Hello, Mar,
Since the number of moles of the gas remains the same between the two conditions, we can y=use a simplified form of the gas law:
Where the subscripts are for initial (1) and final (2) conditions. The temperature must be in Kelvin. [At 0 C, we'd be dividing by 0, which the mathematicians have forbidden the chemists to do.].
Make a table and rearrange the equation to to for V2. This helps minimize calculation errors. Remember that temperature needs to be converted to Kelvin (add 273 to 40 C).
Rearrange for V2
V2 = (P1V1T2)/(P2T1)
Before you do any calculation, make a prediction. Will the volume go up or down, and by approximately how much? The pressure more than doubles, so the gas should be compressed to a lower volume by almost a factor of 3 (3.78/1.34). The temperature goes up, but it is a smaller percentage increase (315/297). So we'll look for a volume that decreases to about a third.
Plug in the numbers and solve to get V2 = 25.2 Liters. That's about what we predicted, so I'm comfortable that it is a reasonable answer. It is easy to make calculation errors, so some prediction is helpful.
I hope this helps,
Bob
