Gas State: Ideal Gas Law

Lecture 10

Standard temperature and pressure (STP):273.15K (0C or 32F)

101325 Pa (1 atm or 760 torr)

Under STP the volume of 1 mol of an ideal gas is called the standard molar volume:

22.4141 L or 22.4 L (or dm3)

One mol of gas in different conditions

Gas laws’ emphases:

Boyle’s law focuses on pressure;Charles’s law focuses on temperature;Avogadro’s law focuses on amount of gas,

and all the above listed laws connect the above mentioned effects to the gas volume. Let us combine:

PV=nRT

Universal gas constant

PV=nRT

R=PV/nT

R=(1atm x 22.4141L) /(1mol x 273.15K)=

=0.0821 (atm x L)/(mol x K)

Universal gas constant

PV=nRT

R=PV/nT

R=(101325Pa x 0.0224141m3) /(1mol x 273.15K)=

=8.314 J/(mol x K)

The ideal gas law becomes one of the individual gas lawswhen two of the four variables are kept

constant.

Typology of gas law problems:

A change in one of the four variables causes a change in another, while the two remaining variables remain constant.

One variable is unknown, but the other three are known and no change occurs.

A sample problem

on finding an unknown gas variable at fixed conditions.

A sample problem

on using gas laws to determine a balanced equation.

THE END