Question

What is the balanced chemical equation of Ca2 +H2O >C2H2 + Ca(OH)2?

Answer 1

I think you mean `CaC_2` rather than `Ca_2`, otherwise where is the C atom in the product coming from?!

This is the reaction between calcium carbide and water, which produces ethyne, (old name acetylene) which is highly flammable.

To balance the equation, firstly look at the carbon atoms. We have 2 in the `CaC_2` and 2 in the `C_2H_2`, so we can see that they have 1:1 stoichiometry. Now look at the calciums. We have 1 in the `CaC_2` and one in the `Ca(OH)_2` so they also have 1:1 stoichiometry.

Now look at O atoms.There are 2 of them in `Ca(OH)_2` and 1 in `H_2O`, so we have two water molecules for every one calcium hydroxide. his means the balanced equation (even without balancing for hydrogen atoms) looks like:
`CaC_2 + 2H_2O -> C_2H_2 + Ca(OH)_2`

We can check that this is balanced using the H atoms. Four in the two water molecules on the left; two in the ethyne and two in the calcium hydroxide on the right, so they balance too as they should.