Question

A) One mole of ideal gas is kept in a container with fixed volume. We add another mole of the same gas. If we are keeping pressure in container at the same level, what happens with absolute temperature of gas?

it stays the same

it quadruples

it drops 4 times

it doubles

it halves

B) Temperature of ideal gas sample increased from 2000C to 4000C while pressure was kept the same. We can predict that volume of this gas:

Increased 1.42 times

Increased 2 times

Decreased 2 times

Decreased 1.42 times

Answer 1

Question A

Universal gas constant = R

Initial number of moles = n₁ = 1 mol

Initial pressure = P₁

Initial volume = V₁

Initial temperature = T₁

New total number of moles = n₂ = 2 mol

Pressure is kept same and the container has fixed volume.

Pressure after adding 1 mole = P₂ = P₁

Volume after adding 1 mole = V₂ = V₁

Temperature after adding 1 mole = T₂

P₁V₁ = n₁RT₁

P₂V₂ = n₂RT₂

Dividing the two equations,

T₂ = 0.5T₁

Absolute temperature of the gas halves after another mole is added.

Question B

Initial temperature = T₁ = 200 ^oC = 473 K

Initial volume = V₁

Final temperature = T₂ = 400 ^oC = 673 K

Final volume = V₂

The pressure of the gas is kept constant.

V₂ = 1.42V₁

Volume of the gas increased 1.42 times.