WAEC - Chemistry (2015)

• 1

  The negatively charged particle in an atom is the

  回答

  (A)

  Electron
• 2

  How many orbits are contained in an atom with atomic number 13?

  回答

  (D)

  3
• 3

  The Van der waals' forces are dominant intermolecular forces in_______?

  回答

  (B)

  Chlorine
• 4

  The compound formed between ₁₄X and ₁₆Y is _______?

  回答

  (B)

  XY₂
• 5

  The shape of a molecule of water is _______?

  回答

  (A)

  Non-linear
• 6

  A metallic ion Z\(^{2+}\) with an inert gas structure contains 18 electrons. How many protons are contained in this ion?

  回答

  (A)

  20
• 7

  Which of the following pairs of elements forms amphoteric oxides?

  回答

  (D)

  Si and Pb
• 8

  Which of the following pairs of compounds belongs to the same homologous series?

  回答

  (D)

  C₂H₆ and C₄H₁₀
• 9

  The following transition metal ions would be coloured in aqueous solution except________?

  回答

  (D)

  Sc³⁺
• 10

  The gas given off when ethanol reacts with sodium is

  回答

  (B)

  Hydrogen
• 11

  Which of the following halogens is solid at room temperature?

  回答

  (D)

  Iodine
• 12

  The alkaline earth metals have similar chemical properties because________?

  回答

  (C)

  They have the same number of valence electrons
• 13

  The number of unpaired electrons in an atom of an element ₈Q is _______?

  回答

  (A)

  2
• 14

  The bond formed when ammonia reacts with hydrogen ion to form ammonium ion is

  回答

  (B)

  Dative
• 15

  To which group and period respectively does an element with 15 electrons belong?

  回答

  (C)

  5 and 3
• 16

  The shape of a graphite crystal is

  回答

  (D)

  Hexagonal
• 17

  Which of the following oxides is ionic?

  回答

  (B)

  MgO
• 18

  Which of the following substances when boiled with aqueous solution of sodium hydroxide would be hydrolyzed?
  
  i. Protein ii. Fat iii. Polythene

  回答

  (C)

  i and ii
• 19

  Which of the following trioxonitrate(V) salts would decompose on heating to form a metal?

  回答

  (B)

  AgNO₃
• 20

  Consider the following reaction equation:
  C2H4(g) + 3O2(g) \(\to\) 2CO2(g) + 2H2O(g)
  
  The volume of CO2(g) produced at s.t.p when 0.05 moles of C2H4(g) was burnt in O2(g) is
  [Molar Volume of gas = 22.4dm3

  回答

  (B)

  2.24dm³
• 21

  The number of oxygen molecules present in 16.0g of the gas is ______?
  [Avogadro's number = 6.02 x 10²³]

  回答

  (C)

  3.01 x 10²³
• 22

  Consider the following reaction equation:
  SO₄^2-_(aq) + 2H⁺_(aq) + ye^- \(\to\) SO₄^2-_(aq) + H₂O₍₁₎.
  
  The value of y in the equation is

  回答

  (A)

  2
• 23

  The general gas equation was deprived from______?

  回答

  (C)

  Boyle's and Charles' laws
• 24

  The vapour pressure of a liquid depends on:
  I. Temperature II. rate of condensation III. Cohesive forces holding the particles together.

  回答

  (C)

  I and III
• 25

  Which of the following gases will diffuse most rapidly?
  
  [H = 1.00, C = 12.0, O = 16.0, S = 32.0, Cl = 35.5]

  回答

  (C)

  CH₄
• 26

  When a reaction is endothermic,

  回答

  (C)

  Heat content of reactants is less than the heat content of product
• 27

  Which of the following statements about intermolecular distances and cohesive forces between gas is correct? They are

  回答

  (D)

  Large and negligible
• 28

  

  The following diagram illustrates the rate curve that was obtained when Mg reacted with excess dilute HCl.
  
  The diagram became horizontal at X because

  回答

  (C)

  All the Mg has reacted
• 29

  An example of an acid salt is

  回答

  (C)

  NaHSO₄
• 30

  Which of the following oxides can be reduced by hydrogen?

  回答

  (D)

  Silver oxide
• 31

  Solubility is practically applied in

  回答

  (D)

  Solvent extraction
• 32

  Which of the following compounds is the least soluble in water?

  回答

  (B)

  CaSO₄
• 33

  A substance which dissolves readily in organic solvent would

  回答

  (A)

  Be a covalent compound
• 34

  A change in the temperature of a saturated solution disturbs the equilibrium between the

  回答

  (C)

  Dissolved solute and the undissolved solute
• 35

  Which of the following statements about an electrochemical cell is correct? Oxidation occurs

  回答

  (A)

  At the anode
• 36

  Consider the following reaction equation:
  CuO_(s) + H_2(g) \(\to\) Cu_(s) + H₂O₍₁₎
  
  Which substance is oxidized?

  回答

  (C)

  H₂
• 37

  Which of the following metals is the strongest reducing agent?

  回答

  (C)

  Potassium
• 38

  The complete hydrogenation of benzene gives

  回答

  (B)

  Cyclohexane
• 39

  A compound has an empirical formular CH₂O and molecular mass of 90.
  
  [H = 1.00, C = 12.0, O = 16.0]

  回答

  (C)

  C3H6O3
• 40

  Which of the following reactions would take place when concentrated sodium hydroxide solution is added to palm oil?

  回答

  (D)

  Saponification
• 41

  Starch could be converted to glucose by the process of

  回答

  (D)

  Hydrolysis
• 42

  Which of the following compounds is a secondary alkanol?

  回答

  (C)

  3-methylpentan-2-ol
• 43

  Which of the following substances is a heavy chemical?

  回答

  (D)

  Tetraoxosulphate(VI)acid
• 44

  Which of the following process does not take place in domestic water treatment?

  回答

  (C)

  Neutralization
• 45

  A substance responsible for the sour taste of unripe orange is

  回答

  (C)

  Alkanoic acid