Chemistry Neco Past Questions And Answers (Objective and Theory)

Multiple Choice Section:

Which of the following elements is a metalloid?

A) Silicon

B) Oxygen

C) Sodium

D) Iron

Answer: A

What is the formula for methane?

A) CH4

B) CO2

C) H2O

D) C2H6

Answer: A

In the periodic table, elements in the same group have the same number of:

A) Protons

B) Neutrons

C) Electrons

D) Isotopes

Answer: C

Which gas is responsible for the greenhouse effect?

A) Oxygen

B) Carbon dioxide

C) Nitrogen

D) Methane

Answer: B

What is the primary function of enzymes in biological systems?

A) Increase acidity

B) Speed up chemical reactions

C) Inhibit metabolic processes

D) Store energy

Answer: B

Which law states that the total pressure of a mixture of gases is the sum of their partial pressures?

A) Boyle’s Law

B) Charles’s Law

C) Dalton’s Law

D) Gay-Lussac’s Law

Answer: C

What is the role of the nucleus in an atom?

A) Contains electrons

B) Stores energy

C) Contains protons and neutrons

D) Facilitates chemical reactions

Answer: C

Explain the difference between a physical change and a chemical change, providing examples of each.

Discuss the principles behind Le Chatelier’s Principle and its application in predicting the effects of changes in reaction conditions.

Explain the concept of ionization energy and its trends across the periodic table.

Additional Theory Section:

Describe the structure of a water molecule, highlighting its polarity and its significance in various chemical processes.

Discuss the properties and uses of acids and bases in everyday life, providing examples to illustrate their behavior.

Explain the process of radioactive decay and its applications in various fields, including medicine and energy production.

Discuss the principles of chromatography and its applications in separating and analyzing mixtures.

Elaborate on the concept of stoichiometry, providing examples of how it is used to calculate reactants and products in chemical reactions.