Chlorine and iodine are elements in the same group in the periodic table. Chlorine gas is a yellow while aqueous, iodine , #I_2(aq)# is brown.
(a) What observation would be made if chlorine gas is bubbled through aqueous sodium iodide?
Explain using an ionic equation.
(b) Under certain conditions chlorine and iodine react to give iodine trichloride, #ICl_3(s)#. What type of bonding would you (Answered) (a) In an experiment hydrogen chloride gas was prepared and reacted with aluminium
turnings to form a solid Q and gas R as shown below.
(i) Name: Liquid P, Gas R, Solid Q
(ii) Name another substance that could serve the same purpose as the concentrated sulphuric (VI) acid.
(iii) Explain the following observation. When a blue litmus paper was dipped into the water
in the beaker at the end of the (Answered) During laboratory preparation of carbon(IV) oxide gas, dilute hydrochloric acid was added
to Substance L in a conical flask.
(a) Identify substance L.
(b) Write an equation that produces carbon(IV) oxide.
(c) State the observations made when the gas produced when bubbled through calcium hydroxide solution for a long time.(Answered) In Kenya, sodium carbonate is extracted from trona at Lake Magadi.
(i) Give the formula of trona.
(ii) Name the process of extracting sodium carbonate from trona.
(b) The flow chart in Figure 5 summarises the steps involved in the production of sodium carbonate. Use it to answer the questions that follow.
(i) Name the process illustrated in Figure 5.
(ii) Identify the starting raw materials (Answered) Study the flow chart in Figure 1 and answer the questions that follow. Gas N forms a while
suspension with aqueous calcium hydroxide.
(a) Name the anion present in the potassium salt.
(b) Write an ionic equation for the formation of solid M.
(c) Give one use of gas N.(Answered) State a method that can be used to collect dry carbon(IV) oxide gas. Give a reason.(Answered) Explain why it is not advisable to prepare a sample of carbon(IV) oxide using barium carbonate and dilute sulphuric(VI) acid.(Answered) Charcoal is a fuel that is commonly used for cooking. When it burns it forms two
oxides.
(a) Name the two oxides.
(b) State one use of the two oxides.(Answered) The set up below was used to collect a dry sample of a gas.
Give two reasons why the set up cannot be used to collect carbon (IV) oxide gas.(Answered) What is the role of carbon (IV) oxide in fire extinguishing?(Answered) Describe how carbon (IV) oxide can be distinguished from carbon II oxide using calcium hydroxide solution.(Answered) a) Diamond and graphite are allotropes of carbon. What is meant by an allotrope?
(b) Explain way graphite can be used as a lubricant while diamond cannot.(Answered) Graphite is one of the allotropes of carbon.
(a) Name one other element which exhibits allotropy.
b) Explain why graphite is used in the making pencil leads.(Answered) Carbon (II) oxide is described as a “silent killer”.
(a) State one physical property of carbon (II) oxide that can make it a “silent killer”
(b) State and explain one chemical property that makes carbon (II) oxide poisonous to human beings.(Answered) Study the flow chart below and answer the questions that follow.
(a) Give the name of the process that takes place in step I
(b) Give ;
(i) The name of substance G1
(ii) One use of substance F1(Answered) Carbon exists in different crystalline forms. Some of these forms were recently discovered in soot and are called fullerenes
(i) What name is given to different crystalline forms of the same element?
(ii) Fullerenes dissolve in methylbenzene while the other forms carbon do not. Given that soot is a mixture fullerenes and other solids forms of carbon, describe how crystals of fullerenes can be (Answered) Give a reason why ammonia gas is highly soluble in water(Answered) The set-up below was used to collect a dry sample of a gas.
Give two reasons why the set-up cannot be used to collect carbon (IV) oxide gas.(Answered) The diagram below shows a ‘jiko’ when in use. Study it and answer the questions that follow.
(a) Identify the gas formed at region A
(b) State and explain the observation made at region B.(Answered) The diagram below represents part of a set-up used to prepare and collect gas T.
(a) Name two reagents that are reacted to produce both carbon (IV) oxide and carbon (II) oxide.
(b) Write the equation for the reaction which takes place in the wash bottles.
(c) Give a reason why carbon (II) oxide is not easily detected.(Answered) Dry carbon (II) oxide gas reacts with heated lead (II) oxide as shown in the equation below.
#Pb(s) +CO(g)rightarrow Pb(s)+CO_2(g)#
(a) Name the process undergone by lead (II) oxide.
(b) Give a reason for your answer in (a) above.
(c) Name other gas that can be used to perform the same function as carbon
(II) oxide gas in the above reaction.(Answered) The set-up below was used to obtain a sample of iron.
Write two equations for the reactions which occur in the combustion tube.(Answered) In terms of structure and bonding, explain why graphite is used as a lubricant.(Answered) a) The set-up below was used to collect gas F, produced by the reaction between water and calcium metal
(i) Name gas F
ii) At the end of the experiment, the solution in the beaker was found to be weak base. Explain why solution was a weak base.
iii) Give one laboratory use of the solution formed in a beaker.
(b) The scheme below shows some reactions starting calcium oxide. Study it and answer ques(Answered) Carbon (II) oxide gas was passed over heated iron (III) oxide as shown in the diagram below.
(a) Give the observation made in tube P.
(b) Write the equation for the reaction which takes place in tube P.(Answered) Both diamond and graphite have giant atomic structures. Explain why diamond is hard while graphite is soft.(Answered) When steam was passed over heated charcoal as shown in the diagram below, hydrogen and carbon (II) oxide gases were formed.
(a) Write an equation for the reaction which took place.
(b) Name two uses of carbon (II) oxide gas which are also uses of hydrogen gas.(Answered) When carbon (IV) oxide gas was passed through aqueous calcium hydroxide a white suspension was formed.
(a) Write an equation for the reaction that took place.
(b) State and explain the changes that would
occur when carbon (IV) oxide gas is bubbled through the white suspension.(Answered) The apparatus shown below was used to investigate the effect of carbon (II) oxide on copper (II) oxide.
(a) State the observation that was made in the combustion tube at the end of the experiment.
(b) Write an equation for the reaction that took place in the combustion tube.
(c) Why is it necessary to burn the gas coming out of tube K?(Answered) a)What observation would be made if hydrogen sulphide gas was bubbled through a solution of zinc nitrate?
(b) Write an equation for the reaction that takes place in (a) above.(Answered) Explain why burning magnesium continues to burn in a gas jar containing sulphur (IV) oxide while a burning splint is extinguished.(Answered) In an experiment, carbon (IV) oxide gas was passed over heated charcoal
and the gas produced collected as shown in the diagram below.
i) Write an equation for the reaction that took place in the combustion tube.
(ii) Name another substance that can be used instead of sodium hydroxide.
(iii) Describe a simple chemical test that can be used to distinguish
between carbon (IV) oxide and carbon (II) (Answered) The following diagrams shows the structures of two allotropes of carbon. Study them and answer the questions that follow.
(i) Name the allotrope M and N
ii) Give one use of N
(iii) Which allotrope conducts electricity? Explain.(Answered) State and explain the function of tartaric acid in baking powder.(Answered) Explain why it is not advisable to leave jiko with burning charcoal in a closed room where one is sleeping.(Answered) Study the information in the table below and answer the questions that follow.
(The letters do not represent the actual symbols of the elements)
Selects an element which:
(a) Is likely to be in group II of the periodic table
(b) Could be used to make electric cables.
(c) Is likely to be graphite(Answered) The simplified flow chart shows some of the steps in the manufacture of sodium carbonate by Solvay process.
(a) Identify substance L
(b) Name the process taking place in step II
(c) Write an equation for the reaction which takes place in step III.(Answered) When excess carbon (II) oxide gas was passed over heated lead (II) oxide in a combustion tube, lead (II) oxide was reduced.
(a) Write an equation for the reaction, which took place.
(b) What observation was made in the combustion tube when the reaction was complete?
(c) Name other gas which could be used to reduce lead (II) oxide.
(Answered) The diagram below represents a charcoal burner. Study it and answer the question that follows:
Write equations for the reactions taking place at I and I.(Answered) When extinguishing a fire caused by burning kerosene, carbon (IV) oxide is used in preference to water. Explain.(Answered) Write an equation for the reaction that takes place when carbon (II) oxide gas is passed over heated Lead (II) oxide.(Answered) Give a reason why calcium hydroxide solution is used to detect the presence of carbon (IV) oxide gas while sodium hydroxide is not(Answered) The following tests were carried out on three separate portions of a colourless solution R.
(a) From the information in test (i), name a cation which is not present in solution
(b) Identify a cation, which is likely to be present in solution S
(c) Write an ionic equation for the reaction which takes place in test(ii)(Answered) a) What method can be used to separate a mixture of ethanol and propanol?
(b) (i) Explain how a solid mixture of sulphur and sodium chloride can be separated into solid sulphur and solid sodium chloride.
(ii) How can one determine if the solid sulphur is pure?
(c) The table below gives the solubilities of potassium bromide and potassium sulphate at #0^0C# and #40^0C#
(Answered) a) Study the information in the table below and answer the questions that follow. (the letter do not represent the actual symbols of the elements)
(i) What is the general name to the group in which elements P,Q, and R belong?
(ii) What is meant by ionization energy?
iii) Explain why element P have the highest ionization energy.
(iv) When a piece of element Q is placed on water it melts and a (Answered) How does distillation remove hardness from water(Answered) State one cause of temporary hardness in water(Answered) a) A student was supplied with colourless liquid suspected to be water.
(i) Describe two chemical test that could have been used to show that liquid was water.
(ii) How could it have been shown that liquid was pure water?(Answered) Sample solutions of salts were labeled as I, II, III and IV. The actual solutions, not in that order , are lead nitrate, zinc sulphate, potassium chloride and calcium chloride.
(a) When aqueous sodium carbonate was added to each sample separately, a white precipitate was formed in I, III and IV
only. Identify solution II.
(b) When excess aqueous sodium was added to each sample separately, a white (Answered) The table below shows the tests carried out on separate samples of water drawn from a well and the results obtained.
(a) Identify the cation and the anion present in the water.
(b) Write an ionic equation for the reaction which takes place in test (iii)(Answered) When solid magnesium carbonate was added to a solution of hydrogen chloride in methylbenzene, there was no apparent reaction. On addition of water to the resulting mixture, there was vigorous effervescence. Explain these observations.(Answered) State and explain one disadvantage of using hard water in boilers.(Answered) The table below shows the solubility of a salt at various temperatures
What would happen if a sample of a saturated solution of the salt at #40^0#C is heated to #80^0#C? Explain(Answered) The column below was used to soften hard water
(i) Explain how hard water was soften as it passed through the column.
(ii) After sometime the material in the column is not able to soften hard water. How can the material be reactivated?
(b) Give one advantage of using hard water for domestic purposes.(Answered) A bee-keeper found that when stung by a bee, application of a little solution of sodium hydrogen carbonate helped to relieve the irritation from the affected area. Explain.(Answered) The scheme below shows some reaction sequence starting with solid N.
(a) Identify solid N
(b) Write the formula of the complex ion present in solution Q(Answered) Distinguish between a strong and a weak acid. Give an example of each.(Answered) A sample of water drawn from a river passing through an agricultural district was divided into two portions. The first portion gave a white precipitate when acidified barium chloride was added. The second portion when warmed with aqueous sodium hydroxide gave a colourless gas which turned a moist red litmus paper blue.
(a) Identify the ions present in the river water.
(b) Suggest the possible (Answered) Study the information in the table and answer the question below the table.
Describe how a solid sample of substance A could be obtained from a solid mixture of A and B(Answered) (a) Give the formula of an oxide which reacts with both dilute hydrochloric acid and hot concentrated sodium hydroxide
(b) Give the formulae of the products formed when oxide in (a) above reacts with excess hot concentrated sodium hydroxide(Answered) #90cm^3# of 0.01M calcium hydroxide were added to a sample of water containing 0.001 moles of calcium hydrogen carbonate.
(a) Write an equation for the reaction which took place
(b) Calculate the number of moles of calcium ions in #90cm^3# of 0.01M calcium hydroxide.(Answered) What would be observed if soap solution was added dropwise to a sample of the water after the addition of the calcium hydroxide? Give a reason.(Answered) Study the scheme below and answer the questions that follows.
(a) Write the formula of the cation present in solution F.
(b) What property of chlorine is shown in step I.
(c) Write an equation for the reaction which occur in step III.(Answered) In an equation below, identify the reagent that acts as a base. Give a reason(Answered) Study the chart below and answer the questions that follow:
(a) Identify:
(i) The metal ions in solution K
(ii) The white precipitate L
(b) What property of the white precipitate L is illustrated by step I and II?(Answered) Explain the following observation. Chloride dissolves in water to form an electrolyte while the same chloride dissolves in methylbenzene to form a non-electrolyte.(Answered) The table shows how solubility of some substances in water varies with temperature.
Which of the above substances is likely to be a gas? Explain.(Answered) in an experiment, soap solution was added to three separate samples of water. The table below shows the volumes of the soap solutions required to form lather with #1000cm^3# of each sample of water before and after boiling.
a) Which water sample is likely to be soft? Explain.
(b) Name the cause of change in the volume of soap solution used in sample III(Answered)
