Thrice

C
Four times

D
No change

Solution

0° = 273 K
819°C = 1082 K
At a constant pressure, applying Charles' Law:

V₂ = 4V₁
Four times
Question 8
1 / -0

What will be the volume of gas at absolute zero temperature under constant pressure?

A
1000 ml

B
0 ml

C
273 ml

D
100 ml

Solution

0 K is considered as absolute zero and all gases cease to exist at this temperature, i.e. they liquefy much before they acquire this temperature.
Going by Charles' Law, for every 1^oC increase in temperature, the volume increases by of its value at 273 K.
Let V_o be the volume of the gas at 273 K.

V = V_o +
V = V_o
By putting t = - 273°C, we get

V = 0
Question 9
1 / -0

A gas of volume 150 cm³ is taken at 27.3 K. The temperature is then changed to 0°C. What is the new volume of the gas, if pressure is kept constant throughout?

A
0 cm³

B
136 cm³

C
150 cm³

D
1500 cm³

Solution

Charles' law,

V/T = V₁/T₁

V₁ = 150 10

V₁ = 1500 cm³
Question 10
1 / -0

What will be the decrease in volume when 60 cm³ gas at 27°C is cooled to 12°C? (Pressure remains constant.)

A
57 cm³

B
26.6 cm³

C
5 cm³

D
3 cm³

Solution

According to Charles' law,
T = 27 + 273 T₁ = 12 + 273

= 300 K = 285 K

V₁ = 57

Decrease in volume = 60 - 57 = 3 cm³
Question 11
1 / -0

Which of the following represents the ideal gas equation?

A

B

C

D

Solution

According to the ideal gas equation,
Question 12
1 / -0

At what temperature will 500 cm³ of a gas at 20°C occupy half of its original volume?

A
126.5°C

B
146.5°C

C
- 126.5°C

D
173°C

Solution

T₁ = 273 + 20°C = 293°C,

V₂ = = 250 cm³

273 + t =

t = 146.5 - 273

t = - 126.5°C
Question 13
1 / -0

For a fixed mass of an ideal gas at constant temperature, which of the following is true?

A
Plot of V versus p is linear.

B
Plot of V versus p is nonlinear with zero intercept.

C
Plot of pV versus p is linear with a positive slope.

D
Plot of pV versus p is linear with a zero slope.

Solution
Question 14
1 / -0

The total energy of molecules of a gas at a given temperature depends on the

A
number of gaseous molecules

B
volume of the gas

C
pressure of the gas

D
molar mass of the gas

Solution

The total energy of molecules of a gas at a given temperature depends on the number of gaseous molecules.
Question 15
1 / -0

The Kelvin temperature of an ideal gas is

A
proportional to the average potential energy of the molecules

B
proportional to the average speed of the molecules

C
proportional to the average kinetic energy of the molecules

D
inversely proportional to the partial pressure

Solution

The Kelvin temperature of an ideal gas is proportional to the average kinetic energy of the molecules.

K.E. =
Question 16
1 / -0

The density of ammonia at 27°C and 3 atm pressure is about

A
2.07 g cm^–3

B
2.07 g dm^–3

C
2.07 g m^–3

D
2.07 g mm^–3

Solution
Question 17
1 / -0

For a fixed mass of an ideal gas at constant pressure, which of the following statements is true?

A
Plot of volume versus Celsius temperature is linear with a zero intercept.

B
Plot of volume versus Kelvin temperature is linear with a non-zero intercept.

C
Plot of V/T versus T is linear with a positive slope.

D
Plot of V/T versus T is linear with a zero slope.

Solution

According to Charles' law,

V/T = constant

Plot of V/T versus T will give a horizontal straight line with a zero slope.
Question 18
1 / -0

With increase in the value of pressure p, the plot of compressibility factor Z versus pressure p for an ideal gas at 0°C

A
increases

B
decreases

C
first decreases, attains a minimum value followed by an increase

D
remains constant

Solution
Question 19
1 / -0

According to kinetic theory, what is true about collision between gas molecules and with the container, respectively?

A
They are perfectly inelastic; and impart momentum to container wall.

B
They are perfectly elastic; and impart momentum to container wall.

C
They are perfectly inelastic; and do not impart momentum to container wall.

D
They are perfectly elastic, and do not impart momentum to container wall.

Solution

According to kinetic theory, collision between gas molecules are perfectly elastic, and they impart momentum to container wall.
Question 20
1 / -0

The volume of a given mass of a gas at 27°C is 100 cm³. To what temperature must the gas be heated so that the volume increases to 150 cm³?

A
450 K

B
40.5 K

C
405 K

D
415 K

Solution

According to Charles` law,
T = 27 + 273

T = 300 K

T₁ = 450 K