Half Equations Flashcards

1️⃣ Familiarise yourself with the flashcards:

  • Look through all the flashcards to see what's on both sides.
  • Make sure you understand the information on each card. If something's unclear, click the link to the revision notes at the bottom of the page for more details.

2️⃣ Test yourself:

  • Look at the question or prompt on each card and try to remember the answer before flipping it over.
  • Check the answer and make a note of any cards you find challenging and need to go over more.

3️⃣ Consistently Review and Practice:

  • Use spaced repetition: spend more time on the cards you struggle with and go over them more often.
  • Regularly review all the flashcards to help you better understand and retain the information over time.

Note: We may include questions that have multiple correct answers. It's useful to remember specific examples to understand these concepts better.

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What is a half equation in electrolysis?

A half equation is a chemical equation that shows what happens at one electrode, including the electrons gained or lost.

What extra particles always appear in half equations but not usually in normal symbol equations?

Electrons (e−) always appear in half equations.

What happens to ions in a reduction half equation?

In a reduction half equation, ions gain electrons.

At which electrode do reduction half equations happen in electrolysis?

Reduction half equations happen at the negative electrode, called the cathode.

What happens to ions in an oxidation half equation?

In an oxidation half equation, ions lose electrons.

At which electrode do oxidation half equations happen in electrolysis?

Oxidation half equations happen at the positive electrode, called the anode.

Which side of a half equation do electrons appear on in reduction, and which side in oxidation?

In reduction, electrons are on the left side. In oxidation, electrons are on the right side.

Write the half equation for a sodium ion, Na⁺, gaining one electron to form sodium metal.

Na⁺ + e⁻ → Na

Write the half equation for two chloride ions, Cl⁻, forming chlorine gas at the anode.

2Cl⁻ → Cl₂ + 2e⁻

How can you check if a half equation is correctly balanced?

You check that the number of each type of atom is the same on both sides and that the total charge is the same on both sides.