Chemistry · KS3 Y9 · Chemical Reactions

Concentration

ConcentrationFree8:14Heddy Score 3 of 7, below the standard
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What you need to know

  • Concentration in moles tells you how many moles of solute are dissolved in each litre (dm³) of solution.
  • Volume must be changed from cm³ (mL) into litres (dm³) before you calculate, by dividing by 1000.
  • The same relationship can be rearranged to find the moles from concentration × volume, or the volume from moles ÷ concentration.
  • To make a solution of a set concentration, work out the moles needed, change them into a mass using the relative formula mass, dissolve it and make it up to the mark in a volumetric flask.

In this clip

Runs 8:14, from 0:10 to 8:24 of the full video.

Heddy Score3/7, Below the standard
See the seven stars
  • Trusted source · passed. The creator's own upload, live and playable here.
  • On the map · not judged yet. A teacher watched it: it mainly teaches this map topic.
  • Spec-true · not judged yet. Accurate, and right for the current UK specification.
  • Focused · passed. One idea, short enough to watch in one go.
  • Accessible · passed. Good captions, clear sound and pictures.
  • Safe for children · not judged yet. Right for 11 to 16 year olds, with no sales pitch.
  • Proven · not judged yet. Earned from our students: they learn from it, find it helpful and watch it to the end.
★ passed · ☆ pending · ✕ failed
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Our own students' answers. These are what move ★7 Proven.
On YouTube

1.35M views · 23.7K likes · ketzbook 121K subscribers

As reported by YouTube on 2026-11-02. Not part of the Heddy Score.
How the Heddy Score works

Why we picked it

Clear worked examples of concentration calculations, finishing with how to actually make up a solution in the lab.

ketzbook on YouTubechecked 2026-10-22

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