CHEMISTRY

CHEMISTRY  

  1. A mixture of sand, ammonium chloride and sodium is a best separed by (A) sublimation followed by addition of water and filtration (B) sublimation followed by addition of water and evaporation (C) addition of water followed by filtra tion and sublimation (D) addition of water followed by crystallization and sublimation
  2. A pure solid usually melts (A) over a wide range of temperature (B) over a narrow range of temperature (C) at a lower temperature than the impure one (D) at the same temperature as the impure one
  3. For a gas, the relative molecular mass s equal to 2y. what is y? (A) the mass of the gas (B) the vapour density of the gas (C) the volume of the gas (D) the temperature of the gas
  4. An increase in temperature causes an increase in the pressure of a gas because (A) it decreases the number f collision between the molecules (B) the molecules of the gas bombard the walls of the container more frequently

(C) it increases the number of collisions between the molecules (D) it causes the molecules to combine

  1. The shape of ammonia molecule is (A) trigonal planar (B) octahedral (C) square planer (D) tetrahedral
  2. The number of electrons in the valence shell of an element of atomic number (A) 1 (B) 2 (C) 3 (D) 4
  3. A solid that can absorb water from that can absorb water from the atmosphere and forms an aqueous solution is (A) hydrophilic (B) efflorescent (C) deliquescent (D) hydroscopic
  4. A major effect of pollution in coastal waters is the (A) destruction of marine life (B) desalination of the water (C) increase in the acidity of water (D) detoxification of the water
  5. Crude copper could be purified by the electrolysis of concentrated copper (ii) chloride if the crude copper is (A) made both the anode and the cathode (B) made the cathode (C) made the anode (D) dissolve in the solution
  6. Which of the following is true of le Chatelier’s Principle for an exothermic reaction? (A) increase in temperature will cause an increase in the equilibrium constant (B) increase in temperature will cause a decrease in the equilibrium constant (C) addition of a catalyst will cause an increase in the equilibrium constant (D) addition of a catalyst will cause a decrease in the equilibrium constant
  7. Chromatograph is used to separate component of mixtures which differ in their rates of (A) diffusion (B) migration (C) reaction (D) sedimentation
  8. Which of the following is an example of a chemical change (A) dissolution of salt in water (B) rusting of iron (C) melting of ice (D) separating a mixture by distillation
  9. The stability of ionic is generally due to the (A) negative electron affinity of most atoms (B) crystals lattice forces (C) electron pair sharing (D) positive ionization potentials
  10. Which of the following statements is false about isotopes of the same elements? (A) they have same number of electrons in their outermost shells (B) they have different atomic masses (C) they have the same atomic number and the same number of electrons (D) they have the same atomic number but different number of electrons
  11. Helium is often used in observation ballons because it is (A) light and combustible (B) light and non-combustible (C) heavy and combustible (D) heavy and non combustible
  12. When plastics and packaging materials made from chloroethene and burnt in the open, the mixture of gases released into the atmosphere is most likely to contain (A) ethane (B) chlorine (C) hydrogen chloride (D) ethene
  13. Deliquescent substance are also (A) efflorescent (B) anhydrous (C) hygroscopic (D) insoluble

 

  1. The difference between colloids and suspensions is brought out clearly by the fact that while colloids (A) do not scatter light, suspensions do (B) can be separated by filtration, suspensions cannot be so separated (C) can be separated by a membrane, suspension cannot (D) do not settle out on standing, suspensions do
  2. In general, an increase I temperature increases the solubility of a solute in water because (A) more solute dissociate at higher temperature (B) most solutes dissolved with the evolution of heat (C) more solute molecules dissociate at higher temperature (D) most solute dissolve with absorption of heat
  3. Neutralization involves a reaction betweeb H3O+ and (A) Cl (B) OH (C) NO32-
  4. Which of the following solution will have a H<7? (A) Na3SO4(aq) (B) NaCl(aq) (C) Na2CO2(aq) (D) NH4Cl(aq)
  5. Which of the following process leads to increase in entropy? (A) mixing a sample of NaCl and sand (B) consideration of water vapour (C) boiling a sample of water (D) cooling a saturated solution
  6. Sulphur exists in six forms in the solid state. The property is known as (A) isomerism (B) allotropy (C) soropy (D) isomorphism
  7. Aromatic and aliphatic hydrocarbons can be distinguished from each other by the (A) action of bromine (B) use of polymerization reaction (C) action of heat (D) use of oxidation reaction
  8. In the process of silver-planting a metal M, the metal M is the (A) anode and direct current is used (B) cathode and an alternating current is used (C) anode and an alternating current is used (D) cathode and a direct current is used
  9. One method of driving the position of equilibrium of an endothermic reaction forward is to (A) increase temperature at constant pressure (B) decrease pressure at constant temperature (C) cool down the apparatus with water (D) decrease temperature at constant pressure
  10. Oxidation of concentrated hydrochloric acid with manganese (IV) oxide librates gas used in the (A) manufacture of tooth pastes (B) treatment of simple goiter (C) vulcanization of rubber (D) sterilization water
  11. A compound will NOT produce Oxygen on heating is (A) potassium dioxonitrate (III) (B) lead (IV) oxide (C) potassium trioxochlorate (V) (D) potassium trioxochlorate (V)
  12. Which of the following additives could improve the quality of steel? (A) silicon (B) sulphur and phosphorous (C) carbon (D) chromium and nickel
  13. Sodium hydroxide is prepared commercially from sodium hydroxide is prepared commercially from sodium chloride solution by (A) electrolysis using mercury as cathode (B) hydrolysis un steam using catalyst (C) electrolysis using iron as anode (D) treating sodium chloride with ammonia and carbon (IV) oxide
  14. Synthetic detergents are preferred to soap for laundry using hard water because (A) detergents are water soluble while soap is not (B) the calcium salts of detergents are water soluble (C) the magnesium salt of soap is soluble in hard water (D) soap does not have hydrocarbon terminal chain.
  15. Which of these compounds is a normal salt (A) Na2CO3 (B) NaHCO3 (C) NaHSO4 (D) NaHS
  16. A carcinogenic substance is (A) nitrogen(II) oxide (B) carbon (II) oxide (C) asbestos dust (D) sawdust
  17. Calcium tetraoxosulphate(VI) dissolves in water only sparingly to form a (A) colloid (B) solution (C) suspension (D) precipitate
  18. Hardness of water is caused by the presence of the ions of (A) calcium and magnesium (B) calcium and sodium (C) magnesium and silver (D) sodium and potassium
  19. It is difficult to archive an orderly arrangement of the molecules of a gas because they (A) can collide with one another in the container (B) are too small in size (C) have little force of attraction between them (D) have no definite shape
  20. The shape of the s-orbital is (A) elliptical (B) spiral (C) circular (D) spherical
  21. Which of the following mixtures of gasses is likely to burn in flame (A) helium and neon (B) neon and nitrogen (C) neon and hydrogen (D) nitrogen and helium
  22. The property of chlorine which causes hydrogen chloride to be more ionic than the chlorine molecule is its (A) electro negativity (B) electropositivity (C) electron affinity (D) electrovalency
  23. Aluminum hydroxide id used in the dyeing industry as a (A) dye (B) dispersant (C) salt (D) mordant
  24. The shape of the hydrocarbon compound CH4 is (A) square planar (B) linear (D) evaporation
  25. Which of these properties gives a solid its definite shape? (A) strong intermolecular attraction (B) high melting point

(C) high boiling point (D) weak intermolecular attraction

  1. Sugar is separated from its impurities by (A) precipitation (B) crystallization (C) distillation (D) evaporation
  2. The component of an atom that contributes least to its mass is the (A) proton (B) nucleus (C) neutron (D) electron
  3. An element will readily from an electrovalent compound if its electron configuration is (A) 2.8.1 (B) 2,8,4 (C) 2,8,8 (D) 2,8,5
  4. A hetrogenous mixture can be defined as any mixture (A) of a solute and a solvent (B) whose composition is uniform (C) whose composition is not uniform (D) formed by solids and liquids
  5. The density of a certain gas is 1.98gdm-3 at s.t.p. what is the molecular mass of the gas? (A) 44.0g (B) 54.0g (C)

26.0g (D) 31.g (molar volume of gas at s.t.p = 22.4dm3)

  1. A dense white fume is formed when ammonia gas reacts wit (A) O2(g) (B) H2(g) (C) Cl2(g) (D) HCl(g)
  2. The gas that can be dried using concentrated tetraoxosulphate (VI) acid is (A) hydrogen bromide (B) sulphur (IV) oxide (C) hydrogen sulphide (D) ammonia
  3. the most suitable metal that can be used as a lightning conductor is (A) silver (B) copper (C) iron (D) aluminium

 

ANSWERS

1 A 12 B 23 B 24 C 34A 35 A  45A 46 A
2 A 13 B 25 B 36 C 47 A 3 B 14 D 26 A 37 D 48 D
4 B 15 B 16 C 27 D 38 C 49 B
5 D 17 C 28 A 39 A 50
6 D 18 D 29 D 40 D
7 C 19 C 30 A 41 D
8 A C A 20C   21B  22A 31 B 42 A
9 32 A 43 B
10 33 A 44 D
11 B

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