Reactions Unit Review

Which of the following is a simple definition of oxidation?

• the loss of electrons

• the gain of electrons

• an agent that oxidizes something

• an agent that reduces something

Which best describes the oxidizing agent in this reaction?

Cl_2(aq) + 2Br^–_(aq) ---> 2Cl^–_(aq) + Br_2(aq)

• Bromine (Br) is the oxidizing agent because it gains an electron.

• Bromine (Br) is the oxidizing agent because it loses an electron.

• Chlorine (Cl) is the oxidizing agent because it gains an electron.

• Chlorine (Cl) is the oxidizing agent because it loses an electron.

Given the reaction below, which is the substance being oxidized?

Mg + Cl₂ ---> Mg²⁺ + 2Cl^–

• 2CI^–

• CI₂

• Mg

• Mg²⁺

Given the reaction below, which is the substance being reduced?

Mg + Cl₂ ---> Mg²⁺ + 2Cl^–

• 2CI^–

• CI₂

• Mg

• Mg²⁺

In the redox reaction below, which is the reducing agent?

MnO_2(s) + 4H⁺_(aq) + 2Cl^–_(aq) ---> Mn²⁺_(aq) + 2H₂O_(l) + Cl_2(g)

• CI^–

• CI₂

• Mn²⁺

• MnO₂

Which identifies an oxidation-reduction reaction?

• a double replacement reaction

• a neutralization reaction

• a reaction in which oxidation numbers change

• a reaction in which no electrons are transferred

Which of the following is an oxidation-reduction reaction?

• Fe₂O₃ + 3CO ---> 2Fe + 3CO₂

• CuSO₄ + 2NaOH ---> Cu(OH)₂ + Na₂SO₄

• 2NaOH + H₂CO₃ ---> Na₂CO₃ + 2NaOH

• Pb(NO₃)₂ + Na₂SO₄ ---> 2NaNO₃ + PbSO₄

Which of the following is an oxidation-reduction reaction?

• ZnS(s) + 2O₂(g) ---> ZnSO₄(s)

• CaO(s) + H₂O(l) ---> Ca(OH)₂(s)

• 6Li₂O(s) + P₄O₁₀(g) ---> 4Li₃PO₄(s)

• SO₂(g) + H₂O(l) ---> H₂SO₃(aq)

Which type of reaction occurs in the following?

2HgO(s) ---> 2Hg(l) + O₂(g)

• a decomposition reaction in which a metal is reduced

• an acid-base neutralization reaction to produce oxygen gas

• a displacement reaction involving two metals

• a combustion reaction involving burning a metal in oxygen

What is the oxidation number for S in the compound SO₃? (Recall that O has an oxidation number of –2.)

• 0

• +2

• +4

• +6