Ideal Gas Law Example Problem

Ideal Gas Law Example Problem The ideal gas law is  an equation of state the describes the behavior of an ideal gas and also a real gas under conditions of ordinary temperature and low pressure. This is one of the most useful gas laws to know because it can be used to find pressure, volume, number of moles, or temperature of a gas. The formula for the ideal gas law is: PV nRT P pressureV volumen number of moles of gasR   ideal or universal  gas constant   0.08 L atm / mol KT   absolute temperature  in Kelvin Sometimes, you may use another version of the ideal gas law: PV NkT where: N number of moleculesk   Boltzmann constant 1.38066 x 10-23  J/K 8.617385 x 10-5  eV/K Ideal Gas Law Example One of the easiest applications of the ideal gas law is to find the unknown value, given all the others. 6.2 liters of an ideal gas is contained at 3.0 atm and 37  °C. How many moles of this gas are present? Solution The ideal gas law states PV nRT Because the units of the gas constant are given using atmospheres, moles, and Kelvin, its important to make sure you convert values given in other temperature or pressure scales. For this problem, convert  °C temperature to K using the equation: T  °C 273 T 37  °C 273T 310 K Now, you can plug in the values. Solve ideal gas law for the number of moles n PV / RT n ( 3.0 atm x 6.2 L ) / ( 0.08 L atm /mol K x 310 K)n 0.75 mol Answer There are 0.75 mol of the ideal gas present in the system.