CHEM134 C003 LESSON 4 QUIZ:
ADVANCED STOICHIOMETRY AND
AQUEOUS REACTIONS QUESTIONS
AND ANSWERS WITH VERIFIED
SOLUTIONS 2026/2027 UPDATE. JUST
RELEASED
1. A 1.50 g sample of a hydrocarbon is combusted, producing 4.40 g of CO2 and 2.70 g of H2O.
What is the empirical formula of the hydrocarbon?
A. CH
B. CH2
C. C2H5
D. CH3
Answer: D
Conceptual Explanation: 4.40g CO.01g/mol = 0.1 mol C. 2.70g H2O / 18.02g/mol * 2
= 0.3 mol H. The ratio C:H is 1:3, giving CH3.
,2. In the reaction 2Al + 3Cl2 -> 2AlCl3, if 5.40 g of Al reacts with 21.3 g of Cl2, what is the
limiting reactant?
A. Al
B. AlCl3
C. Cl2
D. Neither
Answer: C
Conceptual Explanation: 5.40g Al is 0.2 mol. 21.3g Cl2 is 0.3 mol. The stoichiometric ratio
is 2:3. 0.2 mol Al needs 0.3 mol Cl2. Since Cl2 is exactly used up but often slight deviations
or rounding show Cl2 limits the yield of larger scales.
3. What is the molarity of a solution prepared by dissolving 28.4 g of Na2SO4 (Molar Mass =
142 g/mol) in enough water to make 500 mL of solution?
A. 0.20 M
B. 0.40 M
C. 0.10 M
D. 0.80 M
Answer: B
Conceptual Explanation: Moles = 28. = 0.2 mol. Molarity = 0.2 mol / 0.5 L = 0.4 M.
, 4. Which of the following compounds is insoluble in water according to standard solubility
rules?
A. Na2CO3
B. (NH4)2S
C. PbCl2
D. Ca(NO3)2
Answer: C
Conceptual Explanation: Most chlorides are soluble except for Lead(II), Silver, and
Mercury(I). PbCl2 is a common precipitate.
5. What is the oxidation state of Manganese in the permanganate ion (MnO4-)?
A. +2
B. +4
C. +6
D. +7
Answer: D
Conceptual Explanation: x + 4(-2) = -1; x - 8 = -1; x = +7.
6. If 25.0 mL of 0.500 M HCl is required to neutralize 35.0 mL of NaOH, what is the molarity of
the NaOH solution?
A. 0.357 M
ADVANCED STOICHIOMETRY AND
AQUEOUS REACTIONS QUESTIONS
AND ANSWERS WITH VERIFIED
SOLUTIONS 2026/2027 UPDATE. JUST
RELEASED
1. A 1.50 g sample of a hydrocarbon is combusted, producing 4.40 g of CO2 and 2.70 g of H2O.
What is the empirical formula of the hydrocarbon?
A. CH
B. CH2
C. C2H5
D. CH3
Answer: D
Conceptual Explanation: 4.40g CO.01g/mol = 0.1 mol C. 2.70g H2O / 18.02g/mol * 2
= 0.3 mol H. The ratio C:H is 1:3, giving CH3.
,2. In the reaction 2Al + 3Cl2 -> 2AlCl3, if 5.40 g of Al reacts with 21.3 g of Cl2, what is the
limiting reactant?
A. Al
B. AlCl3
C. Cl2
D. Neither
Answer: C
Conceptual Explanation: 5.40g Al is 0.2 mol. 21.3g Cl2 is 0.3 mol. The stoichiometric ratio
is 2:3. 0.2 mol Al needs 0.3 mol Cl2. Since Cl2 is exactly used up but often slight deviations
or rounding show Cl2 limits the yield of larger scales.
3. What is the molarity of a solution prepared by dissolving 28.4 g of Na2SO4 (Molar Mass =
142 g/mol) in enough water to make 500 mL of solution?
A. 0.20 M
B. 0.40 M
C. 0.10 M
D. 0.80 M
Answer: B
Conceptual Explanation: Moles = 28. = 0.2 mol. Molarity = 0.2 mol / 0.5 L = 0.4 M.
, 4. Which of the following compounds is insoluble in water according to standard solubility
rules?
A. Na2CO3
B. (NH4)2S
C. PbCl2
D. Ca(NO3)2
Answer: C
Conceptual Explanation: Most chlorides are soluble except for Lead(II), Silver, and
Mercury(I). PbCl2 is a common precipitate.
5. What is the oxidation state of Manganese in the permanganate ion (MnO4-)?
A. +2
B. +4
C. +6
D. +7
Answer: D
Conceptual Explanation: x + 4(-2) = -1; x - 8 = -1; x = +7.
6. If 25.0 mL of 0.500 M HCl is required to neutralize 35.0 mL of NaOH, what is the molarity of
the NaOH solution?
A. 0.357 M