A sample of nitrogen dioxide has a volume of 28.6 L at 45.3°C and 89.9 kPa. What is its volume at STP?
We can solve this problem using the combined gas law:
Standard temperature and pressure conditions are
Remember that the temperatures must be in Kelvin, so we must convert the Celsius temperatures:
Since we're trying to find the volume at stp, let's rearrange this equation to solve for
Plugging in known values, we have
The volume of the nitrogen as sample at stp is thus