**Question: **What Is The Formula For The Combined Gas Law?

The combined gas law examines the behavior of a constant amount of gas when pressure, volume and/or temperature is allowed to change.

**Answer: **The combined gas law is expressed as:

P_{i}V_{i}/T_{i} = P_{f}V_{f}/T_{f}

where P_{i} = initial pressure

V_{i} = initial volume

T_{i} = initial absolute temperature

P_{f} = final pressure

V_{f} = final volume

T_{f} = final absolute temperature

It is extremely important to remember the temperatures are absolute temperatures measured in Kelvin, **NOT** °C or °F.

It is also important to keep your units constant. Do not use pounds per square inch for pressures initially to find Pascals in the final solution.