Gas Laws Fundmentals

KINETIC MOLECULAR THEORY KINETIC MOLECULAR THEORY  KMT is a model to explain the behavior of gaseous particles and is based on extensive observations  If a gas follows all the ideas of the KMT, it is said to be an ideal gas

THE KINETIC THEORY 1.All matter is composed of very small particles 2.These particles are in constant motion 3.Collisions between particles are perfectly elastic

PRESSUREPRESSURE  Pressure is defined as force per unit area  Units: kPa, atm, mmHg, torr

VOLUME  Volume is defined as the amount of space an object occupies  Units: cm 3, mL, L

DALTON’S LAW DALTON’S LAW

Dalton’s Law  The physical properties of gases are affected by temperature and pressure  John Dalton found that each gas in a mixture exerts pressure independently of the other gases present

Dalton’s Law  The total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases P total = P 1 + P When a H 2 gas is collected by water displacement, the gas in the collection bottle is actually a mixture of H 2 and water vapor

GIVEN: P gas A = 13.7 KPa P gas B = 5.3 KPa P gas C = 4.5 KPa P total = P A + P B + P C WORK: P total = P A + P B + P C P total =  What is the total pressure in a container if gas A has a pressure of 13.7 KPa, gas B has a pressure of 5.3 KPa and gas C exerts a pressure of 4.5 KPa? Ex. Problem 1: Dalton’s Law The total pressure in the container is P total

GIVEN: P O 2 = ? P CO 2 =.7 atm P N 2 =.12 atm P total =.97 atm WORK: P total = P O 2 + P CO 2 + P N 2 Ex. Problem 2: Dalton’s Law  A mixture of O 2, CO 2, and N 2 has a total pressure of.97 atm. What is the partial pressure of O 2, if the partial pressure of CO 2 is.70 atm and the partial pressure of N 2 is.12 atm. The total pressure is given, you need to find P oxygen.

BOYLE’S LAW BOYLE’S LAW

 Irish chemist ( )  Performed the first quantitative experiments on gases  Used j-shaped tube to study the relationship between pressure of trapped gas and its volume Boyle’s Law

 Boyle’s Law states that at constant temperature the volume of a fixed amount of gas is inversely related to pressure When the volume INCREASES, pressure DECREASES When the volume DECREASES, pressure INCREASES Boyle’s Law: P 1 V 1 = P 2 V 2 Initial conditions Final conditions

GIVEN: V 1 = P 1 = V 2 = P 2 = WORK: P 1 V 1 = P 2 V 2 Ex. Problem #1: Boyle’s Law  The volume of a gas is 200 mL at a pressure of 100 KPa. What is its volume at a pressure of 200 KPa? P 1 V 1 = P 2 V 2

GIVEN: V 1 = P 1 = V 2 = P 2 = WORK: P 1 V 1 = P 2 V 2 Ex. Problem #2: Boyle’s Law  If the pressure of the gas in the 4.0 L volume is 200 KPa what will the pressure be at 2.5 L?