first section of notes given for ch 13

1. I. Describing Properties of Gases

2. I. Describing Properties of Gases (don’t copy) Objectives: know the relationship between pressure and volume of a gas. know the relationship between temperature and volume of a gas. know the relationship between pressure and temperature of a gas. know the relationship between moles of a gas and volume.

3. I. Describing Properties of Gases Four properties are needed to completely describe the state or condition of a sample of a gas: pressure temperature volume moles When any one property of a sample of a gas is changed, other properties change in a predictable way.

4. I. Describing Properties of Gases Pressure All gases exert pressure on their surroundings. pressure – force per unit area Pressure is commonly measured in units of atmospheres (atm), millimeters of mercury (mmHg), and Pascals (Pa). Conversion Factors 1 atm = 760 mmHg 1 atm = 760 torr 1 torr = 1 mmHg 1 atm = 101325 Pa 1 atm = 14.69 psi

5. I. Describing Properties of Gases Boyle’s Law P1V1 = P2V2 Interpretation describes relationship between pressure and volume pressure and volume are inversely proportional as one increases the other decreases

6. I. Describing Properties of Gases Charles’s Law V1 = V2 T1 T2 Interpretation describes relationship between volume and temperature temperature and volume are directly proportional as one increases the other increases

7. I. Describing Properties of Gases Gay-Lussac’s Law P1 = P2 T1 T2 Interpretation describes relationship between pressure and temperature pressure and temperature are directly proportional as one increases the other increases

8. I. Describing Properties of Gases Avogadro’s Law V1 = V2 n1 n2 n – is the symbol for amount of gas in units of moles Interpretation describes relationship between moles of gas and volume moles and volume are directly proportional as one increases the other increases