If a balloon containing 1.200 L of gas at 25°C and 760 mmHg pressure ascends to an altitude where the pressure is 380 and the temperature is 54°C, what will the volume be?

1 Answer
Jan 12, 2017

We use the old relationship: #(P_1V_1)/T_1=(P_2V_2)/T_2#

Explanation:

Of course, we must use values of #"absolute temperature"#. Given the proportionality we could units of pressure and volume of #"foot pounds"# or #"atmospheres"# or #"gallons"# so long as we are consistent. Of course, I will use units of #"litres"#, and #"atmospheres"#.

#V_2=(P_1V_1)/T_1xxT_2/P_2=#

#(1.200*Lxx1*atm)/(293*K)xx(327*K)/((380*mm*Hg)/(760*mm*Hg*atm^-1))~=2.7*L#

But don't trust my arithmetic. You have to do this on paper, and make sure all the given units cancel out to give an answer in #"litres"# as required for a volume. Note that since we decrease the pressure, and INCREASE the temperature, the rise in volume is consistent with our expectation.