Hello!
For this problem, we will be applying Charles' Law:
V1/T1 = V2/T2
Now that we have the formula, let's convert the temperature to Kelvin.
27 + 273 = 300K
Let's plug everything in now!
10/300 = 12.0/x
Simplified:
1/30 = 12.0/x
Cross-multiply:
1x = 30*12.0
x = 360
Check!
10/300 = 12/360
300*12 = 360*10
3600 = 3600
Therefore, you would have to heat the gas at a temperature of 360K in order to raise the volume to 12.0L.