AP Chemical Reactions and Stoichiometry 2

Question 1

When 25.0 mL of 0.200 M Pb(NO₃)₂ is mixed with 35.0 mL of 0.150 M KI, which ion is in excess after the precipitation of PbI₂, and by how many millimoles?

Accepted Answer

I⁻ is in excess by 0.725 mmol

Answer

Pb²⁺ is in excess by 0.200 mmol

Answer

I⁻ is in excess by 1.25 mmol

Answer

Neither ion is in excess; stoichiometric amounts react

Question 2

Consider the reaction: 2H₂O₂(aq) → 2H₂O(l) + O₂(g). If 5.00 g of H₂O₂ (MM = 34.02 g/mol) decomposes and the O₂ gas is collected at 25°C and 1.00 atm, what volume of O₂ is produced? (R = 0.08206 L·atm/mol·K)

Accepted Answer

1.80 L

Answer

0.900 L

Answer

3.60 L

Answer

0.450 L

Question 3

Iron(III) oxide reacts with carbon monoxide: Fe₂O₃ + 3CO → 2Fe + 3CO₂. If 150. g of Fe₂O₃ (MM = 159.7 g/mol) reacts with excess CO, what is the theoretical yield of Fe (MM = 55.85 g/mol)?

Accepted Answer

105 g

Answer

52.4 g

Answer

210 g

Answer

87.5 g

Question 4

What type of reaction is represented by: Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)?

Accepted Answer

Single displacement (single replacement) reaction

Answer

Double displacement (metathesis) reaction

Answer

Decomposition reaction

Answer

Combustion reaction

Question 5

In a combustion analysis of a hydrocarbon, 0.500 g of the compound produces 1.571 g of CO₂ and 0.643 g of H₂O. What is the empirical formula of the hydrocarbon?

Accepted Answer

CH₂

Answer

CH₃

Answer

C₂H₄

Answer

CH

Question 6

Excess zinc reacts with 500.0 mL of a H₂SO₄ solution: Zn + H₂SO₄ → ZnSO₄ + H₂. If 3.40 g of H₂ (MM = 2.016 g/mol) is collected, what is the molarity of the H₂SO₄ solution?

Accepted Answer

3.37 M

Answer

6.73 M

Answer

1.69 M

Answer

0.337 M