THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATION COUNCIL
CHEMISTRY FTNA 2014
(i)An isotope of carbon has an atomic number 6 and a mass number of 14, this means that it has:
6 protons, 8 neutrons, 6 electrons
8 protons, 6 neutrons, 8 neutrons
6 protons, 14 neutrons, 6 electrons
14 protons, 6 neutrons, 14 electrons.
Choose Answer :
(ii) Which of the following gives the correct meaning of air?
Mixture of Nitrogen, Oxygen and dust particles.
Mixture of Nitrogen, Oxygen and Carbon dioxide.
C. Mixture of Nitrogen, Oxygen and Water vapour
Homogenous mixture of gases.
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(iii)Why is water a universal solvent?
It is neither acidic nor basic than any other known liquid.
It dissolves more substances than any other known liquid.
It occurs naturally in all the three states of matter than any other liquid.
It dissolves both organic and inorganic solutes than any other liquid.
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(iv)How many numbers of shells are there in Magnesium atom?
1
2
3
4
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(v)Technicians prefer to use blue flame in welding because:
It is bright and non-sooty
It is light and non-sooty
It is very hot and large
It is very hot and non-sooty
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(vi) Which of the following is the characteristic of solid?
It is packed together but does not have definite size.
It is compact packed and has definite shape and size.
It is loosely packed with irregular order.
It is closely packed with uniform shape.
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(vii)What is the oxidation state of Chlorine in KCIO3?
+2
-5
+5
+3
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(viii) Which of the following is a sequential method of separating mixture of salt and sand?
Evaporation, filtration and decantation
Decantation, evaporation and filtration
Sedimentation, evaporation and filtration
Decantation, filtration and evaporation
Choose Answer :
(ix)Which of the following is the best apparatus for measuring accurately the volume of a given solution?
Measuring cylinder
Burette
Beaker
Conical flask
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(x)The factors that affect the problem being investigated are referred to as:
Dependent factors
Variables
Independent factors
Conditions
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2. Match each item in List A with a correct response in List B by writing its letter bellow the number of the corresponding item in the table provided.
LIST A
LIST B
(i) � � � Method of recovery of both solute and solvent from a liquid.
(ii) � � Method of separating two miscible liquids which their boiling points are close together.
(iii) � Method of separating two immiscible liquids.
(iv) � Method of separating two solids by heating in a way that one changes its state directly to gas.
(v) � � Method of separating coloured components using a moving solvent on materials that absorb such solvent.
(vi) � A suitable method of separating edible oils from seeds.
(vii) Method of separating solid mixture which contains iron.
(viii)Method of separating an insoluble solid from a liquid.
(ix)Method of separating a soluble solid and a solvent.
(x)Method of separating liquids which forms a suspension with a solvent
4.Draw a diagram to show laboratory preparation of oxygen using hydrogen peroxide. In the diagram, label all the compounds and elements involved in the preparation.
Briefly explain how you would distinguish ordinary air from pure oxygen.