Chemistry Triangle Formulas

What does the triangle as a chemical symbol mean?

Part of the answer required them to work out the volume required for a given amount and concentration. The candidate started off by drawing a triangle, then hesitated, eventually giving up in despair. This was my first encounter with formula triangles.

What are they?

Formula triangles are a tool to help students use equations without needing to rearrange them. To use one, cover up the term you’re trying to find to reveal the expression required to calculate it. In the example here it’s the volume: cover up V to see the required equation is moles divided by concentration. Or if you want the number of moles, cover up the n and then, as c and V are side by side, multiply them together.

Connecting maths and science

I dislike formula triangles for a number of reasons. My experience in the admissions interview is not uncommon. While they may be a useful approach for A-level exams (these candidates all had A or A* at chemistry A-level) it doesn’t seem to help much in the long term.

They are a trick that hides the maths: students don’t apply the skills they have previously learned. This means students don’t realise how important maths is for science.1

I’m also concerned that if students can’t rearrange simple equations like the one above, they really can’t manage when equations become more complex.