3 Example Problem #1A. When 400mL of hydrogen at 25oC are heated to 290oC, what will its volume reach?B. A sample of gas at 40mL is heated to 40oC and increases to 750mL. What is the initial temperature of the gas?
4 Boyle’s Law P: Pressure, mmHg, torr, atm, Pa, kPa V: volume, cm3, mL, dm3, L
5 Example #2A. A 1200mL sample of oxygen at 700mmHg is expanded to 5.9L. What is the pressure at the larger volume?B. A 25mL sample of ammonia gas at 400torr is placed under a pressure of 5590torr. What is the new volume?
6 Gay-Lusaac’s Law P: Pressure, atm, Pa, kPa, mmHg, torr T: Temperature, in Kelvin
7 Example #3A. A sample of gas at 450torr at 30oC is heated to 75oC. What pressure will it reach?B. A sample of nitrogen at 50oC and 2.2atm is cooled until the pressure reaches 0.8atm. What temperature did the gas reach?
8 Combined Gas LawAll the letters are the same as before.
9 Example #4A. A sample of gas at 20oC and 800torr has a volume of 475mL. What is its volume at 75oC and 890torr?B. A sample of gas at 35oC and 90mmHg has a volume of 97mL. At what temperature will it reach 300mmHg with a volume of 40mL?
10 Ideal Gas Law P: pressure in atm V: volume in L n: moles R: (gas law constant)T: temperature in K1 atm = 760 torr = 760 mmHg=101.4kPa
11 STPSTP stands for standard temperature and pressure. If a problem says a gas is at STP it is actually giving you two pieces of information:P = 1atm = 760torr = 760mmHg=101.4kPaT = 273K
12 Example #5A. What volume will 50g of chlorine occupy at 30oC and 850torr?B. What pressure will 27g of carbon dioxide exert at 45oC in a 1200mL container?C. What mass of oxygen will occupy 30mL at STP?D. What temperature will 3g of hydrogen exerts 40kPa of pressure in a 90mL container?
14 Dalton’s Law PT = P1 + P2 + P3… PT: total pressure P1, P2, P3: partial pressures of each gas present.
15 Example #6A. The total pressure in a flask is 5atm. If the flask contains 3 gases and the partial pressure of oxygen is 0.85atm, and nitrogen is 1.3atm, what is the partial pressure of the third gas in the flask?