Consider the following five molecules, which are all liquids at room temperature.

1. Which molecule(s) can form hydrogen bonds with other molecules of the same compound?

2. Which of the following five molecules has the highest boiling point?: Pentane, Diethyl ether, 1-Butanol, 1-Propanol, 2-Butanol. Explain your reasoning.

3. Describe a method you might use to separate pentane and 1-butanol, explaining how the properties of the molecules allow you to do so.

4. Consider a cylindrical container partially filled with liquid ethanol (C₂H₆O). How do the rates of ethanol evaporation and condensation change when suddenly a piston enclosing the cylindrical container is moved down, decreasing the volume of the container? How does this system return to equilibrium?

5. Arrange the following compounds in order of increasing volatility. 1-methane, CH₄, 2-ethane, C₂H₆, 3-chloroethane, C₂H₅Cl, and 4-ethanol, C₂H₆O. Explain your reasoning.

6. For each pair of compounds listed below, select the one with a higher boiling point. Justify your selection.

H₂S or H₂Se

CH₃OH or CH₃SH

CH₃OCH₃ or CH₃CH₂OH

CS₂ or CO₂

CO₂ or NO₂

7. All molecules attract one another. Yet two liquids, hexane and water are immiscible. Explain why in terms of all pertinent intermolecular interactions.

8. We know that at 25 ^oC water has a pH = 7.0 and K_w=1 x 10^-14. Interestingly, at 100 ^oC water has a K_w= 51.3 x 10^-14. What is the pH of water at 100 ^oC and is it neutral, acidic, or basic?

9. Consider the relative acidities of the following pairs: H₂SO₄ vs. H₂SO₃; HF vs. HI; CH₂ClCOOH vs. CH₃COOH; H₂O vs. H₂O₂. For each pair, choose the compound of the higher acidity and explain your choice.