1. Unit 9 Exam Review

2. Constants and Formulas
Molar Volume : 22.4 L/mol
Ideal Gas Constant: L*atm/mol *K
Combined Gas Law: P1V1 = P2V2
n1T1 n2T2
Ideal Gas Law : PV = nRT
Dalton’s Law of Partial Pressure: Ptotal = P1 + P2+…Pn

3. Which of the following does not represent the behavior of an ideal gas?
A gas where the pressure is extremely high
A gas where the particles are far apart
A gas where the temperature is extremely low
A gas where the particles bounce off of one another

4. Which of the following describes the behavior of gases (in accordance with KMT)?
A larger gas particle has more KE than a smaller gas particle at the same temp
Gas particles bounce off of one another
Gases exert force on their containers
Gases slow down motion when temperature increases

5. Which formula will you need to solve the following: A sample of air occupies 2.0 L in an engine cylinder has a given pressure. How many liters must the cylinder be compressed to make the pressure 4 times its original pressure?
P1V1 = P2V2 or Boyle’s Law

6. V1/T1 = V2/T2 or Charles’ law
Which formula will you need to solve the following: A gas is heated so that it expands to three times it’s original size. How much does it need to be heated?
V1/T1 = V2/T2 or Charles’ law

7. Which formula will you need to solve the following: Calculate the new pressure of a sample of oxygen occupying 35 mL at STP that gets released into a 1.0 L flask held at 273 K.
P1V1 = P2V2 or Boyle’s Law

8. PTotal = P1(CO2) + P2(SO2) Dalton’s Law of Partial Pressures
Which formula will you need to solve the following: A sample of carbon dioxide is trapped in a flask with sulfur dioxide. The flask is connected to a pressure sensor reading 140. kPa, and pressure of the sulfur dioxide is 60kPa. What is the pressure of the carbon dioxide?
PTotal = P1(CO2) + P2(SO2) Dalton’s Law of Partial Pressures

9. P1/T1 = P2/T2 or Gay-Lussac’s law
Which formula will you need to solve the following: How many degrees Celsius must a sample of ammonia gas in a rigid container be heated in order to double the pressure?
P1/T1 = P2/T2 or Gay-Lussac’s law

10. P1V1 = P2V2 or Combined Gas Law (n is constant) n1T1 n2T2
Which formula will you need to solve the following: If a sample of gas at 1.00 atm and 251 K gets compressed into a 50.0 mL container, causing the temperature to be 311 K and the pressure to be 1.50 atm, what was its original volume?
P1V1 = P2V2 or Combined Gas Law (n is constant)
n1T1 n2T2

11. Solve: If a sample of gas at 1
Solve: If a sample of gas at 1.00 atm and 251 K gets compressed into a 50.0 mL container, causing the temperature to be 311 K and the pressure to be 1.50 atm, what was its original volume?
60.5 mL

12. Which formula will you need to solve the following: How many moles of a gas occupy 400. mL at 760. torr and 50.0 K?
PV = nRT Ideal Gas Law

13. Solve: How many moles of a gas occupy 400. mL at 760. torr and 50.0 K?
R = L*atm/mol *K
Convert torr to atm
Convert ml to L
.0974 mol

14. 2.17 atm (rigid container = constant volume; sealed = constant mole)
Oxygen gas at 35oC in a sealed, rigid container has a pressure of 2.40 atm. If it is cooled to 5oC, what will the new pressure be?
2.17 atm (rigid container = constant volume; sealed = constant mole)

15. 2 NaHCO3(s)  1 Na2CO3(s) + 1 H2O(g) + 1 CO2 (g) If 6
2 NaHCO3(s)  1 Na2CO3(s) + 1 H2O(g) CO2 (g) If 6.00 moles of NaHCO3 react as shown above, how many liters of CO2 gas will be produced at STP?
Convert mol NaHCO3 to mol CO2
Use molar volume because it’s at STP to convert to mol CO2
67.2 L

16. No Calculator on the following questions
#ISeeYou____________
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17. The syringe volume was increased from 2. 07 mL to 6. 13 mL
The syringe volume was increased from 2.07 mL to 6.13 mL. If the original pressure was 1209 torr, what is the pressure when expanded?
~408 torr

18. If a sample of ammonia gas at STP has a volume of 12
If a sample of ammonia gas at STP has a volume of 12.1 L, what will its volume be when heated to 273.0oC at constant pressure?
24.2 L

19. If a gas in a rigid container has a pressure of 2
If a gas in a rigid container has a pressure of 2.05 atm when the temperature is 310. K, what temperature does it need to be heated to in order to reach 4.01 atm of pressure?
~606 K

20. The pressure will triple
What will happen to the pressure of a gas at a constant temperature if its volume is decreased from 3.0 L to 1.0 L ?
The pressure will triple

21. B (most mol with the highest temp)
Which of these identical cylinders is under the greatest pressure? A B C D mol mol mol mol K K K K
B (most mol with the highest temp)

22. A (most amount of moles/particles of gas)
Which of these identical cylinders is under the greatest pressure? A B C D mol mol mol mol K K K K
A (most amount of moles/particles of gas)