**Part I. (8 points) Multiple-choice questions**

**Question 1:** The balanced equation for the decomposition of sodium azide, $\text{NaN}_3$, is \_\_\_\_\_\_\_\_\_\_?  
A. $2 \text{NaN}_3 (s) \rightarrow 2 \text{Na} (s) + 3 \text{N}_2 (g)$  
B. $2 \text{NaN}_3 (s) \rightarrow 2 \text{Na}_2 (s) + 3 \text{N}_2 (g)$  
C. $\text{NaN}_3 (s) \rightarrow \text{Na} (s) + \text{N}_2 (g)$  
D. $\text{NaN}_3 (s) \rightarrow \text{Na} (s) + \text{N}_2 (g) + \text{N} (g)$  

**Question 2:** How many grams of hydrogen are there in 46 g of $\text{CH}_4\text{O}$?  
A. 0.36  
B. 1.5  
C. 2.8  
D. 5.8  

**Question 3:** How many molecules of methane are there in 0.123 mol of methane, $\text{CH}_4$?  
A. $2.46 \times 10^{-2}$  
B. $2.04 \times 10^{-25}$  
C. $7.40 \times 10^{22}$  
D. 0.615  

**Question 4:** For the reaction $\text{GeH}_4 + 3 \text{GeF}_4 \rightarrow 4 \text{GeF}_3\text{H}$, if the reaction yield is 92.6%, how many moles of $\text{GeF}_4$ are needed to produce 8.00 mol of $\text{GeF}_3\text{H}$?  
A. 3.24  
B. 5.56  
C. 6.48  
D. 2.78  

**Part II. (2 points) Long answer question**

**Question 5:** A 3.82-g sample of magnesium nitride, $\text{Mg}_3\text{N}_2$, is reacted with 7.73 g of water. The yield of MgO is 3.60 g. What is the percent yield in the reaction?  
$$\text{Mg}_3\text{N}_2 (s) + 3 \text{H}_2\text{O} (l) \rightarrow 2 \text{NH}_3 (g) + 3 \text{MgO} (s)$$