WAEC - Chemistry (2007)

  • 1
    When sodium atom form the ion Na+,
    Trả lời
    (B)
    it achieves a noble gas configuration
  • 2
    Which of the following statements about rare gases are correct?
    Trả lời
    (A)
    Their outermost shells are fully filled
  • 3
    Which of the following properties is characteristic of the halogens?
    Trả lời
    (A)
    Ability to accept electrons readily
  • 4
    In which of the following atoms is the ionic radius larger than the atomic radius? [11 Na, 12Mg,13AI,17CI]
    Trả lời
    (B)
    Chlorine
  • 5
    A transition metal would be expected to
    Trả lời
    (A)
    from oxides with different formulae
  • 6
    Which of the following properties of atoms generally increases down a group in the periodic table?
    Trả lời
    (C)
    Ionic radius
  • 7
    Which of the following statements about sodium is not true?
    Trả lời
    (B)
    Na is smaller in size than Na+
  • 8
    If the difference between the electronegativities of two elements is large, the type of bond that can be formed between them is
    Trả lời
    (C)
    ionic
  • 9
    Which of the following compounds has hydrogen bonds between its molecules?
    Trả lời
    (A)
    HF
  • 10
    Which of the following species does not contain a co-ordinate bond?
    Trả lời
    (A)
    AI2CI6
  • 11
    14.8 g of a salt (z)dissolved in 250 cm3 of distilled water gives a concentration of 0.80 mol dm-3. Calculate the molar mass of the salt (z).
    Trả lời
    (D)
    74.0 g mol-1
  • 12
    How many atoms are there in one mole of hydrogen gas? [Avogadro's constant = 6.02 x 1023mol-1]
    Trả lời
    (C)
    1.2 x10 24
  • 13
    What is the IUPAC name of the compound represented by the molecular formula NaCIO4?
    Trả lời
    (D)
    Sodium tetraoxochlorate(VII)
  • 14
    When air is successively passed through sodium hydroxide solution, alkaline pyrogallol and then concentrated tetraoxosulphate (VI) acid, its remaining components are
    Trả lời
    (D)
    nitrogen and noble gases
  • 15
    Which of the following gases is light than air?
    Trả lời
    (D)
    NH3
  • 16
    Which of the following statements is true of the molecules of a gas under ideal conditions? The molecules
    Trả lời
    (A)
    move at random
  • 17

    In which of the following compound (s) will heat be absorbed on adding water?

    l. KNO\(_3\) II. Concentrated H\(_2\)SO\(_4\) III. NH\(_4\)CI

    Trả lời
    (C)
    l and lll only
  • 18
    Consider the reaction represented by the equation: Ca(OH)2(aq) + CO 2(g) → CaCO3(s) + H 2O(l)
    in the reaction above, CO 2 acts as
    Trả lời
    (A)
    an acidic oxide
  • 19
    Which of the following compounds is a basic salt?
    Trả lời
    (D)
    Zn(OH)CI
  • 20
    What process is illustrated below? S(s) ⇌H2O⇌ S (aq)
    Trả lời
    (C)
    Formation of saturated solution of a solid
  • 21
    A solution of a salt X reacts with AgNO3 solution to give white precipitate which dissolves in excess aqueous ammonia. X contains
    Trả lời
    (A)
    CI-
  • 22
    Consider the reaction represented by the following equation: N2(g) + 3H2(g) ⇌ 2NH3(g); ∆H = - 92kJmol1. Finely divided iron is used as catalyst in the reaction in order to
    Trả lời
    (C)
    shorten the time for attainment of equilibrium
  • 23
    Which of these cell notations is the correct representation of a Daniell cell?
    Trả lời
    (A)
    Zn(s) / Zn2+(aq) // Cu2+(aq)/Cu(s)
  • 24
    What is the oxidation number of chromium in K2CrO4?
    Trả lời
    (D)
    +6
  • 25
    What product is formed at the cathode during the electrolysis of concentrated sodium chloride solution using carbon electrodes?
    Trả lời
    (B)
    Hydrogen
  • 26
    Which of the following substances is suitable solvent for perfumes?
    Trả lời
    (B)
    Ethanol
  • 27
    The complete hydrogenation of C 6
    H 6 in the presence of nicked catalyst at 200oC gives
    Trả lời
    (C)
    C 6H 12
  • 28
    Which of the following pairs of substances can be distinguished by use of NaHCO3 solution?
    Trả lời
    (B)
    CH 3CH2OH and CH3COOH
  • 29
    Alkenes undergo the following reactions except
    Trả lời
    (D)
    substitution
  • 30
    Hydrocarbons which react with ammoniacal copper (l) chloride solution conform to the general molecular formula
    Trả lời
    (D)
    CnH2n-2
  • 31
    Consider the reaction below: Vegetable oil \(\frac{H2;NI catalyst}{High temperature}\) product. The reaction is applied in the manufacture of?
    Trả lời
    (B)
    margarine
  • 32
    Which of the following compounds reacts readily with sodium to liberate hydrogen?
    Trả lời
    (B)
    CH3COOH
  • 33
    Glucose reduces Fehling's solution on warming to
    Trả lời
    (A)
    copper (l) oxide
  • 34
    from the following ores is iron extracted? I. Haematite ll. Bauxite III. Magnetite IV. Cassiterite
    Trả lời
    (B)
    l and lll only
  • 35
    Which of the following methods can be used to separate a mixture of two miscible liquids with different boiling points?
    Trả lời
    (B)
    Distillation