WAEC - Chemistry (1994)

• 1

  The components of universal indicator solution can best be separated by

  回答

  (A)

  chromatography
• 2

  The number of replaceable hydrogen atoms in one acid indicates its

  回答

  (A)

  basicity
• 3

  Catalytic hydrogenation of alkenes produces compounds with the general formula

  回答

  (C)

  C_nH_2n+2
• 4

  A measure of the degree of disorder in a chemical system is known as the

  回答

  (D)

  entrophy
• 5

  In any chemical reaction, the total mass of the products is always equal to that of the reactants. This is statement of the law of

  回答

  (B)

  conservation of matter
• 6

  Which of the following is not a property of magnesium oxide?

  回答

  (E)

  Low binding energy
• 7

  Which of the following would increase the rate of reaction of chips of a metal M as shown in the equation below? M_(s) + 2HCI_(aq) → MCI_2(aq) + H_2(g)

  回答

  (D)

  Grinding the metal into powder
• 8

  The oxidation number of phosphorus in \(PO_4^{3-}\) is

  回答

  (E)

  +5
• 9

  The number of atoms in 1.2g of carbon - 12 isotope is

  回答

  (B)

  6.02 x 10₂₂
• 10

  Tetraoxosulphate (lV) acid is described as strong acid because it is highly

  回答

  (E)

  ionized in water
• 11

  The following will decolourize acidified potassium tetraoxomanganate (VII) solution except

  回答

  (C)

  pentane
• 12

  Polyatomicity is illustrated by molecules of

  回答

  (A)

  sulphur
• 13

  Calcium is usually extracted by the electrolysis of its

  回答

  (E)

  chloride
• 14

  When naphthalene on heating changes from the solid state directly to the gaseous state it undergoes

  回答

  (B)

  sublimation
• 15

  Which of the following occurs when an aqueous solution of sodium hydroxide is electrolysed using graphite electrodes?

  回答

  (C)

  Oxygen gas is produced at the anode
• 16

  If the volume of a given mass of gas at 0^oC is 27.3cm³, what will be the volume of the gas at 10^oC, pressure remaining constant?

  回答

  (B)

  28.3cm³
• 17

  Glucose can be obtained from starch by

  回答

  (C)

  hydrolysis
• 18

  How many faradays of electricity are required to liberate 9g aluminium? (AI = 27)

  回答

  (C)

  1.0
• 19

  When water is dropped on calcium carbide, the gaseous product is an

  回答

  (C)

  alkyne
• 20

  Mg\(_2\) + 2HCI\(_{(aq)}\) → MgCI\(_{2(g)}\) + H\(_{2(g)}\).

  From the equation above what mass of hydrogen would be produced if 12.0 g of magnesium reacted completely with dilute hydrochloric acid? (H = 1, Mg = 24)

  回答

  (A)

  1.0g
• 21

  The positive of an element in the Periodic Table is determined by

  回答

  (D)

  the number of protons in its atom
• 22

  Which of the following electronic structures belongs to a noble gas?

  回答

  (C)

  1s²2s²2p⁶3s²3p⁶
• 23

  In a chemical reaction, the reacting species possess energy of motion known as

  回答

  (D)

  kinetic energy
• 24

  The following compounds will decompose on heating except

  回答

  (B)

  K₂CO₃
• 25

  Which of the following reactions is accompanied by the first ionization energy of an element X?

  回答

  (D)

  X _(g) → X⁺ _(g) +^e-
• 26

  What is the molar of hydrogen sulphide gas in the reaction H₂SO_4(aq) + 3H₂S_(g) → 4S_(s) + 4H₂O _(l)n represented by the following equation?

  回答

  (A)

  Reducing agent
• 27

  Alkanols have unexpectedly high boiling points relative to their molar masses because of intermolecular

  回答

  (A)

  hydrogen bonding
• 28

  Sodium chloride is used in the following processes except in the

  回答

  (A)

  treatment of polluted water
• 29

  The gaseous product formed when ammonia is passed over heated copper (ll) oxide is

  回答

  (B)

  nitrogen
• 30

  Which of the following is not a halogen?

  回答

  (A)

  Silicon
• 31

  Which of the following is likely to have the highest degree of hardness?

  回答

  (E)

  Lime water
• 32

  Study the reaction represented by the equation: Alkanol + Alkanoic acid + conc. H\(_2\)SO\(_4\) → Alkanoate + water.  The type of process involved in the reverse reaction is

  回答

  (C)

  hydrolysis
• 33

  Destructive distillation of coal means

  回答

  (C)

  heating coal in the absence of air
• 34

  When magnesium ribbon burns in air, the products are

  回答

  (C)

  magnesium oxide and steam
• 35

  The following compounds contain the same type of bonds except

  回答

  (B)

  hydrogen chloride