UNIBEN General Paper 2007/2008 Past Questions

a sample of orange juice has pH of 3.80. what is the molar concentration of hydrogen ion in the juice?

which of the following is not acidic?

calculate the current in ampere to produce 18.0g of aluminium in 1.50hours (Al=27, F=96500C)

calculate the oxidation number of Cl₂O₂

the nuclei in the hydrogen molecule are held together by

which of the following statement about catalysis is true?
1. a small amount of catalyst often affects the rate of a reaction for a long time
2. a catalyst is always chemically unchanged at the end of a reaction
3. the effect of a catalyst is often enhanced by adding promoters
4. a catalyst is always physically unchanged
5. a catalyst always speeds up the rate of chemical reaction

when K₂Cr₂O₇ dissolves in water, the following equilibrium is established
Cr₂O₇^-2(aq)+H₂(l) → 2CrO₄²(aq) orange yellow
start the colour observed on adding a few drops dilute H₂SO₄ to the system

which of the following statements is NOT true of hydrogen sulphide?

which of the following are products of acid hydrolysis of sucrose?

what is the concentration (in mol/dm³) of a solution containing 0.38g of potassium hydroxide 100cm³ of solution?
(K=39,H=1.0,16)

determine the distance between points P(8,5,3) and Q(2,1,-2)

one person walks south-east at 4m/s and another heads north at 3m/s. how far apart are they in 10 seconds if they started from the same point simultaneously?

the centre of gravity of a rectangular subject is at

a uniform meter rule of weight 1.0N is pivoted at the 40cm mark. a weight of 2.0N is hung at the 15cm mark. where must weight 2N be placed to balance the rule?

two lane mirror inclined at angle of 60°C to each other. determine the number of images in the two mirrors

when an oil drop is placed gently on a clean water surface of area 100³

when illuminated by light beam, a smoke particle in oxygen gas can be seen moving indifferent directions all the time viewed in a microscope. this is because

a siren having a ring of 200 holes makes 132 revolutions per minute. a jet of air is directed on the set of holes. calculate the frequency of the note produced (take the speed of sound in air as 350m/s)

a concave mirror of focal length 20cm form image 1/2 the size of the object. determine the distance of the object

a pool of water is 12m deep, what is its apparent depth (refractive index of water is 4/3)

in the optical system of the eye and lens camera, which statements is not true?

a cell needed 0.30m of the wire of a potentiometer to balance its e.m.f, but only 2.0m of its s.p.d. when a resistance of 4Ω was connected across its terminals. calculate the internal resistance of the cell.

when a steady current move in a long solenoid P, it said that

a transformer has a primary coil of 400 turns and a secondary coil of two hundred turns. if the primary coil is connected to 240 a.c. mains, calculate the efficiency given that the current in the primary coil is 3A and in the secondary 5A

when a P-n junction of a semi-conductor is forward biased

which of these is the largest single cell in the body ?

blue-green algae belong to the phylum

the concept of antibiotic started with the work pf

the botanical name of yellow yam is

which of the following tissues are made up of dead tissues

which of the following is not a function of the liver

alkaline pyrogallol was used in an experiment. that experiment must have been connected with

the enzyme that breaks down cane sugar

the largest single bone in the human body is the

auxins are produced in the

the hormone which tones up the muscles of a person in time of danger

a diet with a high concentration of iodine will probably be needed by a patient suffering from a malfunction of the

the sampling method is most often used in ecological study of a habitat because,

which of the following groups of factors is completely abiotic?

nitrogen-fixing bacteria and cowpea demonstrate an ecological association known as

plants that live in salty water are called

a sample of salt was put into a measuring cylinder and water was added to it. after the mixture was shaken the cylinder was left undisturbed for one hour. this experiment was probably performed to:

a farmer X working in a swamp did not eat any food nor drink any water. which of these diseases can he not contact?

which of the following elements maybe added to drinking water to lessen dental decay

a man with normal haemoglobin gets married to a woman who has a sickle cell haemoglobin. they have a child who has the sickle cell trait, which of the following genotype could be associated with the child's haemoglobin?

trichloromethane is a solvent used to remove grease from clothing. how after use is the solvent separated from the grease?

Arrange the following elements of the second period in the order of increasing atomic radius: lithium, berylium, boron, carbon

argon is used in gas filled electric lamps because

if 250cm³ of a saturated solution of potasssium trioxonitrate (V) at 30°C produced 3.4g of the dry salt, calculate the solubility of the salt at 30°(K=39,N=14,0=16)

calculate the mass of ZnSO₄ produced where ZnCO₃ is added to 50.0cm³ of 4mol/dm³ H₂SO₄. the equation for the reaction is;
ZnCO₃₂SO₄ → ZnSO₄+CO₂+H₂Omega
(Zn=65,S=32,0=16)