How many moles is 135 L of ammonia gas at STP?
Since we're at STP, we can use the ideal gas law equation.
- P represents pressure (could have units of atm, depending on the units of the universal gas constant)
- V represents volume (must have units of liters)
- n represents the number of moles
- R is the universal gas constant (has units of
- T represents the temperature, which must be in Kelvins.
Next, list your known and unknown variables:
At STP, the temperature is 273K and the pressure is 1 atm. The proportionality constant, R, is equal to 0.0821
Now we have to rearrange the equation to solve for n:
Plug in the given values: