Question

At pressure P and absolute temperature T a mass M of an ideal gas fills a closed container of volume V. An additional mass 2M of the same gas is added into the container and the volume is then reduced to$\frac { V } { 3 }$ and the temperature to $\frac { T } { 3 }$ The pressure of the gas will now be:

• A. $\frac { P } { 3 }$
• B. P
• C. 3 P
• D. 9 P

Answer 1

Answer: (C)

3 P

Answer 2

If M₀ is molecular mass of the gas then for initial condition

PV= .RT ...(1)

After 2M mass has been added

P'. $\frac { V } { 3 } = \frac { 3 M } { M _ { 0 } } \cdot R \cdot \frac { T } { 3 }$ ...(2)

By dividing (2) by (1) P' = 3P