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.

276.

The only metal that is anti-bacterial is?

A.

Iron

B.

Sodium

C.

Alluminium

D.

Copper

Correct answer is D

Aluminium sulfate is a salt soluble in water and is mainly used as a coagulating agent in the purification of drinking water.

Copper demonstrated the greatest antimicrobial activity. The silver coatings demonstrated the second most antimicrobial surface.

277.

A solution contains 20g of solute in 180g of solvent. If the solvent is water, what is the concentration of the solution in terms of mass by mass percentage

A.

11.%

B.

22.2%

C.

10%

D.

20%

Correct answer is C

Mass of Solution = Mass of Solute + Mass of Solvent → 20g + 180g

: Mass of Solution = 200g

Mass Percent = \(\frac{Mass of Solute}{Mass of Solution} * 100%\)

Mass percent = \(\frac{20}{200} * 100%\)

Mass percent = 10%

278.

The nucleus of an atom consists of?

A.

Electrons and neutrons

B.

Electrons and protons

C.

Protons and neutrons

D.

None of the above

Correct answer is C

An atom nucleus is made up of protons and neutrons.

An electron is a negatively charged subatomic particle that orbits the nucleus of an atom.

279.

The metal used to recover copper from a solution of copper sulphate is?

A.

Na

B.

Ag

C.

Hg

D.

Fe

Correct answer is D

The ideal metals to use for the task of recovering copper from an aqueous solution of copper sulphate are metals that are stronger reducing agents than copper but not reactive enough to react with the water that the solution consists of.

 Zinc, Aluminium, Iron are relatively inexpensive and being unreactive on exposure to water.

280.

The nucleus of a hydrogen  atom consist of a?

A.

1 proton only

B.

1 proton, 2 neutron

C.

1 neutron only

D.

1 electron only

Correct answer is A

The hydrogen atom is the simplest of all atoms: it consists of a single proton and a single electron