Post Utme Abia State University Chemistry Past Questions and Answers

Question 1:

Elements in the same period in the periodic table have the same ____________

A. Chemical propertles
B. Physical propertles
C. Number of shells
D. Atomic number

Question 2:

Calculate the percentage by mass of nitrogen in calcium trioxonitratre (v)
\((\mathrm{Ca}=40, \mathrm{~N}=14, \mathrm{O}=16)\)

A. \(17.1 \%\)
B. \(27.6 \%\)
C. \(8.5 \%\)
D. \(13.1 \%\)

Question 3:

Which of the following salts is slightly soluble in water?

A. \(\mathrm{Na}_{2} \mathrm{CO}_{3}\)
B. \(\mathrm{PbCl} 2\)
C. \(\mathrm{AgCl}\)
D. \(\mathrm{CaSO}_{4}\)

Question 4:

Permanent hardness of water can be removed by ____________

A. Adding caustic soda
B. Boiling
C. Filtration
D. Adding slaked lime

Question 5:

An isotope has an atomic number of 15 , and a mass number of 31 .
The number proton it contains is ____________

A. 16
B. 15
C. 46
D. 31