One mole of each of the following compounds is strongly heated and any gas produced is collected at room temperature and pressure. From which compound is 24dm3 of gas likely to be collected? (One mole of any has occupies 24dm3 at room temperature nd pressure)

Question

A. MgCl2
B. MgCO3
C. Mg(NO3)2
D. Mg(OH)2

Answer 1

Here is how you do B part. (A will not decompose to release a gas)
MgCO3 ==> MgO + CO2
Balance the equation; it is balanced now.
1 mole MgCO3 will give 1 mole CO2; therefore, B will give off 24 dm^3 of gas. But B is not the only answer,