Question

Q3 What is the temperature at which 80 cm3 of a gas should be heated

to increase its volume by 20% without changing the pressure? (Given that
the initial temperature of the gas is 25°C)​

Answer 1

The final temperature of the gas : 84.6 °C

Further explanation

Charles's Law

When the gas pressure is kept constant, the gas volume is proportional to the temperature

`\tt (V_1)/(T_1)=(V_2)/(T_2)`

T₁=initial temperature=25°C+273=298 K

V₁=initial volume=80 cm³

volume increment : 20% x 80 cm³=16 cm³

V₂ = Final volume = 80 cm³ + 16 cm³ = 96 cm³

So the final temperature :

`\tt T_2=(V_2* T_1)/(V_1)\\\\T_2=(96* 298)/(80)\\\\T_2=357.6~K=84.6^oC`