Neo Shi Zhang (18) 10-2-11

Hydrogen Sulfide


Hydrogen sulfide, with its chemical name of H2S, is a harmful element that is made up of two harmless elements, hydrogen and sulfur. It is found in volcanic mountains, natural water, and the human body also gives off a little of it. However, it can be fatal if found in large amounts. Small amounts of it can also be found in crude petroleum. it is slightly heavier than air, and reacts with water to form a weak acid. It also reacts with metal to form metal sulfides.
Hydrogen sulfide is a covalent bond between hydrogen ions and a sulfur ion. Its chemical reaction is as follows:


FeS + 2 HCl = FeCl₂ + H₂S


This reaction is when ferrous sulfide is heated gently with a strong acid, thus producing the element of hydrogen sulfide.


Harmful effects


It is a strong poison and is also highly flammable, thus making it extremely dangerous. It is able to poison several systems in the body, but mostly only the nervous system. It forms a bond with iron in the mitochondrial cytochrome enzymes, thus preventing cellular respiration, causing a quick death.Although it can be resisted at low levels, but at high levels such as 300-355ppm, the oxidative enzymes become overwhelmed and cellular respiration comes to a halt. Danger symptoms of hydrogen sulfide poisoning are eye irritation, a sore throat and cough, nausea, shortness of breath, and fluid in the lungs. Below is the chart for the toxicity of hydrogen oxide:

• 0.00047 ppm is the recognition threshold, the concentration at which 50% of humans can detect the characteristic odor of hydrogen sulfide, normally described as resembling "a rotten egg".
• Less than 10 ppm has an exposure limit of 8 hours per day.
• 10–20 ppm is the borderline concentration for eye irritation.
• 50–100 ppm leads to eye damage.
• At 100–150 ppm the olfactory nerve is paralyzed after a few inhalations, and the sense of smell disappears, often together with awareness of danger.
• 320–530 ppm leads to pulmonary edema with the possibility of death.
• 530–1000 ppm causes strong stimulation of the central nervous system and rapid breathing, leading to loss of breathing.
• 800 ppm is the lethal concentration for 50% of humans for 5 minutes exposure (LC50).
• Concentrations over 1000 ppm cause immediate collapse with loss of breathing, even after inhalation of a single breath.

Constituent elements


Hydrogen


Hydrogen has the chemical symbol of H, with a atomic number of 1. It is the lightest and the most abundant chemical, constituting about 75% of earth's chemical masses. It is found in the 1st period and is the simplest element. It is extremely flammable and will burn in any amount of oxygen. It usually explodes with a spark, heat or sunlight. However, as it is extremely light, flames tend to flare upwards and not cause much damage. Even so, it is important to keep it away from large amount of oxygen and heat.


Sulfur


Sulfur is denoted with the chemical symbol of S and has the atomic number of 16. It is an abundant non-metal. It is also an essential element for life and is mainly used for fertilizers, but other uses include black gunpowder, matches, insecticides and fungicides.It has only a faint odor and is a electrical insulator. It melts above 100 degree celsius and easily sublimes.


Structure: