Question

A sample of hydrogen has a volume of 1107 mL when the temperature is 101.9 degC and the pressure is 0.867 atm. What will be the volume of the gas at STP?

Answer 1

`(P_1V_1)/T_1=(P_2V_2)/T_2`

Explanation:

So what is `"STP"`? Standards differ across curricula. I use the IUPAC standard of `273.15*K`, and `0.98692*atm`. (The pressure is this absurd value because this represents `100*kPa`. Chemists usually prefer to work in `"atmospheres"`, as this may be directly measured in a laboratory with a mercury column.)

For the calculation, `V_2` `=` `(P_1*V_1*T_2)/(T_1*P_2)`

`=` `(0.867*atmxx1107*mLxx273.15*K)/(375.1*Kxx0.987*atm)`

`=` `??mL`

Clearly, the expression gives an answer in `mL`, as is required for a volume.