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This exam is typed by the Buni Academy administrators with the purpose of helping our brothers and sisters in academic means. There is no partnership with any institution so incase of any errors (typing, spellings etc) no one will be held responsible.

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

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?

(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?

SECTION A (15 Marks)

Answer all questions in this section. Each item carries 1 mark

1. Write the letter of the best answer in the answer booklet .

(i) A vernier scale reads –0.2 mm when closed and 5.7 mm when used to measure the diameter of a piece of wire. What is the true diameter of the wire?

A 0.2 mm B 5.9mm C 5.5 mm D 5.7mm

(ii) Which of the following three quantities are vectors?

A Force, Work and Energy

B Weight, Work and Power

C Velocity, Acceleration and Power

D Displacement, Velocity and momentum

(iii) A bus which is heavily overloaded on its basement carrier is unlikely to overturn because:

A it will run fast down hill

B its center of gravity is high

C its center of gravity is low

D its equilibrium is neutral

(iv) The three advantages of mercury over alcohol in thermometers are that mercury

A has high B.P, colored and does not stick to the wall

B is very sensitive to heat, has low B.P and colored

C is colorless, has high B.P and does not stick to the wall

D is sensitive, has low B.P and does not stick to the wall

(v) The basic condition of a wave diffraction to occur is that the

A wave must travel at high speed

B width of the slit is about the same size as the wavelength of the wave

C wavelength of the wave must be greater than the size of the slit

D wavelength of the wave must be shorter than the size of the slit

(vi) What will happen to the leaf of a negatively charged leaf electroscope if alpha particles strike its cap? The leaf will

A rise further and stay up

B fall and stay down

C rise further and then fall

D fall and then rise again

(vii) The galaxy in which the solar system is a part is called

A constellation

B the universe

C the Milky Way galaxy

D a group of stars

(viii) Two characteristics of the image formed by a plane mirror are

A laterally inverted and virtual

B magnified and laterally inverted

C virtual and smaller than the object

D always larger and at the same distance behind the mirror as the object is in front

(ix) A magnetic material can be a magnet when

A all its domains are aligned in different directions

B its domains are aligned such that the N-pole face in one direction and the S-poles in another direction

C its domains are demagnetized

D its domains are aligned such that their poles face in one direction

(x) Lenz’s law can be applied to predict the

A magnitude of back emf in a circuit

B magnitude of induced current in a circuit

C direction of the applied emf across the circuit

D direction of the induced emf or back emf in a circuit

(xi) When a radioactive source was tested by adding sheets of different material between the source and G.M counter, the results were as follows:

Sheet added	Effect on G-M counter
Paper	Larger fall in the count rate
3mm aluminum	No significant change
Thick lead	Count rate decreases, but not to zero

The source therefore was emitting

A α-particles and β-particles

B α-particles and ᴕ-rays

C β-particles and ᴕ-rays

D α-particles, β-particles and ᴕ-rays

(xii) The half life of an element is 12 hours.

What fraction of an element has disintegrated in 72 hours?

A 1/64 B 1/16 C 1/32 D 1/72

(xiii) The main function of an electric motor is to

A produce motion from electric current

B make magnetism

C produce electricity from motion

D form an electromagnet

(xiv) A horizontal electron beam passed between two parallel horizontal plates X and Y, plate X being above Y. An electric field is set up such that plate Y is at positive potential. What will happen to the beam? It will deflect

A upwards

B sideways to the left

C downwards

D sideways to the right

(xv) The main difference between p n p and n p n transistor is that

A the majority charge carriers in p n p are electrons but in n p n are holes

B the majority charge carriers in p n p are holes but in n p n are electrons

C the minority charge carriers in p n p are holes but in n p n are electrons

D in n p n holes are repelled from the negative terminal but in p n p the electrons are repelled.

SECTION B (45 marks)

Answer All questions. Each question carries 9 marks

2. (a) What is meant by the moment of a force at point? State its SI Unit.

(b) State the conditions for a body to be at equilibrium when subjected to a number of parallel forces.

(c) A uniform wooden bar AB of length 120 cm weighing 1.2 N rests on two sharp edged supports C and D placed 10 cm from its either ends. A 0.20 N hangs from a loop of a string 30 cm from A and a 0.90 N load hangs at 40 cm from B. Find the

(i) reaction at C

(ii) reaction at D

3. (a) Differentiate between heat and temperature

(b) Explain why water is not used as a thermometric liquid

; what does this statement mean?

(ii) Calculate the specific heat capacity of mercury, if 980 J of heat is required to raise the temperature of 7 g of mercury form 0

to 1000

4. (a) Define an echo

(b) Name any two factors that affect the speed of sound in air

(d) A person standing 99 m from the foot of the mountain claps his hands and hears an echo 0.6 seconds later. Calculate the speed of sound in the air.

5. (a) Define the ampere and potential difference.

(b) Derive an expression for the equivalent resistors R₁, R₂ connected in parallel

(c) Three cells each of emf 1.5 V and internal resistance 0.6Ω are joined in series to form a battery and connected across a 5Ω resistor. Calculate

(i) the current and

(ii) the p.d between the terminals of the cell

6. (a) Define the terms: astronomy, galaxy and constellation.

(b) (i) Explain why the sun looks much bigger and hotter than the rest of the stars

(ii) Name three heavenly bodies which are closest to the sun

SECTION C (40 marks)

Answer any FOUR (4) questions

7. (a) (i) Define the term pressure

(ii) Mention any two phenomena which show that air exerts pressure.

(b) Explain

(i) how the chain and ball flushing tank works

(ii) what will happen to the tank when the atmospheric pressure decreases.

thrust exerted on this end by the atmosphere, if the atmospheric pressure is 1.01

10⁵ N/m².

8. (a) What is meant by the principle focus of a converging lens?

(b) What happens to the image of an object placed between the principle focus and the converging lens. Illustrate your answer by using a ray diagram

(i) the distance of the image from the lens

(ii) the magnification

(iii) the height of the image formed.

9. (a) What is meant by

(i) The angle of declination?

(ii) The angle of dip?

(iii) A magnetic pole?

(b) How can you test the polarity of a magnet? Explain briefly why attraction is not a sure test for polarity.

(ii) How are neutral points obtained in an electric field and in a magnetic field?

10. (a) State Faraday’s law of electromagnetic induction

(b) (i) What are the eddy currents?

(ii) Mention one advantage and one disadvantage of eddy currents.

(c) Calculate the current that will flow through a 3Ω resistor connected to a secondary coil of a transformer of 60 turns if the primary coil of 1200 turns is connected to a 240 a.c supply. Assume no losses.

11. (a) What are

(i) Alpha, α-particles

(ii) Beta, β-particles

(iii) Gamma, ᴕ-rays?

(b) A radon nucleus ²²²₈₆Rn emits an α-particle followed by a β-particle. What are the atomic number and mass number of the nuclei formed after emission?

(c) A radioactive element has a half life of 3 minutes. If the initial count rate 512 per minute, how long does it take to reach a count rate of 64 per minute? What fraction of the original amount is left?

12. (a) (i) How are intrinsic and extrinsic semi conductors different?

(ii) Explain briefly how an extrinsic semi conductor is made.

(b) When a transistor is connected into a circuit to determine the characteristics curve, the following results are obtained.

Ih(microA)	20	40	60	80	100
Ic(milli A)	1.1	2.3	3.2	4.4	5.5

(i) Plot the graph of Ic against Ih

(ii) Draw the best straight line through the points

(iii) Calculate the slope.

(iv) What property of a transistor does its slope represent?

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