CHE 111 Homework #3 (Chapter 10 and 11) (30 pts total) Multiple Choice Questions ( 2 pts each) 1. What type of attractive forces are being overcome when liquid nitrogen boils at 77K ? a.) hydrogen bonding b.) dispersion forces c.) covalent bonds d.) dipole-dipole forces 2. Which of the hydrogen atoms in a formic acid molecule can form hydrogen bonds with other molecules of formic acid? a.) none of the hydrogen atoms b.) all of the hydrogen atoms c.) the hydrogen bonded to carbon d.) the hydrogen bonded to oxygen 3. Which arrow on the phase diagram corresponds to the phase transition of liquid to gas? a.) A b.) B c.) C d.) D e.) E f.) F 4. Which of the following solvents would you expect NaCl to be most soluble in? a.) water b.) acetone c.) isopropanol d.) hexane 5. Which of the following gaseous solutes has the highest solubility in water? a.) He b.) N2 c.) CH3Cl d.) O2 6. Explain the trend observed in the boiling points of alkanes. What intermolecular forees are involved? (5 pts) 7. Based on the diagram below, explain: I) Why the boiling points increase from CH4 to SnH4. 2pts) II) Why the boiling point of H2S is higher than the boiling point of SiH4. (2pts) III) Why the boiling point of H2O is much higher than the boiling poins of H2S,H2Se, and H2Te. 8. Carbon has two solid phases (graphite, diamond), one liquid phase, and one gas phave ( 5 pts). 1) Identify cach of the phases of carbon on its phase diagram below. II) Identify the triple point(s) on the phase diagram. Is there a critical point for carbon shown? III) What phase is carbon at 5000K and 10KPa ? 9. Benzene (organic solvent) has a freezing point of 5.5C,A0.450m solution of benzoic acid in this solvent has a freezing point of 3.2C. Calculate the kf of benzene ( 4pts)