How many moles are there in 88g of carbon dioxide?

To work this out we need the equation:
Number of moles = Mass (in grams) / Mr (relative formula mass)
We know the mass of carbon dioxide already (88g). We need to work out the Mr of carbon dioxide. The Mr can be calculated by adding up all of the relative atomic masses of each atom in the compound. In carbon dioxide (CO2) we have 1 carbon atom, and 2 oxygen atoms. The relative atomic masses of carbon and oxygen are given in the periodic table in the top left corner.
Mr of CO2 = 12 + 16 + 16 = 44
Using this we can now work out the number of moles in 88g of CO2:
Moles = 88 / 44 = 2 moles