Classify the computers that are used to control air traffic in the airport. Explain your answer. (Answered)
Give a short description of three types of microcomputers. (Answered)
Differentiate between the home and end keys on the keyboard. (Answered)
Mention four ways of preventing dust accumulation in a computer laboratory and on computer
systems and equipment. (Answered)
Name the generation of computers that used the following devices for the first time.
i)Floppy disk ii)Optical disk
iii)Voice recognition devices
iv)Monitor. (Answered)
Define peripheral devices. Give any two examples. (Answered)
List three precautions that should be taken when laying cables in a computer laboratory. (Answered)
Outline the procedure for shutting down a computer. (Answered)
Explain how a cordless mouse works. (Answered)
Describe the following mouse actions. (Answered)
Give three ways in which computers are used in the health sector. (Answered)
State four precautions that should be taken when handling a diskette. (Answered)
Give one application of a floppy disk. (Answered)
List any three embedded computers. (Answered)
State and explain three behaviors that should be avoided in a computer laboratory. (Answered)
List three factors that might have been considered when setting aside the room for computer laboratory. (Answered)
List any four differences between the present computers and the pre-electronic age computers. (Answered)
Describe the process of cold-booting a computer. (Answered)
Differentiate between job replacement and job displacement and relate to computerization of
organization. (Answered)
List three uses of computer in entertainment. (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)