Reacting Quantity Practice Questions

1:  Calculate the number of moles of  i) sodium hydroxide in 25 cm3 of 1.5 mol dm-3 sodium hydroxide solution and  ii) nitric acid in 10 cm3 of 3.0 mol dm-3 nitric acid

2:  Calculate the mass of  i) hydrogen chloride in 500 cm3 of 2 mol dm-3 hydrochloric acid and ii) ammonia in 20 cm3 of a solution of 8M ammonia

3:  Calculate the concentration in mol dm-3 and in g dm-3 of a solution made by dissolving 2.92g of potassium hydroxide in 400cm3 of solution

4:  Calculate the mass of lithium required when reacting with excess hydrochloric acid to produce 10.0dm3 of hydrogen gas at r.t.p.

5:  6.54g of a metal M reacts fully with excess nitric acid producing 2.40 dm3 of hydrogen at r.t.p. Calculate the Ar of the metal, and hence identify the metal. The equation for the reaction is M(s) + 2HNO3(aq) → M(NO3)2(aq) + H2(g)

6:  Magnesium oxide (MgO) was added to 10.0cm3 of 0.500 mol dm‑3 sulphuric acid and the solution warmed until no more magnesium oxide reacted. The remaining unreacted magnesium oxide was filtered off, and the colourless solution obtained was allowed to crystallize. What is the maximum mass of magnesium sulphate, MgSO4.7H­2O, that could be obtained by this method?

7:  10.0cm3 of a solution of sodium hydroxide was neutralized by 12.5cm3 of 0.100M hydrochloric acid. Calculate the concentration in mol dm-3 of the alkali.

8:  25.0cm3 of a 0.0500M solution of sodium hydroxide was titrated against sulphuric acid of unknown concentration. The average titre at the endpoint was 21.00cm3 of sulphuric acid. Calculate the concentration of the acid.

9:  A sample of calcium carbonate is heated in a Bunsen flame, causing some of it to thermally decompose into calcium oxide. The mass of calcium carbonate used was 10.0g. The carbon dioxide released during the decomposition was collected and it volume at room temperature and pressure was found to be 1.80dm3. Calculate the %yield of calcium oxide in this thermal decomposition.