1. Unit 9 Exam Review

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

3. 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

4. No Calculator on the following questions
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5. 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
.08 mol

6. 1.6 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 -65oC, what will the new pressure be?
1.6 atm (rigid container = constant volume; sealed = constant mole)

7. 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?
~400 torr

8. 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

9. How many moles of gas are present if a sample of butane gas is held in a sealed liter container at a temperature of 42.0 K and is under 765 torr of pressure?
~40 mol

10. 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 503 K and the pressure to be 1.50 atm, what was its original volume?
37.5 mL

11. 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?
~620 K

12. 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

13. 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)

14. 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)

15. Convert mol NaHCO3 to mol CO2
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 L CO2
67.2 L

16. Convert L O2 to L H2 using the mole ratio

17. Convert L N2O to L NH4NO3 with mole ratio
44.0
Convert L N2O to L NH4NO3 with mole ratio
because it’s at STP divide by 22.4L to convert to mol NH4NO3
Multiply by formula mass (80.052)
~160 g

18. Write a balanced equation for the combustion of methane (CH4)
Grams
Write a balanced equation for the combustion of methane (CH4)
Convert L CH4 to L H2O with mole ratio
because it’s not at STP use PV=nRT to calculate mol of H2O
Multiply by formula mass of water
9.74g H2O(g)