Jamb Chemistry 1997 Past Questions and Answers

Question 6:

• JAMB 1997

The temperature of a body decreases when drops of liquid placed on it evaporate because?

A. The atmospheric vapour pressure has a cooling effect on the body
B. A temperature gradient exists between the drops of liquid and the body causing the latter to vaporate
C. The heat of vapourization is drawn from the body causing it to cool
D. The random motion of the liquid molecules causes a cooling effect on the body

Question 7:

• JAMB 1997

The electron configuration of two elements with similar chemical properties are represented by?

A. 1s²2s²2p⁵ and 1s²2s²2p⁴
B. 1s²2s²2p⁴ and 1s²2s²2p⁶3s¹
C. 1s²2s²2p⁶3s¹ and 1s²2s¹
D. 1s²2s²2p⁴ and 1s²2s¹

Question 8:

• JAMB 1997

In the periodic table, what is the property that decreases along the periodic and increases down the group?

A. Atomic number
B. Electron affinity
C. Ionization potential
D. Atomic radius

Question 9:

• JAMB 1997

Two elements, P and Q with atomic numbers 11 and 8 respectively , combine chemically to form the compound P_xQ_Y. The respective values of x and y are?

A. 1 and 1
B. 1 and 2
C. 2 and 1
D. 3 and 1

Question 10:

• JAMB 1997

Oxygen is a mixture of two isotopes 16-O and 18-O with relative abundances of 90% and 10% respectively. The relative atomic mass of oxygen is?

A. 16.0
B. 16.2
C. 17.0
D. 18.0