Ideal Gas Law Formula
The Ideal Gas Law was created to show the relationship between pressure, volume, number of moles of gas and temperature. It is a combination of Boyle's Law and Charles' Law. It shows the equation of a hypothetical ideal gas. Pressure and volume have an inverse relationship with each other (when 1 goes up the other goes down) but have a direct relationship with Temperature (when they go up, temperature goes up)
The equation for the Ideal Gas Law is:
PV = nRT
P = Pressure (atm)
V = Volume (Liters – L)
n = Number of moles (mol)
R = The Ideal Gas Constant (0.08206 L-atm/mol-K)
T = Temperature (Kelvin)
Ideal Gas Law Formula Questions:
1.) How many moles of gas are contained in 890.0mL at 21 °C and 750mm Hg?
Answer: The Volume is V = 890.0mL and the Temperature is T = 21°C and the Pressure is P = 750mmHg.
To use the Ideal Gas Law Equation, you must covert Volume to Liters, Temperature to Kelvin and Pressure to Atmosphere.
V = 890mL/1000 = 0.89L
T = 21°C + 273 = 294K
P = 750mmHg/760 = 0.987atm
Plug into the Idea Gas Law Equation
PV = nRT
0.987atm(0.890L) = n(0.08206L-atm/mol-K)(294K)
n = 0.037moles
There are 0.037moles of gas contained.
2.) Calculate the volume 3.00 moles of a gas will occupy at 24°Celsius and 762.4 mm Hg.
Answer: The number of moles is n = 3.00moles, temperature is T = 24°C and pressure is P = 762.4 mmHg
To use the Ideal Gas Law Equation, you must convert Temperature to Kelvin and Pressure to Atmospheres.
T = 24 + 273 = 297K
P = 762.4/760 = 1.003atm
Plug into the Ideal Gas Law Equation
PV = nRT
1.003atm(V) = 3.00moles(0.08206L-atm/mol-K)(297K)
V = 72.897L
The volume of the gas would be 72.897 Liters