Chemistry - Reactions - Gas given off and solid remaining after heating

[jahrollins]

Homework Statement

If the following substances were heated what gas would be given off and what solid would remain? strontium carbonate, zinc carbonate, and iron carbonate.

Homework Equations

N/A

The Attempt at a Solution

So I presume carbon dioxide would be given off and the 3 substances would become oxides. I'm don't get what would form a solid though?

 

[chemisttree]

The oxides would form the solid. To find the oxides, just remove CO2 from the empirical formula.

 

[jahrollins]

So all the oxides would be solids? I thought it might be that... but the way the question was presented made me think it would just be one.