Describe the process of separating Sodium chloride crystals mixed with Calcium carbonate powder.      (3mks)

The electronic configuration for elements represented by letters A , B and C are A 2.8.6 , B 2.8.2 , C 2.8.1

(a) Select the element which forms:

i)  A double charged cation.        (1mk)

ii)  A soluble carbonate.        (1mk)

(b) Which element has the shortest atomic radius.         (1mk)

An element Q can be represented as  

(a) Draw the structure of the ion        (2mks)

(b)  How does its ionic radius compare with its atomic radius?.        (1mk)

Potassium is isotopic and has a relative atomic mass (R.A.M) of 39.5 , work out the percentage abundance of each isotope. The three isotopes , ³⁹K , ⁴⁰K , ³⁸K  (0.01%)             (3mks)

The table below shows PH values of solution A to E.

Which solution:

(a) Contains the largest concentration of hydroxyl ions?        (1/2mk)

(b)  is likely to be a solution of Aluminium chloride.        (1/2mk)

(c) is likely to be a solution of carbon (IV) oxide.         (1/2mk)

(d) is likely to be a solution of magnesium chloride.       (1/2mk)

The table below gives some properties of gases D and E.

(a) Describe how one would obtain a sample of gas E from a mixture of gases D and E.              (2mks)

 (b) Name one apparatus that can be used to measure accurate volume of gases in the laboratory      (1mk)

The diagram below shows three methods for collecting gases in the laboratory.

(a) Name methods A and B.              (1mk)

A………………………………………………………..

B………………………………………………………..

(b) From the methods above, identify one that is suitable for collecting Sulphur (IV) oxide. Explain      (2mks)

(a) Identify two substances that are reacted to regenerate ammonia gas in the Solvay process.     (2mks)

(b) Write down a balanced chemical equation for the reaction above.      (1mk)

15cm³ of ethanoic acid (CH₃COOH) was dissolved in water to make 500cm³ of solution. Calculate the concentration of the solution in moles per litre.

(C = 12 , H = 1 , O = 16 , density of ethanoic acid is 1.05g/cm³)           (3mks)

Gas P was passed over heated magnesium ribbon and hydrogen gas was collected as shown in the diagram below:

(a) Name gas P.                                                  (1mk)

(b) Write an equation for the reaction that takes place in the combustion tube.      (1mk)

(c) State one precaution necessary at the end of this experiment.     (1mk)