Question 821:

• JAMB 1993

The function of the copper (ll)tetraoxosulphate (IV) in dilute H₂SO₄ in the figure above is to

A. Dry the gas
B. Absorb phosphine impurity
C. Absorb ethene impurity
D. From an acetylide with ethyne

Question 822:

• JAMB 1993

The dissolution of common salt in water is a physical change because

A. The salt can be obtained by crystallization
B. The salt can be recovered by the evaporation of water
C. Heat is not generated during mixing
D. The solution will not boil at 100^oC

Question 823:

• JAMB 1993

At 25^oC and 1atm, a gas occupies a volume of 1.50dm³. What volume will it occupy at 100^oC and 1atm?

A. 1.88 dm³
B. 6.00 dm³
C. 18.80 dm³
D. 18.80 dm³
E. 60.00dm³

Question 824:

• JAMB 1994

A mixture of sand, ammonium chloride and sodium chloride is best separated by?

A. Sublimation followed by addition of water and filteration
B. Sublimation followed by addition of water and evaporation
C. Addition of water followed by filtration and sublimation
D. Addition of water followed by crystallization and sublimation

Question 825:

• JAMB 1994

A pure solid usually melts?

A. Over a wide range of temperature
B. Over a narrow range of temperature
C. At a lower temperature than the impure one
D. At the same temperature as the impure one