Question

Which equation represents the combined gas law?

Answer 1

The correct option is P1V1 / T1 = P2V2 /T2.

The combine gas law states that the ratio of the product of pressure, volume and absolute temperature of a gas is always a constant. Mathematically, the law is represented by P1V1 / T1 = P2V2 /T2; where

P1 and P2 = Initial and final pressure of the gas

V1 and V2 = Initial volume and the final volume of the gas

T1 and T2 = Initial temperature and final temperature of the gas.

Combine gas law was formed by the combination of Boyle's law, Charles' law and Gay Lussac's law.

Answer 2

Explanation :

Combined gas law comes from the combination of Boyle's law, Charles law and Gay Lussac's law.

According to Boyle's law,

At constant temperature, pressure of a gas is inversely proportional to its volume.

i.e. $P\propto\dfrac{1}{V}$

$PV=constant$..........(1)

Where,

P is the pressure of gas

V is the volume of gas

According to Charles law,

At constant pressure, volume of a gas is directly proportional to its temperature.

i.e. $V\propto T$

$\dfrac{V}{T}=constant$..............(2)

Where, T is the temperature.

According to Gay Lussac's law,

At constant volume, pressure of gas is directly proportional to its temperature.

i.e. $P\propto T$

$\dfrac{P}{T}=constant$..............(3)

Combining equation (1) (2) and (3)

$\dfrac{PV}{T}=constant$...............(4)

Equation (4) is the combined gas law.

Or, $\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}$

So, correct option is (c).