A rectangle whose area is 96m² is such that its length is 4metres longer than its width.

Find

(a) It dimensions                                                                  (3 Marks)

(b) Its perimeter                                                                         (1 Mark)

A salesman gets a commission of 2.4% on sales up to Sh. 100,000. He gets additional commission of 1.5% on sales above this. Calculate the commission he gets for sales worth Sh. 280,000.           (3 Marks)

The circle below whose area is 18.05cm² circumscribes triangle ABC where AB = 6.3cm, BC = 5.7cm and AC = 4.2cm. Find the area of the shaded part.                                        (4 Marks)

Find x if     3^2x+3  +  1  =  28                            (2 Marks)

Simplify:                                                      (3mks)

Mr. Owino spends 1/4 of his salary on school fees. He spends 2/3 of the remainder on food and a fifth of what is left on transport. He saves the balance. In certain month he saved Sh. 3400. What was his salary?                             (3 marks)

Evaluate                                 (2mks)

(a) starting with magnesium oxide, describe how you can obtain a dry sample of magnesium Carbonate      (3mks)

(b)

(i) Give one example of an acid salt               (1mk)

(ii) When sodium nitrate was heated a solid A and gas B were produced identify solid A and gas B              (2mks)

Solid A...................................................................................................

Gas B.....................................................................................................

(iii) State two uses of gas B produced in (ii) above               (2mks)

(c) State two factors that should be considered when choosing a fuel     (2mks)

(a) define the term electrolysis            (1mk)

(b) State two functions of a salt bridge during electrolysis        (2mks)

(c) The reduction potential of elements K, L, M, and P are as given below.

 (i) Which letter represents the, strongest reducing agent? give a reason         (2mks)

(ii) Which two letters represent elements whose half cells would form an electrochemical cell with the largest e.m.f?               (1mk)

 (iii) Calculate the e.m.f of the cell formed in (ii) above                    (2mks)

 (d) During the electrolysis of a molten chloride of metal Q, a current of 0.25A was passed though the molten chloride for 2 hours and 10minutes. Given that 0.9grams of metal Q were deposited at the cathode.

(i) Calculate the quantity of electricity passed               (1mk)

 (ii) Charge carried by the ions of metal Q given that R.A.M of metal Q is 84        (3mks)

(a) Calamine is one of the ores from which zinc can be extracted from

(i) Name any other ore from which zinc can be extracted from        (1mk)

(ii) The calamine is usually decomposed by heating to obtain substance M as shown below 

Identify substance M                           (1mk)

.....................................................................................................

(iii) Identify two methods that can be used to obtain zinc from substance M         (2mks)

(b) During the extraction of zinc, name two gases likely to emitted into the air and that are likely to cause pollution            (2mk)

(c) State one likely pollution effects of each of the gases you have mentioned in (a) above  (2mks)

(d) State one possible use of zinc metal (1mk)