Question 66:

• JAMB 1978

The periodic classification of elements is an arrangement of the elements in order of their

A. Atomic Weights
B. Isotopic Weights
C. Molecular Weights
D. Atomic Numbers
E. Atomic Masses

Question 67:

• JAMB 1978

In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?

A. 5cm³
B. 10cm³
C. 20cm³
D. 25cm³
E. 50cm³

Question 68:

• JAMB 1978

A small quantity of solid ammonium chloride (NH₄Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone

A. Distillation
B. Sublimation
C. Precipitation
D. Evaporation
E. Decomposition

Question 69:

• JAMB 1978

Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

A. P will form an electrovalent bond with R
B. Q will form a covalent bond with S
C. R will form an electrovalent bond with S
D. Q will form an electrovalent bond with S
E. Q will form a covalent bond with R

Question 70:

• JAMB 1978

An element X forms the following compounds with chlorine; XCl₄, XCl₃, XCl₂. This illustrates the

A. Law of multiple proportions
B. Law of chemical proportions
C. Law of simple proportions
D. Law of conservation of mass
E. Law of definite proportions