Problem 4
The concept of chemical equilibrium is very important. Which one of the following statements is the most correct way to think about equilibrium? (a) If a system is at equilibrium, nothing is happening. (b) If a system is at equilibrium, the rate of the forward reaction is equal to the rate of the back reaction. (c) If a system is at equilibrium, the product concentration is changing over time. [Section 4.1]
Problem 5
You are presented with a white solid and told that due to careless labeling it is not clear if the substance is barium chloride, lead chloride, or zinc chloride. When you transfer the solid to a beaker and add water, the solid dissolves to give a clear solution. Next an \(\mathrm{Na}_{2} \mathrm{SO}_{4}(a q)\) solution is added and a white precipitate forms. What is the identity of the unknown white solid?
Problem 6
Which of the following ions will always be a spectator ion in a precipitation reaction? (a) \(\mathrm{Cl}^{-}\), (b) \(\mathrm{NO}_{3}^{-}\) (c) \(\mathrm{NH}_{4}^{+}\), (d) \(\mathrm{S}^{2-}\), (e) \(\mathrm{SO}_{4}^{2-}\).
Problem 7
The labels have fallen off three bottles containing powdered samples of metals; one contains zinc, one lead, and the other platinum. You have three solutions at your disposal: \(1 \mathrm{M}\) sodium nitrate, \(1 M\) nitric acid, and \(1 M\) nickel nitrate. How could you use these solutions to determine the identities of each metal powder?
Problem 8
Explain how a redox reaction involves electrons in the same way that a neutralization reaction involves protons.
Problem 9
What kind of reaction is the "water-splitting" reaction? \(\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{H}_{2}(g)+1 / 2 \mathrm{O}_{2}(g)\) (a) an acid-base reaction (b) a metathesis reaction (c) a redox reaction (d) a precipitation reaction
Problem 10
An aqueous solution contains \(1.2 \mathrm{~m} M\) of total ions. (a) If the solution is \(\mathrm{NaCl}(a q),\) what is the concentration of chloride ion? \((\mathbf{b})\) If the solution is \(\mathrm{FeCl}_{3}(a q),\) what is the concentration of chloride ion?
Problem 12
You are titrating an acidic solution with a basic one, and just realized you forgot to add the indicator that tells you when the equivalence point is reached. In this titration, the indicator turns blue at the equivalence point from an initially colorless solution. You quickly grab a bottle of indicator and add some to your titration beaker, and the whole solution turns dark blue. What do you do now?
Problem 13
State whether each of the following statements is true or false. Justify your answer in each case. (a) Electrolyte solutions conduct electricity because electrons are moving through the solution. (b) If you add a nonelectrolyte to an aqueous solution that already contains an electrolyte, the electrical conductivity will not change.
Problem 14
State whether each of the following statements is true or false. Justify your answer in each case. (a) When acetone, \(\mathrm{CH}_{3} \mathrm{COCH}_{3},\) is dissolved in water, a conducting solution results. (b) When ammonium nitrate, \(\mathrm{NH}_{4} \mathrm{NO}_{3},\) dissolves in water, the solution is weakly conducting and basic in nature.
