Jamb Chemistry Past Questions and Answers

Question 681:

• JAMB 1991

A given quantity of a gas occupies a volume of 228 cm³ at a pressure of 750mm Hg. What will be its volume at atmospheric pressure?

A. 220 cm³
B. 225 cm³
C. 230 cm³
D. 235 cm³

Question 682:

• JAMB 1991

A sample of a gas exerts a pressure of 8.2 atm when confined in a 2.93 dm³ container at 20°C. The number of moles of gas in the sample is?
(R = 0.082 litre atm / deg mole)

A. 1.00
B. 2.00
C. 3.00
D. 4.00

Question 683:

• JAMB 1991

Atoms of element X (with 2 electrons in the outer shell). combine with atoms of Y (with 7 electrons in the outer shell). Which of the following statements is FALSE? The compound formed?

A. Has formula XY
B. Is likely to be ionic
C. Contains X²⁺ ions
D. Contains Y^- ions

Question 684:

• JAMB 1991

The electronic configuration of an elements is 1s²2s²2p⁶3s²3p³. How many unpaired electrons are there in the element?

A. 5
B. 4
C. 3
D. 2

Question 685:

• JAMB 1991

The ions X_- and Y₊ are isoelectronic, each containing a total of 10 electrons.
How many protons are in the nuclei of the neutral atoms of X and Y respectively?

A. 10 and 10
B. 9 and 9
C. 11 and 9
D. 9 and 11