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