Question

Which equation represents the combined gas law?

Answer 1

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(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`

`(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`

`(P)/(T)=constant`..............(3)

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

`(PV)/(T)=constant`...............(4)

Equation (4) is the combined gas law.

Or,
`(P_1V_1)/(T_1)=(P_2V_2)/(T_2)`

So, correct option is (c).

Answer 2

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.