1) When concentrated sulfuric acid is added to dry sucrose, C₁₂H₂₂O₁₁1, a black residue of pure carbon is produced. An equation for the reaction is
2C₁₂H₂₂O₁₁(s) + 2H₂SO₄(aq) + O₂(g) => 22C(s) + 2CO₂(g) + 24H₂O(g) + 2SO₂(g)

M(C₁₂H₂₂O₁₁) = 342.0 g mol–1
The mass of carbon residue that could be produced by the reaction of 50.0 g of sucrose with excess concentrated
sulfuric acid is
A. 0.159 g
B. 0.877 g
C. 19.3 g
D. 38.6 g

Solution

2) In an experiment, 0.051 mol of sodium hydroxide, NaOH, reacted completely with 0.017 mol of citric acid, C₆H₈O₇. Which one of the following equations correctly represents the reaction between citric acid and the sodium hydroxide
solution?

Solution

3) The emergency oxygen system in a passenger aircraft uses the decomposition of sodium chlorate to produce oxygen. At 76.0 kPa and 292 K, each adult passenger needs about 1.60 L of oxygen per minute. The equation for the reaction is

2NaClO₃(s) => 2NaCl(s) + 3O₂(g)

M(NaClO₃) =106.5 g mol–1

The mass of sodium chlorate required to provide the required volume of oxygen for each adult passenger per minute is:
A. 3.56 g
B. 5.34 g
C. 7.85 g
D. 53.7 g

Solution

4) In which one of the following compounds is sulfur in its lowest oxidation state?
A. SO₃
B. HSO4^-
C. SO₂
D. Al₂S₃

Solution

5) What is the pH of a 0.0500 M solution of barium hydroxide, Ba(OH)₂?
A. 1.00
B. 1.30
C. 12.7
D. 13.0

Solution

6) The reaction between hydrogen peroxide and ammonium ions is represented by the following equation.
3H₂O₂(aq) + 2NH₄ ⁺(aq) => N₂(g) + 2H⁺(aq) + 6H₂O(l)
Which one of the following is the correct half-equation for the reduction reaction?

Solution