Vocabulary:
Pressure Standard Atmospheric pressure Atmosphere
Torr Boyle’s Law Charles’ Law
Avagadro’s Law Ideal Gas equation Ideal gas
Gas Constant (R) STP Partial pressure
Mole Fraction Dalton’s law of partial pressure Kinetic Molecular theory
Effusion Graham’s law Diffusion
Van der Waals Equation
· AP Chemistry [Keep for Reference]
10 · Gases and Their Properties Study List
Measuring Pressure
£ Know the pressure of the atmosphere at sea level measured in atm, kPa, mmHg, torr, psi
£ Convert one pressure unit into another
£ Understand how to measure pressure using a U-tube manometer, open-end manometer, and a barometer
Recognizing Graphs
£ Recognize from a graph whether two variables are directly or inversely proportional.
£ Manipulate a curve graph to give a straight-line graph
Boyle’s Law
£ Sketch a P vs. V graph
£ State Boyle’s Law
£ Recognize situations of Boyle’s Law
£ Do Boyle’s Law problems
Charles’ Law
£ Sketch a V vs. T graph
£ State Charles’s Law
£ Explain why temperatures must be in K
£ Recognize situations of Charles’s Law
£ Do Charles’s Law problems
Combined Gas Law
£ Know the Combined Gas Law (P,V&T)
£ Show how each of the gas laws is a special case of the Combined Gas Law
£ Know Avogadro’s Law (V&n)
Ideal Gas Law
£ Know the Ideal Gas Law
£ Given the molar volume of a gas (22.414 L at STP) determine values of R, the ideal gas constant, with different pressure units
£ Do Ideal Gas Law problems
Twists on the Ideal Gas Law
£ Derive the gas density equation from the Ideal Gas Law
£ Do gas density problems
£ Calculate molar mass from P, V, and T data
Stoichiometry
£ Do Gas Laws and Stoichiometry problems by determining mass or moles of a substance
Dealing with Mixtures of Gases
£ Know Dalton’s Law of Partial Pressures
£ Do Partial Pressure problems
£ Apply this to gases collected over water
Explaining the Gas Laws
£ Know the principal features of the Kinetic Molecular Theory of gases
£ Be able to explain why each of the gas laws works in terms of the Kinetic Molecular Theory
Why Do All Gases Act The Same?
£ Derive Graham’s Law of Effusion from rms or KE of two gases
£ Do Graham’s Law problems
Real Gases vs. Ideal Gases
£ Compare van der Waal’s equations for Real gases with the Ideal Gas Law
£ Know the correction factors that appear in the Real Gas Law
Chemistry: Manometers
Directions: Solve the following problems. Show your work, including proper units, to ensure full credit.
1. 2. 3.
Ans. (#1) = ______Ans. (#2) = ______Ans (#3) = ______
4. 5. 6.
Ans. (#4) = ______Ans. (#5) = ______Ans (#6) = ______
7. 8. 9.
Ans. (#7) = ______Ans. (#8) = ______Ans (#9) = ______
10. 11. 12.
Ans. (#10) = ______Ans. (#11) = ______Ans (#12) = ______
13. 14. 15.
Ans. (#13) = ______Ans. (#14) = ______Ans (#15) = ______
Answers: 1. 1.24 atm 2. 253 mm Hg 3. 297 mm Hg 4. 1.06 atm 5. 808 mm Hg 6. 564 mm Hg
7. 58.6 kPa 8. 205.8 kPa 9. 1.96 atm 10. 0.92 atm 11. 109.8 kPa 12. 1045 mm Hg
13. 69.0 kPa 14. 1.00 atm 15. 515 mm Hg
Gas Law Practice:
Boyle’s Law
7. Equation for Boyle’s Law:
8. How do these two factors relate to each other?
9. A gas occupies 12.3 L at 825.7 mmHg. What will the pressure be when the volume is
75 L?
10. A gas occupies 25 L at 2.5 atm. What is the volume if the pressure changes to 1.5 atm?
11. You have 50 L of CO2 gas at standard temperature and pressure (STP). What would need to be done to the pressure to cut the volume of gas in half?
Charles’ Law
12. Equation for Charles’ Law:
13. How do these two factors relate to each other?
14. What does temperature actually measure?
15. At 27.8 °C, a gas occupies 1500 mL. What volume will it have at 100.0 °C?
16. What temperature (in K) must a gas be if it occupied 1.396 L at 72.3 °C and now occupies 1.044 L?
17. At -32.7 °C, a gas takes up 0.750 mL. What temperature, in °C, would be needed to reduce the volume to half that amount?
18. A volume of 2.15 mL of Oxygen was collected in the lab at a temperature of 17 °C and 740.2 mmHg. After a day, the volume of the gas has become 2.21 mL and the barometer reading (for air pressure) had not changed. What is the new temperature in the lab (in °C)?
19. If the temperature at which a gas is collected is doubled, what happens to the volume if pressure remains constant?
Combined Gas Law:
*When using the Combined Gas Law you must convert temperature from degrees Celsius to Kelvin.
1. At a pressure of 405 kPa and a temperature of 200 K, the volume of a gas is 6.00 cm3. At what pressure will the new temperature and volume be 300 K and 4.00 cm3?
2. At 189 K and a pressure of 600 torr, a sample of nitrogen gas has a volume of 32.0 cm3. What volume does the gas occupy at 242 K and 675 torr?
3. A volume of gas at 1.10 atm was measured at 22°C and 326 cm3. What will be the volume if the gas is cooled to -10°C and the pressure is adjusted to 1.90 atm?
4. The gas in a balloon occupies 2.25 L at 298 K and 300 kPa. At what temperature will the balloon expand to 3.50 L and 220 kPa?
5. A sample of gas has a volume of 852 mL at 25°C and 2.0 atm. What Celsius temperature is necessary for the gas to have a volume and pressure of 945 mL and 1.3 atm?
6. If 36.5 m3 of a gas are collected at a pressure and temperature of 755 mm of Hg and 280 K respectively, what volume will the gas occupy if the pressure and temperature are changed to 632 mm of Hg and 305 K?
7. O2 gas in a canister with a volume of 40 L at 25°C and 0.7 atm is compressed to a volume and pressure of 32.5 L and 1.4 atm. At this new volume and pressure what will the temperature of the gas be in degrees Celsius?
8. At a pressure of 13.6 atm, a gas occupies 62.1 cm3 at a temperature of 80°C. If the temperature is raised to 110 °C, at what volume will the pressure be 8.9 atm?
Ideal Gas Law:
9. What volume will 2.50 mol of hydrogen (H2) occupy at -20.0 °C and 1.5 atm?
10. How many moles of sulfur dioxide are held inside a 67.4 L canister at a pressure of 0.25 atm and a temperature of 40.0 °C?
11. At what temperature will a 0.450 L vessel hold 4.0 mol carbon dioxide (CO2) gas at a pressure of 1.25 atm?
12. A neon light bulb (cylinder shaped, with a volume of 0.0026 L) at 0.0 °C and 1 atm contains how
many moles of gas?
13. A balloon contains 25.0 grams helium (He) gas at room temperature (22 °C) and occupies a volume of 75.0 L. How much pressure does the He gas exert on the walls of the balloon?
14. At what temperature will 2.5 mol nitrogen gas exert a pressure of 10.0 atm in a 2.0 L container?
15. Determine the pressure exerted by 0.122 moles of oxygen gas in a 1.50 L container at room temperature (22 °C).
Graham’s Law
1. Under the same conditions of temperature and pressure, how many times faster will hydrogen effuse compared to carbon dioxide?
2. If the carbon dioxide in Problem 1 takes 32 sec to effuse, how long will the hydrogen take?
3. What is the relative rate of diffusion of NH3 compared to He? Does NH3 effuse faster or slower than He?
4. If the He in Problem 3 takes 20 sec to effuse, how long will the NH3 take?
5. An unknown gas diffuses 0.25 times as fast as He. What is the molecular mass of the unknown gas?
FRQ
2003 B
A rigid 5.00 L cylinder contains 24.5 g of N2(g) and 28.0 g of O2(g)
(a) Calculate the total pressure, in atm, of the gas mixture in the cylinder at 298 K.
(b) The temperature of the gas mixture in the cylinder is decreased to 280 K. Calculate each of the following.
(i) The mole fraction of N2(g) in the cylinder.
(ii) The partial pressure, in atm, of N2(g) in the cylinder.
(c) If the cylinder develops a pinhole-sized leak and some of the gaseous mixture escapes, would the ratio in the cylinder increase, decrease, or remain the same? Justify your answer.
A different rigid 5.00 L cylinder contains 0.176 mol of NO(g) at 298 K. A 0.176 mol sample of O2(g) is added to the cylinder, where a reaction occurs to produce NO2(g).
(d) Write the balanced equation for the reaction.
(e) Calculate the total pressure, in atm, in the cylinder at 298 K after the reaction is complete.
A student collected a sample of hydrogen gas by the displacement of water as shown by the diagram above. The relevant data are given in the following table.
GAS SAMPLE DATAVolume of sample / 90.0 mL
Temperature / 25°C
Atmospheric Pressure / 745 mm Hg
Equilibrium Vapor Pressure of H2O (25°C) / 23.8 mm Hg
(a) Calculate the number of moles of hydrogen gas collected.
(b) Calculate the number of molecules of water vapor in the sample of gas.
(c) Calculate the ratio of the average speed of the hydrogen molecules to the average speed of the water vapor molecules in the sample.
(d) Which of the two gases, H2 or H2O, deviates more from ideal behavior? Explain your answer.