2016 Chemistry WAEC SSCE (School Candidates) May/June

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Chemistry 1 - Objective Test Questions

The following atoms of carbon ₁₂C, ₁₃C and ₁₄C can be described as
1. allotropes
2. isomers
3. isotopes
4. isotones
An atom X consists of 6 protons, 6 electrons and 7 neutrons. Which of the following representations of the atom is correct?
1. ${\ce {^{13}_{6}X}}$
2. ${\ce {^{13}_{7}X}}$
3. ${\ce {^{19}_{6}X}}$
4. ${\ce {^{19}_{7}X}}$
How many electrons are present in ${\ce {^{9}_{4}Be^2+}}$ ${\ce {^{9}_{4}Be^2+}}$ ?
1. 2
2. 4
3. 5
4. 6
When element ₂₀Y combines with element ₈Z
1. a covalent compound YZ is formed
2. a covalent compound ZY is formed
3. an ionic compound YZ is formed
4. an ionic compound ZY is formed
The boiling points of HF, H₂O and NH₃ increase in the order of
1. NH₃ < H₂O < HF
2. H₂O < HF < NH₃
3. HF < NH₃ < H₂O
4. NH₃ < HF < H₂O
Chemicals that are produced in small quantities and with very high degree of purity are
1. bulk chemicals
2. fine chemicals
3. heavy chemicals
4. light chemicals
The mass of potassium hydroxide required to make 300.0 cm³ of 0.4 moldm³ solution is [KOH = 56.0]
1. 26.88 g
2. 13.44 g
3. 6.72 g
4. 3.36 g
Metals can be stretched into wires because they are
1. ductile
2. good conductors
3. lustrous
4. malleable
Aluminum is used in the manufacture of aircraft because it
1. is hard and brittle
2. is light and resist corrosion
3. has high density and conducts electricity
4. is malleable and ductile
An unsaturated solution differs from a saturated solution at a given temperature because it
1. cannot dissolve more solute
2. can hold more solute than it can actually dissolve
3. can still dissolve more solute at that given temperature
4. form crystal more easily on cooling
Which of the following arrangements shows increasing order of reactivity of the halogens?
1. F₂ > Cl₂ > Br₂ > I₂
2. I₂ < Br₂ < Cl₂ < F₂
3. F₂ < Cl₂ < Br₂ < I₂
4. I₂ > Br₂ > Cl₂ > F₂
The shape of the water molecule is
1. linear
2. pyramidal
3. tetrahedral
4. V-shaped
Which of the following elements would produce coloured ion in aqueous solution?
1. Calcium
2. Copper
3. Magnesium
4. Sodium
The minimum amount of energy required for effective collisions between reacting particles is known as
1. activation energy
2. bond energy
3. kinetic energy
4. potential energy
The bond formed between H₂O and H⁺ to form the hydroxonium ion H₃O⁺ is
1. dative
2. covalent
3. electrovalent
4. ionic
An element X forms the following oxides X₂O, XO and XO₂. This phenomenon illustrates the law of
1. conservation of mass
2. definite proportion
3. mass action
4. multiple proportions
How many moles of oxygen would contain 1.204 x 10²⁴ molecules? [Avogadro's constant (N_A) = 6.02 x 10²³]
1. 1
2. 2
3. 3
4. 4
Which of the following statements about solids is correct?
1. Solids particles are less orderly than those of a liquid
2. Solids have lower densities than liquids
3. Solid particles have greater kinetic energies than those of liquids
4. Solid particles cannot be easily compressed
Which of the following apparatus can be used to measure a specific volume of a liquid accurately?
1. Beaker
2. Conical flask
3. Measuring cylinder
4. Pipette
The general gas equation ${\tfrac {PV}{T}}=K$ ${\tfrac {PV}{T}}=K$ is a combination of
1. Boyle's and Charles' laws
2. Boyle's and Graham's laws
3. Charles' and Graham's laws
4. Dalton's and Graham's laws
The spreading of the scent of a flower in a garden is an example of
1. Brownian motion
2. diffusion
3. osmosis
4. Tyndal effect
Propane and carbon(IV)oxide diffuse at the same rate because [H = 1.00, C = 12.0, O = 16.0]
1. they are both gases
2. their molecules contain carbon
3. they have the same relative molecular mass
4. both are denser than air
The energy which accompanies the addition of an electron to an isolated gaseous atom is
1. atomization
2. electronegativity
3. electron affinity
4. ionization
An aqueous solution of (NH₃)₂SO₄ is
1. acidic
2. alkaline
3. amphoteric
4. neutral
When NH₄Cl_(s) is dissolved in water, the container feels cold to the touch. This implies
1. the process is endothermic
2. the process is exothermic
3. NH₄Cl forms a saturated solution
4. NH₄Cl is highly soluble in water
The pH of four solutions M, N, Q and R are 2,6,8 and 11 respectively. Which of the following deductions about the solutions is correct?
1. The pH of N is increased when the solution is diluted
2. The pH of Q is increased when the solution is evaporated
3. M is the most alkaline solution
4. R is the most acidic solution
Consider the following reaction equation: H₃O_(aq) + OH^-_(aq) $\longrightarrow$ $\longrightarrow$ 2H₂O_(l). The reaction represents
1. esterification
2. hydrolysis
3. neutralization
4. redox
The refreshing characteristics taste of fizzy drinks is due to the presence of
1. carbon(IV)oxide
2. glucose
3. hydrogen
4. sodium citrate
Chemical equilibrium is attained when
1. all the reactants have been completely used up
2. the reaction goes to completion
3. the concentration of reactants and products remain constant
4. the concentration of reactants and products are equal
Which of the following factors will affect the rate of the reaction represented by the following equation? 2HCL_(aq) + CaCO_3(s) $\longrightarrow$ $\longrightarrow$ CaCl_(aq) + H₂O_(l) + CO_2(g) I. Pressure II. Concentration III. Nature of reactant IV. Temperature
1. I and II only
2. II, III and IV only
3. I, II and III only
4. I, II, III and IV
On evaporation to dryness, 350 cm³ of saturated solution of salt Z gave 55.5 g of salt. What is the solubility of the salt? [Z = 101]
1. 1.57 moldm^-3
2. 3.14 moldm^-3
3. 6.28 moldm^-3
4. 12.56 moldm^-3
Which of the following salts when dissolved in water will form a solution that will change blue litmus red?
1. CH₃COONa
2. NH₄Cl
3. NaCl
4. KCl
Which of the following bonds are broken when ethanol is boiled? I. Covalent bonds II. Ionic bonds III. Hydrogen bonds
1. I only
2. II only
3. III only
4. I, II and III
A compound with molecular formula CH₂O₂ is
1. a carbohydrate
2. a carboxylic acid
3. an alkanol
4. an ester
The quality of electricity required to discharge 1 mole of univalent ion is
1. 9600 C
2. 48250 C
3. 96500 C
4. 193000 C
Chlorine water is used as a bleaching agent because it is
1. an acidic solution
2. an alkaline solution
3. an oxidizing agent
4. a reducing agent
Which of the following substances is a non-electrolyte?
1. H₂SO₄
2. CH₃COOH
3. C₆H₁₂O₆
4. NH₄Cl
The oxidization number of Sulphur is +4 in
1. Na₂S₂O₃
2. H₂SO₃
3. H₂SO₄
4. SO₃
Consider the following ionic equation: Cr₂O₇^2- + 14H⁺ + ne^- $\longrightarrow$ $\longrightarrow$ 2Cr³⁺ + 7H₂O. The value of n in the equation is
1. 7
2. 6
3. 3
4. 2
Consider the following half-cell reactions: Al _(s) $\longrightarrow$ $\longrightarrow$ Al³⁺ _(aq) + 3e^-; Cu²⁺ _(aq) + 2e^- $\longrightarrow$ $\longrightarrow$ Cu _(s). The over-all equation for the reaction is
1. Al _(s) + Cu²⁺ _(aq) $\longrightarrow$ Al³⁺ _(aq) + Cu _(s)
2. 2Al _(s) + Cu²⁺ _(aq) $\longrightarrow$ 2Al_(aq) + Cu _(s)
3. 2Al _(s) + 3Cu²⁺ _(aq) $\longrightarrow$ 3Cu _(s) + 2Al³⁺ _(aq)
4. 3Al _(s) + 2Cu²⁺ _(aq) $\longrightarrow$ 2Cu _(s) + 3Al³⁺ _(aq)
Amino acids are obtained from proteins by
1. hydrolysis
2. oxidation
3. polymerization
4. reduction
When a compound X is heated with tetraoxosulphate(VI)acid, it produces an alkene. X is an
1. Alkane
2. Alkanol
3. Alkanoate
4. Alkyne
Ripening of fruits is hastened by using
1. Ethanol
2. Ethane
3. Ethene
4. Ethyne
The compound that makes palm wine taste sour after exposure to the air for few days is
1. Ethanol
2. Ethanoic acid
3. Methanol
4. Methanoic acid
Which of the following compounds is/are secondary alkanols? I. CH₃CH(CH₃)CH₃OH II. CH₃CH₂CH(OH)CH₃ III. CH₃C(OH)(CH₃)CH₃
1. I only
2. II only
3. I and III only
4. II and III only
Consider the following reaction equation: C₂H_4(g) + 3O_2(g) 2CO_2(g) + 2H₂O_(l). The volume of oxygen at s.t.p that will be required to burn 14g of ethene is [C₂H₄ = 28; Molar volume of gas at s.t.p = 22.4 dm³]
1. 67.2 dm³
2. 33.6 dm³
3. 11.2 dm³
4. 3.73 dm³
Which of the following sources of energy contributes to green-house effect?
1. natural gas
2. nuclear
3. wind
4. solar
A consequences of global warming is
1. air pollution
2. flooding
3. increased humidity
4. water pollution
Which of the following metals is common to both brass and bronze?
1. Aluminium
2. Copper
3. Lead
4. Iron
The alkanol obtained from the production of soap is
1. Dihydric Alkanol
2. Tertiary Alkanol
3. Trihydric Alkanol
4. Monohydric Alkanol

Chemistry 2 - Theory Questions

Section A - For All Candidates

1. What are nucleons?
2. State Graham's law of diffusion.
3. Explain briefly why aluminium does not corrode easily.
4. State three examples of periodic properties.
5. State two reasons why real gases deviate from ideal gas behaviour.
6. List three uses of fractional distillation in industry.
7. What factors determine the selective discharge of ions at the electrodes during electrolysis?
8. State the type of reaction represented by each of the following equations:
  1. C₂H₆ + Br₂ $\longrightarrow$ C₂H₅Br + HBr;
  2. C₂H₄ + Br₂ $\longrightarrow$ CH₄Br₂
9. Name the products formed when butane burns in limited supply of air.
10. List three methods of separating a solid from a liquid.

Section B

1. Consider the following atoms: ${\ce {^{R}_{T}X; ^{S}_{T}X}}$ ${\ce {^{R}_{T}X; ^{S}_{T}X}}$
  1. State the phenomenon exhibited by the two atoms.
  2. What is the difference between the atoms?
  3. Give two examples of elements that exhibit the phenomenon stated in (ai)
  4. If T is 17, write the electron configuration of the element
2. 1. State two differences between metals and-non-metals with respect to their: I. physical properties; II. chemical properties.
  2. Give one example of each for the following compounds: I. an amphoteric oxide; II. a hydride which evolves hydrogen when reacted with water; III. a trioxocarbonate (IV) salt which is readily decomposed on heating; IV. a chloride salt which is readily hydrolyzed in water.
3. 1. State three characteristic properties of transition metals.
  2. Write the electron configuration of ₃₀Zn
  3. Explain briefly why zinc is not considered as a typical transition element.
4. Consider the reaction represented by the following equation:- Na₂CO_3(aq)+ MgCl_2(aq)---->2NaCl_(aq)+ MgCO_3(aq). Calculate the mass of sodium trioxocarbonate (IV) needed to produce 3.36 of magnesium trioxocarbonate (IV). [C = 12.0, O = 16.0, Na = 23.0, Mg = 24:0 ]
1. 1. Define structural isomerism.
  2. State the class of alkanols to which each of the following compounds belongs: I. CH₃C(CH₃)₂OH; II. CH₃CH(CH₃)CH₂OH; III. CH₃CH₂CH(CH₃)OH.
2. 1. Write the formulae of the products formed in the following reactions: I. ${\ce {CH3CH2COOH ->[K(s)]}}$ II. ${\ce {CH3CH2COOH->[{C_{4}H_{9}OH,heat}][{Conc.H_{2}SO_{4}}]}}$ III. ${\ce {CH3CH2CH2CH2OH->[{H^{+}/KMnO_{4}}][{(excess)}]}}$
  2. Name the major product(s) of each of the reactions in 3(b)(i).
3. A gaseous hydrocarbon R of mass 7.0 g occupies a volume of 2.24 dm³ at s.t.p. If the percentage composition by mass of hydrogen is 14.3, determine its:
  1. empirical formula;
  2. molecular formula. [H = 1.00, C = 12.0, Molar volume of gas at s.t.p. = 22.4 dm³]
4. Draw the structures of the isomers of the alkene with molecular formula C₄H₈

Section C - For Candidates in Nigeria, Sierra Leone, The Gambia and Liberia

1. 1. Name a suitable drying agent for the preparation of carbon (IV) oxide in the laboratory.
  2. Using one chemical test, distinguish between carbon (II) oxide and carbon (IV) oxide.
2. 1. Describe briefly how oxygen and nitrogen could be obtained separately from air on an industrial scale
  2. State how a lighted splint can be used to distinguish between samples of oxygen and nitrogen.
3. 1. Give one reason why bauxite is usually preferred as the ore for the extraction of aluminum.
  2. List two main impurities. usually present in bauxite.
  3. State the function of sodium hydroxide solution in the extraction of aluminum from its ore.
  4. Explain briefly why it is difficult to extract aluminum by chemical reduction of aluminum oxide
  5. Write an equation for the reaction of aluminum oxide with aqueous sodium hydroxide.
4. 1. The melting and boiling points of sodium chloride are 801°C and 1413°C respectively. Explain briefly why sodium chloride does not conduct electricity at 25°C but does so between 801°C and 1413°C.
  2. State the reason why sodium metal is stored under paraffin oil in the laboratory.
5. 1. State what would be observed when aqueous sodium trioxocarbonate(IV) is added to a solution containing iron (III) ions
  2. Write a balanced equation for the reaction in 4(e)(i).
1. 1. Determine the oxidation number of sulphur in Na₂S₂O₃
  2. Name the allotropes of sulphur.
  3. State two ways in which the structure of graphite and diamond are similar.
2. 1. Name two green-house gases.
  2. State one effect of an increased level of green-house gases on the environment.
  3. State one source from which nitrogen (I) oxide is released into the environment.
  4. Write a chemical equation to show the effect of heat on each of the following compounds: I. KNO_3(s) II. AgNO_3(s)
3. 1. Describe briefly how pure crystals of calcium chloride could be obtained from a solution of calcium chloride
  2. Explain briefly each of the following observations: I. ammonia gas is highly soluble in water; II. boiling point of chlorine is lower than that of iodine
4. Consider the reaction represented by the following equation:- 2NaCl + H₂SO_4(s) → Na₂SO_4(s) + 2HCl_(g). Calculate the volume of HCl gas that can be obtained at s.t.p. from 5.85 g of sodium. chloride. [ Na = 23.0, Cl = 35.5, Molar volume of gas at s.t.p. = 22.4 dm³]

Chemistry 3 - Practical Questions

All your burette readings (initials and final) as well as the size of your pipette must be recorded but no account of experimental procedure is required. All calculations must be done in your answer booklet.

A solution of 0.050 moldm^-3 H₂C₂O₄ (ethanedioic acid). B is a solution of KMnO₄, (potassium tetraoxomanganate (VII), of unknown concentration.
1. Put B into the burette. Pipette 20.0 cm³ or 25.0 cm³ of A into a Conical flask and add about 10.0 cm³ of dilute H₂SO₄, Heat the mixture to about 40°C - 50°C and titrate it while still hot with B. Repeat the titration to obtain consistent titre values. Tabulate your results and calculate the average volume of B used. The equation of reaction is; 2MnO₄ ^-_(aq) + 5C₂O₄ ^2-_(aq) + 16H⁺_(aq) → 2MnH²⁺_(aq) + 8H₂O_(l) + 10CO_2(g)
2. From your results and the information provided, calculate the:
  1. concentration of MnO₄^- in B in moldm^-3;
  2. concentration of KMnO₄^- in B in gdm^-3;
  3. volume of CO₂ evolved at s.t.p when 25.0 cm³ of H₂C₂O₄ reacted completely. [0 = 16.0, K= 39.0, Mn = 55.0, Molar volume of gas at s.t.p.= 22.4 dm³mol^-1] Credit will be given for strict adherence to the instructions. for observations precisely recorded and jor accurate inferences. All tests, observations and inferences must be clearly entered in your answer book in ink, at the time they are made.
C is a mıxture of two salts, containing one cation and two anions. Carry out the following exercises on C. Record your observations and identify any gas(es) evolved. State the conclusion you draw from the result of each test.
1. Put all of C in a beaker and add about 10 cm³ of distilled water. Stir well and filter. Keep the filtrate and the residue.
2. To about 2 cm³ of the filtrate, add few drops of AgNO_3(g), followed by HNO_3(aq). Add excess NH_3(aq) to the resulting mixture.
3. 1. Put all of the residue into a clean test tube and add about 5 cm³ of HNO_3(aq)
  2. To about 2 cm³ of the solution from 2(c)(i), add NaOH_(aq) in drops and then in excess
  3. To another 2 cm³ of the solution from 2(c)(i), add NH_3(aq) in drops and then in excess.
1. What difference in physical properties enable the separation of mixtures by:
  1. simple distillation;
  2. paper chromatography;
  3. fractional distillation.
2. Give a reason for each of the following practices during titration in the laboratory:
  1. White tile is placed under the conical flask.
  2. Burette readings are always recorded to two decimal places.
3. Calculate the volume of 2.5 moldm^-3 stock HCl required to prepare 500 cm³ of 0.20 moldm^-3 HCI.