# a certain mass of gas occupies volume of 2 litre at STP. keeping the pressure constant , at what temperature would the gas occupy a volume of 4 litre?

At STP, Pressure, P

_{1}= 1 atm and Temperature, T

_{1}= 273 K

Final Volume, V

_{2}= 4L

To find: Final temperature, T

_{2}

Solve: As we know

PV = nRT

Now, for given number of moles at constant pressure volume is directly proportional to temperature. We can write as

$\frac{{\text{V}}_{\text{2}}}{{\text{V}}_{\text{1}}}=\frac{{\text{T}}_{\text{2}}}{{\text{T}}_{\text{1}}}\phantom{\rule{0ex}{0ex}}\frac{4}{2}=\frac{{\text{T}}_{\text{2}}}{273}\phantom{\rule{0ex}{0ex}}{\text{T}}_{\text{2}}=273\times 2\phantom{\rule{0ex}{0ex}}=546\text{K}$

Temperature in degree Celsius = 546-273

= 273

^{0}C

The correct option is (2).

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