Question

A sample of air occupies 3.8 L when the pressure is 1.2 atm and temperature at 25 Celsius. What pressure( in atm) will the gas have at 100 Celsius when the volum is held constant?

Answer 1

Answer : The final pressure of the gas will be, 1.5 atm

Explanation :

Gay-Lussac's Law : It is defined as the pressure of the gas is directly proportional to the temperature of the gas at constant volume and number of moles.

`P\propto T`

or,

`(P_1)/(T_1)=(P_2)/(T_2)`

where,

`P_1` = initial pressure of gas = 1.2 atm

`P_2` = final pressure of gas = ?

`T_1` = initial temperature of gas =
`25^oC=273+25=298K`

`T_2` = final temperature of gas =
`100^oC=273+100=373K`

Now put all the given values in the above equation, we get:

`(1.2atm)/(298K)=(P_2)/(373K)`

`P_2=1.5atm`

Thus, the final pressure of the gas will be, 1.5 atm