RMM of magnesium oxide=24+16=40
40g=1mol
therefore 62.5g will have =62.5/40=1.5625 moles
1.5 litres contain 1.5625 mols
therefore 1 litre =1*1.5625/1.5=1.042M
Metal ore has other elements in it as well. Also sediment and stone might cover the ore. We don't want to have a phone with sediment on it do we? thus these few reasons are why.
You would want to know everything just Incase anything happens because maybe you get lost
The limiting reagent is fully consumed during the reaction
