Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

1,131.

S block elements of the periodic table one made up of

A.

groups 1, 2, 3

B.

groups 1, and 2

C.

group 3

D.

group 3 to 7

Correct answer is B

S block elements only are made up of group 1 and 2 options A,C,D takes place of the other blocks in the periodic table p,d,f etc.

1,132.

In the electrolysis of CuSo4(g) using platinum electrode the reaction at the anode is

A.

4H+ 4e - 2H2

B.

4OH= 4e- + 2H2O + O2

C.

2OH - 2e- = 2OH

D.

2OH- + 2OH = 2H2O + O2

Correct answer is B

40H − 4e → 2H2O + O2is the reaction of sun at the anode in the electrolysis of CuSO4 (g) using platinum particles. Option A,C,D are not formed as a result of the equation

1,133.

The principal constituent of natural gas is

A.

methane

B.

ethane

C.

propane

D.

Butane

Correct answer is A

Methane CH4.A. is the principal and commercial constituent natural gas. Option B,C,D are also constituent of natural gas but they are not commercial and of economic importance

1,134.

Chlorine consisting of two isotope of mass number 35 and 37 in the ratio 3:1 has an atomic mass of 35.5. Calculate the relative abundance of the isotope of mass number 37

A.

20

B.

25

C.

60

D.

75

Correct answer is B

Let the relative abundance of the energy with mass 37 be
Total relative abundance of the isotope of mass 359100-k)
Total mass of isotope of mass 37-37x, while that of 35-359(100x)
-37x + 3500 − 35 − 35.5
-37x + 3500 − 35n − 35.5
Mean mass of chlorine atom − (2n + 3500)/ ÷ 100
= 35.5
2x + 3500 − 3550yx = 50/2

1,135.

Chlorine gas turns damp starch-iodide paper

A.

pink

B.

colourless

C.

red

D.

dark blue

Correct answer is D

Chlorine turns a damp starch iodide paper into dark blue or blue black.