23/04/2020 Senior Class WAEC/NECO/UTME Mock Exams(Chemistry) 23/04/2020 0Comments by Gate Academy Please, fill out the information below to continue. NAME EMAIL PHONE NUMBER 1. Freshly boiled tap water tastes different from ordinary tap water because all the germs have been killed it contains more dissolved oxygen it contains less dissolved air the water molecules are now smaller it contains more carbon(iv)oxide 2. When hydrogen sulphide gas is passed through an acidified solution of potassium heptaoxo dichromate(vi), the orange colour changes to green. This is because the +6 state of Cr is reduced to +3 state chromium(vi) ion is oxidized sulphide ion changes to sulphur atom +3 state of Cr is oxidized to +6 state hydrogen sulphide is a good oxidizing agent 3. N2(g) + 3H2(g) ↔ 2NH3(g); ∆H = -90kj/molIn the equation above, the yield of ammonia can be decreased by Adding a catalyst Increasing the temperature Increasing the pressure Removing the ammonia as it is formed 4. Which of the following is not a separation technique? hydration filtration crystallization evaporation distillation 5. Fructose and glucose are isomers with a molecular formula C6H12O6. Which of these statements is true of both? fructose gives a brick red ppt with Fehlings solution but glucose does not glucose and fructose are non-reducing sugars fructose has an alkanone group while glucose has an alkanal group both have an alkanal group fructose has an alkanal group while glucose has an alkanone group 6. Most commonly used Rodenticides are _______ in nature. Anti Coagulant Anti solvent Non anti coagulant Anti pesticides 7. CuSO4.5H2O can be obtained from an aqueous solution of copper(ii)tetraoxosulphate(vi) by Precipitation Using chromatography Crystallization Evaporation to dryness 8. Which of the following is true of Ionisation energy? it is unaffected by nuclear charge the higher the screening effect, the higher the ionization energy it increases across the period it is the energy due to electron gain it increases down the group 9. Which of the following statements is NOT correct about the compound represented below?COOH|COOH it produces effervescence with saturated NaHCO3 solution its name is ethanedioic acid its b.p is higher than that of the corresponding alkane it is a di-carboxylic acid it has a basicity of 4 10. Dilute HCl produces a gas with each of the following compounds EXCEPT copper(ii)trioxocarbonate(iv) iron(ii)sulphide sodium trioxosulphate(iv) sodium tetraoxosulphate(vi) calcium trioxocarbonate(iv) 11. When an atom gains an electron, it becomes A cation An anion Positively charged Chemically inactive A non-metal atom 12. N2O4(g) ↔ 2NO2(g)In the endothermic reaction above, more product formation will be favoured by Decreasing the temperature An increase in pressure A decrease in volume Increase in volume 13. Dilute HCl produces a gas with each of the following compounds EXCEPT sodium tetraoxosulphate(vi) sodium trioxosulphate(iv) iron(ii)sulphide copper(ii)trioxocarbonate(iv) calcium trioxocarbonate(iv) 14. Which of the following is NOT a halogen? bromine astatine iodine fluorine silicon 15. Where are Bio-chemical compounds used? Food preservatives Skin Treatments Cooking Oils All of the above 16. In which of the following compounds does sulphur have an oxidation number of +4 H2S H2SO4 H2S207 SO3 Na2SO3 17. A synthetic rubber is having__________weight. Higher resistance Higher atomic Lower density Higher molecular 18. An element Y has the electronic configuration 1s2 2s2 2p6 3s2 3p4 To what period does it belong in the periodic table? 4 5 6 3 19. When ammonium chloride is dissolved in water in a test tube, the test tube feels cooler showing that? The solution is unsaturated Sublimation has occurred Ammonia gas is evolved The process is endothermic 20. Allotropes of an element differ in their? Physical Property Electronic Configuration Mass number Chemical Property 21. Which of the following is true of gamma (γ) rays? They are negatively charged are neutral travel at very low speed are positively charged have no ionizing power 22. Lemon is a source of ................acid lactic amino ethanoic ascorbic citric 23. The Azimuthal quantum number which corresponds to the f-orbital is 3 0 6 1 2 24. What term is used to describe an oxide whose aqueous solution turns blue litmus red Amphoteric oxide Strong electrolyte Basic oxide Acid anydride 25. H2(g) + I2(g) ↔ 2HI(g) In the reaction, increasing the pressure will have no effect on the equilibrium position favour the forward reaction favour the backward reaction increase the concentration of HI decrease the concentration of HI 26. Which of the following substances decompose when an electric circuit is passed through it? tetra chloromethane zinc rod dilute hydrochloric acid glucose solution 27. The gaseous product formed when ammonia is passed over heated copper(ii)oxide is Nitrogen(i)oxide Hydrogen Nitrogen Nitrogen(ii)oxide Oxygen 28. The electrolyte used in lead accumulator cell is Ammonium chloride paste Manganese(iv)oxide Ammonium chloride solution Tetraoxosulphate(vi) acid solution 29. Which of the following decreases when a given mass of gas is compressed to half its initial volume? Number of molecules present Atomic radius of each particle Average intermolecular distance Frequency of collisions 30. The catalyst generally used in the synthesis of methanol from carbon(ii)oxide and hydrogen is zinc oxide copper-zinc oxide nickel platinum vanadium(v)oxide 31. An element Y has the electronic configuration 1s2 2s2 2p6 3s2 3p4 How many lone pair of electrons are present in element Y? 4 3 1 2 32. The kinetic theory of gases can be used to explain all the following EXCEPT Expansion of gases Dalton's atomic theory Gay-Lussac's law Diffusion of gases Graham's law 33. Chemical equilibrium is attained when Concentration of the reactants is greater than that of the products Concentrations of the products and reactants remain constant Reactants in the system are used up Concentration of products is greater than that of the reactant 34. Solid NH4Cl and KCl are mixed together. How could they be separated easily? Dissolution of the mixture in water followed by filtration Precipitation by the addition of AgNO3 solution to the mixture dissolved in water Decantation of an aqueous solution of the mixture Sublimation Extraction 35. What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?[H=1, O=16] 72.0g 54.0g 36.0g 8.0g 36. When hydrogen sulphide gas is passed through an acidified solution of potassium heptaoxo dichromate(vi), the orange colour changes to green. This is because the +6 state of Cr is reduced to +3 state +3 state of Cr is oxidized to +6 state hydrogen sulphide is a good oxidizing agent sulphide ion changes to sulphur atom chromium(vi) ion is oxidized 37. The following salts can be prepared by a double decomposition reaction EXCEPT KCl BaSO4 BaCO3 PbCl2 AgCl 38. The condition for spontaneous reaction is ΔG < 0 ΔH > 0 ΔG = 0 ΔG > 0 ΔS < 0 39. When excess ammonia is added to an aqueous copper(ii)tetraoxosulphate(vi), a deep blue solution of copper(ii)tetraamine is formed. The type of bond in copper(ii)tetraamine is hydrogen bond covalent bond ionic bond van der waals coordinate covalent bond 40. Which of the following alloys contain Tin and Lead? brass bronze solder coinage metal steel 41. A finely divided form of a metal burns more readily in air than the rod form because the rod has Different chemical properties Protective oxide coating Smaller surface area Higher molar mass 42. The loss of molecules of water of crystallization to the atmosphere by some crystalline salt is known as Effervescence Hygroscopy Deliquescence Efflorescence 43. The bleaching of wood pulp for making paper by sulphur(iv)oxide is a process of desulphurisation oxidation reduction refining vulcanization 44. Which of the following substances decompose when an electric circuit is passed through it? tetra chloromethane zinc rod dilute hydrochloric acid glucose solution 45. 15dm³ of a gas at s.t.p. in a tube was pressed by a piston whose pressure was increased to twice its original value at the same temperature. The volume of the gas in dm³ at this new pressure is 7.5dm³ 12.0dm³ 30.0dm³ 5.0dm³ 10.0dm³ 46. What is the pattern of the degree of electropositivity of elements in the periodic table? Remains constant across a period Decreases across a period Remains constant down a group Decreases down a group and across period Increases across a period 47. An element Y has the electronic configuration 1s2 2s2 2p6 3s2 3p4 What is the symbol of element Y in the periodic table? Ar S P Si 48. Water gas is a mixture of? Nitrogen and Hydrogen Carbon and Hydrogen Carbon(ii)oxide and hydrogen Carbon(iv)oxide and hydrogen 49. What is the composition of soap? Sodium and Potassium salt mixed with chemicals Sodium salt with fatty acids. Both a & b Potassium salt with fatty acids 50. What will be the effect of increase in pressure on the following system at equilibrium?2NH3(g) ↔ N2(g) + 3H2(g) The concentration of ammonia will increase The forward reaction will be favoured Activation energy will decrease The reaction will go to completion 51. Substance Q reacts with cold water to form a solution which turns red litmus blue?Substance Q could be Phosphorus Calcium Nitrogen Sulphur 52. What volume of distilled water would be added to 30cm³ of 18mol/dm³ HCl in order to dilute it 20 times? [ H=1, Cl=35.5, M.V=22400cm³] 12cm³ 542cm³ 600cm³ 360cm³ 27cm³ 53. In which of the following compounds does sulphur have an oxidation number of +4 H2SO4 Na2SO3 SO3 H2S H2S207 54. Example(s) of colloids include:I. emulsionsII. solsIII. FogIV. smoke III and IV Only I, II and III Only I and II Only IV Only I, II, III and IV 55. Which of the following alloys contain Tin and Lead? steel solder brass coinage metal bronze 56. Consider the reaction represented by the equation:H2(g) + I2(g) ↔ 2HI(g) ΔH = -ve Which of the following statements about the equation is correct? pressure will have no effect on the production of HI(g) increase in temperature will favour the forward reaction the addition of a catalyst will change the equilibrium position the removal of HI(g) formed will favour the backward reaction increase in pressure will favour the forward reaction 57. Which is not used as an alkali? Sodium hydroxide Potassium hydroxide Nitrogen hydroxide Carbon hydroxide 58. An element Y has the electronic configuration 1s2 2s2 2p6 3s2 3p4 How many shared pair of electrons are present in element Y? 4 6 5 7 59. RDX is chemical compound. How is it used? As an composition As an explosive As an reactor As an nuclear weapon 60. The catalyst generally used in the synthesis of methanol from carbon(ii)oxide and hydrogen is platinum nickel vanadium(v)oxide copper-zinc oxide zinc oxide 1 out of 60 Time is Up! Time's up