Regents
Name:________________________
Chemistry
Key
Date:_________________
Mr. Grodski III
Gargoil Goblin Vapor Pressure
Given the following graph answer the following questions
1. Which liquid has the highest vapor pressure?
A
2. Which liquid has the lowest boiling point?
A
3. Which liquid has the weakest intermolecular attractions?
A
4. Which liquid has the lowest vapor pressure?
B
5. Which liquid has the highest boiling point?
B
6. Which liquid has the strongest intermolecular attractions?
B
7. Which liquid is the most volatile?
A
8. Which liquid has the highest heat of vaporization? Remember that Hv is the heat
required to be absorbed to change a liquid to gas….
B
9. Evaporation is endothermic or exothermic?
Endothermic
10. What is the normal boiling point of liquid A?
about 74 degrees C
11. What is the vapor pressure of any liquid at its normal boiling point?
760 torr or 101.3 kPa or 1 atm
12. Sublimation is the phase change from the solid phase directly to the gas phase. What
can you say about a solids intermolecular attractions and vapor pressure if it
sublimes?
High vapor pressure and weak intermolecular attractions
13. How are vapor pressures, boiling points, and intermolecular attractions interrelated?
HIgh vapor pressure = Low boiling point = weak intermolecular forces
Regents
Name:________________________
Chemistry
Date:_________________
Mr. Grodski III
Goblin Gas Pressure
1. Define the following terms:
a. vapor pressure –
The force due to the collisions of a gas that results from evaporation.
The pressure above a liquid that results from evaporation.
b.
"rate of evaporation"
boiling point – The temperature when atmopheric pressure equals vapor pressure
"The maximum rate of evaporation"
c. normal boiling point- Temperature
of boiling at Standard Pressure
2. How are vapor pressure and temperature related?
Directly
3. How are atmospheric pressure and boiling points related?
Directly
4. Why does the vapor pressure of a liquid increase as the temperature increases?
More liquid molecules have enough kinetic energy to overcome the intermolecular forces of each other
Table H
5. If the atmospheric pressure is 30 kPa, what temperature will the water boil at?
70 degrees C
9. If the atmospheric pressure is 200 kPa, what temperature will the water boil at?
116 degrees C
10. If water boils at 70°C, what must be the atmospheric pressure?
30 kPa
11. What is the vapor pressure of ethanol at its normal boiling point?
101.3 kPa
12. What is the vapor pressure of cyclohexane at its normal boiling point?
101.3 kPa
13. If gas is collected over water and the barometric pressure on this day is 770 mm Hg,
what is the partial pressure of the oxygen gas if the gas collected is a 50% mixture of
O2(g) and N2(g).
for another day.....