If we include the mass of the reactants and products in the balanced chemical equation, we will get something like this: Verifying law of conservation of massįrom the equation, the mass of the reactants (2.02 g + 253.80 g = 255.82 g) is equal to the mass of the products (255.82 g). Recall that the 2.02 g/mole is the molar mass of H 2.ġ mole of I 2 molecules = 1 mole x 253.80 g/mole = 253.80 g of I 2Ģ mole of HI molecules = 2 mole x 127.91 g/mole = 255.82 g of HI We know that molar mass is the mass in grams of 1 mole of a substance.įrom equation A, we can calculate the mass of:ġ mole of H 2 molecules = 1 mole x 2.02 g/mole = 2.02 g of H 2 We can also relate mole to mass in grams.
Interpreting equations in moles, and molecules How to convert from mole to mass in grams Thus, we can say that:ġ mole of H 2 = 1 mole x 6.02 x 10 23 molecules/1 mole = 6.02 x 10 23 molecules of H 2.ġ mole of I 2 = 1 mole x 6.02 x 10 23 molecules/1 mole = 6.02 x 10 23 molecules of I 2.Ģ moles of HI = 2 mole x 6.02 x 10 23 molecules/1 mole = 12.04 x 10 23 molecules of HI.īelow, we write the mole and number of molecules under each chemical. Since 1 mole of any substance contains 6.02 x 10 23 particles (Avogadro’s number), we can interpret equation A in terms of the total number of particles in a mole. How to convert from mole to number of molecules Once we do that, we can use the mole concept to work back to figure out the number of molecules in a substance. This means that it’s more useful to interpret the chemical equation in terms of moles. For example, we can say that: 1 dozen H 2 molecules reacts with 1 dozen I 2 molecules to give 2 dozen HI molecules.Ĭhemists usually count individual atoms or molecules by weighing a bunch of them. To ease this confusion a little, we can relate a mole to a dozen. It’s sometimes confusing to interpret the mole this way. We will say that 1 mole of H 2 molecules reacts with 1 mole of I 2 molecules to give 2 moles of HI molecules. To interpret equation A in terms of moles, Recall that the number 1 is implied when you don’t see a number written in front of a chemical symbol or formula in a chemical equation. We will say that 1 molecule of H 2 reacts with 1 molecule of I 2 to give 2 molecules of HI. H 2 + I 2–> 2HI To interpret equation A in terms of molecules, Now, let’s call this chemical equation as equation A: Now, let’s apply our understanding to interpret the following equation in terms of molecules and moles.įor example, when hydrogen (H 2) reacts with iodine (I 2) to produce hydrogen iodide (HI), we can write a balanced chemical equation for the reaction as: H 2 + I 2–> 2HI. To interpret the chemical formula in terms of moles, we will say 1 mol of CO 2 consists of 1 mol of carbon (C) and 2 mol of oxygen (O). To interpret the chemical formula in terms of molecules, we will say 1 molecule of CO 2 consists of 1 atom of carbon (C) and 2 atoms of oxygen (O). While the subscripts can be interpreted as atoms or moles. The coefficients can be interpreted as molecules or moles. You can interpret a balanced chemical equation in one of two ways:īut first, a molecule consists of at least two or more atoms bonded together.Īs you can see, a molecule usually consists of coefficients and subscripts. How to interpret a balanced chemical equation