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Chemistry
WAEC / WASSCE 1998
Nature of Matter & Separation Techniques
The liquid product of the destructive distillation of coal is
A
kerosene
B
ethanol
C
ammoniacal liquor
D
paraffin oil
E
aqueous ammonia
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #36637)
Chemistry
WAEC / WASSCE 1998
Organic Chemistry I: Hydrocarbons & Crude Oil
Which of the following alkanes has the highest boiling point?
A
pentane
B
ethane
C
propane
D
butana
E
hexane
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #36638)
Chemistry
WAEC / WASSCE 1998
Organic Chemistry I: Hydrocarbons & Crude Oil
Petrol consists mainly of
A
polymers
B
alkanoates
C
hydrocarbons
D
alktanols
E
alkenes
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #36643)
Chemistry
WAEC / WASSCE 1998
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Dehydration of ethanol produces
A
ethanoic acid
B
propan-1,2,3-triol
C
ethene
D
ethanal
E
methanol
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #36644)
Chemistry
WAEC / WASSCE 1998
Organic Chemistry I: Hydrocarbons & Crude Oil
When alkanols react with sodium, the ga evolved is
A
hydrogen
B
oxygen
C
methane
D
ethyne
E
carbon (IV) oxide
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #36645)
Chemistry
WAEC / WASSCE 1998
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
The products of the reaction between CH3CH 2COOH and CH3OH are H 2
O and
A
CH 3CH2COOCH3
B
CH3CH 2COOCH 2CH 3
C
CH3CH2CH2COOH
D
CH3CH2CH2OH
E
CH3COOH
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #36646)
Chemistry
WAEC / WASSCE 1998
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
A positive reaction to Fehling's test indicates the presence of
A
strach
B
reducing sugars
C
oxidizing agents
D
alkanoic acids
E
alkanols
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #36648)
Chemistry
WAEC / WASSCE 1998
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following compounds is used as a gaseous fuel?
A
CH 3-COO-CH2-CH3
B
CH 3-CH 2-CH 2-CH 3
C
CHCI 3
D
CH 3-CH2-COOH
E
CH3-C=CH
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #36649)
Chemistry
WAEC / WASSCE 1998
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
All your burette readings (initial 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 book.
A is a solution containing 14.0gdm\(^{-3}\) of potassium hydrogen tetraoxosulphate (VI). B is a solution of sodium hydroxide.
(a) Put A into the burette and titrate with 20.0cm\(^{-3}\) or 25.0 cm\(^{-3}\) portion of B using methyl orange, as Indicator. Record the volume of your pipette. Tabulate your burette readings and calculate the average volume of A used.
(b) From your results and the information provided, calculate the:
(i) concentration of A in mol dm\(^{3}\)
(ii) concentration of B in g dm\(^3\)
(iii) volume of A (in dm\(^{-3}\)) that would produce one mole of Sodium tetraoxosulphate (VI) in solution. The equation for the reaction is:
2KHSO\(_{4(aq)}\) + 2NaOH\(_{(aq}\) \(\to\) K\(_2\)SO\(_{4(aq)}\) + NaSO\(_{4(aq)}\) + 2H\(_2\)O\(_{(l)}\) [H = 1; O = 16, Na = 23, KHSO\(_4\) = 136gmol\(^{-2}\)]
A
CH 3-COO-CH2-CH3
B
CH 3-CH 2-CH 2-CH 3
C
CHCI 3
D
CH 3-CH2-COOH
E
CH3-C=CH
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Burette readings
1st Rough
2nd Rough
3rd Rough
Final burette reading in cm\(^3\)
24.80
24.00
26.00
Initial burette reading cm\(^3\)
0.00
0.00
2.00
Difference in cm\(^{3}\)
24.80
24.00
24.00
(a) Average volume of A used = \(\frac{24.00 + 24.00}{2}\)
= 24.00 cm
Volume of pipette (i.e) B = 25.00cm
(b)(i) Concentration of A = \(\frac{140}{136}\) 0.103 mol dm\(^3\)
(ii) The equation for the reaction
2KHSO\(_4\) + 2NaOH \(\to\) K\(_2\)SO\(_4\) Na\(_2\)SO\(_4\) + 2H\(_2\)O; From equation mole ratio is 1:1 or 2:2
\(\frac{C_AV_A}{C_BV_B}\) = 1
Where C\(_A\) is the concentration of A,
A\(_A\) is the volume of A,
C\(_B\) is the concentration of B
V\(_B\) is the volume of B
C\(_B\) = \(\frac{0.103 \times 23}{C_B \times 25}\)
= 40 x C\(_B\) = 40 x C\(_B\)
= 40 x 0.0948
= 3.79 g/dm\(^3\)
(iii) From the equation, 2 mole KHSO\(_4\) will produce or yield 1 mole Na\(_2\)SO\(_4\)
1 dm\(^3\) of A contains 0.103 mole - volume of A that contains 2 moles KHSO\(_4\) = \(\frac{2}{0.103}\) = 19.4 dm\(^3\)
Source: Official Exam / Past Question Archive
Chemistry
WAEC / WASSCE 1998
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
Copy and complete the following table
Element
Number of Neutrons
Electronic Configuration
Group in the periodic Table
\(^{23}_{11}Na\)
---
1s\(^{2}\)2s\(^{2}\)2p\(^{6}\)3s\(^{1}\)
1
\(^4_2He\)
2
----
---
----
7
1s\(^{2}\)2s\(^{2}\)2p\(^{2}\)
----
medium Difficulty
Verified Correct Answer: Option
Chemical Principles & Mechanism
Element
Number of Neutrons
Electronic Configuration
Group in the periodic Table
\(^{23}_{11}Na\)
12
1s\(^{2}\)2s\(^{2}\)2p\(^{6}\)3s\(^{1}\)
1
\(^4_2He\)
2
1s\(^{2}\)
O or VIII or 8
\(^{13}_6C\)
7
1s\(^{2}\)2s\(^{2}\)2p\(^{2}\)
IV or 4
Source: Myschool Past Questions Archive (Record #54249)
Chemistry
WAEC / WASSCE 1998
Kinetic Theory of Matter & Gas Laws
Solution
(a) State two postulates of the kinetic theory of gases.
(b) Write two chemical properties that are common to both carbon (IV) oxide and sulphur (IV) oxide.
medium Difficulty
Verified Correct Answer: Option
Chemical Principles & Mechanism
Postulates of the kinetic theory of gases (any two)
(a)(i) Molecules move randomly in straight lines or molecules are in constant motion.
(ii) Molecules collide with one another and with the walls of container, the collision of the molecules are elastic.
(iii) The temperature of the gas is a measure of the average kinetic energy of its particle i.e the kinetic energy of the particles is proportional to the temperature of the gas.
(iv) Volume of the gas particle is negligible compared to the volume of the container.
(v) The attraction or repulsion of the gas particles is negligible.
(b) Chemical properties common to SO\(_2\) and CO\(_2\).
(i) They react with bases to form salts.
(ii) They turn lime water milky or the milkiness disappears with excess gas
(iii) They are acid anhydrides and turn moist or damp litmus paper red.
Source: Myschool Past Questions Archive (Record #54250)
Chemistry
WAEC / WASSCE 1998
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
(a)(i) Arrange the following elements in the order of increasing reactivity. Iron, Lead, Magnessium, Aluminium.
(ii) Which of the following elements in (a)(i) above reacts with sodium hydroxide to give hydrogen?
(b) What property of tetraoxosulphate (VI) acid does each of the following reactions illustrate?
(I) S + 2H\(_2\)SO\(_4\) ---> 3SO\(_4\) + 2H\(_2\)O
(ii) MgO + H\(_2\)SO\(_4\) ---> MgSO\(_4\) + H\(_2\)O
(iii) C\(_{12}\)H\(_{22}\)C\(_{11}\) + H\(_2\)SO\(_4\) ---> 12C + H\(_2\)SO\(_4\) + 11H\(_2\)O
medium Difficulty
Verified Correct Answer: Option
Chemical Principles & Mechanism
(a) In increasing order of reactivity
(i) Lead < Iron < Aluminium < Magnesium OR Magnesium > Aluminium > Iron > Lead.
(ii) Give H\(_2\) with NaOH, Aluminium and lead
(b) H\(_2\)SO\(_4\) behaves as
(i) oxidising agent in reaction with S
(ii) typical acid (neutralisation) in reaction with MgO
(iii) dehydrating agent in reacticn with Cl\(_2\)H\(_{22}\)O\(_{11}\).
Source: Myschool Past Questions Archive (Record #54251)
Chemistry
WAEC / WASSCE 1998
Non-Metals & Their Compounds
Solution
(a) What is the IUPAC name of Fe\(_2\)(SO\(_4\))\(_3\)?
(b)(i) Write an equation to represent the reaction of hydrogen sulphide with iron (III) chloride solution.
(ii) Mention one change observed during the reaction in (b)(i) above.
medium Difficulty
Verified Correct Answer: Option
Chemical Principles & Mechanism
(a) IUPAC name of Fe\(_2\)(SO\(_4\))\(_3\) is iron (iii) tetraoxosulphate (VI)
(b)(i) Equation of reaction of H\(_2\)S and FeC\(_3\) is 2FeCI\(_3\) + H\(_2\)S \(\to\) 2FeCl\(_2\) + 2HCI + S.
(ii) Changes observed. Brown solution changes to green and yellow deposit is formed.
Source: Myschool Past Questions Archive (Record #54252)
Chemistry
WAEC / WASSCE 1998
Organic Chemistry I: Hydrocarbons & Crude Oil
Solution
(a)(i) What is the general formula for alkanoic acids?
(ii) State two chemical properties of ethanoic acid.
(b) Which of propene, butane and pentane
(i) will decolorize acidified KMnO\(_4\) solution?
(ii) can be easily polymerized?
(iii) is an isomer of methylpropane?
(iv) can be obtained from an alkanol by dehydration?
medium Difficulty
Verified Correct Answer: Option
Chemical Principles & Mechanism
(i) General formula for alkanoic acid is C\(_n\)H\(_{2n + 1}\) COOH. Two chemical properties of ethanoic acid
- Reacts with alkanols to form ethanoates or alkanoates or esters (esterification)
- Reacts with trioxocarbonate (IV) or hydrogen trioxocarbonate (IV) to produce carbon (IV) oxide
- Reacts with sodium hydroxide or potassium hydroxide to form sodium or potassium ethanoate.
(b)(i) Propene will decolorize acidified KMnO\(_4\) solution
(ii) Propene can easily be polymerised
(iii) Butane is an isomer of methylpropane
(iv) Propene can be obtained from alkanol by dehydration.
Source: Myschool Past Questions Archive (Record #54253)
Chemistry
WAEC / WASSCE 1998
Reaction Rates & Chemical Equilibrium
Solution
(a)(i) What is meant by the activation energy of a reaction?
(ii) State the effect of a catalyst on activation energy.
(b) What substance serves as a catalyst in each of the following?
(I) Hydrogenation of oils
(ii) Biochemical reactions.
medium Difficulty
Verified Correct Answer: Option
Chemical Principles & Mechanism
(a)(i) Definition: Activation energy. Activation energy is the minimum energy which reactant particles (reaction complex or reacting particles) must possess before a reaction can occur.
(ii) A Catalyst: It lowers or alters the activation energy or provides an alternative pathway with a lower activation energy.
(b)(i) (finely divided) nickel (platinum, paladium), catalyses the hydrogenation of oils.
(ii) Enzymes catalyse biochemical reactions.
Source: Myschool Past Questions Archive (Record #54254)