Test: Air - 1 - JAMB MCQ

The natural gaseous constituents of air are nitrogen (approximately 78%), oxygen (approximately 21%), and water vapor (variable amount).

Nitrogen is the most abundant component of air, constituting approximately 78% of its volume.

Argon is present in air in trace amounts, approximately 0.93% by volume.

The separation of air components is based on the principle of fractional distillation, where the different boiling points of the components are utilized.

The composition of air can vary due to human activities, seasonal changes, and variation in altitude.

Carbon dioxide is essential for photosynthesis, as plants use it to produce glucose and release oxygen.

Carbon dioxide is a greenhouse gas that contributes to the greenhouse effect, leading to global warming.

Oxygen is necessary for the process of combustion and is also vital for respiration in living organisms.

Neon gas is used in neon signs due to its characteristic red-orange glow when electricity passes through it.

Argon is primarily used in the industry for welding and cutting metals. It is an inert gas, which means it does not react with other substances under normal conditions. This makes it ideal for creating an inert atmosphere during welding processes, where it helps protect the metal being worked on from reacting with oxygen and other gases in the air.

Argon is commonly used as a shielding gas in processes such as gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW). It is also used in plasma cutting, where it is directed at high temperatures to melt and remove metal. The use of argon in these applications helps to improve the quality of welds, reduce oxidation and porosity, and enhance overall weld performance.

While argon can be used in other applications, such as filling balloons or enhancing fire extinguishers, its most significant industrial use is indeed in welding and cutting metals.