2009 Exam03v2 - CHE132S09Ex03 Multiple Choice Identify the...

CHE132S09Ex03
Multiple Choice
Identify the choice that best completes the statement or answers the question. There are 20 questions, each counting 5%,
plus one challenging bonus question for a bonus 5%..
1. Which one of the following statements regarding solubility, the enthalpy of solution (  H), and the entropy of
solution (  S), is not correct?
A) The solubility of a solid increases with increasing temperature when both the enthalpy of
solution and the entropy of solution are positive.
B) The solubility of gases generally decreases with increasing temperature because both the
enthalpy of solution and the entropy of solution are negative.
C) Dissolving a substance in a solvent can be either an exothermic or an endothermic process.
D) The reason NaCl is very soluble in water and AgCl is insoluble is a consequence of the
larger hydration energy for NaCl compared to AgCl..
E) Enthalpies of solution are the sum of lattice energies and hydration energies with the
appropriate + and – signs.
2. Purveyors of salts from the Dead Sea advertise that it is healthy to bath in a saturated solution of magnesium
chloride (MgCl
2
, 95.21 g/mol, K
sp
= 740). How much magnesium chloride would you have to purchase to make
up 10.0 L of bath water saturated with magnesium chloride?
3. This problem is from a NY Times article. Researchers tested a group of 28 doctors. The doctors were told that a
five-year old child suffering a potentially fatal allergic reaction to peanuts needed an emergency injection of 0.12
mg of epinephrine. The bottles of epinephrine are labeled 10.0 mL of a 1:1000 aqueous solution. What volume of
this solution would you inject if you were the doctor?

4. Like dissolves like because __________________.