Post Utme Chemistry Past Questions and Answers

Question 16:

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

Question 17:

A small quantity of solid ammonium chloride was heated gently in a test tube; the solid gradually disappeared to produce a mixture of 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

Question 18:

\(\mathrm{CH}_{4}\) has this geometry:

A. Trigonal
B. Planar
C. Tetrahedral
D. Octahedral
E. Linear

Question 19:

Chlorine, consisting of two isotopes of mass numbers 35 and 37 , has an atomic mass of \(35.5\).
The relative abundance of the isotope mass 37 is ____________

A. 20
B. 25
C. 50
D. 75

Question 20:

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

A. Atomic weights
B. Isotopic weights
C. Molecular weights
D. Atomic numbers