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.

296.

Which of the following are chemical changes? 

I. cooking of food
II. digestion of food
III. freezing of water
IV. water is heated up

A.

I and II

B.

I, II, and III

C.

III and IV

D.

all of the above

Correct answer is A

No explanation has been provided for this answer.

297.

Which of the following is a non-metal that remains liquid at room temperature?

A.

Chlorine

B.

Phosphorus

C.

Bromine

D.

Helium

Correct answer is C

Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest halogen and is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour.

298.

Which one of the following is not a mixture?

A.

Air

B.

Mercury

C.

Milk

D.

Cement

Correct answer is B

A  mixture is a material made up of two or more different chemical substances which are not chemically combined. 

Mercury is a chemical element with the symbol Hg and atomic number 80.

299.

A 'breath test' used by traffic police to check drunken driving uses?

A.

Tumeric on filter paper

B.

Silica gel coated with saliva nitrate

C.

Potassium permanganate-sulphuric acid

D.

Potassium dichromatic-sulphuric acid

Correct answer is D

The earliest developed breathalyzer was based on reaction of alcohol if present in the exhaled air with a cocktail of chemicals containing sulfuric acid, potassium dichromate, silver nitrate, and water. Silver nitrate catalyzes the reaction between alcohol and potassium dichromate in acidic medium.

300.

What is the chemical name for the compound CuCO\(_{3}\)?

A.

Copper (iii) carbonate

B.

Copper (ii) carbonate

C.

Copper (i) carbonate

D.

Copper

Correct answer is B

Copper(II) carbonate or cupric carbonate is a chemical compound with formula CuCO\(_{3}\)