Ordinary level 2026 south west regional mock chemistry 2
Ordinary level 2026 south west regional mock chemistry 2
I’ve extracted the data from the second image, following the structure of the examination paper.
e) Complete the following table on techniques of separation of mixtures.
| TECHNIQUE | Example of mixture | property that enables separation |
| rice grains and rice husk | ||
| simple distillation | Ethanol and water | |
| Beans and corn | Particle size |
(4 marks)
(TOTAL=20 MARKS)
7) In a pre-laboratory test class, a teacher carried out tests to identify the following chemicals; X, Y and Z using reagents and jotted down his observations in some cases as shown the table below.
a) Study and complete the table below.
| S/N | TEST PROCEDURE | OBSERVATION | INFERENCE |
| (i) | X gives a golden yellow flame colour to a non-luminous Bunsen flame | (3 marks) | |
| (ii) | To $2\text{cm}^3$ of a solution X, $2\text{cm}^3$ of dilute hydrochloric acid was added. | A colourless gas is evolved, which turns lime water milky. | (2 marks) |
| (iii) | A portion of Y and sodium hydroxide was heated in a test tube. | A pungent gas produced which turns red litmus blue. | (2 marks) |
| (iv) | To $2\text{cm}^3$ of a solution Y was added three drops of acidified barium chloride. | Presence of sulphate ion. (2 marks) | |
| (v) | To $2\text{cm}^3$ of solution Z in a test tube was added sodium hydroxide solution. | The presence of Iron(III) ion (2 marks) | |
| (vi) | To $2\text{cm}^3$ of solution Z in a test tube was added acidified silver nitrate solution. | A white precipitate was formed. | (1 mark) |
c) Identify the chemicals X, Y and Z.
X: ____________________ Y: ____________________ Z: ____________________ (3 marks)
d) In a cement factory, quicklime is a raw material. Quicklime is obtained by heating limestone in a kiln. Quicklime is collected at the bottom while the waste gas is collected at the top of the Kiln. In one of such experiments, the following data was obtained.
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Mass of limestone introduced into the kiln = $10\text{g}$
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Mass of quicklime (calcium oxide) collected = $5.5\text{g}$
The equation for the conversion of limestone into quicklime is:
$$CaCO_3(s) \xrightarrow{\Delta} CaO(s) + CO_2(g)$$
i) From the above equation calculate the theoretical yield of quicklime
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