Earth (chemistry)

From Wikipedia, the free encyclopedia

The chemical term earths was historically applied to certain chemical substances, once thought to be elements, and this name was borrowed from one of the four classical elements of Plato. "Earths" later turned out to be chemical compounds, albeit difficult to decompose, such as rare earths and alkaline earths.

Actually, earths are metallic oxides, and the corresponding metals were classified into the corresponding groups: rare earth metals and alkaline earth metals.

Carbon dioxide is given off when acid is put on calcium carbonate such as in chalk, limestone and marble.

When rocks get hot enough, they melt and change into a liquid called magma.This happens to rock inside the Earth. The thin crust of the Earth is made fom solid rock. Hot molten rock inside the Earth is called magma.

Sometimes magma comes up from inside the Earth. This happens when a volcano errupts.When magma cools, it sets hard. The magma that has set outside the Eart's crust has made a rock called basalt.

The new rocks that are made when magma sets are called ingeneous rocks.