-
When air is bubbled through pure water of pH 7.0, the pH drops to 6.0. Explain.
Date posted:
November 1, 2019
-
The sketch below shows a graph of temperature against time obtained when a gaseous substance was cooled.
Explain what happens to the gaseous substance between:
a)T and U
b)U and V
c)V and W
Date posted:
November 1, 2019
-
The flow chart below illustrates the extraction of Zinc. Study it and answer the questions that follow:
a) Name:-
i) Gas Q
ii) Liquid R
(iii) Residues S
b) Name the sulphide ore used
c) Before the ore is roasted, it is first concentrated;
(i) Explain why it is necessary to concentrate the ore
(ii) Explain briefly the process of concentrating the ore
d) Write an equation for the reaction that takes place in the:-
(i) Roaster
(ii) Reaction chamber
(e) (i) Name one major impurity present in the sulphide ore used
(ii) Write an equation to show how the impurity in (e)(i) above is removed
f) Given that the sulphide ore contains only 45% Zinc sulphide by mass, calculate :
(i) The mass in grams of Zinc sulphide that would be obtained from 250kg of the ore.
(ii) The volume of Sulphur (IV) oxide that would be obtained from the mass of sulphide
ore at room temperature and pressure
(Zn = 65.4, S = 32.0, O= 16.0, I mole of gas occupies 24.0 liters at r.t.p)
Date posted:
November 1, 2019
-
The diagram below is a flow chart for the extraction of copper. Study it and answer the questions that follow:
(a) Write the formula of the major ore of copper metal
(b) Name process II
(c) Give an equation for the reaction that occurs in stage III
(d) Explain what happens in stage IV
(e) Write half cell equations occurring at the anode and cathode in stage VII
(f) Draw a simple diagram showing the set-up that is used in electrolytic purification of copper
Date posted:
November 1, 2019
-
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) Write an equation for the reaction which takes place in step 3
Date posted:
November 1, 2019
-
The stages shown in the following diagram can be used to extract zinc from its oxide.
Name the stage and the process taking place in it:-
Stage 1
Stage 2
Stage 3
Date posted:
November 1, 2019
-
What properties of aluminium and its alloys make it suitable for use in making aircraft parts
Date posted:
November 1, 2019
-
Suggest one manufacturing plant that can be set up near zinc extraction plant. Give
reasons for your answer
Date posted:
November 1, 2019
-
Give one environmental hazard associated with the extraction of zinc metal
Date posted:
November 1, 2019
-
You are provided with 20.0cm3 of 2M sodium hydroxide solution. Explain how you would prepare a solution of sodium hydroxide whose concentration is 0.16M.
Date posted:
October 31, 2019
-
A manufacturing company operates an imprest of sh.10,000. On 1/6/2013 the petty cashier had a balance of sh. 4000. She received a reimbursement to restore it on 5/6/2013.
The following transactions took place during the month:
June 8 Paid Amos a creditor sh. 500
June 9 Paid postage sh. 300
June 10 Paid for cleaning for sh. 480
June 11 Bought stamps for sh. 180
June 12 Paid for cleaning sh. 750
June 13 Paid for travelling sh. 400
June 14 Paid for tea leaves sh. 450
June 15 Paid for stationery sh. 450
Required:
Prepare the petty cash book for the manufacturing company for the month of June 2013
with the following analysis column.
Travelling, cleaning, stationery, tea, postage, ledger account.
Date posted:
October 31, 2019
-
The following account balances were extracted from the books of Maisha Traders as at 30th June 2013.
Prepare a trial balance for the business.
Date posted:
October 31, 2019
-
The following is a list of source documents. Indicate the book of original entry related to each document.
Date posted:
October 31, 2019
-
Name four sources of energy which are environmentally friendly.
Date posted:
October 31, 2019
-
Study the cash book below and answer the questions that follow:
a)Balance the cash book as at 11.1.014.
b)State the transactions that took place on:
i)5.1.014
ii)8.1.014
iii)10.1.014
iv)State the name used to refer to the entry on 10.1.014
Date posted:
October 31, 2019
-
In the spaces provided write decrease, increase or no effect to show the effects of each one of the following transactions on the assets, liabilities and capital.
Date posted:
October 31, 2019
-
Complete the sentences below using the correct option from those given in brackets.
1. We _______________________ to have construction work start in January. (intent/intend)
2. When their children were grown up, Kahiga and his wife __________________ (adapted/adopted) a son.
3. This school has been chosen as the centre of _____________________ in the county. (excellency/excellence)
Date posted:
October 31, 2019
-
The following diagram represents the electrolysis of dilute sodium chloride solution using inert
electrodes
Determine the electrode at which different electrolytic products would be produced if the solution is electrolysed for several hours. Explain
Date posted:
October 31, 2019
-
Read that passage below and answer the questions that follow.
Even though tattoos are sometimes associated with rebellion, they have longstanding history among
communities around the world. Tahitians, for instance used tattoos as a permanent way of preserving their
culture and to show social ranking. Early Christians, on the other hand, often had the sign of a cross tattooed on their bodies, particularly their faces and arms, representing a permanent mark of the believer's faith.
The word 'tattoo' is derived from a Tahitian word tatau that means to mark. Tatau has been suggested to be the onomatopoeic sound tap, tap, tap made by the tapping of a tattoo instrument as it works on skin while 'au' is associated with the cry of pain a person gives when being tattooed.
The first ever tattoo to be found on a human being was found on a mummified iceman in 3,300BC with 58
tattoos on his body, which contained lines and dots. This is nothing, however, compared to Scottish Tom
Leopard, recorded as the world's most tattooed person, with 99.9 per cent of his body covered in leopard
skin design. Guinness world records record that the only part of his body that remained untattoed is the skin between his toes and inside of his ears.
When receiving a tattoo, the skin is pierced between 50 to 3,000 times per minute by a needle in the tattoo machine. Most tattoo machines consists of four parts: the needle, the tube that holds the ink, an electric motor, and a foot pedal that controls the movement ; almost similar to how a sewing machine works.
Sterilization and disposable materials are crucial to tattooing because tattoos are created by thousands of puncture marks to the skin, each of which could be infected. The autoclave is a safe popular way to sterilize any tattoo equipment that is not disposable. A combination of heat, steam and pressure kills all bacterial and organisms to prevent infection.
In the late 18th and early 19th centuries, tattoos were dangerous to have. European 'head hunters' caused a
terror by collecting tattooed Maori heads. As the odd sport became popular, more Moaris were murdered to
meet the demand. In the time, slaves began being tattooed so that their heads could be cut off and sold.
Luckily, however, Christian missionaries in the cook Island condemned the practice of tattooing quoting
the Bible “… do not cut your bodies for the dead or put marks on yourself….” They tried to stamp out the
custom going as far as trying to remove tattoos by rubbing the skin with sandstone in a practice that was
known as ' holy stoning'. This was the primitive forerunner to modern tattoo removal known as
dermabrasion, where the skin is 'sanded' to remove layers. Dermabrasion has now largely given way to
laser surgery as a popular means of tattoo removal.
While tattoos bring colour to humanity, research has shown that unclean tattooing practices can transmit
diseases such as hepatitis B. Some pigments used in tattoos contain metals that can cause pain during a
Magnetic Resonance Imaging (MRI) test, or even affect the resulting MRI image. Because of the possible
negative effects tattoos pose to humans, those keen on getting one have to be very careful before they get
one. That said, it is important to note that presently, many tattoo artists earn a good living out of the art.
(a) From paragraph one, state two historical uses of tattoos.
(b) According to the writer state the origin of the word tattoo.
c) What is most striking about Tom Leopard.
(d) What was the risk associated with tattooing in the 18th and 19th centuries.
(e) State two modern ways of tattoo removal.
(f) Many tattoo artists earn a good living out of the art. (Add a question tag)
(g) In note form state the negative effects of tattooing.
(h) What are the benefits of tattooing as suggested in the passage?
(i) Explain the meaning of the following words as used in the passage
Mummified
Sterilize
Pigments
Earn a good living
Date posted:
October 31, 2019
-
Fill in the following gaps with the most appropriate word
The setting of a story ________ to the time and place where the story takes place. The setting may shift
from one place to _________________________as the story progresses and end somewhere else, or it
might move elsewhere and come back to the _____________________________ place, hence completing
a full circle. Sometimes the setting _________________ be static (no change. Time is also important for
the setting. This could be told in the story, or could be ____________________________ by the events in
the of the story. For example ,if the story ______________________around a modern setting, with modern
buildings and technological devices, this alludes to the time of setting-i.e. the recent past.
__________________________ if the show grass-thatched huts as dwelling places of the character, this
could be an indication that either the setting is in the____________________________ of the rural areas
,or the story was written was some time __________________________the past
It is important to _____________________________ the setting of a story as this helps us to understand
the theme, the behavior and attitudes of the characters in the story better.
Date posted:
October 31, 2019
-
Eleza dhima ya sentensi hii.
Rudi ulikotoka.
Date posted:
October 31, 2019
-
The standard hydrogen electrode is used as the reference electrode. Some of the difficulties in using hydrogen gas as an electrode are:
- Hydrogen is a gas at 25oC
- Hydrogen does not conduct electricity
-The half-cell reaction,
is slow and takes long to reach equilibrium.
Explain how these difficulties are solved in the standard hydrogen electrode
Date posted:
October 31, 2019
-
Give the chemical formula of Zinc blende
Date posted:
October 31, 2019
-
The following is an equation for the reaction between ammonia and water
Name the base in the backward reaction
Date posted:
October 31, 2019
-
Calculate the volume at s.t.p of hydrogen evolved when 2A of electricity are passed
through dilute sulphuric acid for 2hours.
(Molar gas volume at s.t.p = 22.4dm3, one Faraday= 96500coulombs)
Date posted:
October 31, 2019
-
State Faradays First Law of Electrolysis
Date posted:
October 31, 2019
-
Copper (II) sulphate solution was electrolysed using copper electrode. A Current of 0.5A was
passed for 64.3 minutes and a mass of 0.64g of copper was deposited. (Cu = 63.5)
a) Which electrode decreased in mass during electrolysis? Explain
b) Calculate the quantity of charge needed to deposits 1 mole of copper
Date posted:
October 31, 2019
-
A student set up the experiment shown below. Study it and answer the questions that follow.
a) State any two observations the student made during the experiment
b) Explain what happens to the pH of the resultant solution at the end of the experiment
Date posted:
October 31, 2019
-
The following table shows the standard reduction potentials of some half cells. Study the table and refer to it to answer the questions that follow;
a) Identify the strongest oxidizing agent
b) Which substance would be used to oxidize R- ion to the atom R
c) Study the cell represented below;
i) Identify the electrodes
ii) Write equations for the reaction taking place in each half- cell
iii) Determine the cell equation and the electromotive force (e.m.f) of the cell represented in
(c) above
iv) In which direction does the electrons flow in the external circuit of the cell whose e.m.f
is determined in (iii) above
d) A steady current of 2.5A was passed for 15 minutes through a cell containing divalent ions
M2+. During this process 0.74g of metal M was deposited (IF = 96500C)
i) Calculate the quantity of electricity passed in this cell
ii) Determine the relative atomic mass of M
Date posted:
October 31, 2019
-
Changanua sentensi ifuatayo kwa njia ya matawi.
Anampenda wake sana lakini alimpiga sana
Date posted:
October 31, 2019