KCSE CHEMISTRY QUESTIONS AND ANSWERS PER TOPIC
(a) Name the method that can be used to obtain pure iron (III) chloride from a mixture of iron (III) chloride and sodium chloride.
(b) A student was provided with a mixture of sunflower flour, common salt and a red dye. The characteristics of the three substances in the mixture are given in the table below.
The student was provided with ethanol and any other materials needed.
Described how the student can separate the mixture into its three components c) The diagram below show part of a periodic table. The letters do no represent the actual symbols of elements. Use the diagram to answer the questions that follow.
i) Explain why the oxidizing power of W is more than that of X
ii) How do the melting points of R and T compare? Explain iii) Sketch an element that could be used i) In weather ballons ii) For making a cooking pot d i) Classify the substances water, iodine, diamond and candle wax into elements and compounds
​ii) Give one use of diamond
ANSWERS
​(a)Sublimation
(b)Add ethanol to the mixture . Filter and evaporate filtrate to obtain red dye . Add water to the residue . Filter to obtain sunflower flour . Evaporate filtrate to obtain salt . OR Add H,O to mixture , filter , residue is sunflower , evaporate the water ; add ethanol to the residue filter . The filtrate is red dye. (3 marks) (c)(i) W accepts electrons more readily than X. W has small atomic radius/ W has less energy levels than X/ W has less screening effect than X/ W has greater effective nuclear attraction than X. W is more electro negative than X. (ii) T has a lower melting point than R because it exists in simple molecular form with weak Van der Waals forces while R has strong metallic bonds. ​Related Chemistry Questions and Answers on Acids, Basesand Salts Form 4 Level
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