In the laboratory the reaction that took place was a synthesis reaction. A synthesis reaction is a type of chemical reaction in which two or more simple substances combine to form a new product. Reactants can be elements or compounds. In this case it is a gas and a metal that will react and produce a compound. The general form of a synthesis reaction is A + B → AB. For this lab to be successful it is necessary to know the percentage composition, the empirical and molecular formula, the law of conservation of mass, moles and molar mass, quality and quantity. For starters, the percent composition of a compound is the percentage of the total mass that each element has in that compound. Each compound would have a certain percentage composition. To calculate the percent composition of a compound, you should determine the total molecular mass of the compound. For example, for H2O the total molar mass would be 18.00 g/mol. You would then plug the mass of one of the elements and the molar passage into the equation % weight (mass) of element = (total mass of element present ÷ total mass of compound) x 100 to find out the percent composition. So for oxygen it would be % O = (16.00 g ÷ 18.00 g/mol) x 100 which would be equivalent to 88.9%. Therefore the percentage composition of O in this compound is approximately 88.9%. Furthermore, the molecular formula is the number and type of atoms existing in a single molecule of a substance. The empirical formula also called the simplest formula is the ratio between the elements present in the compound. The key difference between these two is that the empirical formula shows the simplest positive integer ratio between the atoms of each element present in a compound while the molecular formula of a compound is a way… half of the paper… .arbon. One mole of water would have the molar mass of 18 g/mol (H2O molar mass: (1.008x2) + 16.00 = 18.016 g/mol). Furthermore, the law of conservation of mass was first established in 1789 by a French chemist named Antoine Lavoisier. The law states that mass is neither created nor destroyed in any ordinary chemical reaction. Or more simply, the mass of the substances produced (products) by a chemical reaction is always equal to the mass of the reacting substances (reactants). For example, 1.00 g of carbon + 5.34 g of sulfur = 6.34 g of carbon disulfide. In any chemical reaction the mass of the things produced will be the same as the reactant used. The mass of things reacted is equal to the mass of things produced. So if you react with 1 kg of stuff, the result will also be 1 kg of stuff. Materials do not “disappear” nor are other materials “created”. This is because mass is neither created nor destroyed.