Chemistry calculations practice: stoichiometry, pH and buffers with answers
Molar mass, moles, concentration, pH, buffers and titration from general chemistry: you do the maths yourself and type in the result. Five problems, new every day, with worked solutions and the typical exam mistake. Free and without an account.
Keep practising for free, with your progress
The basics without a daily limit in a free account, plus one exam-level task a day. Every level, the exam mode and the AI tutor from €4.99 once or with Plus.
Task
37.8 g of sodium hydrogen carbonate (NaHCO₃) are dissolved in water and made up to 100 mL. Work out the concentration. Atomic masses (g/mol): H 1.01 · C 12.01 · O 16.00 · Na 22.99.
Amount in mol (4 decimal places)
Concentration in mol/L (3 decimal places)
Numbers like 12.5 or 0.025, with as many decimals as asked. Masses and amounts count within 1%, pH values within ±0.02.
Topics with formulas and practiceMolar mass and moles · Concentration and dilution · pH of strong acids and bases · Stoichiometry …
How the trainer works
Work it out, don’t guess
Molar mass, moles, pH: you type the number, e.g. 98.09 or 0.025. Masses count within 1%, pH values within ±0.02.
With worked solutions
After each problem you see the solution step by step and the typical mistake that costs marks in the exam.
Always new problems
Every problem is generated with new numbers, without AI and always computed correctly. You practise the method, not memorising answers.