Chem RA

BASES AND ALKALIS

A base is a substance that can react with acid and neutralise it.

Bases are usually:

• metal oxides, such as copper oxide
• metal hydroxides, such as sodium hydroxide, or
• metal carbonates, such as calcium carbonate

most bases are insoluble meaning they don't dissolve in water

if a base is soulable in water it is called an alkali

THE EARLY ATMOSPHERE

There was intense volcanic activity for the first few billion years of Earths existence, so the gases that were given off from volcanoes formed the majority of the early atmosphere. This meant there was lots of carbon dioxide and little to no oxygen. When the volcanoes went dormant stopped erupting and the earth cooled down, this meant most of the water vapour condensed and formed the oceans. With there now being water there was precipitation and this meant that plants grew. The plants absorbed the carbon dioxide and released oxygen. The carbon dioxide was also locked up in fossil fuels and sedimentary…