You have a balloon containing 3 l of air at stp in a vacuum chamber. what will the volume of the balloon be when you reduce the pressure to 50 kpa and increase the temperature to 450 k? a) 7.00 l b) 9.89 l c) 0.68 l d) 5.46 l

We can use the combined gas law equation to find volume of gas 

P - pressure 
V - volume 
T - temperature
parameters at STP conditions are on the left side and parameters for the second instance are on the right side of the equation 
standard temperature is 273 K and standard pressure is 10⁵ Pa
substituting the values in the equation 

V = 9.89 L 
new volume is 9.89 L
answer is B) 9.89 L

It conforms what ever surface its in.

The answer is 1.82 j/g°c