\(concentration~in~g/dm^3 = \frac{mass~of~solute~in~g}{volume~in~dm^3}\) The units for concentration can also be shown as g dm-3, but this means the same as g/dm 3. 8 g of sodium hydroxide is ...
Work out how many atoms of each element there are in the chemical formula. Add together the A r values for all the atoms of each element present.