mercury laura rogers chemistry 12 – a block mrs.mclellan
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Mercury Laura RogersChemistry 12 – A BlockMrs.McLellan
Mercury
HgHg is the symbol for Hydrargyrum, which translates to liquid silver
Transition Metal
Can have the charge +1 or +2
Atomic mass is 200.6
Electronegativity is 1.9
Atomic number is 80
Either one or two valance electrons
Properties of MercuryMercury is:
Metal – transition metal
Liquid at room temperature
Heavy
Silver in colour
When poured on smooth surfaces, it rolls around and forms into little balls
Melting point of 38.842°C
Boiling point of 356.58°C
Fair conductor of electricity
Poor conductor of heat
Very poisonous when vaporized
Where is mercury is found?
Mercury is rarely found free in nature
Mercury is extracted from ore, and is often used to purify silver and gold
Mercury exists in the form of a red ore called cinnabar that is composed of mercury and sulfur
In the Earth’s crust mercury is not easily found compared to other elements, yet it is not considered rare, because when it is found there are large amounts and in high concentration
Methylmercury
Microorganisms turn mercury into methymercury which is highly toxic
Very toxic
Organic form of mercury
Methlymercury is the cause of mercury poisoning
Easily absorbed into aquatic species tissue, but not easily removed
Animals higher on the food chain contain higher amounts of methylmercury
Mercury Poisoning Mercury is highly poisonous and causes nerve damage
Mercury is released into the air when coal is burnedAfter being in the air the mercury settles into the land and water
If it gets on ones unbroken skin, or inhaled it is absorbed very quickly, very easily absorbs into the air, which people breathe in then get poisoned…
There are acute and chronic forms of mercury poisoning:
Acute – less common in present day – cause ulcers in the stomach and intestine lining, harms ones kidney and ability to urinate
Chronic – causes diarrhea, slow reflexes, tremor, poor coordination and impaired vision
The brain is the most susceptible organ to be affected
More Mercury Poisoning People have died from mercury poisoning in the past and in present day
In the 1800s mercury salt was used on hats, which poisoned and killed people. “Mad as hatters” is derived from this
In the present day mercury poisoning is usually due to food intake
In Minimata Bay, Japan thousands were posited and lost their lives due to contaminated fish
Minimata Disease is caused by methlymercury poisoning
Other deaths have been caused by:Flour made from seed grain treated with methylmercury that affected 6500 people in Iraq
Meat from animals raised on mercury-tainted grain in America and New Mexico
Unborn children are also at risk of mercury poisoningMethylmercury travels to the placenta from mother to the fetus
Children born with Minimata diseasemaychavegrowth deficiency,severe mental problems, an abnormally small head, be blind or deaf
“The U.S. Food and Drug Administration (FDA) as of 1999 recommends limiting consumption to 1 kilogram (2.2 pounds) of fish and shellfish a week and considers 1 part per million of mercury in seafood to be safe. However, top predator fish such as shark and swordfish can have mercury concentrations over 1 part per million. The FDA recommends no more than one serving a week of these two fish for most people and no more than one serving a month for pregnant or nursing women or those who may become pregnant.”
http://www.medterms.com/script/main/art.asp?articlekey=10991
Mercury in the water table
Mercury is released into the air when large amounts of coal are burned to make energy
Once the mercury is in the air, it gets into the water table
The mercury builds up in sea creatures like fish and shellfish
In certain, more acidic bodies of water there are higher amounts of mercury
When the pH levels are between 7 and 5, the mercury concentrations in the water will increase due to movement of mercury in the ground
Then microorganisms convert the mercury into methylmercury, which makes it easier to absorb
What not to do with mercury
Do NOT:Sweep – it will break up the mercury into smaller pieces, increasing the surface area making more go into the air
Vacuum – it will release the mercury into the air and increase the mercury level
Wash mercury contaminated clothing – it will contaminate your washer, all the clothes, the water, and when the clothes are put in the dryer the mercury will be released into the air
Pour it down the drain – it will pollute your septic tank, clog your drain and get into the water table
Eat a lot of fish when you are pregnant
Uses for mercury
Thermometers
Diffusion pumps
Barometers
Mercury vapor lamps
Mercury switches
Pesticides
Batteries
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