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

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

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

How much energy is required to vaporize 32 How much energy is required to vaporize 32.9 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

How much energy is required to vaporize 32 How much energy is required to vaporize 32.9 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

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

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

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

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

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