Seniorhighub

Give the names of the two main major components of cement

Clay is a major raw material for the formation of clinker which is powdered to give cement. Name two components of clay that may undergo separate reaction to give clinker.

Name the main source of the calcium in the clinker and what process or processes does raw material goes through during the formation of clinker

Preamble: Differentiate the given function

y = 2x – 3 / x + 1

dy/dx = 5/(x + 1)2

y = x + 2/ 2x - 1

dy/dx = -5/ (2x - 1)2

y = x / x + 3

dy/dx = 3/ (x + 3)2

Preamble: A cylinder of mass 0.200kg and moment of inertia 0.250kg/m2 slides and rolls on a horizontal surface. Find the kinetic energy of the cylinder for the given translational speed V and angular speed Ω.

V = 4.00m/s and = Ω = 2.00rad/s

1.65 J

V = 2.00m/s and = Ω = 4.00rad/s

0.600 J

V = 4.00m/s and = Ω = 4.00rad/s

1.80 J

What name is given to the thicken glandular and non-segmented section of the body wall near the head in earthworms and leeches which secretes a viscid sac in which the eggs are deposited

which organ in invertebrates occurs in peers and performs a function similar to the vertebrate kidney

The earthworm has no special respiratory organs. How does exchange of gases take place?

Elemental calcium burns in air to give calcium oxide. Calculate the mass in grams of calcium oxide that can be obtained from 110.0 grams of pure calcium if the yield is 100%. Give your answer to 1 place of decimal. Atomic mass for calcium is 40.0 and that for oxygen is 16.

In the preparation of calcium oxide by the burning of calcium metal. 10.0grams of the metal used 12.6 grams of the oxide. Calculate the percentage yield of this preparation. Give your answer to 1 place of decimal. Atomic mass for calcium is 40.0 and Oxygen is 16.

If in another preparation of calcium oxide, the yield is only 80%. What mass in gram of calcium oxide can be obtained from 27.0grams of calcium? Give your answer to 2 places of decimal. Atomic mass for calcium is 40.0 and Oxygen is 16.

Preamble: Determine the possible range of values of k if the given equation has no real root.

3x2 + 2kx + 2k = 0

0 < k < 6

kx2 + 2kx – 1 = 0

-1 < k < 0

5x2 – 2kx + k = 0

0 < k < 5

The work function of a metal is 4 eV. Calculate the speed of the fastest electrons that can be ejected from the metal when it is illuminated by 5eV protons.

The work function of a photo cathode is 3.0 eV. Calculate the speed of the fastest electron that can be ejected by 4.8 eV photons.

Calculate the speed of the fastest electron that can be ejected from a metal of work function 2.8 eV when it is illuminated by 3.25 eV photons.

Preamble: Name the plant hormones to which the description refers

Causes stem elongation and growth, responsible for formation of adventitious and lateral root, inhibit leaf loss, promote cell division together with cytokinin

Auxin / indole-3-acetic acid

increases ethylene production, enforces dormancy of lateral buds produced by shoot epical meristems and other immature parts

Auxin / indole-3-acetic acid

stimulate cell division (auxin), promote chloroplast development, delays leaf aging, promote formation of buds, inhibit formation of lateral root produced by root epical meristems and immature fruit

Cytokinin

Preamble: The small batteries used in wrist watches and calculators are referred to as alkaline Dry cells.

What is the electrolyte which also serves as the salt bridge in these batteries?

The electrolyte is a paste that contains that contains Manganese(IV) oxide and Potassium Hydroxide

What is the anode of the alkaline battery?

Zinc

The bacterial content of outdoor air depends on many factors. Name one main factor each.

Preamble: An incandescent light bulb operates at a surface temperature of 3000 K. The surface area of the filament is 1.5 × 10^-5 m² and its emissivity is 0.25. The Stephan-Boltzmann constant is 5.7 × 10^-8 W m² K^-4, the Wien displacement law constant is 2.9 × 10^-3 K m and the speed of light is 3 × 108 m/s.

Find the radiant power emitted by the filament.

17W

Calculate the intensity of radiation at a distance of 20 m from the filament.

0.003W/m²

Determine the most intense frequency in the spectrum of the lamp.

3 × 10¹⁴Hz

If one reacts Propanoic acid with thionyl chloride, SOCI₂ what product will be obtained?

When a molecule of an alkanoic acid is refluxed with an alkanol in the presence of a mineral acid, a nucleophilic reaction takes place. Which species acts as the nucleophile?

When a molecule of an alkanoic acid is refluxed with an alkanol in the presence of a mineral acid, an ester is formed. What role does the mineral acid play? Explain in detail.

Why should good drainage and ploughing lead to increased soil fertility?

Which natural areas or situations might favour denitrification?

Under what conditions do gases deviate from Boyle's law?

How does the kinetic theory of matter account for Charles' law?

Human beings, like other animals harbour a wide array of normal microorganisms both on and in their bodies. Give one important role each that the normal microorganisms plays in the body economy.

Preamble: An incompressible fluid is pumped across a horizontal pipe from A section with radius 10 cm to other sections with different radii. The flow speed in the first section is 2 m/s. Determine the flow speed in the section with the given radius.

20 cm

0.5m/s

5 cm

8m/s

2 cm

50m/s

Preamble: Find an expression for the area of……

An equilateral triangle of side of length s.

^{√3 × ϰ2}/₄

An equilateral triangle of height h.

h²/_√3

A square with a diagonal of length d.

d²/₂

Preamble: A moving coil voltmeter with internal resistance 10 kΩ and full-scale deflection at 1 ν is to be used with multipliers in order to measure voltages higher than 1 ν. Determine the multiplier required for the given voltage range.

10 V

90 kΩ

50 V

490 kΩ

100 V

990 kΩ

Preamble:Solve the absolute inequality;

| 2ϰ + 1 | < 9

-5 < ϰ < 4

| 2ϰ - 3 | > 7

ϰ < -2 or ϰ > 5

| 3ϰ - 2 | < 10

-8/3 < ϰ < 4

What is the linear momentum of a 5 kg object moving at 4 m s^-1 due east?

A moving object has a linear momentum of magnitude 50 N s. What force is applied parallel to the direction of motion of the object can stop it in 5 s?

At what speed will the magnitude of linear momentum of a moving 2 kg object be 80 N s ?

Three main factors influence the first ionization of an atom. (a) Atomic radius (b) stability of electronic configuration (c) effective nuclear charge. Which of these factors determine the trend of first ionization potential in elements in Group in the Periodic Table?

Preamble: Distinguish between plants cells and animal cells with respect to the following:

Forms of storage of excess glucose.

Plants cells stores glucose in the form of starch whiles animal stores glucose in the form of glycogen

Outermost covering of the cells.

Outermost covering in plant cell is the cell wall while in animal cell it is the cell membrane.

Plastids

Plant cells have plastids (chloroplast) while animal cell has no plastids.

Preamble: Find the first four terms of the sequence defined by the recurrence relation.

U_{n + 1} = 2U_n , U₁ = 2

2, 4, 8 and 16

U_{n + 1} = U_n + 2 , U₁ = 2

2, 4, 6 and 8

U_{n + 1} = U_n – 2, U₁ = 2

2, 0, -2, -4

Preamble: A 2 nC charged particle moving at 10 m s^-1 enters a uniform 0.4 T magnetic field with its velocity perpendicular to the field. No other fields are present.

What is the change in kinetic energy of the particle after 10 s?

0

What is the work done by the magnetic field on the charged particle when the particle travels a distance of 0.1 m?

0

Find the net force on the charge.

8 × 10^-9 N

Calculate the volume of oxygen to be released at STP in the electrolysis of dilute sodium chloride solution using carbon electrodes after passing a charge of 1/6 Faraday. Molar volume of a gas at STP is 22.4 dm³. Give your answer to two places of decimal.

Calculate the volume of oxygen to be released at STP in the electrolysis of molten alumina after passing a charge of 0.3 Faraday. Molar volume of STP is 22.4 dm³. Give your answer to two places of decimal.

In the electrolysis of molten KBr, it is found that after passing a certain amount of charge, 5.6 dm³ of bromine gas is evolved. Calculate the moles of potassium that would have been discharged. Molar volume of a gas at STP is 22.4 dm³.

Preamble: Give the branches of biology that deal with the following:

The study of structure and forms of organisms.

Anatomy and Morphology

The study of fossils and all aspects of extinct life.

Palaeontology

The study of functions of living organisms and individual organs, tissues, and cells of which they are composed.

Physiology

Preamble: Find the ϰ-intercept and the y-intercept of the graph of the given curve.

y = 3ϰ -12

y = -12 and x =4

y = ϰ² – 4

y = 4 and x ± 2

2ϰ – 5y = 10

x = 5, and y =-2

Preamble: Describe the following types of placentation in plants in terms of the arrangement of ovules.

Parietal

The ovules are born on the inner surface of the ovary wall.

Axile

The ovules are arranged along the central axis of the ovary wall.

Free central

The ovules are arranged at the central portion without any connection to the ovary wall.

Preamble: Express the repeating decimal as a rational number

0.6666…..

⅔

0.7777….

⁷/₉

0.9999….

1

How are the rates of effusion of two gases leaking from an opening of a container related, assuming temperature and pressure are the same?

Find the angular frequency of free oscillations of a simple pendulum which has a bob of mass 0.2 kg and a string of length 40 m.

The period of a simple pendulum on the surface of earth is 20 s. find the period of the pendulum of the surface of a celestial body where the acceleration due to gravity is four times as large as on earth.

A 2.0 m simple pendulum is found to have a frequency of 0.35 Hz. What is the local acceleration due to gravity?

Preamble: Give the location or the site of action of the enzyme in mammals.

Lactase

Ileum (small intestines)

Renin

Stomach

Pancreatic lipase

Duodenum

Preamble: Find the conjugate of the surd.

3 + 2 √2

3 - 2√2

√2 - √3

√2 + √3

-2 + √5

-2 - √5

How many moles of nitrogen gas at STP are present in a vessel of volume 14.0 dm³? Molar volume of gas at STP is 22.4 dm³. Give your answer to three places of decimal.

Calculate the number of moles of silica (SiO₂) in 1 kg of gold ore that contains only 1.00% gold, the rest being sand.
Si = 28.0,   O = 16.0

Calculate the number of moles of ethanol in 120 cm³ of 50% ν/ν aqueous ethanol. For this calculation assume that the specific gravity of ethanol is the same as that of water. Molar mass of ethanol is 46. Give your answer to 2 places of decimal.

Preamble: The specific heat capacity of water is about 4200 J kg^-1 K^-1.

How much heat is needed to bring 0.5 kg of water of 20°C to the boil?

170kJ or 16800J

Kofi scalds the back of his hand when he spills 10g of boiling water on it. How much thermal energy did his tissues absorb if the water cools to his skin temperature of 37°C?

2.6kJ

Find the final temperature of 200g of water at 20°C when it absorbs 8400 J of heat.

30°C

Preamble: State how the following features adapt the tapeworm to its habitat.

Suckers

It uses them to attach to the intestinal walls of the host.

Thick cuticle

The thick cuticle resists digestive enzymes and gut secretion

Large surface area

The Large surface area is for absorption of nutrients and excretion of substances

Preamble: Find in radians the sum of the interior angles of a polygon with the given number of sides.

20 sides

18π rad

32 sides

30π rad

51 sides

49π rad

Preamble: Give an SI unit for the physical quantity measured by the given instrument.

Vernier callipers

Meters

Manometer

Pascal

Pyrometer

Kelvin

Define acid according to the Lewis concept.

Define a base according to the Brønsted – Lowry concept.

What is a buffer?

Which pigment is responsible for the bright red and purple colours of flowers that are adaptive for attracting pollinators?

Why is Neurospora used as genetic material?

What name is given to Plant hormones that induce cell division and shoot formation?

Preamble: Given that a × b = a² – 2ab + b² evaluate:

5 × 3

4

7 × 5

4

5 × (-2)

9

Preamble: The intensity 2 m from a point source of light is 25 W m^-2.

What is the intensity 5 m from the source?

4 W/m²

How far from the source is the intensity 10 mW m^-2 ?

100m

How far from the source is the intensity 16 times its value 2 m from the source?

0.5m

After passing 2.0 Faraday of charge through molten M_gCl₂ only 20g of magnesium is harvested. What is the percentage efficiency of the electrolytic process? Give your answer to one place of decimal.  Mg = 24.0

30 g of organic compound were recrystallized twice the same solvent. If the rate of recovery after each recrystallization is 90%, how many grams of the organic compound would be left? Give your answer to 1 place of decimal.

When a measured volume of water is added to solid C_aO , solid C_a(OH)₂ is formed. If on adding water to 28 g of C_aO only 30 g of slaked lime is harvested, what was the percentage efficiency of the method? Give your answer to one place of decimal.
C_aO = 56.0    C_a(OH)₂ = 74.0

Which famous scientist introduced the idea of natural selection?

What name is given to Animals which eat both plants and other animals?

What name is given to a change of the DNA in an organism that results in a new trait?

Preamble: Convert the given unit to a unit containing SI base units.

J s (joule seconds)

kgm²/s

W h (watt hour)

kgm²/s²

N s(Newton second)

kgm/s

Give the isomer of 1-pentanol that is a butanol and also a tertiary alkanol.

Give one positional isomer of cyclohexene.

Give the stereoisomer of 1,3-dichlorocyclopentane that will not show optical isomerism.

Preamble: Give as an algebraic expression

Twenty less than the product of a number and two

2x - 20

One half subtracted from the quotient of a and b

a/b – ½

The difference of three times a number and 4

3x - 4

Preamble: Give the Phylum of the following fungi.

Yeast

Ascomycota

Rhizopus

Zygomycota

Penicillium

Ascomycota

A converging lens of focal length 0.20 m. Find the image distance when the object distance is 0.45 m

Find the object distance for an image distance of 15 cm in a converging lens of focal length 5.0 cm.

Determine the focal length of a converging lens in which an image distance of 0.10 m corresponds to an object distance of 0.025 m.

Preamble: A steel vessel containing 3 moles of nitrogen, 5 moles of helium and 7 moles of oxygen is found to have a total pressure of 600kPa at 30°C.

Calculate the mole fraction of the nitrogen gas.

0.2

Calculate the partial pressure of the oxygen gas.

280kPa

Calculate the combined partial pressure of helium and oxygen.

480kPa

Preamble: Find the solution set for ϰ in the given inequality:

| 3ϰ – 4 | < 5

-⅓ < x < 3

| ϰ + 4 | < 9

-13 < x < 5

| ϰ – 3 | > 1

x < 2 or x > 4

Preamble: Find the remainder R when the polynomial f(ϰ) is divided by the linear term.

f(ϰ) = ϰ³ – 6ϰ² + 3ϰ – 2 divided by (ϰ - 2)

12

f(ϰ) = 3ϰ³ – 10ϰ² + 7ϰ + 6 divided by (ϰ + 1)

20

f(ϰ) = 2ϰ³ + 7ϰ² + 8ϰ – 16 divided by (ϰ - 1)

1

Give the name of the tissue that separates the xylem and the phloem of the vascular bundles of dicot stems.

Name the process by which solutions in living cells move against concentration gradient.

Photosynthesis generally takes place in which parts of the plant?

Find the power dissipated by a 5 Ω resistor when a potential difference of 2 V is applied across it.

Determine the current in a 10 Ω resistor when it dissipates 360 W

A 10 k Ω resistor is rate at 0.25 W. What is the maximum potential difference that can safely be applied across it?

If you are given a water soluble solid salt, and you are required to dissolve it in approximately 100 cm³ of water, which glassware will be most appropriate?

What are the main features of a laboratory pan balance?

Give two main differences between a watch glass and an evaporating dish.

Preamble:Find the ratio ϰ : y given:

(ϰ - y)/2 = (ϰ + y )/3

5 : 1

(ϰ + 3y)/5 = (ϰ + y)/2

1 : 3

(2ϰ - y)/3 = (ϰ + 2y)/5

11 : 7

Name the structure that prevents bony fishes from sinking in water.

Which part of the gill of a bony fish is responsible for gaseous exchange?

Name the structure in bony fishes that enables the fish strain tiny food particles out of water for feeding purposes.

How does the strength of the electric field produced by a point vary with distance from the charge?

The distance between a point charge and an observation point is doubled. How does the electrostatic potential change?

How does the strength of the electric field produced between two very large parallel plates carrying equal but opposite charge vary with distance from one of the plates?

If the half- life of a reaction is 1 minute, calculate the rate constant of the reaction and give your answer in the scientific notation to two places of decimal.

The decay constant of a radioactive substance is 7.7 × 10^-3 s^-1. Calculate the half – life of the substance.

A radioactive substance has a half-life of 5 hours. What percentage of the initial activity will be left after 20 hours?

Preamble: Give the structures of locomotion in the following organisms.

Trypanosome

Flagella

Paramecium

Cilia

Plasmodium

They have no locomotory structure

Preamble: Find the sum and the product of the roots of the quadratic equation.

2ϰ² + 1/2ϰ - 1/3 = 0

The sum is (-¼) and the product is (-⅙)

1/3ϰ² + 2ϰ + 5 = 0

The sum is -6 and the product is 15

3ϰ² - 2ϰ + 1 = 0

The sum is ⅔ and the product ⅓

Preamble: The fundamental charge is approximately 1.6 × 10^-19 C.

What is the change in kinetic energy of a proton when it is accelerated through a potential difference of 2.0 V?

3.2 × 10^-19J

An alpha particle is accelerated through the same potential difference of 2.0 V. Find the change in its kinetic energy.

6.4 × 10^-19J

What potential difference is needed to change the kinetic energy of a photon by 8.0 × ^-19 J ?

5v

How many elements, including hydrogen, are present in Group 1, of the Periodic Table?

How many elements are present in the 4th Period of the Main Group Elements?

How many elements are present in Group 8 or 18 of the Periodic Table?

Preamble: Explain the following methods of fertilizer application.

Broadcasting

This is the spreading of fertilizer evenly all over the field.

Ring method

This is where fertilizer is applied around the base of a plant 5cm away.

Top dressing

This refers to the second application of fertilizer several weeks after the first dose have being applied.

Preamble:

64^2/3

16

625^-3/4

1/125

243^4/5

81

Preamble: An object is at rest on the floor of a bus moving with a steady velocity on a horizontal road.

If there is no friction between the object and the floor of the bus, what is the force needed to keep the object moving with the bus?

0N

What happens to the object when the bus stops suddenly?

The object will be jerked forward in the bus because it has inertia.

Why does the object slide forward when the bus stops suddenly?

Because no force has acted on it to stop it motion.

Calculate the pH of 10 cm³ of 0.10 moldm^-3 HCl diluted with water to 100cm³.

Calculate the pH of 0.10 moldm^-3 solution of KOH.

Calculate the pH of a solution made by mixing 10cm³ of 0.2 moldm^-3 NaCl solution with 10cm³ of 0.2 moldm^-3 HCl solution.

Preamble: Simplify

√2 × √32

8

√3 × √12

6

√5 × √2 × √10

10

Which of the following forms of energy is possessed by the molecules of an ideal gas: thermal, potential, kinetic?

An ideal gas is compressed isothermally so that its volume is halved. Which of the following properties of gas molecule is doubled: thermal energy, internal energy, kinetic energy?

Which of the following properties of an ideal gas determines its internal energy: pressure, temperature, volume?

Preamble: Mention the class of food substances for which the following tests are used.

Biuret test

Proteins

Sudan III test

Fat and oil

Million's test

Proteins

Preamble:Use parenthesis to ensure that the sum is correct

13 − 1 × 3 × 3 + 8² = 670

(13 - 1 × 3) × (3 + 8²)

13 − 1 × 3 × 3 + 8² = 172

(13 - 1) × (3 × 3 + 8²)

13 − 1 × 3 × 3 + 8² = 1210

(13 - 1 × 3) × (3 + 8)²

Preamble: A 5.0 nC charge lies 2.0 m east of a 2.0 nC charge. The coulomb law constant is approximately 9.0 × 10⁹ m/f.

What is the electrostatic potential midway between the charges?

63V

Find the magnitude of the electrostatic field strength midway between the charges.

27V/m or 27N/C

Find the energy of a -0.10 pC charge placed midway between the charges

-6.3pJ

Define an endothermic process.

Define a closed system in thermodynamics.

What do we call a system that does not allow either heat or mass exchange with its surrounding?

Ribosomes reside in 4 main places in almost all eukaryotic cells. Name one each.

Give two essential features of the glass discharge tube used by J.J Thompson in the experiment that lead to the discovery of the electron.

In the J.J Thompson's experiment, what was observed in the glass tube when electricity, was switched on and what name was given to what he observed.

J.J. Thompson observed the formation of the Cathode Rays. Describe two of the tests carried out on the ray and the respective conclusion drawn.

Preamble:Find the quadrant in which the angles lies.

420°

1^st quadrant

240°

3^rd quadrant

285°

4^th quadrant

An animal has 48 chromosomes in each of its body cells. How many of these chromosomes came from its male parent?

The nucleus of a cell contains a fixed number of chromosomes. Before mitosis, each chromosome replicates to produce how many chromatids.

A cell in the basal layer of the skin contains 46 chromosomes and divides by mitosis to produce new skin cells. How many chromosomes will the basal cell have after 5 successive divisions?

What is an adiabatic process?

What is an isobaric process?

What is an isometric process?

Preamble: A circle has a center at the origin and a radius of length 10. Determine if the given point lies on the circle or not.

(√19 , 9)

It lies on the circle

(-√51 , 7)

It lies on the circle

(-8, √37)

It does not lie on the circle

Which of these elements in plants is required in small quantities?
 a. Boron,  b. Nitrogen ,  c. Phosphorus  d. Magnesium

Which of the following processes cannot be carried out by the mammalian stomach?
 a. Absorption of glucose,  b. Secretion of hydrochloric acid,  c. Secretion of gastric juice,  d. Production of trypsin

Which of these products obtained from analysing sweat from skin is not an excretory product?
 a. Urea,  b. Water ,  c. Salts,  d. Dust

The magnitude of the linear momentum of a 2 kg object is 18 N s. find the speed of the object.

Find the mass of an object whose linear momentum has magnitude 5 N s when its speed is 5 m s^-1

What is the linear momentum of a 4 kg object moving at 5 m s^-1 due south?

Preamble: Explain how the following factors affect the rate of diffusion in living cells.

Nature of particles.

The smaller the particle, the faster they move from one cell to another.

Concentration gradient.

The greater the concentration gradient, the greater the rate of diffusion.

Temperature.

The higher the temperature, the higher the kinetic energy increase and if kinetic energy increase the velocity will increase and hence leads to high rate of diffusion.

Preamble: Rationalize the denominator

$2/$_{2 −√3}

4 + 2√3

$1/$_{3 +2√2}

3 - 2√2

²/_{4 −√15}

8 + 3√15

Preamble: Which of the given units are equivalent?

J, N s, N m, W s

J, N m, W s

N, kg m s² , J m^-1, VC m^-1

N, J m^-1, VC m^-1

A s, J V^-1, N s T^-1 m^-1, V s

A s, J V^-1, N s T^-1 m^-1

Consider the equilibrium reaction. A_(g) + 2 B_(g) → 2 C_(g) State the effect of increase in the internal pressure on the position of the equilibrium

Consider the equilibrium reaction. A_(g) + 2 B_(g) → 2 C_(g) If at equilibrium more of gaseous A is introduced, explain what happens to the equilibrium constant.

Consider the reversible reaction: CO_(g) + 3 H_2(g) → CH_4(g) + H₂O_(g) + heat At which temperature will the equilibrium constant be greater, 300K or 500K?

Name the first step in carrying out ecological studies in a terrestrial habitat.

What name is given to a situation where only specified tress in a forest reserve is cut down?

A farmer cultivating leafy vegetables will require fertilizers with a relatively high content of which mineral?

Preamble: Find the equation of the line. . . .

Through the point A(1, 1) and parallel to the line with equation 2ϰ – 3y = 5,

2x – 3y + 1 = 0

Through the point B(2, -1) and perpendicular to the line with equation y = -1,

x = 2

Through the point C(2, 3) and parallel to the line with equation y = 5.

y = 3

A 0.2 kg object moving at 6 m s^-1 collides head-on with becomes embedded in a stationary abject of mass 0. 4 kg. Determine the speed of the composite object after the collision.

A stationary 0.6 kg object spontaneously disintegrates into two pieces and one piece, of mass 0.2 kg, flies off with speed 20 m s^-1.Find the speed of the other piece.

A steel ball of mass 0.8 kg moving at 5 m s^-1 collides head-on with a stationary block and stops. What is the mass of the block if it moves with speed 2 m s^-1?

Calculate the enthalpy change of the following reaction:
CO_(g) + 3 H_2(g) → CH_4(g) + H₂O_(g) given that the enthalpies of formation in kJmol^-1 of CO_(g), CH_4(g) and H₂O_(g) , are -110, -75.0 and -241 respectively.

If the enthalpy change for the reaction;
CH_4(g) + 4 Cl_2(g) → CCl_{4 (I)} + 4HCI_(g), is -433 kJmol^-1,then calculate the enthalpy of formation of HCI_(g) given that the enthalpies of formation in kJmol^-1 of CH_4(g) and CCl_{4 (I)} are -75 and -140 respectively.

Calculate the enthalpy change of the reaction: 2 S_(s) + 3 O_2(g) → 2 SO_3(g) , given that the enthalpy of formation of SO₃ gas is -198kJmol^-1

What is the SI prefix for 10¹²?

What power of ten corresponds to the SI prefix atto?

How many gigahertz make one megahertz?

How many elements are present in Group 8 or 18 of the Periodic Table?

What are the first and the last elements in Period 3 of the periodic table?

What is the atomic number of the first element in the first period of the d-transition elements?

A customer pays GH¢840 for an item at a discount of 20%. Find the original price.

An item originally listed at GH¢2000 is sold at a discount of 15%. Find the sales price.

At a sales, a radio originally listed at GH¢500 is sold for GH¢350. Find the % discount.

Preamble: Distinguish between dicotyledonous plants and monocotyledonous plants with reference to the following:

Type of root system

Dicotyledonous have tap root system whereas Monocotyledonous have adventitious root system.

Arrangement of vascular bundles

Dicotyledonous are scattered whereas Monocotyledonous are in circular or cylindrical pattern.

Arrangement of leaf veins

Monocotyledonous have parallel venation whereas Dicotyledonous have net venation

What is the time constant of a series of RC circuit containing a 10Ω resistor and a 5 µF capacitor?

Find the time constant of a series RL circuit containing a 10Ω resistor and a 5 µH inductor.

Determine the inductance in a series RL circuit containing a 10Ω resistor and whose time constant is equal to that of a series RC circuit containing a 10Ω resistor and a 5 µF capacitor?

Methanoic acid has a pK_a of 3.76. Calculate the pK_b of the methanoate ion.

Calculate the PH of a 0.10 moldm^-3 solution of methanoic acid, whose ppK_a is 3.76.

Calculate the pH of 0.5 moldm^-3 solution of HCI. Assume log₁₀ 5 = 0.70.

Preamble: Find the values of ϰ for which the expression is undefined.

ϰ/(ϰ² + 1)

It is always defined

ϰ/(ϰ² - 1)

x = 1 or x = -1

(ϰ -2)/(ϰ + 1)(ϰ -3)

x = -1 , x = 3

Preamble: State the differences between the male gametes and the female gametes of human with regard to the following:

Their relative numbers

Male gametes are produced in large numbers as compared to female gametes.

Their shape

Male gametes have long tails with conical head whereas female gametes are spherical in shape.

Their size

Male gametes are smaller than female gametes.

What is the mechanical advantage of a simple gear train with a 20 tooth gear driving a 40 tooth gear?

Find the velocity ratio of a simple gear train comprising of a 20 tooth gear driving a 40 tooth gear.

Find the velocity ratio of a simple gear train comprising three gears: a 20 tooth gear driving a 40 tooth gear which in turn drives an 80 tooth gear.

Preamble: Consider the following reversible chemical reaction which is exothermic in the forward direction; A _(g) + B _(g) → 3 C _(g).

At equilibrium how will an increase in temperature affect the equilibrium constant.

It will decrease the equilibrium constant.

At equilibrium how will an increase in pressure affect the equilibrium constant.

The will be no effect on the equilibrium constant.

At equilibrium how will an increase in volume affect the equilibrium position.

The reaction will move backwards.

Preamble: Find the base number if the sum is correct.

352 + 135 = 531

Base 6

323 + 144 = 1022

Base 5

435 + 247 = 704

Base 8

Which of these is the terminal portion of the alimentary canal of a mammal?
 a. Appendix  b. Stomach  c. Rectum  d. Colon

Which of these tissues serves the function of support and water conduction in plants.
 a.Parenchyma  b. Phloem  c. Sclerenchyma  d. Xylem

Which of the following best describes an organism which lives on the remains of dead plants?
 a.Ectoparasite  b. Saprophyte  c. Commensal  d. Symbiont

A 1.0 N force makes an angle of 30° with the vertical. Find the horizontal component of the force.

The horizontal component of a force is 2.0 N. find the magnitude of the force if it makes an angle of 60° with the horizontal.

A horizontal 4.0 N force is in equilibrium with an oblique force of magnitude 8.0 N. Find the angle the oblique force makes with the horizontal.

A balloon containing 3 moles of oxygen and 5 moles of helium has a pressure of 160 kPa. How many moles of nitrogen must be pumped into the balloon so as to increase the total pressure to 200 kPa.

A sealed vessel contains 6 moles of oxygen, 8 moles of nitrogen and 10 moles helium. Calculate the mole fraction of the oxygen and give your answer to 2 places of decimal.

A sealed flask that contains 6 moles of oxygen, 9 moles of nitrogen and 10 moles of helium has a total pressure of 400 kPa. Calculate the partial pressure of the nitrogen.

Preamble:Express in exponential form.

3√ϰ²

X^2/₃

√√ϰ

X^1/₄

5√ϰ³

X^3/₅

In 1911 Rutherford proposed the nuclear model of the atom, based on the results of the α - scattering experiment in which he was assisted by Geiger and Marsden. Give any one observation they made and the conclusion Rutherford drew from that observation.

A disc spins freely with angular momentum 50.0 J s and angular velocity 4.00 rad s^-1. Find its moment of inertia.

A disc spins with moment of inertia 20 kg m² spins at a uniform rate from rest to an angular speed of 15 rad s^-1 in 6 s. What is the net torque acting on the disc?

A net torque on a spinning disc is 8.0 N m when its angular velocity changes at a rate of 0.50 rad s^-2. Find its moment of inertia.

How would you destarch the leaves of a potted plant?

In a school laboratory, what is the simplest way of checking that destarching has been effective?

Preamble:Find the maximum value of the function:

y = 5sin(ϰ + 30°) + 2

7

y = 2 − 5cos(ϰ − 30°)

7

y = 5 + 3cos(30° − ϰ)

8

Preamble: when Silver (I) oxide is heated alone at temperature over 100°C, it decomposes to metallic silver. The balanced equation is as follows: 2Ag₂O → 4Ag + O₂
  Atomic mass: Ag = 108.0 ,   O = 16.0

Calculate the mass of silver metal that can be obtained from 23.2 g of the oxide if the conversion is only 90% efficient. Give your answer to two places of decimal.

19.44 grams

Calculate the mass of the silver oxide that needs to be heated in order to obtain 64.8 g of silver, assuming the process is 100% efficient. Give your answer to one place of decimal.

69.6 grams

Calculate the volume of oxygen at STP that can be obtained from heating 92.8 g of silver (I) oxide. The molar volume of gas is 22.4 dm³ at STP. Give your answer to two places of decimal.

4.48dm³

Name the high resistance that separates the p- and n- type regions of a pn junction.

What happens to the width of the depletion region of a pn junction when the junction is reverse biased?

What physical process accounts for the presence of the depletion layer in an un- biased pn junction?

Preamble: State whether the characteristics of flowers are regarded as adaptations to pollination by bees:

White or coloured petals

It is regarded as an adaptation to pollination by bees.

Anthers and stigma protruding from the flower.

It is not regarded as an adaptation to pollination by bees.

Spiky and sticky pollen grains.

It is regarded as an adaptation to pollination by bees.

If your are provided with a mixture or a suspension of a solid in a solvent, name the piece of equipment or glassware that will be needed to perform suction filtration.

Preamble: The fundamental charge is approximately 1.6 × 10^-19 C.

The net charge on an object is -4.8 × 10^-17C. What is the number and type of excess fundamental particles on the object?

300 and it is electrons.

The net charge on a metal sphere is 6.4 × 10^-17C. what must be done to change on it to 3.2 × 10^-17 with the least change in mass?

To remove 600 electrons from it

Find the final net charge when 1000 electrons are added to a metal sphere carrying a net charge of 1.6 × 10^-16C.

0

Preamble: Factorise the trinomial completely

5ϰ² – 36ϰ + 7

(x - 7)(5x -1)

12ϰ² – 18ϰ + 6

6(2x – 1) (x -1)

8ϰ² – 2ϰ – 10

2(4x - 5)(x + 1)

Preamble: State the difference between crustaceans and insects with respect to the following:

Body division

Insects have 3 body divisions while crustaceans have 2 body divisions.

Type of eye

Crustaceans have a pair of stocked eye while insects have a pair of compound eye.

Respiratory organ

The respiratory organ of crustaceans is the gill whereas that of the insect is the trachea.

300 cm³ of a 0.24 moldm^-3 KOH solution is diluted to 900 cm³. What is the new concentration of the KOH solution?

100 cm³ of a 0.100 moldm^-3 HCI solution is added to 400 cm³ of 0.05 moldm^-3 HCI solution. What is the total mmole of HCI in the resultant solution?

200 cm³ of a 0.100 moldm^-3 HCI solution was added to 300 cm³ of 0.25 moldm^-3 solution of KOH.

An object falling vertically downward has a speed of 5 m/s. Find the distance it falls in 2 s.

An object is launched vertically upward with speed 10 m/s. Find the greatest height above the launch point it attains.

A soccer ball is dropped from a height of 0.8 m. Find the speed of the ball when it strikes the ground.

3√(-125)

3√(-40)

3√(-32)

Preamble: State the main type of vitamin that humans can obtain by eating the following types of food.

Yeast, Unpolished rice, Milk, Beans, Palm wine.

Vitamin B1(Thiamine)

Liver, Eggs, Fish, Milk. Palm oil, Fresh vegetable.

Vitamin A

Citrus fruits and Green vegetables

Vitamin C