1. Lecture Presentation
Unit 7: Gas Laws
Day 3

2. Warm Up
TAKE OUT: All Assignments due today (Partial Pressures and Book Problems)
BE READY TO SHOW ME: To save time, I will stamp the sheet
TIME: 16 MINUTES
WHEN DONE: Sketch apparatus of demonstration

3. Agenda
Demo: 55 gallon drum
Kahoot
Answer Questions

4. Demo: 55 gallon drum
SKETCH: Apparatus CONVERT: 55 gallons to liters (3.79 liter=1 gallon) TIME: 3 MINUTES WHEN DONE: Discuss with your table partner what you think will happen and why

5. Demo: 55 gallon drum
How many liters of gas before drum places in the ice? What is the temperature of the gas before placed in ice? (boiling water) How many moles of gas? Assuming that the volume of the 55 gallon drum was cut in half at the end of the demo, what was the pressure inside?

6. Which of these is not a unit used to measure gas pressure?
atmosphere
Torr
Pascal
d. pound
Answer: d

7. Avogadro’s Boyle’s Charles’s d. Gay-Lussac’s
As a helium-filled balloon rises, its volume increases. This is an example of _______ Law.
Avogadro’s
Boyle’s
Charles’s
d. Gay-Lussac’s
Answer: b

8. Avogadro’s Boyle’s Charles’s d. Gay-Lussac’s
A balloon filled with hot air rises. This is an example of _______ Law.
Avogadro’s
Boyle’s
Charles’s
d. Gay-Lussac’s
Answer: c

9. number of moles mass pressure d. temperature
Avogadro’s Law states that the volume of a sample of a gas is proportional to the _______ of the gas.
number of moles
mass
pressure
d. temperature
Answer: a

10. Standard temperature and pressure (STP) equals (X) atmosphere(s) and (Y) degrees Celsius.
X = 0, Y = 25
X = 1, Y = 0
X = 1, Y = 25
d. X = 0, Y = 0
Answer: b

11. A sample of 2.0 moles of nitrogen (N2) gas at STP occupies a volume of _______ liters.
11.2
22.4
44.8
d. 89.6
Answer: c

12. A sample of 4.0 grams of methane (CH4) gas at STP occupies a volume of _______ liters.
5.6
11.2
22.4
d. 44.8
Answer: a

13. A gas sample with a mass of 88. 0 mg occupies 50
A gas sample with a mass of 88.0 mg occupies 50.0 mL at 750 Torr and 27 degrees Celsius. The gas is _______. CO
CO2
SO2
d. SF6
Answer: b
88.0 mg = g
50 mL = 0.05 L
750 torr =0.98 atm
27 C = 300 K
n=(.98*.05)/( *300)

14. Combining the ideal-gas equation with the density formula demonstrates that as the molar mass of a gas ___, the density of the gas ___.
increases; increases
decreases; increases
increases; decreases
changes; changes in an unpredictable way.
Answer: a

15. The partial pressure of each gas in a mixture of gases is proportional to the _______ of the gas.
mass
molecular weight
square root of the molecular weight
d. mole fraction
Answer: d

16. Kelvin temperature Celsius temperature number of moles d. pressure
The kinetic-molecular theory of gases states that the average kinetic energy of the gas particles is proportional to the _______ of the gas.
Kelvin temperature
Celsius temperature
number of moles
d. pressure
Answer: a

17. Neon gas undergoes effusion _______ krypton gas does.
slower than
at the same rate as
twice as fast as
d. four times as fast as
Answer: c

18. A gas is most likely to exhibit ideal behavior at (X) temperature and (Y) pressure.
X = low, Y = low
X = low, Y = high
X = high, Y = low
d. X = high, Y = high
Answer: c

19. According to its van der Waals constants, which gas below best approximates ideal behavior?Ne Ar Kr
d. Xe
Answer: a

20. Which gas below has the smallest density at STP?Ar Kr Ne
d. Xe
Answer: c