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.

3,291.

Water can be obtained as the only product during the?

A.

combustion of hydrocarbons

B.

neutraliization of an acid by base

C.

combustion of hydrogen

D.

electrolysis of brine

Correct answer is C

In flame of pure hydrogen burning in air, the hydrogen (H2) reacts with oxygen (O2) to form water \(H_2O\) with the release of energy. 

Hydrocarbon combustion refers to the chemical reaction where a hydrocarbon reacts with oxygen to create carbon dioxide, water, and heat.

The electrolysis of brine yields chlorine, hydrogen and sodium hydroxide.

3,292.

When sodium trioxocarbonate (IV) decahydrate loses its water of crystallization to the atmosphere, the process is?

A.

deliquescence

B.

efflorescence

C.

hygroscopic

D.

effervesecence

Correct answer is B

efflorescence, spontaneous loss of water by a hydrated salt, e.g  Sodium trioxocarbonate (IV) decahydrate \(Na_2CO_3. 10H_2O)\) also known as washing soda

3,293.

The mixture of gases used in a photographer's flash tube is?

A.

argon and krypton

B.

krypton and xenon

C.

helium and argon

D.

argon and xenon

Correct answer is B

krypton and xenon for high-speed pictures in a photographer's flash tube

3,294.

The type of bonding in \({Cu(NH_3)_4}^2\)+ is?

A.

coordinate covalent

B.

electrovalent

C.

metallic

D.

covalent

Correct answer is A

\({Cu(NH_3)_4}^2\)+: The bonding in this ion consists of coordinate covalent bonds with all bonding electrons supplied by the nitrogen atom.

3,295.

Which quantum number divides shells into orbitals?

A.

Principal

B.

Arzimuthal

C.

Magnetic

D.

Spin

Correct answer is B

The principal quantum number, n, describes the energy of an electron and the most probable distance of the electron from the nucleus.

In other words, it refers to the size of the orbital and the energy level an electron is placed in.

The azimuthal quantum number is a quantum number for an atomic orbital that determines its orbital angular momentum and describes the shape of the orbital.