Spotting Redox

Part of the Oxidation and Reduction section of Coddy's Chemistry journey. Lesson 6 of 27.

Write every oxidation number on both sides. Some change: it is a redox reaction. None change: it is not.

CuO + H₂ → Cu + H₂O: Cu goes +2 to 0 (reduced), H goes 0 to +1 (oxidized).

Two balances: black copper oxide, 8.0 g, and the pink copper left after heating it in hydrogen, 6.4 g

Hydrogen takes the oxygen away: the copper is reduced

NaOH + HCl → NaCl + H₂O: Na +1, O −2, H +1 and Cl −1 on both sides. No change: not redox.

Challenge

Hot black copper(II) oxide is put in a stream of hydrogen. It turns into pink copper metal, and drops of water form. Which element is oxidized, and which is reduced?

Try it yourself

Oxidation numbersFollow the electrons

CuOH₂CuH₂O

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Oxidation and Reduction

1Electron Transfer

What Is Oxidation Oxidation Numbers Rules for Oxidation Numbers Oxidation Numbers in Ions Recap - Number Painter

4Metals and Reactivity

The Reactivity Series Displacement Reactions Metals and Acids Corrosion and Rust Recap - Metal Contest

2Redox Reactions

Spotting RedoxOxidizing Agents Reducing Agents Electrons Passed Recap - Who Gave Electrons

5Electrochemistry

Electrolysis Electrolysis of Melts Cells and Batteries Recap - Smelter

3Half-Equations

Writing Half-Equations Balancing with Electrons Half-Equations in Acid Combining Half-Equations Recap - Permanganate

6Practice Problems

Recap - Bleach and Iodide Recap - Copper and Silver Recap - Bromine Redox