Part I. (8 points) Multiple-choice questions
Question 1: The balanced equation for the decomposition of sodium azide, NaN3, is __________?
A. 2NaN3(s)→2Na(s)+3N2(g)
B. 2NaN3(s)→2Na2(s)+3N2(g)
C. NaN3(s)→Na(s)+N2(g)
D. NaN3(s)→Na(s)+N2(g)+N(g)
Question 2: How many grams of hydrogen are there in 46 g of CH4O?
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?
A. 2.46×10−2
B. 2.04×10−25
C. 7.40×1022
D. 0.615
Question 4: For the reaction GeH4+3GeF4→4GeF3H, if the reaction yield is 92.6%, how many moles of GeF4 are needed to produce 8.00 mol of GeF3H?
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, 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)