Redox Reactions

The sum of the oxidation numbers in SCN^- is equivalent to

• 0

• -1

• +1

• +3

The sum of the oxidation numbers in Na₂CO₃ is equivalent to

• 0

• -2

• +1

• -1

Which of the following represents oxidation?

• C → CH₄

• Fe³⁺ → Fe²⁺

• Cl₂ → 2Cl^-

• Zn → ZnO

Which of the following represents reduction?

• C →  CO
• N₂ →  NH₃
• Zn  →   Zn²⁺ 
• H₂ →  H₂O

In the reaction Zn + 2HCl --> ZnCl₂ + H₂

which element, if any, is oxidized?

• Zinc

• Hydrogen

• Chlorine

• None

In the reaction
2Ca(s) + O₂(g) --> 2CaO(s), calcium is __________

• Reduced
• Synthesized
• Oxidized
• None of the above

Which statement is true:
Mg → Mg²⁺ + 2e^–

• Mg gains 2 electrons
• Mg_²⁺ loses 2 electrons
• Mg loses 1 electron
• Mg loses 2 electrons

What substance is oxidized in the following reaction?
4Fe + 3O₂ --> 2Fe₂O₃

• Iron
• Fluorine
• Oxygen

Is calcium oxidized or reduced in the following reaction? 
2CaO--> 2Ca + O₂

• Oxidized
• Reduced

Which of the following half reactions correctly represents a reduction half reaction?

• Fe →Fe²⁺ + 2e^-
• Pb⁴⁺ + 2e^- →Pb²⁺
• 2O^-2 →O₂ + 4e^-
• Fe + 3e^- →Fe³⁺