Waec Chemistry Past Questions and Answers

Question 1696:

• WAEC 2021

How many coulombs of electricity would liberate 1.08g of Ag from a solution of silver salt?
[Ag = 108.0; 1F = 96500 C]

A. 96500 C
B. 9650 C
C. 965 C
D. 9.65 C

Question 1697:

• WAEC 2021

The Bohr model of the atom proposed the existence of ____________

A. The nucleus
B. Electron shells
C. Nucleons
D. Neutrons

Question 1698:

• WAEC 2021

The 25°C evaporation of a 100 cm${}^3$ solution of K${}_2$CO${}_3$ to dryness gave 14g of the salt. What is the solubility of K${}_2$CO${}_3$ at 25°25C? [K${}_2$CO${}_3$ = 138]

A. 0.01 mol dm${}^{-3}$
B. 0.101 mol dm${}^{-3}$
C. 1.01 mol dm ${}^{-3}$
D. 10.0 mol dm${}^{-3}$

Question 1699:

• WAEC 2021

How many molecules of oxygen would occupy a volume of 2.24 cm${}^3$ at s.t.p?
[Molar volume at s.t.p = 22,400 cm${}^3$, Avogadro's number = 6.02 x 10${}^{23}$]

A. 3.01 x 10${}^{20}$
B. 3.01 x 10${}^{27}$
C. 6.02 x 10${}^{19}$
D. 6.02 x 10${}^{27}$

Question 1700:

• WAEC 2021

The isotopes of neon are represented by the symbols ${}^{20}$${}_x$ Ne, ${}^{21}$ ${}_y$ Ne, and ${}^{22}$ ${}_z$ Ne. The relationship between x, y, and z is?

A. X > y > z
B. X < y < z
C. X = y= z
D. X < z < y