Porque es importante hacer un calculo de impurezas antes de la reaccion

(apex) when a cup of water is dropped, as the cup falls, the water in the cup falls out true or false?

How many moles of gas are present if p=11 atm, v=12l, t=185k?

An excess of lithium oxide undergoes a synthesis reaction with water to produce lithium hydroxide li2o+h2o→2lioh if 1.05 g of water reacted, what is the theoretical yield of lithium hydroxide? a) 5.83 x 10–2 g lioh b) 1.17 x 10–1 g lioh c) 2.79 x 100 g lioh d) 1.40 x 100 g lioh