Redox Test

A redox reaction always involves

• a change in oxidation number

• a change of phase

• a transfer of protons

• the formation of ions

As an atom is oxidized, the number of protons in the nucleus

• decreases

• increases

• remains the same

• depends on the atom

In all oxidation-reduction reactions, there is conservation of

• charge, but not mass

• mass, but not charge

• neither mass nor charge

• both mass and charge

Tags

NGSS.HS-PS1-7

Which half-reaction equation represents the reduction of an iron(II) ion?

• Fe2+ → Fe3+ + e−

• Fe2+ + 2e− → Fe

• Fe3+ + e− → Fe2+

• Fe → Fe2+ + 2e−

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What is the total number of moles of electrons needed to completely reduce 6 moles of Ni2+(aq) ions?

• 2 moles

• 3 moles

• 6 moles

• 12 moles

Given the balanced ionic equation representing the reaction in an operating voltaic cell: Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) The flow of electrons through the external circuit in this cell is from the

• Cu anode to the Zn cathode

• Cu cathode to the Zn anode

• Zn anode to the Cu cathode

• Zn cathode to the Cu anode

Given the balanced equation representing a reaction: CH4 + 2O2 → CO2 + 2H2O During this reaction, the oxidation state of H changes from

• +1 to −1 as electrons are transferred

• +1 to −1 as protons are transferred

• −1 to +1 as electrons are transferred

• −1 to +1 as protons are transferred

Consider the equations A, B, C, and D. (A) AgNO3 + NaCl → AgCl + NaNO3 (B) Cl2 + H2O → HClO + HCl (C) CuO + CO → CO2 + Cu (D) NaOH + HCl → NaCl + H2O Which two reactions are redox equations?

• A and C

• B and C

• C and D

• A and D

What is the oxidation number of carbon in NaHCO3?

• −2

• +2

• −4

• +4

Oxidation occurs at the anode in

• electrolytic cells, only

• voltaic cells, only

• neither electrolytic cells nor voltaic cells

• both electrolytic cells and voltaic cells