Question

How would you balance the following equation: CaO3 --> CaO+CO2?

Answer 1

You have a typo in your question:

`CaCO_3(s) rarr CaO(s) + CO_2(g)uarr`

Explanation:

If you HEAT a carbonate sufficiently, the reaction above occurs.

We could reverse this reaction by bubbling carbon dioxide thru calcium hydroxide:

`Ca(OH)_2(aq) + CO_2(g) rarr CaCO_3(s)darr + H_2O(l)`.

In fact, this second reaction is a test for carbon dioxide. Carbon dioxide gas should turn limewater (`Ca(OH)_2(aq)` milky (i.e. a precipitate of white `CaCO_3` occurs). When you do this reaction yourself in the lab, you should always do a test first: i.e. treat saturated calcium hydroxide with carbonated water (i.e. water with saturated with `CO_2`). What do you see?

Are these reactions balanced? How do you know?