Chemistry past questions: NECO SSCE 2003

38 objective questions, with answers. Free to read and practise.

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38 questions, one at a time, marked as you go or at the end. No account needed.

1.
A calcium atom and a calcium ion have the same
1. A.chemical properties
2. B.electric charge
3. C.electronic structure
4. D.number of electrons
5. E.number of neutrons
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Answer: E number of neutrons
2.
An atom of element X has an electronic configuration of \(1s^22S^22p^63s^23p^3.\) In which group of the periodic table is X?
1. A.\(\text{0}\)
2. B.2
3. C.3
4. D.4
5. E.5
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Answer: E 5
3.
An organic compound gave the following results on analysis: C = 29.3% ; H = 5.7%; Br = 65%. What is the empirical formula of the compound? [C = 12, H = 1, Br=80]
1. A.C\(H _{3}\) Br
2. B.\(C _{2} H _{5}\) Br
3. C.\(C _{3} H _{5}\) Br
4. D.\(C _{3} H _{7}\) Br
5. E.\(C _{4} H _{9}\) Br
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Answer: D \(C _{3} H _{7}\) Br
4.
At s.t.p, a mole of chlorine occupies 22.4dm3. If the temperature is changed to 35°C and the pressure to 750mHg the of the new volume will be [Cl = 35.5]
1. A.\(\frac{760\times 22.4\times 308}{750\times 273\times 35.5} dm^3\)
2. B.\(\frac{760\times 22.4\times 308}{750\times 273}dm^3\)
3. C.\(\frac{750\times 22.4\times 35.5}{760\times 273}dm^3\)
4. D.\(\frac{760\times 22.4\times 35.5}{750\times 22.3\times 273}dm^3\)
5. E.\(\frac{760\times 22.4\times 35.5}{750\times 308}dm^3\)
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Answer: B \(\frac{760\times 22.4\times 308}{750\times 273}dm^3\)
5.
B is an isotope of the element \(^{238} _{92}Ur\) . The isotope B has
1. A.46 protons and 119 neutrons
2. B.92 protons and 92 neutrons
3. C.92 protons and 146 neutrons
4. D.92 protons and 238 neutrons
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Answer: C 92 protons and 146 neutrons
6.
Chlorine displaces bromine from aqueous potassium bromide because
1. A.bromine is a liquid at room temperature
2. B.bromine is weakly acidic
3. C.bromine has a greater atomic radius than chlorine
4. D.chlorine is a stronger oxidising agent than bromine
5. E.the density of chlorine is less than the density of bromine
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Answer: D chlorine is a stronger oxidising agent than bromine
7.
Chlorine is used in water purification because it
1. A.bleaches impurities in the water
2. B.decolorizes water
3. C.destroys bacteria
4. D.is extremely soluble in water
5. E.is pleasant tasting
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Answer: C destroys bacteria
8.
Ethene decolourises acidified potassium tetraoxomanganate(VII) solution. Which gas will decolourise bromine water?
1. A.C\(H _{4}\)
2. B.\(C _{2} H _{6}\)
3. C.\(C _{3} H _{6}\)
4. D.\(C _{3} H _{8}\)
5. E.\(C _{6} H _{6}\)
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Answer: C \(C _{3} H _{6}\)
9.
How many Faradays of electricity are required to liberate 9g of aluminium? [Al = 27]
1. A.0.1
2. B.0.3
3. C.1
4. D.2.7
5. E.3
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Answer: C 1
10.
In the reaction \(2H_{2}S(g) +\) S\(O_{2}(g)\) → \(2H_{2}\)SO(I)+3S(s)S\(O_{2}\)is acting a\(s _a\)gent
1. A.a bleaching
2. B.a dehydrating
3. C.an oxidizing
4. D.a precipitating
5. E.a reducing
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Answer: C an oxidizing
11.
Naturally occurring lithium consists of 90% \(^7_3Li \text{ and 10% } ^6_3 Li.\) What is the relative atomic mass of lithium?
1. A.6
2. B.6.8
3. C.6.9
4. D.7
5. E.7.1
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Answer: C 6.9
12.
Small amounts of compounds of transition metals are sometimes added to glass during manufacture in order to make the glass
1. A.acquire certain colours
2. B.easier to melt
3. C.easier to mould
4. D.little brittle
5. E.more transparent
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Answer: A acquire certain colours
13.
The boiling point of water is higher than the boiling point of ethanol because
1. A.the bonding in water is electrovalent (ionic) whereas the bonding in ethanol is convalent
2. B.the hydrogen bonding between water molecules is stronger than the hydrogen bonding between ethanol molecules
3. C.water has a higher lattice energy than ethanol
4. D.water has hydrogen bonding between its molecules but ethanol has no hydrogen bonging between its molecules;
5. E.water is a better solvent than ethanol
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Answer: B the hydrogen bonding between water molecules is stronger than the hydrogen bonding between ethanol molecules
14.
The number of hydrogen ions in 1.0dm \(^3\) of a 0.25 mole tetraoxosulphate(Vl) acid solution is [Avogadro constant = 6.02 x 10 \(^{23}\) ]
1. A.1.45x\(10 ^{23}\)
2. B.1.50 x l\(0 ^{23}\)
3. C.3.00x\(10 ^{23}\)
4. D.3.15x\(10 ^{23}\)
5. E.6.00x\(10 ^{23}\)
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Answer: B 1.50 x l\(0 ^{23}\)
15.
The pH of water is 7. What is the pH of orange juice?
1. A.7
2. B.above 10
3. C.below 2
4. D.between 5.5 and 6.5
5. E.between 7.5 and 8.5
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Answer: D between 5.5 and 6.5
16.
The reaction \(C_{2}H_{6}\) → \(C_{2}H + H_{2}\) is known as
1. A.dehydration
2. B.dehydrogenation
3. C.displacement
4. D.hydrogenation
5. E.reduction
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Answer: B dehydrogenation
17.
What change will occur during the electrolysis of brine using carbon electrodes?
1. A.Chlorine will be given off at the anode
2. B.Oxygen gas will be given off at the anode
3. C.Sodium will be deposited at the cathode
4. D.The resulting solution, after electrolysis, will be acidic
5. E.The volumes of hydrogen and chlorine given off during the same time are equal
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Answer: A Chlorine will be given off at the anode
18.
What change will occur to the equilibrium mixture \(2CrO^{2-}_4(aq) + 2H^+(aq) ⇔ Cr_2O^{2-}_7(aq) + H_2O(l)\) when excess sodium hydrogen solution is added?
1. A.A yellow precipitate of Cr(OH\() _{3}\) is formed
2. B.An orange precipitate of Cr(OH\() _{3}\) is formed
3. C.The colour changes from orange to yellow
4. D.The colour changes from yellow to orange
5. E.There is no visible reaction
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Answer: C The colour changes from orange to yellow
19.
What is formed when starch is completely hydrolysed?
1. A.fructose
2. B.glucose
3. C.lactose
4. D.maltose
5. E.sucrose
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Answer: B glucose
20.
What is the change in the oxidation number of phosphorus in the following reaction? 4P\((s) + 5O_{2}(\)ag) → \(2P_{2}O_{5}(s)\)
1. A.0 to 2
2. B.0 to 5
3. C.4 to 2
4. D.4 to 5
5. E.4 to 10
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Answer: B 0 to 5
21.
What is the concentration (mol dm \(^{-3}\) ) of a solution containing 28 g of potassium hydroxide per 100 cm \(^3\) of solution? (K=39; H=1; O=16)
1. A.0.01
2. B.0.05
3. C.1.0
4. D.5.0
5. E.2.8
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Answer: D 5.0
22.
What is the IUPAC name of CH3CCI=C(CH3)2?
1. A.2-chloro -3 methylbut -2yne
2. B.2 -chloro -3 methylbut -2ene
3. C.2 -chloro -3 methylbutene
4. D.3- methyl -2-chlorobut -2-ene
5. E.3- methyl -2. chlorobut -2 yne
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Answer: B 2 -chloro -3 methylbut -2ene
23.
What is the number of moles of Na \(_H\) CO \(_3\) in 250cm \(^3\) of its solution if the solution contains 8.4 g of Na \(_H\) CO \(_3\) in 1 dm \(^3\) of the solution. [Na = 23, 0 = 16, C = 12, H = 1)
1. A.1
2. B.0.25
3. C.0.05
4. D.0.025
5. E.0.01
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Answer: D 0.025
24.
What mass of copper is deposited when 6.5g of granulated zinc reacts with excess copper(II) tetraoxosulphate(VI) solution? The equation for the reaction is: Zn(s) + \(CuSO_4(aq)→ ZnSO_4(aq)+ Cu(s)\) [CU= 64; Zn=65]
1. A.3.2 g
2. B.3.25 g
3. C.6.4 g
4. D.6.5 g
5. E.64.0 g
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Answer: C 6.4 g
25.
What mass of silver is deposited when a current of 2.6 A is passed through a solution of a silver salt for 40 minutes? [Ag= 108 ; F=96500C]
1. A.6.89g
2. B.6.93g
3. C.6.98g
4. D.7.04g
5. E.7.12g
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Answer: C 6.98g
26.
Which compound will give propane when it Is dehy drated by an excess of hot, concentrated tetraoxosvlphate(VI) acid?
1. A.C\(H _{3}\) C\(H _{2}\) CHO
2. B.C\(H _{3}\) C\(H _{2}\) CH2OH
3. C.C\(H _{3}\) C\(H _{2}\) COQH
4. D.C\(H _{3}\) C\(H _{2} 0\)CH
5. E.C\(H _{3}\) C\(H _{3}\) OH
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Answer: B C\(H _{3}\) C\(H _{2}\) CH2OH
27.
Which element is the most electronegative?
1. A.calcium
2. B.fluorine
3. C.iodine
4. D.oxygen
5. E.sodium
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Answer: B fluorine
28.
Which formula is used to indicate the degree of acidity of an acid?
1. A.\([H^+] = ^{\text{mass of acid relative}} molecular mass of acid\)
2. B.F = number of H+ = ions x molar mass of the acid
3. C.Kw = [H+][OH-]
4. D.pH = - lo\(g _{10} [H+]\)
5. E.pKa = -lo\(g _{10}\) Ka
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Answer: D pH = - lo\(g _{10} [H+]\)
29.
Which hydrocarbon does NOT exhibit structural isomerism?
1. A.\(C _{3} H _{6}\)
2. B.\(C _{4} H _{6}\)
3. C.\(C _{4} H _{8}\)
4. D.\(C _{4} H _{10}\)
5. E.\(C _{5} H _{12}\)
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Answer: A \(C _{3} H _{6}\)
30.
Which is NOT a synthetic polymer?
1. A.nylon
2. B.Orion
3. C.Perspex
4. D.polystyrene
5. E.wool
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Answer: E wool
31.
Which metal bromide is widely used in photography?
1. A.calcium bromide
2. B.magnesium bromide
3. C.potassium bromide
4. D.silver bromide
5. E.sodium bromide
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Answer: D silver bromide
32.
Which metal is a constituent of both bronze and solder?
1. A.copper
2. B.lead
3. C.silver
4. D.tin
5. E.zinc
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Answer: D tin
33.
Which metal is extracted from bauxite?
1. A.aluminium
2. B.calcium
3. C.copper
4. D.magnesium
5. E.tin
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Answer: A aluminium
34.
Which method is used for the purification of copper from its ore?
1. A.distillation
2. B.electrochemical
3. C.electrolysis
4. D.neutralization
5. E.reduction
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Answer: C electrolysis
35.
Which separation technique is routinely applied in the petroleum industry?
1. A.chromatography
2. B.distillation
3. C.evaporation
4. D.fractional crystallization
5. E.fractional distillation
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Answer: E fractional distillation
36.
Which statement is NOT true about the composition of starch?
1. A.It contains only the atoms of carbon, hydrogen oxygen
2. B.It is a polysaccharide
3. C.Its empirical formula is \(C _{2} H _{2} 0\)
4. D.It is made from the monomer\(C _{6} H _{12} O _{6}\)
5. E.The hydrogen and oxygen atoms are in the ratio 2:1
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Answer: C Its empirical formula is \(C _{2} H _{2} 0\)
37.
Why does the treatment of cotton fabrics with dilute acids weaken the materials?
1. A.Cotton is hydrolysed completely to glucose
2. B.The fabrics are soluble in dilute acids
3. C.The molecular chains are partially broken
4. D.The molecular chain length f the fabric increases
5. E.The thread holding the fabric together Is completely destroyed
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Answer: C The molecular chains are partially broken
38.
Why is tetraoxosulphate(VI) acid NOT used for making carbon dioxide from calcium carbonate? It is
1. A.a dehydrating agent
2. B.a strong acid
3. C.an oxidising agent
4. D.dibasic
5. E.forms insoluble calcium tetraoxosulphate(Vl)
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Answer: E forms insoluble calcium tetraoxosulphate(Vl)

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