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SECTION
A (15 Marks)
This section consists of fifteen multiple-choice
items. Answer ALL the items
1.
Choose the letter corresponding to the correct
alternative and write it in the answer booklet provided.
(i)
A gas at 273C under a pressure of1600 mmHg
occupies a volume of 190cm3.
What is the volume of the gas at STP?
A.
200 cm3
B.
350 cm3
C.
400 cm3
D.
200 cm3
(ii)
What volume of 0.2M h2SO4 will be required to
neutralize completely 25.0cm3 of 0.05M KOH?
A.
0.656 cm3
B.
6.125 cm3
C.
6.315 cm3
D.
3.125 cm3
(iii)
Which of the following statements does NOT
support the fact that “ Water is a compound ”?
A.
The hydrogen and oxygen in water can not be
separated by physical means.
B.
The physical and chemical properties are quite
different from those of the constitue ts
C.
Hydrogen can be separated from water at boiling
point of water
D.
The formation of water is always accompanied by
the production of heat, light and sound.
(iv)
If element X is one of the elements found in the
periodic table which are called “alkali earth metals” , then element X is
likely to be found in ?
A.
Group II
B.
Group I
C.
Group IV
D.
Grouo VII
(v)
Which of the following sets of compounds is NOT
an example of a homologous series?
A.
Ethene, methane and acetylene
B.
Propene, butane,ethene
C.
Methanol,ethanol and propanol
D.
Formic acid,acetic acid and propanoic acid
(vi)
Anti-acid drugs which are used to control
excess stomach acidity are actal, eno/s,
Andrews’ liver salt and other commercial names. Chemically these anti –acid
drugs contain a substance which neutralize the acid; one of these substances is
sodium hydrogen carbonate. Below is balanced chemical equation of the action of
the substance on hydrochloric acid:
A.
NaHCO3 +
2HCL NaCl + 2CO2 +H2O
B.
2NaHCO3 +HCl 2NaCl +2CO2 +H2O
C.
NaHCO3
+ HCL NaCl + CO2 + H2O
D.
2NaHCO3 +
2HCl 3NaCl + 3CO2 + 2H2O
(vii)
Why is carbon dioxide used in fire
extinguishers?
A.
It is denser
than air
B.
It turns
lime water milky
C.
It does not support burning
D.
It is colourless and odourless
(viii)
Cutting down tress without planting others is
bad for animals because?
A.
It spoils nice shade C. The amount of carbon
dioxide in air will become less
B.
It makes the earth look ugly D. the amount of oxygen n air will become
less
(ix)
The discharge of cations during electrolysis is?
A.
Oxidation
B.
Reduction
C.
Neither oxidation nor reduction
D.
Both oxidation and reduction
(x)
Diamonds and graphite differ because?
A.
Graphite is impure carbon
B.
Carbon
has a different vacancy in the two forms
C.
The atoms in diamond are larger than those in
graphite
D.
Carbon atoms are differently arranged
(xi)
If Anna
wants to electrplate a spoon with copper by using copper sulphate solution, she should
arrange the electrode in the following way
A.
Spoon as anode and coper as cathode
B.
Spoon as cathode and copper as anode
C.
Spoon as anode
carbon as cathode
D.
Spoon as cathode and copper sulphate as anode
(xii)
Which of the following nitrates will not evolve
nitrogen dioxide when heated?
A.
Potasium nitrate
B.
Silver nitrte
C.
Mercury nitrate
D.
Lead nitrate
(xiii)
The quantity of electricty needned to deposite 1
mole of aluminium in the electrolysis of aluminium sulphate is?
A.
96500 coulombs
B.
289500 coulombs
C.
386000 coulombs
D.
193000 coulombs
(xiv)
The chemical equation CH4
+ Cl2 CH3Cl + HCL represents an example of
A.
Polymerization
B.
Addition reaction
C.
Substitution reaction
D.
Esterification reaction
SECTION B (40 Marks)
(Answer ALL questions in this section)
2.
(a) state
Avogadro’s law
(b) define the term mole
(c)
Solid calcium carbonate (CaCO3) reacts with excess nitric acid (HNO3)
liberating
Carbon dioxide gas to form
soluble calcium nitrate and water. Calculate the amount of
Nitric acid needed to dissolve 5g
of calcium carbonate.
3.
(a) state Faraday’s laws of electrolysis.
(b)An element X has a relative atomic mass
of 88. When a current if 0.5A was passed
through
Fused chloride of X for 32 minutes and 10 seconds, 0.44g of X were
deposited at the cathode.
(i)calculate the number of Faradays needed to liberate one mole of X
(ii)Write the formula of the X ion
(iii)write the formula of hydroxide of X
4.
(a)differentiate between SATURATED and
UNSATURATED hydrocarbons.
(b)when a solution of sucroce is Fermented by yeast, ethanol is formed.
This ethanol can be isolated from the liquid by
fractional distilation.
(i)Explain the meaning of the two terms
bolded
(ii)What is the purpose of the yeast?
(iii)Write down the structural formula of ethanol and give its name under the IUPAC system
(iv)Give the balanced chemical equation when
Ethanol reacts with sodium
metal.
Ethanol reacts with
concntrated sulphuric acid at 180C
NOTE: Name the produt in each reaction
5.
(a)The following list of elements is arranged in
order of an ACTIVITY SERIES.
Na,Mg,Zn,Fe,H,Cu,Hg.
From these elements, name
(i)a metal which reacts with cold water
(ii)a metal which burns in steam but does not react with cold water
(iii)any other element which reacts when heated in steam
(iv)an element which has oxide which decomposes on heating
(v)those elements which do not displace hydrogen from dilute
hydrochloric acid
(b)write balanced chemical equation when
(i)a named metal in (a)(i) above reacts with cold water
(ii)an oxide of the named element in (a) (iv)above is heated
SECTION C (45 marks)
Answer question number 6 and any TWO(2) questions from this
section
6.
(a)Name four (4) forms of organic manures which
are commonly available in Tanzania
(b)In
what ways does
the addition of organic manures affect
the condition of the soil?
(c)
(i) State three(3) types of
mineral fertilizers which are commonly
used in Tanzania.
(ii) Indicate the nutrients
provided by each of the mineral fertilizers stated in c(i) above.
7.
(a) Define the following terms:
(i)Exothermic reaction
(ii)Endothermic reaction
(b)State Le Chatelier’s principle.
(c)The equation for the dissociation of
calcium carbonate is
CaCO3 CaO +
CO2 H=+175.5 kJ/mol
What will be the effect on the proportion
of calcium carbonate in the equilibrium mixture if
(i)the temperature is increased
(ii)the pressure is increased?
What
is the necessary conditio for manufacture of calcium oxide from calcium carbonate in
large scale?
8.
(a)By naming the reagents, stating the
conditions whenever possible and writing a balanced
equation for each,describe how
ethene could be converted into
(i)An acid from an alcohol
(ii)chloroethane
(iii)1,2-dibromoethane
(iv)ethanol
(b)Give the balanced equations showing how
the following substances may be obtained:
(i)An acid from an alcohol
(ii)An ester from an acid
9.
(a)State :
(i)charle’s law.
(ii)Boyle’s law of gases.
(b)Write the equation of state of an ideal
gas
(c)A
gas accupies 90cm3 at 11C and 550mmHg. At what temperature
will it have a volume of
80cm3 if the pressure is adjusted
to 750mmHg?
10.
Study
carefully the figure below and then answer the questios which follow
(a)Name the apparatus.
(b)What is
the element obtained by using the apparatus in figure 1.
(c)State
What the letters A,B,C,D,E,F and G represent.
(d)Name
the ore used in this process.
(e)Is the
element in(b) a metal or a non-metal?
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