Gases Behavior and Laws Kinetic Molecular Theory All

Gases Behavior and Laws

Kinetic Molecular Theory • All matter is composed of atoms • The molecules of a gas are very small compared to the distances between them. • These particles are in rapid, random, constant straight line motion. • There are no attractive forces(IM) between gas molecules.

Kinetic Molecular Theory • Molecules collide with one another and the sides of a container. • Energy is conserved in these collisions. • The average kinetic energy of all the molecules is proportional to the temperature.

Characteristics of Gases • • Temperature Volume Pressure Number of moles

Temperature • Measurement of kinetic energy of molecules • Units: Kelvin (K) ___0 C + 273 = ____K Absolute Zero: the coldest temperature, all motion of molecules stops(-273 o. C)

Pressure (P) • Force per unit area • Units of Pressure 1 atm = force of air pressure at sea level 760 mm. Hg 14. 7 lbs/in 2 101, 325 Pa

STP • • Standard Temperature and Pressure Temperature at 0 o C or 273 K Pressure of 1. 0 atm, the pressure at sea level. STP is used to compare gases.

Volume • Amount of space that a gas occupies • Measured in Liters(L) • 1 mole of gas at STP is 22. 4 L

Boyle’s Law • • • Relationship between pressure and volume P 1 V 1=P 2 V 2 As the pressure increases, volume decreases If temperature and moles are constant Inverse Relationship

Boyle’ law practice Click on Pictures to link to tutorial problems.

Charles’ Law • Relationship between Volume and Temperature • As Temperature increases Volume also increases • If Pressure and number of moles are constant • Direct Relationship

Charles Law Practice • Click on picture for practice problems

Ideal Gas Law • • • PV=n. RT P= pressure in atms V= volume in L N= number moles R= constant of 0. 0821 T= temperature in K

Gas Law Problems • Basic Problem • Gas law Stoichiometry Problem • Click above for link to practice problems

End of Gas laws • Check out the tutorial on the Links page of the website