1. COMBINED GAS LAW AND AVOGADRO’S PRINCIPLE

2. COMBINED GAS LAW P1V1P2V2T1T2P1V1P2V2T1T2 =

3. EXAMPLE 1 A gas at 110 kPa and 30.0 ˚ C fills a flexible container with an initial volume of 2.00L. If the temperature is raised to 80.0 ˚ C and the pressure increased to 440 kPa, what is the new volume? Given: P 1 = 110 kPaP 2 = 440 kPa T 1 = 30.0 ˚ C =303KT 2 = 80.0 ˚ C = 353K V 1 = 2.00LV 2 = ? 110 (2.00)440 (V 2 ) 303353 110 (2.00)440 (V 2 ) 303353 = V 2 = 0.583L ≈ 0.58L

4. EXAMPLE 2 An unopened bottle of soda contains 46.0 mL of gas confined at a pressure of 1.30 atm and temperature of 5.00 ˚ C. If the bottle is dropped into a lake and sinks to a depth at which the pressure and temperature changes to 1.52 atm and 2.90 ˚ C, what will be the volume of gas in the bottle? Given: V 1 = 46.0 mLV 2 = ? P 1 = 1.30 atmP 2 = 1.52 atm T 1 = 5.00 ˚ C = 278KT 2 = 2.90 ˚ C = 275.9K 1.30 (46.0)1.52 (V 2 ) 278275.9 1.30 (46.0)1.52 (V 2 ) 278275.9 = V 2 = 39.0mL

5. AVOGADRO’S PRINCIPLE States that equal volumes of gases at the same temperature and pressure contain equal number of particles. The molar volume for a gas is the volume that one mole occupies at 0 ˚ C and 1 atm or STP. This is equal to 22.4L STP (Standard Temperature and Pressure) = 1atm and 0 ˚ C or 1atm and 273K 1 mol of gas at STP = 22.4L

6. EXAMPLE 1 Calculate the volume that 0.881 mol of gas at standard temperature and pressure (STP) will occupy. 0.881 mol22.4 L 1 mol = 19.7 L

7. EXAMPLE 2 How many moles of oxygen gas will be contained in a 5.00L flask at STP? 5.00L O 2 1 mol O 2 22.4 L O 2 = 0.223 mol O 2

8. EXAMPLE 3 Calculate the volume that 200.0 g of methane gas will occupy at STP. 200.0 g CH 4 1 mol CH 4 22.4 L CH 4 16.05 g CH 4 1 mol CH 4 = 279.1 L CH 4

9. EXAMPLE 4 How many grams of carbon dioxide gas are in a 0.75 L balloon at STP? 0.75 L CO 2 1 mol CO 2 44.01 g CO 2 22.4 L CO 2 1 mol CO 2 = 1.5 g CO 2