sea water

[copperstream]

why is sea water always salty????

[Darkblade48]

Sea water tastes salty due to the dissolved salts that are in sea water; a large contributing factor is the amount of dissolved sodium chloride in sea water.

[CaptainPanic]

You can see the sea and ocean as the end-point of every drop of water (in the liquid form).

 

Water rains down on some land, goes to a river and then to sea. When it falls on the land, salts dissolve in the water, in very very small amounts, but still, a little salt always dissolves. This water then flows to the sea.

 

So, all the salt ends up in the sea... The water can evaporate, and rain down again, but the salt cannot evaporate (have you ever seen a boiling salt?).

 

There are several salts that are washed down to sea like that... As mentioned before, Sodium Chloride is the most common in the sea... So why not potassium nirtate (a fertilizer)? After all, potassium nitrate is common on land.

 

The reason is that it's a fertilizer, and the rivers and the sea are also full of plants. These also consume the fertilizer salts.

 

So, my conclusion is that the sea is salt because the salt is washed down to the sea, and cannot evaporate and is not consumed.

[YT2095]

sea water`s also quite rich in other Halides too, Bromine and Iodine for instance, there Is potassium in it also as well as magnesium and calcium.

Sylvite (KCl) is mined from dried up sea beds too.

 

you`re quite right about the Nitrates too, they Are used by the plant matter available.

[CaptainPanic]

My story also goes for other "dead ends" in the water cycle on earth.

 

Inland lakes and seas that have no exit point to open sea become salty too (if you give it enough time). You can think of the Dead Sea in Israel, and lake Aral and the Caspian Sea in Asia. Again, this is because the rivers bring small amounts of salt to the sea, the water evaporates, and the salts stay.

 

Interestingly, the Dead Sea contains very high amounts of salts, and salts different from other seas. It has a large potash industry on its shores (potash is basically potassium carbonate (K2CO3) and other potassium salts, even nitrate). The oceans don't contain lots of carbonates.

 

http://en.wikipedia.org/wiki/Potash

http://en.wikipedia.org/wiki/Dead_Sea

[ChemSiddiqui]

take some sample of sea water and try to heat it at home, after sometime you will see when water would have evaporated, some white residue left behind. It is actually the dissolved salts and minerals in sea water which makes it salty!

[hermanntrude]

There is also a small amount of gold in sea-water. I remember a story about a guy who determined the quantity and decided it would be a profitable venture to go out in a boat and concentrate the gold to collect it as a metal. unfortunately he did his math wrong and came back with minimal amounts

[eruheru]

there are many dissolved ions in sea water that make up the salts in water; sodium, chlorine, potassium, calcium, etc. On average the ocean has a salinity of 35 ppt(parts per thousand) or 3.5% The salts mostly originate from the weathering and erosion of rocks from land and in the ocean itself. All of the major ions exist in a constant proportion so that no matter what the exact salinity, there will be the same ratio of ions. salt water is usually higher where there is high evaporation or at the poles where fresh water is removed but the salts remain in a higher concentration. It is usually lower near river mouths or areas of high precipitation.

[thedarkshade]

sea water`s also quite rich in other Halides too, Bromine and Iodine for instance, there Is potassium in it also as well as magnesium and calcium.

Sylvite (KCl) is mined from dried up sea beds too.

Yeah mostly like you said, but there is not that much iodine and bromine (not so much compared to other ones). The highest level of bromine is in the Dead Sea where it has a percentage of 0.5% and the usual level of iodine in sea water is [math]5 \times 10^{-7}\frac{mol}{dm^3}[/math]

 

edit: and eruheru, you avatar scares me, honestly:doh:!

[Psyber]

My story also goes for other "dead ends" in the water cycle on earth.

 

Inland lakes and seas that have no exit point to open sea become salty too (if you give it enough time). You can think of the Dead Sea in Israel, and lake Aral and the Caspian Sea in Asia. Again, this is because the rivers bring small amounts of salt to the sea, the water evaporates, and the salts stay.

 

Interestingly, the Dead Sea contains very high amounts of salts, and salts different from other seas. It has a large potash industry on its shores (potash is basically potassium carbonate (K2CO3) and other potassium salts, even nitrate). The oceans don't contain lots of carbonates.

 

http://en.wikipedia.org/wiki/Potash

http://en.wikipedia.org/wiki/Dead_Sea

Try Lake Eyre in central Australia. It occasionally has water in it - the rest of the time it is a dry salt pan.

http://en.wikipedia.org/wiki/Lake_Eyre