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There is a constant increase in mass caused by constant addition of CH2 hence the successive heats of combustion are close.
johnmulu answered the question on May 25, 2017 at 08:39
- The flow chart below shows a series of reactions starting with ethanol. Study it and answer the questions that follow. (Solved)
The flow chart below shows a series of reactions starting with ethanol. Study it and answer the questions that follow.
(i) Name: I. Process A. II. Substances B and C
(ii) Explain why it is necessary to use high pressure to change gas B into the polymer.
Date posted: May 25, 2017. Answers (1)
- The structures below represents a portion of a polymer. (Solved)
The structures below represents a portion of a polymer.
Give:
(a) The name of the polymer.
(b) One industrial use of the polymer.
Date posted: May 25, 2017. Answers (1)
- Study the scheme given below and answer the questions that follow. (Solved)
Study the scheme given below and answer the questions that follow.
(i) Name processes I and II
(ii) Identify the products A and B.
(iii) Name one catalyst used in process II.
Date posted: May 25, 2017. Answers (1)
- Ethane and Ethene react with bromine according to the equation given below. (Solved)
Ethane and Ethene react with bromine according to the equation given below.
(i) $C_2H_6(g) \; + \; Br_2(g) \rightarrow C_2H_5Br_2(g) + HBr(g)$
(ii) $C_2H_4(g) \; +\; Br_2(g) \rightarrow C_2H_4Br_2(l)$
Name the type of bromination reaction that takes place in: (i) and (ii).
Date posted: May 25, 2017. Answers (1)
- Give the names of the following compounds (Solved)
Give the names of the following compounds
Date posted: May 25, 2017. Answers (1)
- The scheme below was used to prepare a cleansing agent. Study it and answer the questions that follow. (Solved)
The scheme below was used to prepare a cleansing agent. Study it and answer the questions that follow.
(i) What name is given to the type of cleansing agent prepared by the method shown in the scheme?
(ii) Name one chemical substance added in step II.
(iii) What is the purpose of adding the chemical substance named in (ii) above.
(iv) Name one other suitable substance that can be used in step I
(v) Give one advantage of using the cleansing agent above.
Date posted: May 25, 2017. Answers (1)
- Study the scheme given above and answer the questions that follow. (Solved)
Study the scheme given above and answer the questions that follow.
(i) Name the reagents used in:
Step I.... Step II.. Step IV ...
(ii) Explain one disadvantage of the continued use of items made from the compound formed in step III.
Date posted: May 25, 2017. Answers (1)
- The structure shown below represent two cleansing agents, A and B.(Solved)
The structure shown below represent two cleansing agents, A and B.
Which cleansing agent would be more suitable for washing in water containing magnesium sulphate? Give a reason.
Date posted: May 25, 2017. Answers (1)
- Study the table below and answer the questions that follow:(Solved)
Study the table below and answer the questions that follow:
(i) Which of the compounds is a solid at 10.0 o C? Explain.
(ii) Choose two compounds which are members of the same homologous series and explain the difference in their melting points.
(iii) The compound C3H8O is an alcohol. How does its solubility in water differ from the solubility of C5H12 in water? Explain.
Date posted: May 25, 2017. Answers (1)
- A mixture of pentane and pentanoic acid was shaken with 0.1 M sodium hydroxide solution and let to separate as shown in the diagram below: (Solved)
A mixture of pentane and pentanoic acid was shaken with 0.1 M sodium hydroxide solution and let to separate as shown in the diagram below:
Name the main component in layer W.
Give a reason for the answer.
Date posted: May 25, 2017. Answers (1)
- A compound whose structure is shown below is found in a detergent(Solved)
A compound whose structure is shown below is found in a detergent
With reference to the structure, explain how the detergent removes grease during washing
Date posted: May 19, 2017. Answers (1)
- The diagram below represents a set-up of an electrolytic cell that can be used in the production of aluminium. (Solved)
The diagram below represents a set-up of an electrolytic cell that can be used in the production of aluminium.
(a) Give a reason why the electrolytic process is not carried out below 950oC.
(b) Give a reason why the production of aluminium is not carried out using reduction process.
Date posted: May 19, 2017. Answers (1)
- The flow chart below shows some process involved in the industrial extraction of zinc metal. (Solved)
The flow chart below shows some process involved in the industrial extraction of zinc metal.
(a) Name one ore from which zinc is extracted.
(b) Write the equation of the reaction taking place in unit II.
(c) Name two uses of zinc metal.
Date posted: May 19, 2017. Answers (1)
- The diagram below shows a simplified furnace used in the extraction of zinc. Study it and answer the questions that follow; (Solved)
The diagram below shows a simplified furnace used in the extraction of zinc. Study it and answer the questions that follow;
(i) Name two other substances that are also introduced in the furnace together with roasted ore.
(ii) In which physical state is zinc at point Y in the furnace? Give a reason.
(iii) Suggest a value for the temperature at point X in the furnance. Give a reason
Date posted: May 19, 2017. Answers (1)
- Iron is obtained from haematite using a blast furnance shown in figure 5 below. (Solved)
Iron is obtained from haematite using a blast furnance shown in figure 5 below.
(a)Four raw material are required for the production of iron. Three of these are iron oxide hot air and Limestone. Give the name of the fourth raw material.
(b) Explain why temperature in the region marked Y is higher than that of the incoming hot air.
Date posted: May 17, 2017. Answers (1)
- During the extraction of aluminium from its ores, the ore is first purified to obtain alumina. The flow chart below shows the stages in the extraction of aluminium from alumina. (Solved)
During the extraction of aluminium from its ores, the ore is first purified to obtain alumina. The flow chart below shows the stages in the extraction of aluminium from alumina.
(a) Name
(i) Substance C1
(ii) Process D1
(b) Give two reasons why aluminium is used extensively in the making of cooking pans.
Date posted: May 17, 2017. Answers (1)
- The flow chart below shows a sequence of chemical reactions starting with copper. Study it and answer the questions that follow. (Solved)
The flow chart below shows a sequence of chemical reactions starting with copper. Study it and answer the questions that follow.
In step 1, excess 3 M nitric (V) acid was added to 0.5 g of copper powder.
(i) State two observations which were made when the reactions was in progress.
(ii) Explain why dilute hydrochloric acid cannot be used in step 1.
Date posted: May 17, 2017. Answers (1)
- Below is a simplified diagram of the Downs Cell used for the manufacture of sodium. Study it and answer the questions that follow. (Solved)
Below is a simplified diagram of the Downs Cell used for the manufacture of sodium. Study it and answer the questions that follow.
(i) What material is anode made of? Give a reason
(ii) What precaution is taken to prevent chlorine and sodium from re-combining?
(iii) Give any two uses of sodium
Date posted: May 17, 2017. Answers (1)
- The flow chart below shows steps used in the extraction of zinc from one of its ores. (Solved)
The flow chart below shows steps used in the extraction of zinc from one of its ores.
(a) Name the process that is used in step 2 to concentrate the ore.
(b) Name one use of zinc other than galvanizing
Date posted: May 16, 2017. Answers (1)
- The extraction of iron from its ores takes place in the blast furnace. Below is a simplified diagram of a blast furnace. Study it and answer the questions that follow. (Solved)
The extraction of iron from its ores takes place in the blast furnace. Below is a simplified diagram of a blast furnace. Study it and answer the questions that follow.
Name
(i) One of the substance in the slag.
(ii) Another iron ore material used in the blast furnance.
(iii) One gas which is recycled.
Date posted: May 16, 2017. Answers (1)