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The Periodic Table

The Alkaline Earth Metals - Reaction with Oxygen (burning in air).

How do the Alkaline Earth Metals React with Oxygen?

Alkaline earth metals all react quickly with oxygen.
Calcium is stored under oil to prevent oxygen
from reaching the surface and reacting with the bare metal.

Magnesium and calcium will both burn in air when heated
to give the corresponding oxides (see below).

They are sometimes used in the chemicals in fireworks.

How does Magnesium React with Oxygen?

Magnesium burns in air with a brilliant white flame
to form magnesium oxide. Magnesium oxide is a base.

magnesium  +  oxygen  arrow   magnesium oxide.
2Mg(s)  +    O2(g)    arrow          2MgO(s)

How does
Calcium React with Oxygen?

Calcium burns in air with a red flame to form calcium oxide.

calcium  +  oxygen  arrow  calcium oxide (quicklime).
2Ca(s)  +  O2(g)      arrow        2CaO(s)                    

Calcium oxide is alkaline. Calcium oxide reacts with water
to form calcium hydroxide (slaked lime).
See also the manufacture and uses of lime.

calcium oxide  +  water    arrow    calcium hydroxide.
CaO(s)    +  H2O(l)   arrow        Ca(OH)2(s)

Although calcium hydroxide is written as solid (s), it is sparingly
in water (it dissolves a little). The solution is
called lime water and is used in the test for carbon dioxide gas.

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