- Explain how the hotness of a Bunsen burner flame can be increased. (1 mark)
- When dilute hydrochloric acid was reacted with solid B, a colourless gas which extinguished a burning splint was produced. When an aqueous solution of solid B was tested with blue litmus paper, the paper turned red/ pink.
- Identify the anion present in solid B. (1 mark)
- Write an ionic equation for the reaction between solid B and dilute hydrochloric acid. (1 mark)
- Identify the anion present in solid B. (1 mark)
- Dry ammonia gas was passed over heated lead (II) oxide and the products passed over anhydrous copper (II) sulphate as shown in the diagram below.
State:-
Two observations made in the combustion tube. (2 marks)
- The property of ammonia gas shown in the experiment. (1 mark)
-
Two observations made in the combustion tube. (2 marks)
- Starting with zinc sulphate solution, describe how a sample of zinc oxide can be obtained. (3 marks)
- Explain how conduction of electricity takes place in the following:
- Iron metal. (1 mark)
- Molten lead (II) iodide (1 mark)
- Iron metal. (1 mark)
- 100 cm3 of a sample of ethane gas diffuses through a porous pot in 100 seconds. What is the molecular mass of gas Q if 100 cm3 of the gas diffuses through the same porous pot in 121 seconds under the same conditions? (3 marks)
(C = 12.0, H = 1.0)
- Draw and name the isomers of butyne. (2 marks)
- State one use of polystyrene. (1 mark)
- Draw and name the isomers of butyne. (2 marks)
- Complete the nuclear reaction below:
(a)
(1 mark)
(b) State two uses of radioisotopes in health. (2 marks)
- The table below shows the relative molecular masses and boiling points of pentane and ethanoic acid.
Explain the large difference in boiling points between ethanoic acid and pentane. (2 marks)
- One of the ores of copper has the formula, CuFeS2.
- Describe how iron in the ore is removed during extraction of copper metal. (1 mark)
- State two environmental problems associated with extraction of copper metal. (2 marks)
- Describe how iron in the ore is removed during extraction of copper metal. (1 mark)
- Study the flow chart below and answer the questions that follow.
Identify Z and M. (2 marks)
Z
M
- The table below shows the pH values of solutions A, B, C and D.
Solution A B C D pH 2 7 11 14
Select solutions in which a sample of lead (II) hydroxide is likely to dissolve. Give reasons for each solution selected. (3 marks)
- 100 cm3 of 0.05M sulphuric (VI) acid were placed in a flask and a small quantity of anhydrous sodium carbonate added. The mixture was boiled to expel all the carbon (VI) oxide. 25 cm3 of the resulting solution required 18 cm3 of 0.1 M sodium hydroxide solution to neutralise it. Calculate the mass of sodium carbonate added. (Na = 23; O = 16.0; C = 12.0) (3 marks)
- When 20 cm3 of 1 M sodium hydroxide was mixed with 20 cm3 of 1 M hydrochloric acid, the temperature rose by 6.70C. Assuming the density of the solution is 1 g/cm3 and the specific heat of the solution is 4.2 Jg-1 k-1;
- Calculate the molar heat of neutralization. (2 marks)
- When the experiment was repeated with 1 M ethanoic acid, the temperature change was found to be lower than with 1 M hydrochloric acid. Explain. (1 mark)
- Calculate the molar heat of neutralization. (2 marks)
- Study the set-up below and answer the questions that follow.
- Write an equation for the reaction between ammonia and copper (II) oxide. (1 mark)
- During the experiment, the colour of the contents in the water trough changed. State the colour change observed and give an explanation. (2 marks)
- Write an equation for the reaction between ammonia and copper (II) oxide. (1 mark)
- A measuring cylinder fitted with moist steel wool was inverted in a trough of water as shown in the diagram below.
- State and explain the observations made in:
- Moist steel wool after four days. (1 mark)
- Water level in the measuring cylinder after four days. (1 mark)
- What would be the effect of the steel wool moistened with salty water? (1 mark)
- State and explain the observations made in:
- In an experiment of rates of reaction, potassium carbonate was reacted with dilute sulphuric (VI) acid.
- What would be the effect of an increase in the concentration of the acid in the rate of the reaction? (1 mark)
- Explain why the rate of reaction is found to increase with temperature. (2 marks)
- What would be the effect of an increase in the concentration of the acid in the rate of the reaction? (1 mark)
- Use the part of the periodic table given below to answer the questions that follow. (Letters are not the actual symbols of the elements.)
- Identify the element that forms giant covalent structures. (1 mark)
- Identify one element that does not form compounds. (1 mark)
- Write the formula for the nitride of M. (1 mark)
- Identify the element that forms giant covalent structures. (1 mark)
- Draw a set-up that can be used to separate a mixture of sand and iodine. (3 marks)
- In the contact process, during the production of sulphur (VI) oxide, a catalyst is used. Give two reasons why vanadium (V) oxide is preferred to platinum. (2 marks)
- Given that the atomic number of Y is 13 and that of Z is 9:
- Write the electronic arrangement of Y and Z; (1 mark)
- Draw the dot (.) and cross (x) diagram for the compound formed by Y and Z. (1 mark)
- Write the electronic arrangement of Y and Z; (1 mark)
- The set up below was used to separate a mixture of methanol and propanol. Study it and answer the questions that follow.
- State the function of X. (1 mark)
- Which liquid will collect first in the beaker? Give a reason. (1 mark)
- State the function of X. (1 mark)
- Study the flow chart below and answer the questions that follow.
- Name the process in step I. (1 mark)
- Identify the reagent in step II. (1 mark)
- Give one use of ethane. (1 mark)
- Name the process in step I. (1 mark)
- A student electrolysed dilute sodium chloride solution using inert carbon electodes.
Name the products at: (2 marks)- Anode;
- Cathode.
- If the experiment was repeated using concentrated sodium chloride instead of dilute sodium chloride solution, write the half equation at the anode. (1 mark)
- A student electrolysed dilute sodium chloride solution using inert carbon electodes.
- An organic compound had the following composition 37.21% carbon, 7.75% hydrogen and the rest chlorine. Determine the molecular compound of the formula mass of the compound is 65. (C = 12.0; H = 1.0; Cl = 35.5). (3 marks)
- Cotton is a natural polymer. State one disadvantage and one advantage of this polymer. (2 marks)
- Name a suitable solvent for extracting an indicator from flowers; (1 mark)
- Give a reason why the indicator named in (a) above is used. (1 mark)
- Name a suitable solvent for extracting an indicator from flowers; (1 mark)
- A student used the set up below to prepare a sample of nitrogen gas.
- State the function of potassium hydroxide in the set up. (1 mark)
- Give a suitable metal M for use in the combustion tube. (1 mark)
- Give a reason why the nitrogen gas obtained is not pure. (1 mark)
- State the function of potassium hydroxide in the set up. (1 mark)
- What is meant by the term radical? (1 mark)
- The table below contains atoms that form common radicals. Complete the table to show radicals formed from various atoms.
- What is meant by the term radical? (1 mark)
- A gas full of chlorine water was inverted over water and allowed to stand for some time.
- State and explain two observations made in the gas jar after some time. (2 marks)
- Write the equation for the reaction between chlorine and a hot concentrated potassium hydroxide. (1 mark)
- State and explain two observations made in the gas jar after some time. (2 marks)
