Jamb Chemistry Past Questions and Answers

Question 226:

• JAMB 1981

Allotropes are elements having?

A. Different physical but the same chemical properties
B. Different chemical but the same physical properties
C. The same chemical and physical properties
D. Different atomic structure
E. The same position in the periodic table

Question 227:

• JAMB 1981

A polymerization reaction is one in which?

A. Small molecules form giant molecules
B. Atoms form molecules
C. Giant molecules form small molecules
D. Molecules form volatile compounds
E. A molecule rearranges itself

Question 228:

• JAMB 1981

Which of the following is the electronic configuration of sodium?
(Atomic number of Na = 11)

A. 1s² 2s²2p⁶ 3s²
B. 1s² 2s²2p⁶ 3s² 3p1s² 2s²2p⁶ 3s¹
C. 1s² 2s²2p⁶ 3s¹
D. 1s² 2s²2p⁶ 3s^°
E. 1s² 2s²2p⁶ 4s¹

Question 229:

• JAMB 1981

In the reaction of oxygen with hydrogen to produce water, which of the following statements is true?

A. One atom of hydrogen reacts with two atoms of oxygen to give one molecule of water
B. Two atoms of hydrogen react with two atoms of oxygen to give two molecules of water
C. One molecule of oxygen reacts with one molecule of hydrogen to give two molecules of water
D. One molecule of hydrogen reaccts with two molecules of oxygen to give three molecules of water
E. One molecule of oxygen reacts with two molecules of hydrogen to give two molecules of water

Question 230:

• JAMB 1981

Na₂CO₃ + 2HCI → 2NaCI + H₂O + CO₂. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53g of sodium carbonate is dissolved in hydrochloric acid?
(1 mole of gas occupies 22.4 dm³ at s.t.p)
(Na = 23, C = 12, O = 16)

A. 44.8 dm³
B. 11.2 dm³
C. 100.1 dm³
D. 3.0 dm³
E. 22.4 dm³