All Questions
You are provided with:
i) Solution A which is 2.0M hydrochloric Acid (HCl)
ii) Solution B, which is 0.1 M sodium thiosulphate (Na2S2O3)
iii) Solution C which is alkali of 0.1 M concentration
You are required to:
i) Find the effect of change of temperature on the rate of reaction between sodium thiosulphate, solution B, and hydrochloric Acid, solution A.
ii) Prepare a dilute solution of hydrochloric acid, solution A
iii) Write an ionic equation for the reaction between hydrochloric acid, solution A, and the alkali solution C.
Procedure I
Using a measuring cylinder measure 10 cm3 of solution B into a clean 100cm3 glass beaker. Place it together with its contents on a white piece of paper marked with a cross (X) on it with bold blue print. Measure the temperature of the solution and record it as shown in the table below.
Using a clean measuring cylinder, measure 5cm3 of solution A. add it to the contents of the beaker containing solution B and immediately start the stop watch. Record the time it will take for the cross (X) to become invisible when viewed above the reaction mixture in the beaker.
Wash the glass beaker used and repeat the experiment at the temperature indicated in the table below by warming sodium thiosulphate solution B to the stated temperature before adding hydrochloric Acid, solution A.
Table I
|
Experiment number
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
|
Volume of hydrochloric Acid, solution A (1 cm3) |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
|
Volume of sodium thiosulphate solution B(cm3) |
10 |
10 |
10 |
10 |
10 |
10 |
10 |
10 |
|
Temperature (0C) of sodium thiosulphate, solution B |
Room temp. |
30 |
35 |
40 |
45 |
50 |
55 |
60 |
|
Time in seconds
|
|
|
|
|
|
|
|
|
|
Reciprocal of time 1/t per seconds, S-1 |
|
|
|
|
|
|
|
|
(6 marks)
- On the grid provided, plot a graph of reciprocal of time 1/t against temperature (3 marks)
b) Comment on the effect of change in temperature on the rate of reaction between sodium
thiosulphate, solution B and hydrochloric acid, solution A. (1mark)
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
c) Use your graph to determine:
i) The time taken by the reaction when the temperature is 580C. (1mark)
ii) The temperature at which the rate of the reaction is 0.045 sec-1. (1mark)
Procedure II
Using a clean measuring cylinder, place 12.5 cm3 of solution A in a 250ml volumetric flask. Add 200 cm3 of distilled water and shake. Add distilled water upto the mark. Label this solution D. Fill a burette with solution D. Using a pipette and pipette filler, place 25.0 cm3 of solution C into a 250 ml conical flask. Add two drops of phenolphthalein indicator and titrate with solution D until the pink colour disappears.
Record your results in table II. Repeat the titration two more times and complete the table.
Table II
|
I |
II |
III |
|
|
Final Burette Reading(cm3) |
|
|
|
|
Initial Burette Reading(cm3) |
|
|
|
|
Volume of solution D (cm3) |
|
|
|
(5 marks)
d) Calculate:
- The average volume of solution D used. (1 mark)
- Moles of hydrochloric Acid, solution D used. (1 mark)
- Moles of Alkali solution C used. (1mark)
- Determine the reacting mole ratio between the hydrochloric acid, solution D, and the alkali, solution C. (1 mark)
- Write ionic equation for the reaction between hydrochloric acid, solution A and
alkali, solution C. (1mark)
Place all solid R provided into a clean boiling tube then add about 10cm3 of distilled water. Shake
the contents thoroughly then filter. Retain both the filtrate and residue. Divide the filtrate into four
equal portions.
(a) To the first portion, add sodium hydroxide solution dropwise until in excess.
|
Observation |
Inference |
|
(½ mark) |
(½ mark) |
(b) To the second portion, add about 2cm3 of Barium Chloride Solution.
|
Observation |
Inference |
|
(1 mark) |
(1 mark) |
(c) To the third portion, add 3 drops of lead (ii) nitrate solution provided followed by about 2cm3 of
2M nitric (V) acid and shake the mixture.
|
Observation |
Inference |
|
(1 mark) |
(1mark) |
(d) To the fourth portion, add 3 drops of acidified potassium manganate (VII).
|
Observation |
Inference |
|
(1 mark) |
(1 mark) |
(e) Transfer all the residue into a clean boiling tube, then add about 2cm3 of 2M nitric acid and add about 3cm3 of distilled water when all the solid has dissolved. Divide the resulting product into three equal portions.
(i) To the 1st portion add sodium hydroxide solution drop wise until in excess.
|
Observation |
Inference |
|
(½ mark) |
(½ mark) |
(ii) To the second portion, add ammonia solution drop wise until in excess.
|
Observation |
Inference |
|
(½ mark) |
(½ mark) |
(iii) To the third portion, add a few drops of potassium iodide solution.
|
Observation |
Inference |
|
( ½ mark) |
(½ mark) |
You are provided with the following;
- a rectangular glass block
- 4 optical pins
- 2 thumb pins
- a soft board
- a plain paper
Proceed as follows:
a) Place the glass block on the plain paper with one of the largest face upper most. Trace round the glass block using a pencil as shown below.
b) Remove the glass block and construct a normal at B. Construct an incident ray AB of angle of incidence, i = 200.
(c) Measure the breadth b of the glass block (1 mark)
……………………………………………………………
(c) Replace the glass block and trace the ray ABCD using the optical pins.
(d) Remove the glass block and draw the path of the ray ABCD using a pencil.
(e) Measure the length L and record it in the table below
|
Angle i0 |
L (cm) |
L2 (cm) 2 |
|
Sin2i |
|
20 |
|
|
|
|
|
30 |
|
|
|
|
|
40 |
|
|
|
|
|
50 |
|
|
|
|
|
60 |
|
|
|
|
|
70 |
|
|
|
|
(6 marks)
(f) Repeat the procedure above for the angles of incidence given.
(g) Calculate the values of 
and Sin2 I; and record in the table above.
(h) Plot a graph of (y-axis) against Sin2i. (5 marks)
(i) Calculate the gradient S of the graph (3 marks)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Given that the equation of that graph is; 
(j) Determine the value of n (3 marks)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(k) Present your work sheet; attached to the exam paper (2 mark)
You are provided with the following:
- 2 new dry cells size D
- A cell holder
- A switch
- A millimeter of range 0 to 1 mA
- A capacitor labeled C
- 8 connecting wires; at least four with crocodile clips on one end
- A stopwatch
- A carbon resistor labeled R
Proceed as follows
Connect the circuit as shown in the figure 1below, where P and Q are crocodile clips.
a) Close the switch S
b) Name the process which takes place when the switch S is closed (1 mark)
c) Connect the crocodile clips P and Q. Observe and record the highest reading of the millimeter Io
(1 mark)
d) Open the switch S and at the same time start the stopwatch to measure the time taken for the current to decrease to four fifth the value of Io i.e. 4/5Io. Record your value in the table 1.
e) Close the switch S for a second time and observe the deflection in the millimeter. (the pointer should rise back to the same initial value Io)
f) Repeat part (b) for other values of current as shown in the table 1 below. (8 marks)
|
Current I(mA) |
4/5Io
|
3/4 Io
|
2/3 Io |
1/2 Io |
2/5 Io |
1/3 Io |
1/4 Io |
|
Your calculated fraction of Io(mA) |
|
|
|||||
|
Time t(s)
|
g) Plot a graph of Current I (y – axis)(mA) against time t(s) (5 marks)
h) From your graph, findW the value of I when t = 10s. (2 marks)
i) Given that A = 10W, determine the value of A. (2 marks)
j) Determine the voltage across R att = 10sgiven that R = 4.7kΩ (1 mark)
(a) Explain the role played by insurance industry in promoting the development of Kenyan economy. (10mks)
(b) Explain clearly the tools of monetary policy used by the central bank to control inflation. (10mks)
(a) Jane,a petty cashier was given Sh ,2000 on 1st June 2005. During the month, she made the following payments:
2005 June
2 Stationery Sh 100, staff tea Sh 80.
5 Telephone bill Sh 50, postage stamps Sh 100.
8 Travelling Sh 200, telephone Sh 100.
10 Stationery Sh 50, staff tea Sh 100.
15 Postage stamps Sh 50, travelling Sh 100.
20 Sundry expenses Sh 100.
23 Stationery Sh 80, telephone Sh 40.
25 Travelling Sh 50, sundry expenses Sh 100.
28 Envelopes Sh 20, staff tea Sh 50.
30 Adhiambo, a creditor, was paid Sh 100.
(a) Use the following analysis columns to prepare a petty cash book:
Stationery, Staff tea, Travelling. Telephone, Sundry expenses. Ledger accounts. (12 mks)
(b) Explain five demerits that a country may suffer when the government becomes a major investor in business. (8 mks)
(a) Explain clearly the problems associated with expenditure approach method in measurement of national incomes. (10mks)
(b) Outline five reasons why ethical practices is necessary in product promotion. (10mks)
(a) Discuss five benefits that a customer may get by using Automated Teller Machine (ATM) for financial transactions. (8 mks)
(b) The following trial balance related to Kimani’s business as at 31st December 2012
DR(SHS) CR(SHS)
Stock on 1st January 2003 60,000
Purchases and sales 400,000 580,000
Returns 20,000 50,000
Debtors and Creditors 65,000 40,000
Premises 540,000
Machinery 200,000
Fixtures and fittings 100,000
Carriage outwards 8,000
Wages and salaries 30,000
Discounts 25,000 32,000
Commissions 16,000 14,000
Cash in hand 70,000
Capital 818,000
1,534,000 1,534,000
REQUIRED:
Prepare a trading profit and loss account for the period ended 31st December 2012 and a balance sheet as at that date if the closing stock was worth shs 70,000 (12 mks)
(a) Explain clearly the malpractices by traders against which consumers may need protection by the government. (10mks)
(b) Explain clearly with the aid of a diagram the change in equilibrium as a result of a change in demand of a commodity. (10mks)
(a) Highlight five characteristics of an efficient tax system. (10mks)
(b) Differentiate between a public limited company and a public corporation. (10mks)
Identify four reasons why many youths in urban centre are starting hawking businesses. (4mks)
a)………………………………………………………………………………………….
b)………………………………………………………………………………………….
c)…………………………………………………………………………………………....
d)…………………………………………………………………………………………....