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Drying agents are substances that can be used to obtain a dry sample of a gas by removing its moisture content.
Examples:
* Anhydrous calcium chloride (for any gas except ammonia)
Ammonia will react with calcium chloride.
4NH3 (g) + CaCl2 (s) –> CaCl2.4NH3 (s)
* Concentrated sulfuric acid (for any gas except alkaline gases such as ammonia)
* Calcium oxide
(for any gas except acidic gases such as CO2 and SO2)
Kinetic Particle Theory states that all matter is made up of tiny, discrete particles that are in constant, random motion.
The start line above the solvent level allows the solvent to move past the start line, carrying the dissolved samples along with it.
With the start line below the solvent level, the samples on the start line will dissolve in the solvent right at the beginning, contaminating the whole solvent, causing the chromatogram to be inaccurate.
For substances used in preparing food and drugs, it is important to ensure that only permitted substances are being used.
If a substance is impure, and laced with some other substances, these unapproved impurities might not be safe for human consumption, and lead to undesirable effects on human health.
To determine the purity of a substance, test its melting point or boiling point.
If it melts or boils at a fixed temperature, it is a pure substance.
Another method is to carry out a chromatography of the substance.
If it separates out into only one spot on the chromatogram, it is a pure substance.
A small amount of concentrated sample is placed on the starting line of a chromatography paper. The chromatography paper is placed inside a beaker containing a solvent. The solvent level should be below the starting line.
As the solvent moves up the paper, it separates the sample into its respective components.
The chromatography paper is removed before the solvent reaches the edge of the other end of the paper.
Downward delivery: chlorine gas, carbon dioxide gas, sulfur dioxide gas
Upward delivery: hydrogen gas, ammonia gas
Displacement of water: hydrogen gas, carbon dioxide gas
The source of sulfur dioxide comes from burning of fossil fuels, and volcanic activity.
Sulfur dioxide can dissolve in rain water high up in the atmosphere, forming acid rain.
Acid rain speeds up the corrosion of buildings and structures made of limestone or reactive metals, like steel.
Acid rain makes water too acidic, which can be harmful to aquatic organisms.
Acid rain removes essential metal ions needed by plants, such as calcium, potassium, magnesium ions from the soil, affecting the health of plants.