An environmental engineer is monitoring the treatment of acidic wastewater in an industrial holding pond.
The treatment process neutralises the acid by adding magnesium hydroxide, Mg(OH)2\text{Mg(OH)}_2Mg(OH)2. During one monitoring cycle, the engineer records that 15.5 kg15.5\text{ kg}15.5 kg of magnesium hydroxide has been added to the pond.
Calculate the number of moles of magnesium hydroxide used in this treatment cycle. (Ar:Mg=24.3;O=16.0;H=1.0)(A_r: \text{Mg} = 24.3; \text{O} = 16.0; \text{H} = 1.0)(Ar:Mg=24.3;O=16.0;H=1.0)
Give your answer to 3 significant figures.
91 exam-style questions on OCR GCSE Chemistry Monitoring chemical reactions. Each one has a worked solution and a mark scheme showing where the marks go.