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.

3,051.

147N + X → 178O + 11 H. In the above reaction, X is a?

A.

neutron

B.

helium atom

C.

litgium atom

D.

deuterium atom

Correct answer is B

No explanation has been provided for this answer.

3,052.

How many lone pairs of electron are there on the central atom of the H2O molecules?

A.

1

B.

2

C.

3

D.

4

Correct answer is B

In a water molecule, oxygen is bonded to two hydrogen atoms. Leaving oxygen with four electrons which pair up with one another to form two lone pairs of electrons.

3,053.

The nucleus of the isotope tritium, contains?

A.

two neutrons with no protons

B.

one neutron and one protons

C.

two neutrons and one proton

D.

two neutrons, one proton and one electron

Correct answer is C

No explanation has been provided for this answer.

3,054.

An increase in temperature causes an increase in pressure of a gas in a fixed volume due to an increase in the?

A.

number of molecules of the gas

B.

density of the gas molecules

C.

number of collisions between the gas molecules

D.

number of collisions between the gas molecules and the walls of the container

Correct answer is D

No explanation has been provided for this answer.

3,055.

If 100 cm3 of oxygen pass through a porous plug in 50 seconds, the time taken for the same volume of hydrogen to pass through the same porous plug is?



(O = 16, H = 1)

A.

10.0 s

B.

12.5 s

C.

17.7 s

D.

32.0 s

Correct answer is B

100 cm3 of O2 diffuse 50 sec
∴ 100 cm3 of H2 → (100) / (100) x (50) /(1)
t1 50 sec
molecular mass H+ → 2 x 1 = 2
molecular mass of O2 16 x 2 = 32

T2 = t1 √M2/M1 = t2 = 50 √2/32

50√0.625 = 50 x 0.25 = 12.5 secs