Balancing Redox Reactions
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. Assume you are in the process of balancing the half-reaction listed below. At this point, you need to begin balancing hydrogen atoms by adding hydrogen ions (H⁺) to one side of the equation. NO₃⁻ → NO + 2 H₂O Select the half-reaction that has the correct number of hydrogen ions, on the correct side, in order to balance the reaction. A. 4 H⁺ + NO₃⁻ → NO + 2 H₂O B. NO₃⁻ → NO + 2 H₂O + 4 H⁺ C. 8 H⁺ + NO₃⁻ → NO + 2 H₂O D. NO₃⁻ → NO + 2 H₂O + 8 H⁺
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the balanced half-reaction for MnO₄⁻ → Mn²⁺? A. MnO₄⁻ + 8H⁺ + 5e⁻→ Mn²⁺ + 4H₂O B. MnO₄⁻ + 8H⁺ → Mn²⁺ + 4H₂O + 5e⁻ C. MnO₄⁻→ Mn²⁺ + 6e⁻ D. MnO₄⁻ → Mn²⁺ + ½ O₂ + 6e⁻
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the balanced oxidation half-reaction for the unbalanced oxidation-reduction reaction? Na + Cl₂ → NaCl A. Na → Na⁺ + e⁻ B. Cl₂ + 2e⁻ → 2Cl⁻ C. Cl₂ → 2e⁻ + 2Cl⁻ D. Na + e⁻ → Na⁺
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for H₂O when NH₃ + NO₂ → N₂ is balanced in acid? A. 12 B. 3 C. 6 D. 4
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for H₂O when PbO₂ + I₂ → Pb²⁺ + IO₃⁻ is balanced in acid? A. 4 B. 10 C. 2 D. 6
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when H₂O₂ + Cr₂O₇²⁻→ O₂ + Cr³⁺ is balanced in base? A. 8 B. 4 C. 2 D. 6
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when MnO₄⁻ + Fe²⁺ → Mn²⁺ + Fe³⁺ is balanced in acid? A. 4 B. 1 C. 2 D. 6
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when PbO₂ + I₂ → Pb²⁺ + IO₃⁻ is balanced in base? A. 8 B. 2 C. 6 D. 4
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the overall reaction for the following half-reactions? Reduction half-reaction: Ag⁺ + e⁻ → Ag Oxidation half-reaction: Ni⁰ → Ni²⁺ + 2 e⁻ A. 2 Ag⁺ + Ni → 2 Ag + Ni²⁺ B. 4 Ag⁺ + 2 Ni → 4 Ag + 2 Ni²⁺ C. Ag⁺ + Ni⁰ → Ag + Ni²⁺ D. Ag⁺ + 2 Ni → Ag + 2 Ni²⁺
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the overall reaction for the following half-reactions? Reduction half-reaction: Hg²⁺ + 2 e⁻ → Hg Oxidation half-reaction: Cr → Cr³⁺ + 3 e⁻ A. 3 Hg²⁺ + 2 Cr → 3 Hg + 2 Cr³⁺ B. Hg²⁺ + Cr → Hg + Cr³⁺ C. 6 Hg²⁺ + 6 Cr → 6 Hg + 6 Cr³⁺ D. 2 Hg²⁺ + 3 Cr → 2 Hg + 3 Cr³⁺
A
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. How many electrons are needed to balance each of the following half-reactions? Reduction half-reaction: Fe³⁺ + __e⁻ → Fe Oxidation half-reaction: Al → Al³⁺ + __e⁻ Overall reaction: Fe³⁺ + Al → Fe + Al³⁺ A. 0 electrons B. 3 electrons C. 2 electrons D. 6 electrons
B
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when H₂O₂ + Cr₂O₇²⁻→ O₂ + Cr³⁺ is balanced in acid? A. 5 B. 7 C. 1 D. 3
B
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when MnO₄⁻ + Fe²⁺ → Mn²⁺ + Fe³⁺ is balanced in base? A. 2 B. 8 C. 4 D. 6
B
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when MnO₄⁻ + H₂S → S + MnO is balanced in base? A. 8 B. 2 C. 6 D. 4
B
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation, while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the balanced reduction half-reaction for the unbalanced oxidation-reduction reaction? Na + Cl₂ → NaCl A. Na + e⁻ → Na⁺ B. Cl₂ + 2e⁻ → 2Cl⁻ C. Cl₂ → 2e⁻ + 2Cl⁻ D. Na → Na⁺ + e⁻
B
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. Assume you are in the process of balancing the half-reaction listed below. At this point, all of the atoms are balanced, but the charge needs to be balanced. You will complete this step by adding electrons to one side of the equation. 10 H⁺ + NO₃⁻ → NH₄⁺ + 3 H₂O Select the half-reaction that has the correct number of electrons, on the correct side, in order to balance the reaction. A. 10 H⁺ + NO₃⁻ → NH₄⁺ + 3 H₂O + 9 e⁻ B. 10 H⁺ + NO₃⁻ → NH₄⁺ + 3 H₂O + 8 e⁻ C. 10 H⁺ + NO₃⁻ + 8 e⁻ → NH₄⁺ + 3 H₂O D. 10 H⁺ + NO₃⁻ + 9 e⁻ → NH₄⁺ + 3 H₂O
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. Assume you are in the process of balancing the half-reaction listed below. At this point, you need to begin balancing oxygen atoms by adding water to one side of the equation. Cr₂O₇²⁻ → 2 Cr³⁺ Select the half-reaction that has the correct number of water molecules, on the correct side, in order to balance the reaction. The half-reaction will not be completely balanced. A. Cr₂O₇²⁻ + H₂O → 2 Cr³⁺ B. Cr₂O₇²⁻ + 7 H₂O → 2 Cr³⁺ C. Cr₂O₇²⁻ → 2 Cr³⁺ + 7 H₂O D. Cr₂O₇²⁻ → 2 Cr³⁺ + H₂O
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. How many electrons are needed to balance each of the following half-reactions? Reduction half-reaction: Sn²⁺ + __e⁻ → Sn Oxidation half-reaction: Co → CO²⁺ + __e⁻ Overall reaction: Sn²⁺ + Co → Sn + Co²⁺ A. 0 electrons B. 6 electrons C. 2 electrons D. 3 electrons
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for H₂O when MnO₄⁻ + H₂S → S + MnO is balanced in acid? A. 3 B. 5 C. 6 D. 4
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for H₂O when NH₃ + NO₂ → N₂ is balanced in base? A. 6 B. 3 C. 12 D. 4
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for H₂O when SO₄²⁻ + Br₂ → S₂O₃²⁻ + BrO₃⁻ is balanced in acid? A. 12 B. 6 C. 1 D. 24
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when SO₃²⁻ + MnO₄⁻ → SO₄²⁻ + Mn²⁺ is balanced in acid? A. 6 B. 2 C. 3 D. 1
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when Sn²⁺ + IO₃⁻ → Sn₄⁺ + I⁻ is balanced in acid? A. 2 B. 4 C. 3 D. 1
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when Sn²⁺ + IO₃⁻ → Sn₄⁺ + I⁻ is balanced in base? A. 4 B. 3 C. 6 D. 2
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What substance is added to balance oxygen in a half-reaction? A. H₂O₂ B. O₂ C. H₂O D. O⁻
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What substance is added to balance the hydrogen in a half-reaction? A. H₂O₂ B. H₂O C. H⁺ D. H₂
C
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for H₂O when SO₄²⁻ + Br₂ → S₂O₃²⁻ + BrO₃⁻ is balanced in base? A. 3 B. 4 C. 1 D. 2
D
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for H₂O when S²⁻ + NO₃⁻ → S + NO is balanced in acid? A. 3 B. 2 C. 1 D. 4
D
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when SO₃²⁻ + MnO₄⁻ → SO₄²⁻ + Mn²⁺ is balanced in base? A. 3 B. 2 C. 1 D. 6
D
Redox reactions can be written as two half-reactions, focusing on the gain or loss of electrons by one of the chemical substances. One half-reaction shows the oxidation while the other shows the reduction. When the two half-reactions are combined, the overall reaction is obtained. The half-reactions can aid in the balancing of redox equations because the number of each element must be balanced as well as the number of electrons gained and lost. What is the coefficient for OH⁻ when S²⁻ + NO₃⁻ → S + NO is balanced in base? A. 4 B. 2 C. 6 D. 8
D
