Chemistry, 1979, JAMB Exam, Exam, Paper 1 | Objectives

Paper Info

Year :

1979

Title :

Chemistry

Exam :

JAMB Exam

Paper 1 | Objectives

31 - 40 of 49 Questions

#	Question	Ans
31.	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? A. the coke is a powerful reducing agent and easily converts the iron oxide to iron B. the calcuim carbonate reacts with SiO₂ an earthly impurity in the ore, to from calcuim silicate C. the coke will react with the iron produced to form steel D. all the carbondioxide required in the process comes from the decomposition of the calcium carbonate E. the calcium carbonate decomposes to give calcium oxide, which then forms calcium silicate with the earthly impurity	E
32.	Which of the following statements is true? A. an increase in the temperature of a given mass of gas increases the number of gas molecules B. an increase in the temperature of the gas does not affect the kinetic energy C. an increase in the pressure of the gas is proportional to the increase in volume D. a increase in the pressure of a gas is proportional to the decrease in volume at constant temperature E. a decrease in the pressure of the gas decreases the number of gas molecules present Show Content Detailed Solution The basic concept of Boyle's law.	D
33.	The vapour density of a gas may be defined as A. the mass of a unit volume of the gas compared to an equal volume of water vapour B. the mass of a unit volume of the gas compared to an equal volume of hydrogen C. the mass of a unit volume of the gas compared to an equal volume of oxygen D. the mass of a unit volume of the gas minus the vapour pressure of water E. two times the relative molecular mass of the gas	B
34.	The reaction 3C(s) + 2Fe₂O₃(s) = 4Fe(s) + 3CO₂(g): \(\Delta\)H =46.0 kJ is A. isothermic B. adiabatic C. isobaric D. endothermic E. exothermic	D
35.	The solution of a sample in a tube will be identified as a chloride if it gives A. a white precipitate on addition of AgNO₃ and barium chloride solutions B. a white precipiate when acidified with HCI, and then AgNO₃ solution added C. a white precipitate when acidified with dilute HNO₃ and then AgNO₃ solution added D. a white precipitate when acidified with dilute H₂SO₄ and then barium nitrate solution added E. a pungent smell of chlorine gas when dilute HCI and MnO₂ are added	C
36.	Hydrogenation may be effected by A. the removal of hydrogen from an alkane in the presence of a catalyst B. the addition of hydrogen to an alkane in the presence of a catalyst C. the addition of hydrogen to an alkyne D. the removal of hydrogen from an alkyne E. the addition of hydrogen to an ethyl alcohol	C
37.	Two metallic ions associated with hard water are A. copper and zinc B. magnesium and silver C. calcium and magnesium D. potassium and tin E. sodium and lead	C
38.	Bronze is an alloy of A. copper, zinc and nickel B. aluminium and copper C. copper and zinc D. tin and zinc E. tin and copper	E
39.	Phosphorus burns in oxygen according to the equation P₄ + 50₂ → P₄O₁₀. 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] A. 20 B. 20 C. 24 D. 20 E. 20 Show Content Detailed Solution P₄ + 50₂ → P₄O₁₀ for the complete combustion of 124 grammes of phosphorus we need 5 x 22.4 litres of O₂ for 12.4 gms of P₄ we need \(\frac{5 \times 22.4}{124} \times \frac{12.4}{1}\) \(\frac{22.4}{2}\) = 11.2 litres	B
40.	On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced? A. SO₂ (g) + FeS (s) B. SO₃ (g) +FeS(s) C. SO₂ (g) + SO₃(g) D. SO₂ (g) + H₂S (g) E. SO₃(g) + H₂S(g)	C

31.	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? A. the coke is a powerful reducing agent and easily converts the iron oxide to iron B. the calcuim carbonate reacts with SiO₂ an earthly impurity in the ore, to from calcuim silicate C. the coke will react with the iron produced to form steel D. all the carbondioxide required in the process comes from the decomposition of the calcium carbonate E. the calcium carbonate decomposes to give calcium oxide, which then forms calcium silicate with the earthly impurity	E
32.	Which of the following statements is true? A. an increase in the temperature of a given mass of gas increases the number of gas molecules B. an increase in the temperature of the gas does not affect the kinetic energy C. an increase in the pressure of the gas is proportional to the increase in volume D. a increase in the pressure of a gas is proportional to the decrease in volume at constant temperature E. a decrease in the pressure of the gas decreases the number of gas molecules present Show Content Detailed Solution The basic concept of Boyle's law.	D
33.	The vapour density of a gas may be defined as A. the mass of a unit volume of the gas compared to an equal volume of water vapour B. the mass of a unit volume of the gas compared to an equal volume of hydrogen C. the mass of a unit volume of the gas compared to an equal volume of oxygen D. the mass of a unit volume of the gas minus the vapour pressure of water E. two times the relative molecular mass of the gas	B
34.	The reaction 3C(s) + 2Fe₂O₃(s) = 4Fe(s) + 3CO₂(g): \(\Delta\)H =46.0 kJ is A. isothermic B. adiabatic C. isobaric D. endothermic E. exothermic	D
35.	The solution of a sample in a tube will be identified as a chloride if it gives A. a white precipitate on addition of AgNO₃ and barium chloride solutions B. a white precipiate when acidified with HCI, and then AgNO₃ solution added C. a white precipitate when acidified with dilute HNO₃ and then AgNO₃ solution added D. a white precipitate when acidified with dilute H₂SO₄ and then barium nitrate solution added E. a pungent smell of chlorine gas when dilute HCI and MnO₂ are added	C

36.	Hydrogenation may be effected by A. the removal of hydrogen from an alkane in the presence of a catalyst B. the addition of hydrogen to an alkane in the presence of a catalyst C. the addition of hydrogen to an alkyne D. the removal of hydrogen from an alkyne E. the addition of hydrogen to an ethyl alcohol	C
37.	Two metallic ions associated with hard water are A. copper and zinc B. magnesium and silver C. calcium and magnesium D. potassium and tin E. sodium and lead	C
38.	Bronze is an alloy of A. copper, zinc and nickel B. aluminium and copper C. copper and zinc D. tin and zinc E. tin and copper	E
39.	Phosphorus burns in oxygen according to the equation P₄ + 50₂ → P₄O₁₀. 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] A. 20 B. 20 C. 24 D. 20 E. 20 Show Content Detailed Solution P₄ + 50₂ → P₄O₁₀ for the complete combustion of 124 grammes of phosphorus we need 5 x 22.4 litres of O₂ for 12.4 gms of P₄ we need \(\frac{5 \times 22.4}{124} \times \frac{12.4}{1}\) \(\frac{22.4}{2}\) = 11.2 litres	B
40.	On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced? A. SO₂ (g) + FeS (s) B. SO₃ (g) +FeS(s) C. SO₂ (g) + SO₃(g) D. SO₂ (g) + H₂S (g) E. SO₃(g) + H₂S(g)	C