Oxidation and Reduction pop Quiz

The oxidation number of oxygen atoms in compounds is usually

• 0

• -1

• -2

• +1

The part of a reaction that involves only oxidation or reduction is a(n)

• redox reaction.

• reduction reaction.

• oxidation-reduction equation.

• half-reaction.

The sum of the oxidation numbers for all atoms in a polyatomic ion is equal to

• –2.

• 0

• the charge on that ion.

• the charge of the products.

If oxidation is taking place, what also must be occurring?

• electroplating

• electroplating

• electrolysis

• reduction

Another name for an oxidation-reduction reaction is

• oxidizing agent.

• redox reaction.

• reducing agent.

• half-reaction.

The oxidation number of uncombined iodine is

• 0

• -1

• -2

• +1

When Cr3+ changes to Cr0 , the chromium ion is said to have been

• oxidized because it gained 3e–

• oxidized because it lost 3e– .

• reduced because it gained 3e – .

• reduced because it lost 3e– .

The term oxidation arose early in the history of chemistry, when scientists observed elements combining with oxygen in combustion reactions. For example, S(s) + O2(g) → SO2(g) In this reaction,

• . the oxygen is oxidized and the sulfur is oxidized.

• the oxygen is oxidized and the sulfur is reduced.

• the oxygen is reduced and the sulfur is reduced.

• the oxygen is reduced and the sulfur is oxidized.

During oxidation, one or more electrons are removed from a substance, which increases its

• size.

• mass.

• valence.

• oxidation number.

What is the oxidation number of Mn in MnO₄^- ?

• +4

• +5

• +6

• +7