Question

Some gas is trapped in a large syringe by a piston.The atmospheric pressure is 100kpa.The pressure gauge indicates that the gas pressurr is 200kpa above atmospheric pressure.The piston moves outwards and the volume of the gas doubles.The temperature remains constant.What is the new gas pressure?

Answer 1

Answer: The new gas pressure is 150 kPa.

Explanation :

Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

`P\propto (1)/(V)` (At constant temperature and number of moles)

`P_1V_1=P_2V_2`

where,

`P_1` = initial pressure of gas = (100+200) kPa = 300 kPa

`P_2` = final pressure of gas = ?

`V_1` = initial volume of gas = v

`V_2` = final volume of gas = 2v

`300* v=P_2* 2v`

`P_2=150kPa`

Therefore, the new gas pressure is 150 kPa.