Part I. (8 points) Multiple-choice questions

Question 1: The balanced equation for the decomposition of sodium azide, NaN3\text{NaN}_3, is __________?
A. 2NaN3(s)2Na(s)+3N2(g)2 \text{NaN}_3 (s) \rightarrow 2 \text{Na} (s) + 3 \text{N}_2 (g)
B. 2NaN3(s)2Na2(s)+3N2(g)2 \text{NaN}_3 (s) \rightarrow 2 \text{Na}_2 (s) + 3 \text{N}_2 (g)
C. NaN3(s)Na(s)+N2(g)\text{NaN}_3 (s) \rightarrow \text{Na} (s) + \text{N}_2 (g)
D. NaN3(s)Na(s)+N2(g)+N(g)\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 CH4O\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, CH4\text{CH}_4?
A. 2.46×1022.46 \times 10^{-2}
B. 2.04×10252.04 \times 10^{-25}
C. 7.40×10227.40 \times 10^{22}
D. 0.615

Question 4: For the reaction GeH4+3GeF44GeF3H\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 GeF4\text{GeF}_4 are needed to produce 8.00 mol of GeF3H\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, Mg3N2\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?
Mg3N2(s)+3H2O(l)2NH3(g)+3MgO(s)\text{Mg}_3\text{N}_2 (s) + 3 \text{H}_2\text{O} (l) \rightarrow 2 \text{NH}_3 (g) + 3 \text{MgO} (s)

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