Question

An ideal gas is contained in a closed assembly with an initial pressure and

Answer 1

Answer: The final pressure is 116kPa or $116kN/m^2$

Explanation:

The combined gas equation is,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1$ = initial pressure of gas = $250kN/m^2=250kPa$   $(1kN/m^2=1kPa)$

$P_2$ = final pressure of gas = ?

$V_1$ = initial volume of gas = v ml

$V_2$ = final volume of gas = $1.8\times v=1.8vml$

$T_1$ = initial temperature of gas = $75^0C=(75+273)K=348K$

$T_2$ = final temperature of gas = $18^0C=(18+273)K=291K$

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

$\frac{250kPa\times v}{348}=\frac{P_2\times 1.8v}{291}$

$P_2=116kPa$

The final pressure is 116kPa or $116kN/m^2$