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.

1,176.

Flow of current in electrolytes is due to the movement of

A.

electrons

B.

Holes and electron

C.

Ions

D.

Charges

Correct answer is C

No explanation has been provided for this answer.

1,177.

Cathode rays cause an object placed behind a perforated anode to cast a shadow on the screen. This observation shows that the rays

A.

are positively charged

B.

are negatively charged

C.

Have mass

D.

travel in straight lines

Correct answer is D

Rays travels in straight lines and finds its way through any opening available. It could be refracted, reflected or transmitted based on any obstacle. Option A,B,C are not the reason why the cathode are coasted shadows

1,178.

An elements used in production of matches is

A.

nitrogen

B.

aluminum

C.

copper

D.

sulphur

Correct answer is D

Sulphur is an element that burns with a strongly explosive smell, as a result it is explosive smell

1,179.

The weakest attractive force that can be observed between two molecules is

A.

ionic

B.

covalent

C.

co-ordinate covalent

D.

vander Waals

Correct answer is D

Vander Waals are the weakest attractive forces that exist between two molecules. Option A,B,C are not weak forces because the force attraction that exist between their interested molecule are very strong

1,180.

Which of the noble gases has the greatest ionization energy

A.

He

B.

Xe

C.

Ar

D.

Rr

Correct answer is A

Ionization energy: The amount of energy required to remove an electron from an isolated atom or molecule.

Trends down group :

  • Ionization energy decreases down the group.
  • This is due to the shielding or screen effect of the outer electrons from the nucleus.
  • The attraction is weaker and they are more easily removed.
  • Helium and radon both belong to group 8 which are called noble gases.
  • Helium (He) has the highest ionization energy and Radon (Rn) has the lowest ionization energy.