Question

what would you see when magnesium reacts with cold water and steam?

Answer 1

Mg + H2O ==> MgO + H2

Answer 2

Mg + H2O(g) ==> MgO + H2
Mg + H2O(l) ==> Mg(OH)2(s) + H2

Answer 3

how does the rxn proceed? is it violently or calmly?

Answer 4

It is calm in cold water, I am not sure about steam though. Never tried it

Answer 5

You could look up the heat of formation and get some idea how reactive it would be.

Answer 6

With steam (reacts violently)
Mg + H2O(g) → MgO + H2

With cold water (bubbles on the aluminium strip, but reaction is not so vigorous)
Mg + 2H2O(l) → Mg(OH)2(s) + H2