<span>In the balanced equation above, 1 mole of CH4 will react with 2 moles of O2 to produce 1 mole of CO2 and 1 mole of H2O. </span> <span>The mass of 1 mole of CH4 = 12 + (4 * 1) = 16 grams </span> <span>The mass of 2 moles of O2 = 2 * 32 = 64 grams </span> <span>Total mass of reactants = 16 + 64 = 80 grams </span>
<span>The mass of 1 mole of CO2 = 12 + (2 * 16) = 44 grams </span> <span>The mass of 2 moles of H2O = 2 * 18 = 36 grams </span> <span>Total mass of products = 44 + 36 = 80 grams </span>
<span>Before the reaction, there was 80 grams of matter, and after the reaction there is 80 grams of matter! </span> <span>Matter is conserved!