Potassium aluminium sulfate (alum) is a compound with many industrial uses.
The formula of hydrated potassium aluminium sulfate is KAl(SO4)2⋅12H2O\text{KAl(SO}_4)_2 \cdot 12\text{H}_2\text{O}KAl(SO4)2⋅12H2O. How many different elements are shown in this formula? A 4, B 5, C 6, D 7.
Aluminium sulfate can be made from aluminium hydroxide and sulfuric acid. Balance the equation for the reaction between aluminium hydroxide and sulfuric acid: …Al(OH)3+…H2SO4→…Al2(SO4)3+…H2O\dots\text{Al(OH)}_3 + \dots\text{H}_2\text{SO}_4 \rightarrow \dots\text{Al}_2(\text{SO}_4)_3 + \dots\text{H}_2\text{O}…Al(OH)3+…H2SO4→…Al2(SO4)3+…H2O.
Ammonia is manufactured by the Haber process. Chlorine and sodium hydroxide are manufactured using the chlor-alkali process. The list contains some statements about these two processes. Indicate the two correct statements: 1. The raw materials for the chlor-alkali process are nitrogen and sodium chloride; 2. The catalyst used in the Haber process is iron; 3. In the chlor-alkali process, chlorine gas is produced at the cathode; 4. The synthesis of ammonia in the Haber process is a reversible reaction; 5. The main product of the chlor-alkali process is liquid sodium.
80 exam-style questions on Edexcel IGCSE Chemistry Chemical formulae, equations and calculations. Each one has a worked solution and a mark scheme showing where the marks go.