Question

About 60 million tonnes of calcium oxide is made in Britain each year. How would you calculate the mass of calcium carbonate needed to make this amount of calcium oxide?

Answer 1

We need (i) a stoichiometric equation:

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

Explanation:

And (ii) equivalent quantities of calcium oxide...........

`=(60xx10^6*"tonnes"xx10^6*g*"tonne"^-1)/(56.8*g*mol^-1)`

`=1.06xx10^12*"moles CaO"`

Given the 1:1 stoichiometry, we generate `1.06xx10^12*mol` carbon dioxide gas, and CLEARLY we require `1.06xx10^12*mol* CaCO_3`.

And this represents a mass of .....................................

`1.06xx10^12*molxx100.06*g*mol^-1=1.06xx10^14*g=`

`1.06xx10^11*kg`

Note that while this seems a large quantity, this is almost exclusively used for the production of mortar and concrete, i.e. building materials.