Redox Reactions

What is an oxidation state?

• The physical state the element is in before a reaction

• The number of atoms of that element in a compound

• The number of electrons transferred in the reaction

• The charge an element would have if it were an ion

What is the most likely oxidation state of aluminum (Al)?

• -3

• +2

• -2

• +3

What is the oxidation state of a lone element?

• It is always 0.

• It is its most likely oxidation state.

• It is the same as in a compound.

• It is always 1.

What is the oxidation state of Cl in HClO₃?

• +5

• -6

• +6

• -1

What happens in an oxidation?

• An element gains one or more electrons.

• A compound breaks up into ions.

• An element loses one or more electrons.

• Two compounds trade partners.

What does it mean for an element to be reduced?

• The element has reacted with oxygen.

• There are fewer atoms in the product than in the reactant.

• The element is in ion form in solution.

• The element has gained one or more electrons.

Which of the following most completely describes a redox reaction?

• A hydrocarbon combustion reaction

• An oxidation and reduction reaction

• A chemical decomposition reaction

• A reaction resulting in electron sharing

How can you identify a redox reaction?

• Electrons have transferred from one atom to another.

• The number of protons has changed in an atom.

• The charges on each side of the equation cancel.

• Metal atoms have rearranged in the compounds.

In the redox reaction AgNO₃ + Na --> NaNO₃ + Ag, which element has been reduced?

• Sodium (Na)

• Oxygen (O)

• Nitrogen (N)

• Silver (Ag)

How does the oxidation state of Li change in the following reaction?

Li(s) + NaOH(aq) --> LiOH(aq) + Na(s)

• It goes from 0 to -1.

• It goes from +1 to +2.

• It goes from 0 to +1.

• It does not change.