Chapter 1 2022/2023
Chapter 1 2022/2023
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a) Magnesium is widely used in constructions and medicines. It occurs in nature as 24Mg, 25Mg and 26Mg. The atomic masses for 24Mg, 25Mg and 26Mg are 23.985 u, 24.986 u and 25.983 u respectively. Determine the percentage abundance of 25Mg and 26Mg if the percentage abundance of 24Mg is 78.99 % and the average atomic mass of magnesium is 24.3.
[5 Marks]
b) The equation for the reaction between SO2 and Br2 is shown below. Write the balanced equation for this reaction under acidic conditions.
SO2 + Br2 → SO42- + Br-
[3 Marks]
c) In an experiment, a student was asked to prepare 250 mL of 0.2 M NaOH solution.
i. Determine the mass of NaOH required to prepare the solution. .
[3 Marks]
ii. Calculate the volume of water needed to prepare another NaOH solution with a concentration of 0.1 M from the solution prepared in(i).
[3 Marks]
d) The reaction equation involved in depletion of ozone, O3, layer as shown below.
O3 (g) + NO (g) → O2 (g) + NO2 (g)
i. An amount 0.740 g of O3 reacts with 0.670 g of NO. Identify the limiting reactant.
[5 Marks]
ii. Determine the mass of NO2 that will be produced.
[2 Marks]
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