Reduction — Science definition

Decrease in oxidation number; electron gain.

Where it is taught

In use

Oxidation is an increase in oxidation number or loss of electrons; reduction is a decrease or gain.

Oxidation Numbers & Redox Equations

Questions using reduction

Problem 1

For Mg+2Ag⁺→Mg²⁺+2Ag, identify oxidation, reduction, both agents and the electron amount per mole of Mg reacted.
Answer and explanation

Mg goes 0→+2 and is oxidized/reducing agent. Ag⁺ goes +1→0 and is reduced/oxidizing agent. One mole Mg transfers two moles electrons, consumed by two moles Ag⁺ in the selected complete account.

Mg goes 0→+2 and is oxidized/reducing agent. Ag⁺ goes +1→0 and is reduced/oxidizing agent. One mole Mg transfers two moles electrons, consumed by two moles Ag⁺ in the selected complete account.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the chemical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 2

Independent chapter check: For Mg+2Ag⁺→Mg²⁺+2Ag, identify oxidation, reduction, both agents and the electron amount per mole of Mg reacted.
Answer and explanation

Mg goes 0→+2 and is oxidized/reducing agent. Ag⁺ goes +1→0 and is reduced/oxidizing agent. One mole Mg transfers two moles electrons, consumed by two moles Ag⁺ in the selected complete account.

Mg goes 0→+2 and is oxidized/reducing agent. Ag⁺ goes +1→0 and is reduced/oxidizing agent. One mole Mg transfers two moles electrons, consumed by two moles Ag⁺ in the selected complete account.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the chemical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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