Explain How the Parts Labelled a and B Are Suited to Their Functions

NAME: ………………………………………………………… INDEX NO ……………………

SCHOOL ..……………………………………………………………………………………………...

1. (a) The diagram below shows some parts of a Bunsen burner. Study it and answer the questions that follow

Explain how the parts labelled A and B are suited to their functions

a) A:…………………………..………………………………………………

(1mk)

b) B:……………………………………………………………………………

(1mk)

(b) State two reasons why most apparatus in the laboratory are made of glass (1mk)

…………………………………………………………………………………………………………………………………………………………………………………………………………

When excess magnesium ribbon is burned in air, two products are formed

(i) Identify the two products (1mk)

(ii) Write two equations of the reactions that form the products in (i) above (2mks)

…………………………………………………………………………………………………………………………………………………………………………………………

Hydrogen gas was passed over heated Lead Oxide as shown in the set up below

(a) Explain why hydrogen is passed through the combustion tube before being lit (1mk)

………………………………………………………………………………………………………………………………………………………………………………………………………

(b) Write an equation for the reaction occurring at the jet. (1mk)

The table below gives some properties of elements X, Y and Z in their solid state. Study it and answer the question that follows.

Solid / Solubility in ethanol / Attraction by magnet
X / Insoluble / Not attracted
Y / Insoluble / Attracted
Z / Soluble / Not attracted

Explain how a pure sample of Z can be obtained from a mixture of X and Z

…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

5.Hydrogen Sulphide gas was passed through a solution of Iron (III) Chloride

(i) State the observations made (1mk)

………………………………………………………………………………………………………………………………………………………………………………………………………………

(ii) Write an ironic equation for the reaction taking place (1mk)

……………………………………………………………………………………………………………………………………………………………………………………………………………

6.The following is an organic compound represented as CH3 CH2 COOCH2 CH3

(i) Determine the organic acid and the alkanol used in its making (1mk)

(ii) Name the organic compound and the gas formed when the alkanol in (i) above is reacted with potassium metal (1mk)

7.When 3.125g of a carbonate MCO3 are heated to a constant mass, the volume of carbon (IV) oxide evolved during the heating is 600cm3 at room temperature and pressure. Calculate the relative atomic mass of M. (Molar volume at r.t.p =24 dm3) (3mks)

8. The table below shows the rate of decay of a sample of a radioactive substance starting with 640g.

Mass (g) / Number of months
640 / 0
80 / 1728

Determine the half life of the radioactive source

9.The apparatus below was a set up to show the catalytic oxidation of ammonia. Study the diagram and answer the questions that follow.

(i) Write an equation for the reaction that takes place in the gas jar (1mk)

(ii) Why is it necessary to have a hot nichrome wire in the gas jar? (1mk)

(iii) Write the formula of the complex ion formed when excess ammonia gas is passed through a solution containing Zn2+ ions (1mk)

10. In an experiment to study diffusion of gases, the following set up was used. Study it carefully and answer the questions that follow.

(a) Draw the set up of the same experiment (only changes in the U-tube need be drawn) after sometime. (1mk)

(b) Give an explanation for the changes (if any) noticed in the set up drawn in (a) above. (2mks)

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

11.When 1.675g of hydrated sodium carbonate was reacted with excess hydrochloric acid, the volume of carbon (iv) oxide gas obtained at room temperature and pressure was 150cm3. Calculate the number of moles of water of crystallization in one mole of hydrate sodium carbonate (Na=23, H=1, C=12, O=16, molar volume at r.t.p. =24 dm3). (3mks)

12.In the equation below, identify the reactant that acts as an acid. Explain how you arrive at your choice

(2mks)

…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

13. A solution of silver nitrate was put in a container made of metal Q for 1 day. Given that

(a) Determine whether or not a reaction occurred between silver nitrate and metal Q.

(b) Can silver nitrate solution be stored in a container made of metal Q? Give a reason.

14.When a burning candle is put into a gas jar of sulphur (iv) oxide gas, it is extinguished but a burning magnesium ribbon continues to burn. Explain these observations. (2mks)

15. (a) Explain why Potassium Carbonate can not be manufactured by the solvay

process. (1mk)

……………………………………………………………………………………………………………………………………………………………………………………………………

(b) Write an equation for the reaction that takes place in the carbonator or solvay

tower in the solvary process (1mk)

16. A student attempted to use the set up below to obtain a sample of aluminium metal

(i) Explain why the student would fail to obtain aluminium metal (1mk)

(ii) State a suitable method that can be used to obtain aluminium from its oxid (1mk)

(iii) Name one ore from which aluminium metal can be extracted. (1mk)

…………………………………………………………………………………………………

17.(a) Use the bond enthalpies given below to find the heat of reaction for

Bond / Bond enthalpy (KJ/mol)
H-H / 436
N-H / 388
NN / 944

(b) Draw an energy level diagram for the reaction in (a) above. (1½mk)

18. The set-up below was used to prepare dry chlorine gas. Study and answer the questions that follow

(a) Name reagents M and substance L

M: ………………………………………………. (½mk)

L: ……………………………………………… (½mk)

(b) A warm red phosphorus was lowered into the gas jar of chlorine using a deflagrating spoon

(i) State any one observation made in this experiment (1½mks)

…………………………………………………………………………………………………………………………………………………………………………………………………………………

(ii) Identify the substance formed in the above reaction (1½mks)

(c) Both substances in (ii) above undergo hydrolysis when exposed to air. Write an equation to show how any one of them undergoes hydrolysis (1mk)

19. An atom of element W (atomic number 11) and an atom of element Y (atomic number 9) combine to form a compound.

(a)Write the formula of the compound (1mk)

………………………………………………………………………………………………………………………………………………………………………………………………………..

(b)State the type of bond present in the compound (1mk)

(c)Identify the type of structure formed (1mk)

20. Starting with copper metal, describe how we can prepare copper (II) carbonate. (3mks)

……………………………………………………………………………………………………………………………………………………………………………………………………….

21. The equation below represents an equilibrium reaction between chromate ions and dichromate ions

(i) What would happen to the above equilibrium if aqueous sodium hydroxide is (2mks)

(ii) Calculate the oxidation number of chromium in Cr2O72- (1mk)

22. The graph below shows the behavior of a fixed mass of a gas at a constant temperature

a) What is the relationship between the volume and pressure of the gas (1mk)

…………………………………………………………………………………………………………………………………………………………………………………………………

b) Calculate the pressure required to compress 12dm3 of nitrogen gas at 1 atmosphere to give a volume of 4dm3 (2mks)

23. (a) A compound Y reacts with chlorine to form another compound whole formula is

What is the formula of compound Y?

(b) (i) In which homologous series does the compound shown below belong

CH3CH2CCCH3 ? (1mk)

(ii) Give the IUPAC name of the compound in (i) above (1mk)

……………………………………………………………………………………………………………………………………………………………………………………………….

24. What mass of copper, and what volume of oxygen (measured at standard temperature and pressure) would be liberated on electrolysis using 9650 coulombs of electricity? (Cu= 63.5, molar volume at s.t.p =22.4 dm3) (3mks)

25. An element M has two isotopes The relative atomic mass of the naturally occurring M is 63.55. Calculate the percentage abundance of each isotope (3mks)

26. When an electric current is passed through copper (II) nitrate solution for several hours. A gas that relights a glowing splint is produced at electrode X

(i) Which of the electrode is the cathode? Give a reason (1mk)

(ii)Write an equation for the formation of the gas electrode X (1mk)

(iii)State the observation that would be made in the copper (II) nitrate solution (1mk)

27. A compound has the following composition by mass

Carbon = 40.0% Hydrogen = 6.7% Oxygen = 53.3%

Given that the relative molecular mass of the compound is 180, determine its molecular formula (C=12.0, H=1.0, O= 16.0) (3mks)

28. The chromatogram below shows the constituents of a flower extract. Study it and answer the question that follow

c) Give a reason to explain the different positions of red and yellow pigments. (2mks)

d) What does the line labelled X represent? (1mk)

29. The melting point of phosphorus trichloride is -910C while that of sodium chloride is 8010C. In terms of structure and bonding explain the difference in their meting points (3mks)