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.

111.

Which type of chemical combination involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions?

A.

Ionic bonding

B.

Hydrogen bonding

C.

Covalent bonding

D.

Metallic bonding

Correct answer is A

Ionic bonding occurs between a metal and a non-metal. The metal atom donates one or more electrons to the non-metal atom, resulting in the formation of positively charged cations and negatively charged anions. These oppositely charged ions are held together by electrostatic forces to form an ionic compound.

112.

What is the trend for ionization energy across a period in the periodic table?

A.

Increases from left to right.

B.

Remains constant

C.

Varies randomly

D.

Decreases from left to right

Correct answer is A

Ionization energy generally increases from left to right across a period. Ionization energy is the energy required to remove an electron from a neutral atom, and as you move from left to right, the atomic size decreases, making it harder to remove an electron, and thus, the ionization energy increases.

113.

Balance the following redox reaction:
Fe\(_2\)O\(_3\) + CO → Fe + CO\(_2\)

A.

Fe\(_2\)O\(_3\) + CO → 2Fe + 2CO\(_2\)

B.

2Fe\(_2\)O\(_3\) + 3CO → 4Fe + 3CO\(_2\)

C.

Fe\(_2\)O\(_3\) + 2CO → 2Fe + 2CO\(_2\)

D.

Fe\(_2\)O\(_3\) + 3CO → 2Fe + 3CO\(_2\)

Correct answer is D

To balance the redox reaction, we need to ensure that the number of atoms of each element and the total charge are the same on both sides of the equation. In this reaction, we can see that the number of oxygen (O) atoms is not balanced. To balance them, we need to add a coefficient of 3 in front of CO\(_2\) to get 3CO\(_2\). Similarly, the number of iron (Fe) atoms is not balanced. To balance them, we need to add a coefficient of 2 in front of Fe to get 2Fe

114.

Identify the reducing agent in the following reaction:
Zn + CuSO\(_4\) → ZnSO\(_4\) + Cu

A.

Cu

B.

Zn

C.

ZnSO\(_4\)

D.

CuSO\(_4\)

Correct answer is B

The reducing agent is the species that undergoes oxidation and causes the reduction of another species. In this reaction, zinc (Zn) is being oxidized to form zinc sulfate (ZnSO\(_4\)) while reducing copper sulfate (CuSO\(_4\)) to copper (Cu).

115.

What is the state of matter in which particles are widely spaced and move freely with high kinetic energy?

A.

Liquid

B.

Solid

C.

Plasma

D.

Gas

Correct answer is D

In the gas state of matter, particles are widely spaced and move freely with high kinetic energy. Gases do not have a definite shape or volume and will fill the entire available space.