Chemistry Past Questions and Answers

Calcium hydroxide is added in the treatment of town water supply to

A hydrated salt of formula MSO<sub style='font-size: smaller;'>4</sub>.xH<sub style='font-size: smaller;'>2</sub> O CONTAINS 45.3% by mass of water of crystalisation. Calculate the value of x [M = 56, S = 32, O = 16, H = 1 ]

Using 50 cm <sup style='font-size: smaller;'>3</sup> of 1 M potassium hydroxide and 100cm <sup style='font-size: smaller;'>3</sup> of 1 M tetraoxosulphate (VI) acid, calculate the respective volumes in cm <sup style='font-size: smaller;'>3</sup> of base and acid that would be required to produce the maximum amount of potassium tetraoxosulphate (IV) [ = 39, S = 32, O = 16, H = 1]

A solution of calcium bromide contains 20 g dm <sup style='font-size: smaller;'>3</sup> What is the molarity of the solution with respect to calcium bromide and bromide ions? [Ca = 40, Br = 80]

The substance ZnO dissolves in sodium hydroxide solution and mineral acid solution to give soluble products in each case. ZnO is therefore referred to as