1. In the industrial preparation of oxygen, state:
(a) How dust particles are removed from air.
(b) Why carbon (IV) oxide is removed before the mixture is cooled.
2. A form four student accidentally mixed Sodium Carbonate and Calcium. How would he obtain a dry sample of Sodium Carbonate from the mixture?
Answer (2)
To industrially prepare oxygen, dust particles are removed using filters or electrostatic precipitators, and carbon dioxide is removed before cooling to maintain purity. In a mixture of Sodium Carbonate and Calcium, water can be added to dissolve the Sodium Carbonate, filtered to remove Calcium, and then evaporated to obtain a dry sample of Sodium Carbonate. These methods ensure that oxygen preparation and separation of Sodium Carbonate are efficient and pure.
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In the industrial preparation of oxygen:
(a) How dust particles are removed from air:
Dust particles are removed from air using filters. In industrial settings, air is typically passed through a series of filters, such as fabric filters or electrostatic precipitators, which can capture and remove particulate matter effectively. This is an important step to ensure that the air used in further processes is clean and free of contaminants.
(b) Why carbon (IV) oxide is removed before the mixture is cooled:
Carbon (IV) oxide, also known as carbon dioxide (CO₂), is removed before the air mixture is cooled to prevent it from freezing and forming dry ice or solid CO₂ when temperatures drop. The low temperature used in the liquefaction process can cause CO₂ to solidify, which would otherwise clog the equipment and disrupt the process. Removing CO₂ ensures an efficient separation of oxygen from other gases by preventing such occurrences.
A form four student accidentally mixed Sodium Carbonate and Calcium. How would he obtain a dry sample of Sodium Carbonate from the mixture?
To separate sodium carbonate (Na₂CO₃) from a mixture with calcium (Ca), the student can follow these steps:
Dissolve the mixture in water: Sodium carbonate is soluble in water, while calcium does not dissolve. By adding water, the sodium carbonate will dissolve, while the calcium remains undissolved.
Filter the mixture: Use a filter paper and funnel to separate the solid calcium from the sodium carbonate solution. The calcium will remain on the filter paper, and the sodium carbonate solution will pass through.
Evaporate the water: Heat the sodium carbonate solution gently to evaporate the water. As the water evaporates, sodium carbonate crystals will start to form.
Dry the sodium carbonate: Collect the crystals once all the water has evaporated and allow them to dry completely to obtain a dry sample of sodium carbonate. This drying can be done by leaving the crystals in a dry, warm place or using a desiccator.
By following these steps, the student can effectively separate and obtain a dry sample of sodium carbonate from the mixture.
