Heating causes Group 2 carbonates to decompose. Write an equation for the decomposition of the carbonate ion.
Describe and explain the way the thermal stability of the Group 2 carbonates varies as atomic number increases.
Lead(II) carbonate, $\text{PbCO}_3$, and zinc carbonate, $\text{ZnCO}_3$, decompose on heating in the same manner as calcium carbonate, $\text{CaCO}_3$. State the relevant data from the Data Booklet and use it to predict the order of thermal stability for these three carbonates.
Dolomite includes the double carbonate of calcium and magnesium, $\text{CaMg(CO}_3)_2$, together with some impurities. When $0.642\,\text{g}$ of a dolomite sample reacts with excess hydrochloric acid, $125.0\,\text{cm}^3$ of $\text{CO}_2$ is produced under room conditions. Calculate the percentage of $\text{CaMg(CO}_3)_2$ in the dolomite sample. Show all your working. Assume that none of the impurities react with $\text{HCl}$.