Bell Work 1.Convert 15.3 atm to kPa 2.Convert 96.3 L of a gas at STP to moles. 3.What is the temperature and pressure at STP? 4.A scientist is trying to determine the pressure of a system that is made up of 4 gases. One gas has a pressure of 20 kPa. Another gas has a pressure of 5 kPa. The remaining two gases have a pressure of 2.5 kPa. What is the total pressure? 5.A system originally has a pressure of 25.2 kPa, a volume of 15.1 L and a temperature of 45.5 ˚C. What is the new volume if the pressure is decreased to 20.0 kPa and the temperature is increased to 60 ˚C? 6.How many moles are in a system that has a pressure of 2.5 atm, a volume of 33.3 L and a temperature of 75.2 ˚C?

Bell Work Get your homework out and leave it on your desk Get with your group and work on the diffusion lab. After which we will go over homework and then take a reality check. If you finish with this lab, use the time to complete the other labs that you may not have completed yet. If that is finished, work on the study guide and review for tomorrow’s test. After reality check, we will review for tomorrow’s test.

Homework Answers m/s g/mol ; slower g/mol; HI 6.64 g/mol; SO m/s

Reality Check 1)In comparing the rates of diffusion of CO 2 with that of Kr, which gas will diffuse faster? 2)To two decimal places, what will v A /v B (treat this as x) be equal to if CO 2 is considered to be A and Kr is considered to be B. 3)What is the molar mass of a gas if it diffuses at a rate of 647 m/s while chlorine (Cl 2 ) gas diffuses at 840 m/s at the same temperature? After you are finished, continue working on the lab.

Make Up Reality Check 1)In comparing the rates of diffusion of NO with that of F 2, which gas will diffuse faster? 2)To two decimal places, what will v A /v B (treat this as x) be equal to if NO is considered to be A and F 2 is considered to be B. 3)What is the molar mass of a gas if it diffuses at a rate of 925 m/s while bromine (Br 2 ) gas diffuses at 620 m/s at the same temperature?

Unit 9 Review Gases

The Game Board

1 Calculate the approximate volume of a 2.50 mol sample of gas at -8.0°C and a pressure of 3.50 atm L

2 In the reaction N 2 (g) + 3H 2 --> 2NH 3 (g), the volume ratio of H 2 to N 2 is___________ 3 to 1

3 A pressure of 165 kPa is equal to _____ atm. 1.63

4 What does the constant bombardment of gas molecules against the inside of a container cause? Pressure

5 What happens to the volume of a gas during compression? The Volume Decreases

6 A sample of a gas has a pressure of 2.25 atm, a volume of 650 mL and a temperature of 36°C. What would the volume of the gas be if the pressure is increased to 3.20 atm and the temperature is decreased to 31°C? mL

7 What temperature is needed to pressurize a 27.3 L container with 6.34 moles of air to kPa? K

8 When pressure, volume, and temperature are known, the ideal gas law can be used to calculate ______________. Molar amount (moles)

9 According to the diagram to the right, what PV/nRT value do ideal gases have all the time? 1.0

10 What is the SI unit of pressure? Pascal

11 If a gas with an odor is released in a room, it quickly can be detected across the room because it ______________. Diffuses

12 A pressure of Pa is equal to _____ psi. 51.5

13 The principle that under similar pressures and temperatures, equal volumes of gases contain the same number of molecules is attributed to ________________. Avogadro

14 Nitrogen reacts with hydrogen to make ammonia [N 2 (g) + 3H 2 (g) --> 2NH 3 (g)]. If one needs to produce 4 L of ammonia, how many liters of nitrogen are needed? 2 L

15 A sample of a gas occupies a volume of 1.1 L at 33°C. What temperature is needed to increase the volume of the gas to 1.9 L, if the pressure remains constant? K or 255°C

16 A 10.5 L sample of a gas has a mass of 95.9 g at 7.6 atm and 35°C. What is the molar mass of the gas? (Hint: divide the given mass by n) g/mol

17 According to the diagram to the right, at what pressure do all the gases most resemble an ideal gas? 0 atm

18 A pressure of 560 mmHg is equal to _____ kPa. 74.7

19 Who is accredited with the idea that in a reaction, two volumes of hydrogen gas will combine with one volume of oxygen gas to produce two volumes of water vapor? Gay-Lussac

20 The pressure of each gas in a mixture is called the ____________________ pressure. Partial

21 A sample of a gas has a pressure of 567 mmHg at 23°C. What would the gas pressure be at 41°C, if the volume remains constant? 601 mmHg

22 To two decimal places, what will v A /v B be equal to if N 2 is considered to be gas A and NO is considered to be gas B. (A diffusion problem) 1.03

23 Standard temperature and pressure for a gas is ____________________ 0°C and 1 atm.

24 The total pressure of a system of four gases is 35 atm. The first gas has a pressure of 5 atm. The second gas has a pressure of 8 atm. The remaining two pressures are the same. What is the partial pressure of the other two gases? 11

25 Charles’s law is the direct relationship between ____________________ and volume. Temperature

26 What is the molar mass of a gas if it diffuses at a rate of 258 m/s while Iodine gas diffuses at 125 m/s at the same temperature? 29.7 g

27 2H 2 O(l) + electricity  2H 2 (g) + O 2 (g) What mass of H 2 O is needed to create L of O 2, if the temperature is 25°C and the pressure is 1.2 atm? 27.6 g

28 The average kinetic energy of random motion is proportional to the temperature in what unit? Kelvin

29 A sample of oxygen occupies 350 mL when the pressure is 5 atm. At constant temperature, what volume does the gas occupy when pressure falls to 3 atm? 583 mL

30 Who developed the concept that the total pressure of a mixture of gases is the sum of their partial pressures? Dalton

31 What is the theory that explains that the behavior of physical systems depends on the combined actions of the molecules constituting the system? Kinetic Molecular Theory

32 A mixture of gases with a pressure of mm Hg contains 60% nitrogen and 40% oxygen by volume. What is the partial pressure of oxygen in this mixture? 320 mm Hg

33 Line D represents water. If the atmospheric pressure in a flask is lowered to 70 kPa, water would boil at what temperature? 92  C

34 T 1 = 76  C P 1 = 4 atmV 1 = 560 mL T 2 = 92  C P 2 = 2 atmV 2 = ? 1171 mL

35 The rate of diffusion of a gas depends on the ____________ of the gas. Molar Mass