Copper

[K18]

Why it is possible for copper to remain on the bed of a lake without reacting with anything?

[dundurn]

No one's replied to you in over 12 hours so I'll give you my guess! I'm assuming we're talking about a freshwater lake so we don't have the heightened salt concentrations of seawater to worry about. At the bottom of a lake there may be little or no current flowing so the water condirions may be constant over long periods. The temperature will be low, not much above freezing, so many chemical reactions that would occur even at room temperature will be inhibited. Any plant detritus in the water will tend to decay over time. The small organisms which do this will absorb much if not all of the available oxygen. The end result is that copper, which if memory serves is a relatively inert metal, will remain unchanged for quite long periods.

[terambulan]

inert until mum polishes it away! ;)

[eltelioni]

This inertness makes copper useful for water pipes.

[Avatar]

he's not on shift

[heathfield]

The copper will have a thin layer of copper oxide on its surface. In a lake bottom, the oxygen levels may be very low, and insufficient to further pemeate this layer. Carbonic and organic acids will remove this oxide, and lead to marked corrosion, but if they are absent, the copper will last for ages