Because seawater contains a lot of salt, of which sodium chloride accounts for about 3%, sodium ions stimulate our taste buds to produce salty taste, so seawater is salty.
Some salt comes from volcanoes under the sea, but most of it comes from rocks in the earth's crust. Rock is decomposed by weathering, releasing salt, which is carried to the sea by river water. In the circulation process of seawater evaporation and then condensation into water, after seawater evaporation, salt remains and gradually accumulates to the existing concentration. The ocean contains so much salt that it can spread a salt layer about 500 feet thick on the global land.
The salt content of seawater in the world's major oceans varies from place to place, with an average of about 3.5%. The most common inorganic salt dissolved in seawater is sodium chloride, which is used daily.
Introduction of elements in seawater
Seawater is a very complex multi-component aqueous solution. Various elements in seawater exist in certain physical and chemical forms. The existing forms of copper in seawater are complicated, and most of them exist in the form of organic compounds.
Only a small part of free ions exist in the form of divalent positive ions, and most of them exist in the form of negative ion complexes. Free copper ions only account for a small part of the total amount of dissolved copper. Seawater is rich in sodium, but its chemical behavior is very simple, and almost all of it exists in the form of Na+ ions.