The standard calculation

2 marks · Normal

During a titration experiment, 22.5 cm³ of 0.250 mol/dm³ potassium hydroxide completely neutralises 27.0 cm³ of a sulfuric acid solution. Calculate the number of moles of potassium hydroxide used in the reaction.

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0.00563 mol

Also accept: 5.625 × 10⁻³ mol; 5.62 × 10⁻³ mol

Common mistakes: Not converting cm³ to dm³; Multiplying instead of dividing

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Marking points

M1 · 1 mark · Converts 22.5 cm³ to dm³ and applies n = c × V formula.

A1 · 1 mark · Correct calculation of moles: 0.00563 mol.

Worked solution

Convert 22.5 cm³ to dm³: 22.5 ÷ 1000 = 0.0225 dm³.

Moles of KOH = 0.250 × 0.0225 = 0.00563 mol