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BECE Past Questions & Answers – 1999 (SCIENCE)

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August 1999

SCIENCE

SECTIONB ESSAY
1hour [60 marks]

Answerthreequestionsonlyfrom this section.
Illustrate your answers wherever possible, with large, clear and fully labelled diagrams. Creditwill be given for clarity of expression and orderlypresentation ofmaterial.
All questions carry equal marks

1. (a) Stateone function ofeach of the followingorgansin humans
(i) skin (ii) lung (iii) kidney (iv) testis

(b) (i) What is vegetativereproduction?
(ii) Name two plants which reproducevegetatively

(c)
Name four main factors which determinetheclimateofaplace

(d)
Definethefollowing: (i) work
(ii) power

(e)
Name theseparation method used in theproduction of each of the followingsubstances
(i) akpeteshie(alcohol) (ii) common salt
(iii) tap water

2.

(a)

Howwouldyou demonstrate that expired aircontains carbondioxide?

(b)
(i) What is an ion
(ii) Givetwo examples of ions

(c) (i) (ii) What is capillaryaction
Statetwo processes which use capillaryaction

(d)
(i) (ii)
What is a lever?
Givetwo examples of second class levers

(e)
(i)
Use anythreeof thefollowingorganisms to construct a food chain. Rat, hawk, okro leaves, toad, cassava, man,grasshopper

(ii)
Listthreeways of keepingthe teeth healthy

3. (a) (i) (ii) Describebrieflywhat happens to amorsel of kenkeyin themouth during eating. Listin order, theparts ofthe digestivesystem of humans

(b) A mixtureof iron filings andsulphuris heated in atest tube
(i) (ii) (iii) Givethe name ofthe compound formed
Write the chemical equation ofthe reaction whichtook place
Statetwo methods of preventingiron from rusting

(c)
(i) (ii)
A boypulledaload through adistanceof 5m.Ifhe exerts a forceof 15Nin thedirection ofthe force, calculate thework done
Convert the followingweights expressedin kilogram force (kgf) to newton (N)
(α) 0.75 kgf
(β) 1.33 kgf
[1 kgf =10 N]

4. (a) (i) Statetwo reasons which indicate that respiration and burning aresimilar processes
(ii) What is cross-pollination?
(iii) Listfour methods bywhich cholera can be controlled and prevented

(b)
(i)
Name thethree coldest planets
(ii) (iii) Stateone reasonwhich accounts forthecoldnessofthe planetsyou havestated. An object of mass 150g occupies avolumeof 250 cm3. Calculateits density.

(c) Name asuitablesolvent for each of the following substances
(i) grease (ii) oilpaint (iii) alcohol (iv) sugar CLICK TO VIEW ANSWERS TO PART 2

August 1999

SCIENCESectionB

SOLUTIONS

ESSAY

1. (a)

Organ
Function

(i)

Skin • Protects theinternal parts ofthe body
• Servesas senseorganfortouch / feeling
• Excretes metabolic wastesubstance, sweat

(ii)
Lung • Excretes carbondioxide
• Absorbs oxygen forrespiration

(iii)
Kidney • Excretes urea
• Produces urine

(iv)
testis • Produces sperms
• Produces the hormone testosterone [anyone(1) foreach]

(b) (i) Vegetativereproduction
Method bywhich plants reproducewithoutthe union of cells or nuclei of cells
Or:
Theprocess wherebyplants produceoffspring from growingparts / buds of theparent plant

(ii)
Plants that reproducevegetatively
Cassava, sugarcane,yam, cocoyam, banana, plantain, ginger, pineapple,etc
[anytwo]

(c) Main factors that determine theclimateofa place
Rainfallpattern, temperature, humidity, altitude(height abovesealevel), sunshine, vegetation, wind [anyfour]

(d) (i) Work
Work is donewhen an applied forcemoves an object in the direction oftheforce.
Or:

Thetransfer ofenergy, measuredas the product ofthe force applied to a bodyand the distancemoved bythat bodyin thedirection ofthe force
Or:
Work = f × d, where f = forceapplied
and d = distance moved in the directionoftheappliedforce

(ii) Power
The timerateof doingwork
Or (mathematically):
Power= Work done/ time

(e)

(i)
SEPARATIONMETHOD
akpeteshie (alcohol) – Distillation

(ii)
commonsalt – Evaporation

(iii)
tap water – Sedimentation

2. (a) Demonstrationthat expired aircontains carbondioxide

 Insert straw or other narrow tubeinto lime watercontained in a transparentcontainer,
 Gentlybreathe outair from themouth into the limewater
 Thelime waterturns milky

(b) (i) ion –
An atomwhich has lost or gained oneor more electrons
Or:
A negativelyor positivelychargedatom

(ii) Examplesofions
Al3+, Cl–, O2-, K+, Mg2+

(c)
(i)
Capillary action
The risingor fallingof thesurfaceofaliquid whereitis in contact with asolid

(ii) Processes which use capillary action

Okro leaves→grasshopper →man

(b) Iron filings andsulphurheatedintest tube
(i) FeS or Iron (II)sulphide
(ii) Fe + S → FeS

(iii) Preventing iron fromrusting
• Painting
• Greasing
• Alloying
• Galvanizing(coating with zinc)

(c) (i) Work done = force × distance
= 15 N × 5 m
= 75 Nm or 75 J

(ii) Conversions
(α) 0.75 kgf = 0.75 ×10 N = 7.5 N

(β)
1.33 kgf
= 1.33 ×10 N
=
13.3 N

4. (a) (i) Similarity betweenrespirationandburning
• Both processes useup oxygenand releasecarbondioxide
• Both are chemical processes / irreversible
• Both processes releaseheat energy(exothermicreactions)

(ii)
Cross-pollination
Thetransfer ofpollengrains from the antherofa flower to thestigmaof another flower
of anotherplant ofthesame species.

(iii)
Methods by which cholera can be controlledand prevented
• Eatinghot meals,
• drinkingclean potablewater,
• washinghands with soapafter visitingthe toilet
• coveringmeals to prevent flies from settlingon them
• keepingour environment clean andfree from filth
• ensuringthat rubbish bins areproperlycovered.
[anyfour]

(b)

(i)

Coldest planets – Uranus, Neptune and Pluto
(ii) Theyarethe farthest awayfrom the sun, hence, verylittle orno heat energyfrom the sun
reaches them.
(iii) Density = mass / volume
= 150 g/ 250 cm3
= 0.6 g/cm3 or0.6 gcm–3

(c)
SUITABLE SOLVENT
(i) grease – turpentine/ kerosene/ petrol

(ii) oilpaint (iii) alcohol (iv) sugar

turpentineIkerosene water

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