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(a) What is meant by rate of reaction. (1 mark)
(b) In the space provided, sketch the diagram of a set-up that can be used to determine the rate of reaction between manganese(IV) oxide and hydrogen peroxide. (3 marks)
(e) A student placed a small amount of liquid bromine at the bottom of a sealed gas jar of air as shown in Figure 4.
(i) Describe what will be observed: (1 mark)
I. after two minutes . II. after 30 minutes
(ii) Use the Kinetic theory to explain the observations: (2 marks)
I. after 2 minutes . II. after 30 minutes
(d) Some plants have seeds that contain vegetable oil.
Expected Response
(a) What is meant by standard electrode potential of a an element? (1 mark)
(b) use the standard electrode potentials given below to answer the questions that follow.
(i) State whether acidified MnO4- can oxidise M2+. Give a reason. (2 marks) (ii) Select two half-cells which when combined will give the highest e.m.f. (1 mark) (iii) Write the cell representation for the cell formed in b (ii). (I mark) (iv) Calculate the E0 value for the cell formed in b (iii). (2 marks) (c) A mass of 1.24g of a divalent metal was deposited when a current of 6A was passed through a solution of the metal sulphate for 12 minutes. Determine the relative atomic mass of the metal.
(1 Faraday = 96,500 C mol-1 (3 marks)
(d) State two applications of electrolysis. (I mark)
Expected Response
(a) What ¡s meant by molar heat of neutralisation? (1 mark)
(b) In an experiment to determine the molar heat of neutralisation, 50 cm3 of 1M hydrochloric acid was neutralised by adding 10 cm3 portions of dilute sodium hydroxide. During the experiment, the data in Table 1 was obtained. 
(iii) Determine from the graph the: I. volume of sodium hydroxide which completely neutralises 50 cm3 of 1M hydrochloric acid. (1 mark) II. change in temperature,△T, when complete neutralisation occurred. (1 mark) (iv) Calculate: I. the heat change, △H when complete neutralisation occurred. (Specific heat capacity = 4.2 Jg-1K-1, density of solution 1.0 gcm-3) (2 marks) II. molar heat of neutralisation of hydrochloric acid with sodium hydroxide. (1 mark) (v) How would the value of molar heat differ if 50 cm3 of 1M ethanoic acid was used instead of 1M hydrochloric acid? Give a reason. (2 marks)
Expected Response
(a) Zinc occurs mainly as zinc blende. Name one other ore from which Zinc can be extracted. (1 mark)
(b) The flow chart in Figure 2 shows the various stages in the extraction of zinc metal. Study it and answer the questions that follow. 
(c) Explain the observations made when zinc metal is added to hot sodium hydroxide. (2 marks)
Expected Response
Figure 3 is a flow chart that shows the process that occurs in the manufacture of nitric (V) acid.
(a) Name substance P, Q, R and S.
To obtain substance R, ammonia is heated at 9000C in the presence of air and a catalyst.
The product is then cooled in air.
(e) When ammonia ¡s reacted with nitric(V) acid, it produces a nitrogenous fertiliser.
Expected Response
(a) Explain the following observations:
(b) A sample of water is suspected to contain aluminium ions (AI3+) . Describe a laboratory experiment that can be carried out to show that AI3+ ions are present in the water sample. (3 marks) (c) In an experiment to determine the number of moles of water of crystallisation of a hydrated compound, Na2S04. X H2O, 5g of the compound were heated strongly to a constant mass.
Expected Response
1.
(a) Alkanes are said to be saturated hydrocarbons.
(b) When the alkane, hexane, is heated to high temperature, one of the products is ethene.
Expected Response
Related Chemistry Questions and Answers on Organic Chemistry II Form 3 Level
​Name an appropriate apparatus that is used to prepare standard solutions in the laboratory. (1 mark)
Expected Response
​volumetric flask
​Related Chemistry Questions and Answers on Simple Classification of Substances Form 1 Level
​Draw in the space provided a labelled diagram of the set-up of the apparatus that can be used to electrolyse molten Lead (II) bromide. (3 marks)
Expected Response
​​Related Chemistry Questions and Answers on Effects of Electric Current on Substances Form 2 Level
When burning magnesium ribbon is introduced into a gas jar full of nitrogen, it continues to burn producing a greenish yellow powder.
Expected Response
140cm3 of nitrogen gas diffuses through a membrane in 70 seconds. Flow long will it take 200cm3 of carbon(IV) oxide gas to diffuse through the same membrane under the same conditions of temperature and pressure. (3 marks)
Expected Response
Chemical tests were carried out on separate samples of water drawn from the same source. The observations made were recorded as shown in Table 4.
State the inferences made in reactions:
Expected Response
Starting with copper turnings. describe how a sample of copper(II) sulphate crystals can be prepared in the laboratory. (3 marks)
Expected Response
are isotopes of element X. They occur naturally in the ratio of 9:1 respectively.
Calculate the relative atomic mass of element X. (2 marks)
Expected Response
The diagram in Figure 6 Shows radiations emitted by a radioactive sample.
Expected Response
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December 2024
AuthorMaurice Atika is a teacher and a netprenuer. |
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