CLAS Chem 1C Chapter 16 (part 1)

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drop-in M 3-4, T/R 4-5 , and F 1-3

1. Indicate the types of forces present for each of the following substances:

a. CCl4d. F2g. H2Sj. H2CO

b. HF e. CH3OHh. KOH

c. NH4Brf. Ari. BH3

2. Using intermolecular forces predict the following:

a. highest melting pointF2 or Br2

b. highest melting pointHF or HCl

c. highest boiling pointHOCH2CH2OH or CH3CH2OH

d. highest boiling pointCH3CH3 or CH3CH2CH3

e. highest vapor pressureCH3CH2OH or CH3OCH3

f. highest vapor pressureCF4 or CH2Cl2

g. highest freezing point MgO or H2O

h. highest surface tension

or

3. Consider the following phase diagrams for water and carbon dioxide respectively which phase is the densest for each substance?

4. Pure compound Z has a triple point at 18 C and 72 torr, a normal melting point at 21 C, and a normal boiling point at 87 C. Which of the following statements regarding compound Z is/are correct?

a. The density of the solid is greater than that of the liquid.

b. Sublimation occurs if starting with a solid at a constant temperature of 17 C while the pressure is decreased until a phase change occurs.

c. Condensation occurs if the temperature is decreased from 55 C to 13 C at a constant pressure of 1.00 atm.

5. The enthalpy of vaporization for water is 44 kJ/mol. What is the boiling point if the atmospheric pressure were 0.33 atm?

ln =

6. Calculate the heat to take 10 g of water vapor from 155 C to ice at -31 C if the pressure is held constant at 1 atm? (Csolid = 2.03 J/gC , Cliquid = 4.18 J/gC , Cgas = 2.02 J/gC, Hfus = 6.01 kJ/mol, and Hvap = 40.7 kJ/mol)

7. Determine the final temperature if a 25 g cube of ice at -7 C is placed in 180 g of water at 64 C and allowed to come to equilibrium. (Csolid = 2.03 J/gC , Cliquid = 4.18 J/gC , Cgas = 2.02 J/gC, Hfus = 6.01 kJ/mol, and Hvap = 40.7 kJ/mol)

8. A 1.9 g sample of water is put into a 4.8 L flask at 50 C. What mass of the water will remain liquid? Assume the temperature stays constant. (Hvap = 40.7 kJ/mol)