One involves reaction of steam and coal and the other involves reaction between methane and steam Hydrogen is made by two complete processes. Step 2 Calculate the mass of water as per equationĬonsider the synthesis of maleic anhydride from benzene as shown on the right.Ĭalculate the atom economy for this reaction. Step 1 Calculate the total mass of reactants as per equation. What is the atom economy of the reaction below in producing water? Step 3 Calculate the theoretical mass of water produced Step 2 Calculate the mol of water 2.00 mol of methane will produce according to the stoichiometry Step 1 Convert mass of methane into mol of methane In this particular reaction 32.0 grams of methane burns completely to produce 66.0 grams of water. Let's do some examples of simple reactions.Ĭonsider the combustion of methane to form carbon dioxide and water. Percentage yield is calculated from the mass of reactants and the mass of products. Where atom economy proves useful, however, is in comparing different reaction pathways to a desired product.Ītom economy is the percentage of the total mass of reactants that successfully converted to the desired product. Atom economy does not take into account yield and does not allow for the fact that many industrial processes deliberately use excess of reactants to increase the yield of a required product. This can be calculated from the balanced chemical equation prior to any reaction taking place. In other words, atom economy is a calculation which measures "how much of the reactant atoms actually form the final product", the higher the atom economy the lower the amount of waste product formed. The ideal atom economy, known as 100% atom economy, for a chemical reaction is taken as the process where all reactant atoms are found in the desired product. Atom economy is the second principle of green chemistry
Chemistry-atom economy and percentage yield Atom economy and percentage yield.Ītom economy and percentage yield are indicators of how efficient a chemical reaction is.