Chapter 1 2025/2026

a) Naturally occurring silver consists of two stable isotopes, 107Ag and 109Ag. The relative atomic mass of silver is 107.87. Show that isotope 107Ag is more abundant.

[3 Marks]

b) An amount of 500 g solution is prepared by dissolving 13.4 g of calcium chloride in water. Calculate the molarity and molality of the solution.

[4 Marks]

c) An amount of 500 g solution is prepared by dissolving 13.4 g of calcium chloride in water. Calculate the molarity and molality of the solutNitrate ion, NO3- can be reduced to nitrous oxide, N2O by anaerobic bacteria in a redox process. During this process, water is also oxidised producing oxygen. Write a balanced equation for this reaction under alkaline condition.

[5 Marks]

i. Determine the amount of AlCl3 produced (in g) if 2.67 g Al reacts with 3.5 g HCl . 

[7 Marks]

ii. Calculate the percentage yield for this reaction if 3.50 g of AlCl3 is produced.   

[2 Marks]