Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

49 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

49 questions
Question 1 of 20 49 total questions
Question 1
jamb 1979

Which of the structural formula above is ethanoic acid is

AA
BB
CC
DD
EE
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Question 2
jamb 1979

The IUPAC name for

A2-methylbut-3-ene
B2-methylbut-4-ene
C3-methylbut-2-ene
D3-methylbut-1-ene
E3-methylpent-1-ene
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Question 3
jamb 1979

Consider the following exothermic reaction \(2SO_{2(g)} + O_{2(g)} = 2SO_{3(g)}\) . If the temperature of the reaction is reduced from 800ºC to 500ºC, and no other change takes place, then

Athe reaction rate increases
Bconcentration of SO3 decreases
Cconcentration of SO3 increases
DSO2 gas becomes unreactive
EO2 gas becomes unreactive
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Question 4
jamb 1979

Pick out the correct statement

AZinc heated to redness reacts with steam to give oxygen and zinc oxide
BZinc heated to redness reacts with steam to give oxygen and hydrogen
CZinc does not react with hot or cold water
DZinc reacts with hot water to form zinc oxide and hydrogen
EZinc reacts very easily with cold water to give zinc oxide and hydrogen
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Question 5
jamb 1979
A piece of metal (M) is dissolved in nitric acid and the resulting solution is treated with a small quantity of sodium hydroxide to produce a white precipitate (B) which redissolves on the addition of excess alkali. The precipitate (B)when ignited in a crucible produces the oxide of the metal(m). The METAL M is
AZn
BCu
CAl
DAu
ECa
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Question 6
jamb 1979
Which of the following raw materials would be required from the smelting of iron ore in a blast furnace?
ACaCO 3
BZn(NO3)2
CCuSO4
DAICI3
ECaSO4
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Question 7
jamb 1979
When excess ethanol is heated to 145 oC in the presence of concentrated sulphuric acid, the product is
Adiethyl ether
Bethyne
Cdiethyl sulphate
Dacetone
Eethanoic acid
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Question 8
jamb 1979

A gas occupies a volume of 30.0 dm\(^3\) at S.T.P. What volume would it occupy at 91\(^0\)C and 380 mm Hg?

A20. 0dm3
B40.0dm3
C60. 0dm3
D80. 0dm3
E100. 0dm3
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Question 9
jamb 1979
One of the following techniques can be used to show that chlorophyll pigment is a mixture of chemical compounds and not a single coloured compound
Acystallization
Bhydrolysis
Csublimation
Dfiltration
Echromatography
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Question 10
jamb 1979

On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced?

ASO2 (g) + FeS (s)
BSO3 (g) +FeS(s)
CSO2 (g) + SO3(g)
DSO2 (g) + H2S (g)
ESO3(g) + H2S(g)
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Question 11
jamb 1979

Phosphorus burns in oxygen according to the equation P\(_4\) + 5 0\(_2\) → P\(_4\)O\(_{10}\). How many litres of oxygen will be required at S.T.P for complete oxidation of 12.4g of phosphorus? [P = 31,O = 16 and molar volume of a gas at S.T.P = 22.4 litres]

A5. 20
B11. 20
C2. 24
D20. 20
E6. 20
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Question 12
jamb 1979
Bronze is an alloy of
Acopper, zinc and nickel
Baluminium and copper
Ccopper and zinc
Dtin and zinc
Etin and copper
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Question 13
jamb 1979
Two metallic ions associated with hard water are
Acopper and zinc
Bmagnesium and silver
Ccalcium and magnesium
Dpotassium and tin
Esodium and lead
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Question 14
jamb 1979
Hydrogenation may be effected by
Athe removal of hydrogen from an alkane in the presence of a catalyst
Bthe addition of hydrogen to an alkane in the presence of a catalyst
Cthe addition of hydrogen to an alkyne
Dthe removal of hydrogen from an alkyne
Ethe addition of hydrogen to an ethyl alcohol
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Question 15
jamb 1979
The solution of a sample in a tube will be identified as a chloride if it gives
Aa white precipitate on addition of AgNO3 and barium chloride solutions
Ba white precipiate when acidified with HCI, and then AgNO3 solution added
Ca white precipitate when acidified with dilute HNO3 and then AgNO3 solution added
Da white precipitate when acidified with dilute H2SO4 and then barium nitrate solution added
Ea pungent smell of chlorine gas when dilute HCI and MnO2 are added
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Question 16
jamb 1979
The reaction 3C(s) + 2Fe2O3(s) = 4Fe(s) + 3CO2(g): \(\Delta\)H =46.0 kJ is
Aisothermic
Badiabatic
Cisobaric
Dendothermic
Eexothermic
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Question 17
jamb 1979
the vapour density of a gas may be defined as
Athe mass of a unit volume of the gas compared to an equal volume of water vapour
Bthe mass of a unit volume of the gas compared to an equal volume of hydrogen
Cthe mass of a unit volume of the gas compared to an equal volume of oxygen
Dthe mass of a unit volume of the gas minus the vapour pressure of water
Etwo times the relative molecular mass of the gas
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Question 18
jamb 1979

Which of the following statements is true?

Aan increase in the temperature of a given mass of gas increases the number of gas molecules
Ban increase in the temperature of the gas does not affect the kinetic energy
Can increase in the pressure of the gas is proportional to the increase in volume
Da increase in the pressure of a gas is proportional to the decrease in volume at constant temperature
Ea decrease in the pressure of the gas decreases the number of gas molecules present
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Question 19
jamb 1979
In the manufacture of iron in the blast furnace, iron (lll) oxide is mixed with coke and limestone, and different reactions occur in the process. Which of the following statements is true with respect to these reactions?
Athe coke is a powerful reducing agent and easily converts the iron oxide to iron
Bthe calcuim carbonate reacts with SiO2 an earthly impurity in the ore, to from calcuim silicate
Cthe coke will react with the iron produced to form steel
Dall the carbondioxide required in the process comes from the decomposition of the calcium carbonate
Ethe calcium carbonate decomposes to give calcium oxide, which then forms calcium silicate with the earthly impurity
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Question 20
jamb 1979

Weighed salts Y and Z were left exposed in the laboratory overnight. In the morning Y had gained weight, and Z had become liquid. What conclusion could be drawn about the nature of the two salts?

AZ is efflorescent
BY and Z are efflorescent
CY and Z are deliquescent
DY and Z are hygroscopic
EY is deliquescent
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