**QUIZ 6 – Chapter 4 Part 2** **Total time: 10 minutes**
### Part I. (8 points) Multiple choice questions **Question 1:** Classify the following reaction: $\text{Na (s)} + \text{H}_2\text{O (l)} \rightarrow \text{NaOH (aq)} + \text{H}_2 \text{(g)}$ * **A.** Neutralization reaction * **B.** Redox reaction * **C.** Single replacement reaction * **D.** Double replacement reaction **Question 2:** Assign the oxidation numbers of the elements on the product side $\text{H}_2\text{O}_2 \text{(l)} \rightarrow \text{H}_2\text{O (l)} + \text{O}_2 \text{(g)}$ * **A.** -1, 0, 1 * **B.** +1, -1, 0 * **C.** +1, -2, 0 * **D.** +1, -1, -2 **Question 3:** When gold dissolves in aqua regia (a mixture of nitric acid and hydrochloric acid), what is reduced? $\text{Au} + 3\text{NO}_3^- + 4\text{Cl}^- + 6\text{H}^+ \rightarrow \text{AuCl}_4^- + 3\text{NO}_2 + 3\text{H}_2\text{O}$ * **A.** $\text{H}^+$ * **B.** $\text{N}^{5+}$ * **C.** $\text{Cl}^-$ * **D.** $\text{Au}$ **Question 4:** What are the respective molarities of sodium and sulfate ions afforded by dissolving 0.500 mol $\text{Na}_2\text{SO}_4$ in water and diluting to 1.33 L? * **A.** 0.542 M and 0.271 M * **B.** 1.34 M and 2.68 M * **C.** 0.752 M and 0.376 M * **D.** 0.338 M and 0.676 M ### Part II. (2 points) Long answer question **Question 5:** What is the molarity of $\text{CH}_3\text{OH}$ in a solution prepared by dissolving 11.7 g of $\text{CH}_3\text{OH}$ in sufficient water to give exactly 230 mL of solution? Give an explanation for your answer.