When 5.0 g of tin reacts with hydrochloric acid, the mass of the products, tin chloride and hydrogen, totals 8.1 g. How many grams of hydrochloric acid were used?
The mass of hydrochloric acid that was used is
The law of conservation of matter/mass states that matter is neither created nor destroyed during a chemical equation in a closed system. So the total mass of the reactants equals the mass of the products.
So, if the mass of the products totals