The diagram below represents a chromatogram of different pigments of a leaf extract. Study it and answer the questions that follow.

a) Name a suitable solvent for the dye (1mk)

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

b) Identify the least soluble pigment in the extract. Give a reason (2mks) ................................................................................................................................................. ................................................................................................................................................. ................................................................................................................................................. .................................................................................................................................................

c) Name the part labeled Y in the diagram above (1mk) ................................................................................................................................................. .................................................................................................................................................

The table below shows pH values of solutions A B C and D. Study it answer the questions that follow

a) Which solution produces bubbles of a gas with zinc metal? Give a reason (2mks) ................................................................................................................................................. ................................................................................................................................................. ................................................................................................................................................. .................................................................................................................................................

b) Which solution is most likely to be wood ash? (1mk) .................................................................................................................................................

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

The diagram below is a sketch of the graph of catalysed decomposition of hydrogen peroxide.

a) What does Z represent? (1mk)

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

b) Name one suitable catalyst that can be used (1mk) ................................................................................................................................................. .................................................................................................................................................

Study the flow chart below and answer the questions that follow.

Identify; a) Solid T (1mk)

...............................................................................................................................................
b) Gas L (1mk)

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

c) Process V (1mk)

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

If it takes 30 seconds for 100cm3 of Carbon (IV) oxide gas to diffuse across a porous plate . How long will it take 150cm3 of Nitrogen (IV) Oxide gas to diffuse across the same plate under similar conditions

A hydrocarbon slowly decolourizes bromine gas in the presence of sunlight but does not decolourize acidified potassium manganate (VII). Name and draw the structural formula of the fourth member of the series to which the Hydrocarbon belongs. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ...............................................................................................................................................

The diagram below shows the set-up that was used to prepare and collect sulphur (IV) oxide gas.

a) Identify solid P (1mk)

....................................................................................................................................
b) Why is it possible to collect Sulphur (IV) oxide as shown? (1mk) .................................................................................................................................... ....................................................................................................................................

c) What happened to the red flower at the end of the experiment? (1mk) .................................................................................................................................... ....................................................................................................................................

Describe a chemical test that you would use to distinguish between nitrogen (I) oxide and nitrogen (II) oxide. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

a) Explain why hard water containing and flowing in lead pipes may be safer for drinking than soft water flowing in the same pipes. (2mks) .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

b) Identify the cations responsible for hardness of water. (1mk)

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

a) State the Hess’s Law of constant heat summation. (1mk)

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

b) Use the thermochemical equations below to answer the questions that follow.

Determine the enthalpy of formation of Calcium carbonate given the equation below;

A weighed sample of crystalline sodium Carbonate . was heated in a crucible until there was no further change in mass. The mass of the sample reduced by 63%. Calculate and hence determine the value of n (Na=23, O=16, C=12, H=1).

The set up below shows an experimental where dry hydrogen gas was passed over heated copper (II) oxide.

a) State and explain an observation made in the combustion tube. (2mks) .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

b) Why is it necessary to burn excess hydrogen gas? (1mk)

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

Starting with copper metal, describe how a sample of crystals of copper (II) Sulphate is prepared in the laboratory. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

The table below gives information about elements J,K,L,M. Which are in the same group of the periodic table. The letters do not represent the actual symbols of the elements. Use the information to answer the questions that follow.

a) What is meant by Ionization Energy (1mk)

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

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

b) Select the element which is the most reactive. Explain (2mks) .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

Below is a structure of Aluminium Chloride

a) Identify the bonds labeled A and B

A.................................................................................................. ( 1mk)

B.................................................................................................. ( 1mk)

b) When aluminium Chloride is dissolved in water the resulting solution has a pH of 3. Explain (2mks) .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

The diagram below shows part of the Solvay process

a) Name solid X (1mk)

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

b) State the process taking place in chamber C (1mk)

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

c) State any one use of sodium carbonate (1mk)

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

a) Define the term isomerism (1mk)

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

b) Draw and name the Isomers of butane (2mks)

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

Study the set-up below and answer the questions that follow

a) Write equations for the reactions at the; i) Cathode (1mk)

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

ii) Anode (1mk)

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

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

b) Give a reason why this experiment is carried out in a fume chamber. (1mk) .................................................................................................................................... ....................................................................................................................................

The graph below shows a curve obtained when water at 220C was heated for 10 minutes. Sodium chloride crystals were added and strongly heated for 15 minutes.

a) What happened to water molecules between points A and B (1mk) ....................................................................................................................................

b) Explain why the temperature rise is not steady between points B and C (2mks) .................................................................................................................................... ....................................................................................................................................

a) Define the term solubility (1mk)

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

b) Study the table below and answer the questions that follow.

A mixture containing 30g of potassium nitrate and 18g of potassium chlorate (V) solution was cooled from 500C to 200C. Determine the mass of the salt that would crystallize out. (2mks)

The following diagram shows the incomplete set-up for the preparation of dry hydrogen chloride gas.

a) Complete the diagram above to show how the dry hydrogen chloride can be collected. (2mks)

b) Write an equation to show the reaction that took place. (1mk) .................................................................................................................................... ....................................................................................................................................

Zinc (II) oxide reacts with acids and strong bases a) Write the equation for the reaction between zinc (II) oxide and

i) Dilute sulphuric (VI) acid (1mk)

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

ii) Sodium hydroxide solution (1mk)

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

6.84g of aluminium sulphate were dissolved in 200cm3 of water. Calculate the concentration of the sulphate ion in moles per litre. (R.f.m of aluminium sulphate is 342)

Nitrogen and Oxygen gases react according to the equation below;

Show the reaction above on an energy level diagram. (3mks)

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

The electron arrangement of both X2+(aq) and Y-(aq) ions is 2;8

a) Write the electron arrangement of:

i) X (1mk) ....................................................................................................................................

ii) Y (1mk) ....................................................................................................................................

b) Write the formula of the compound formed between X and Y. (1mk) .................................................................................................................................... ....................................................................................................................................

The reaction between ammonia gas and water is as follows

Identify the species that acts as an acid in forward reaction. Give a reason for your answer (2mks) .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

Both sodium and aluminium have giant metallic structure but different melting points. Explain .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

Nitrogen gas does not support combustion but a piece of hot magnesium metal reacts with it. Explain

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

Both mercury and molten lead (II) bromide conduct an electric current. State two differences in their electrical conductivity.

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