Help i can't remember chemistry equations
I am struggling to remember equations for the topics transition metals, P3 and aqueous ions. Does anyone have any tips on how to remember them like a mnemonic devise or something easy.
Reply 1
Original post
by Lizzie???I am struggling to remember equations for the topics transition metals, P3 and aqueous ions. Does anyone have any tips on how to remember them like a mnemonic devise or something easy.
Don’t memorise equations. It’s much better to work out formulae where possible and to memorise the formulae of compounds that aren’t easy to work out, then to construct and balance equations where you can. It sounds like a lot of effort, but it’s easier in the longrun.
For example, if I asked you to write an equation for the reaction of phosphorus(V) oxide with sodium hydroxide to make water and sodium phosphate, you would start by writing the following:
NaOH + P4O10 —> Na3PO4 + H2O
(You need to memorise the formula of phosphorus(V) oxide as P4O10 and know that phosphate ions are PO4^3-, so sodium phosphate will be Na3PO4)
As there are four phosphorus atoms on the left hand side, you need to scale the number of sodium phosphates up by 4:
NaOH + P4O10 —> 4Na3PO4 + H2O
You should now notice that there are 12 sodium’s on the right, so scaling up the number of sodium hydroxides by 12:
12NaOH + P4O10 —> 4Na3PO4 + H2O
You should now spot that you need a total of 12 hydrogens on each side, so scaling up the H2O by 6:
12NaOH + P4O10 —> 4Na3PO4 + 6H2O
We have already established that the phosphorus, sodium and hydrogen atoms on each side balance. We can check each side to see if the oxygens balance. On the left, there are 22 oxygens and on the right there are also 22 oxygens, so the equation balances. Hence we have a final answer.
Quick Reply
Related discussions
- Inorganic Chemistry A Level- Help!
- chemistry aqa electrochem
- Revision Techniques To Try Out
- A level chem
- Hi
- Opinions on best time to do hw
- Crashing higher physics
- gcse science combined higher help
- A level Chemistry Study help
- Chemistry at Keele
- A-Level Chemistry Study Group | 2025-2026
- Feel like imperial interview went badly
- Revision tips!
- gcse paper 1 chem
- AQA GCSE Chemistry Paper 1 (Higher Tier) 8462/1H - 27 May 2022 [Exam Chat]
- A-Level Chemistry Study Group 2024-25
- BTEC Applied Science Unit 1 January Resit
- chemistry ocr a level redox question help
- English lit and bio and chem
- Tips on cramming inorganic and physical chem - AQA
Latest
Trending
Last reply 3 months ago
AQA A level chemistry synthetic routes map - what is the best one to memorise?Last reply 8 months ago
AQA Chemistry Electrode Potentials Conventional Representation QuestionLast reply 10 months ago
OCR B Salters A Level Chemistry 2025 Advanced ArticleLast reply 11 months ago
Help with this chemistry question? (A2, acid-base equilibria)
How The Student Room is moderated
To keep The Student Room safe for everyone, we moderate posts that are added to the site.
