1. Tuesday, March 29th Take out your Intermolecular forces practice
Today: phase changes (multiple choice and then practice)

2. A 29. 0 g sample of acetone is heated from a solid at −94. 8°C to −50
A 29.0 g sample of acetone is heated from a solid at −94.8°C to −50.0°C. How much energy is required for this change?
2.80 kJ
5.64 kJ
6.18 kJ
2.96 kJ
7.84 kJ
Melting point
−94.8°C
ΔHfus
5.69 kJ/mol c
2.15 J/g·K
Molar mass
58.01 g/mol
Answer: b

3. A 29. 0 g sample of acetone is heated from a solid at −94. 8˚C to −50
A 29.0 g sample of acetone is heated from a solid at −94.8˚C to −50.0˚C. How much energy is required for this change?
2.80 kJ
5.64 kJ
6.18 kJ
2.96 kJ
7.84 kJ
Melting point
−94.8°C
ΔHfus
5.69 kJ/mol c
2.15 J/g·K
Molar mass
58.01 g/mol
Answer: b

4. How much energy is required to vaporize 32
How much energy is required to vaporize g of ethanol at its boiling point, if its Hvap is 40.7 kJ/mol?
28.9 kJ
3.83 kJ
6.30 kJ
17.6 kJ
7.60 kJ
Answer: a

5. How much energy is required to vaporize 32
How much energy is required to vaporize g of ethanol at its boiling point, if its Hvap is 40.7 kJ/mol?
28.9 kJ
3.83 kJ
6.30 kJ
17.6 kJ
7.60 kJ
Answer: a

6. More than one phase is present.
A sample is at the temperature and pressure indicated by point a on the phase diagram below. What phase is present after the temperature is increased to the critical temperature at constant pressure?
gas
liquid
solid
More than one phase is present.
Answer: a

7. More than one phase is present.
A sample is at the temperature and pressure indicated by point a on the phase diagram below. What phase is present after the temperature is increased to the critical temperature at constant pressure?
gas
liquid
solid
More than one phase is present.
Answer: a

8. What phases are present at point f on the given phase diagram?
gas and liquid
gas and solid
liquid and solid
gas, liquid, and solid
Answer: c

9. What phases are present at point f on the given phase diagram?
gas and liquid
gas and solid
liquid and solid
gas, liquid, and solid
Answer: c

10. Homework Phase Change Practice Read 12.1-12.4 (~15 pages)
Ch 7 and 8 retake deadlines are both this Friday
Ch 9-10 retake deadline is Thursday, April 14th
Your spring break homework will be to
read ch 13 (~40 pages)
do online homework (not set up yet)
Take an AP practice exam