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Wed, Jan 20, 2010. Avogadro’s Hypothesis and lab What to expect on the test Sample prob and review questions Homework. Review Day. Turn in Molar Volume of a Gas Lab (if you did not turn it in last week) Write down the following formulas in your Yellow Packet:
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Wed, Jan 20, 2010 • Avogadro’s Hypothesis and lab • What to expect on the test • Sample prob and review questions • Homework
Review Day • Turn in Molar Volume of a Gas Lab (if you did not turn it in last week) • Write down the following formulas in your Yellow Packet: Boyle’s Law: P1V1 = P2V2 Charles’ Law: V1 = V2 T1 T2 Gay-Lussac’s Law: P1 = P2 T1 T2 Combined Gas Law: P1V1 = P2V2 Ideal Gas Law: PV = nRT T1 T2 R = 8.31 L*kPa/mol*K
Avogadro’s Hypothesis – baggies lab • Equal volumes of gases contain an equal number of particles, but mass varies • When measuring a gas, the ratio of the masses will be equal: Actual mass of N2 molar mass of N2 Actual mass of O2 molar mass of O2 =
What to expect on the test • 10 Multiple Choice • 5 Problems / Calculations Anything covered on the review, in class, in the reading / notes is fair game on the test!
Sample Problem: In lab last week, we collected hydrogen gas through water displacement. This is shown in the following balanced equation: Mg + 2HCl → H2 + MgCl2 a. If 0.0853 g of Mg reacted, how many moles of hydrogen (H2) would be produced? Assume the hydrogen (H2) gas produced is equalized to room pressure which is 87.9 kPa and room temperature which is 25.0˚C. b. Remember that when a gas is collected over water it is mixed with water vapor. Calculate the pressure of just hydrogen (H2) if the vapor pressure of water is 2.95 kPa at 25.0˚C. c. Determine the volume of hydrogen gas that is produced.
Clicker Review • Which of the following represents an inverse relationship? • Pressure vs Temperature • Volume vs Pressure • Volume vs Temperature • Liters vs Moles • Kinetic Energy vs Temperature
Clicker Review • When a substance goes through sublimation, what phase changes are occurring? • Liquid to gas • Gas to liquid • Liquid to solid • Solid to gas • Gas to solid
Clicker Review • Which of the following is NOT true according to the Kinetic Theory? • Particle movement is random • Particle movement is rapid • Particle volume is insignificant as a gas is mostly empty space • Particles lose energy during each collision
Clicker Review • Which of the following gives the correct conditions for STP? • 273K and 760 mmHg • 100oC and 101.3 kPa • 0oC and 1.0 kPa • 0 K and 1.0 atm
Clicker Review • If the temperature of a gas changes from 50 oC to 100oC, what happens to the pressure of the gas? • The pressure decreases by half • The pressure doubles • The pressure does not change • The pressure will triple
Clicker Review • A sample of gas contains 3.00 L of oxygen gas at 53oC. What volume will the gas expand to if the temperature is increased to 252oC? • 14.3 L • 0.631 L • 4.83 L • 1.87 L
Clicker Review • A sample of carbon dioxide has a volume of 5.00L at a temperature of 25.0oC and a pressure of 95.2kPa. Calculate the volume of this gas at STP. • 4.31 L • 51.3 L • 4.70 L • 27.3 L
Clicker Review • Calculate the volume that 14.0 g of N2 gas occupies at a temperature of 22oC and a pressure of 118kPa. • 77.4 L • 21.7 L • 291 L • 10.4 L
Homework: • Moodle lab quiz – closes Mon at 11pm • Complete lab abstract for the Gas Baggies Lab • Upload to Moodle by Monday 2:30pm • Or, print it off and bring in a hard copy • Review – due Friday • Ch 10 and 12 TEST - Friday