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.

261.

The process by which salt and water reacted in a limited way to form an acid or a base is?

A.

Neutral process

B.

Basic acidic process

C.

Hydrolysis

D.

Sublimation

Correct answer is C

- Hydrolysis is any chemical reaction in which a molecule of water breaks one or more chemical bonds.

-Salt hydrolysis is a reaction in which one of the ions from a salt reacts with water, forming either an acidic or basic solution.

262.

The fourteen elements (atomic number 90-103) after actinium are called? 

A.

Actinoids

B.

Nucleotides

C.

Pre-actinum elements

D.

Atomic elements

Correct answer is A

The actinide or actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.

The actinide series derives its name from the first element in the series, actinium.

263.

The molar enthalpy change accompanying the removal of an electron from a gas phase atom or ion in its ground state is called?

A.

Electron gain enthalpy

B.

Ionization enthalpy

C.

Enthalpy change

D.

Enthalpic gas removal

Correct answer is B

- The enthalpy change associated with the removal of the first electron from an isolated gaseous atom.

- Ionization enthalpy is the minimum amount of energy required to detach from an isolated gaseous atom the most loosely bound electron and turn it into a gaseous cation.

264.

In troposphere, the two types of pollutants are?

A.

Gaseous and particulate pollutants

B.

Carbon and metallic pollutants

C.

Natural and man-made pollutants

D.

Sulphuric and nitrogenous pollutants

Correct answer is A

- The troposphere is the first and lowest layer of the atmosphere of the Earth.

- Gases mix at this layer.

- Weather occurs here

- Region where plants and animals breathe and live

- Tropospheric pollution is caused due to the presence of unwanted gaseous or solid components in the air.

265.

One of the following is not a physical property of monosaccharides?

A.

Monosaccharides get charred when heated

B.

Monosaccharides are water-soluble, sweet substances

C.

They are highly vital to the exploration of metals

D.

They can be reduced to sugar alcohols

Correct answer is C

-  Monosaccharides are reducing sugars.

- Pure monosaccharides are water-soluble, white, crystaline solids.

- They taste sweet

- Form a black residue of carbon when dehydrated