Question

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

temperature of 250 kN/m²and 75°C respectively, If the final volume of the system
is increased 1.8 times and the temperature drops to 18°C, determine the final
pressure of the gas.​

Answer 1

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

Step-by-step explanation:

The combined gas equation is,

`(P_1V_1)/(T_1)=(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* 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:

`(250kPa* v)/(348)=(P_2* 1.8v)/(291)`

`P_2=116kPa`

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