 In this video, I want to go over the term molar mass and how it applies in chemistry. So molar mass, the definition, is the massing grams of one mole of a substance. So hopefully by now we know that one mole of any substance is equal to 6.02 times 10 to the 23rd of that particular substance. The molar mass is just taking this one step further and it's giving us a mass of one mole of these items. So in this case, if you look at the periodic table, any periodic table that you might have, and find carbon. Carbon has an atomic number of 6. This is something like what you will see on your periodic table. You will see a number of 6. You will see the C, which is the atomic symbol of carbon. And then you will see a decimal number known as the atomic mass. The atomic mass is equal to the molar mass. The molar mass is the same number as the atomic mass, just measured in grams. So what this tells us is that if we have one mole of carbon atoms, or by Avogadro's number, we know that one mole of carbon atoms is the same as 6.02 times 10 to the 23rd carbon atoms. By going to the periodic table and finding the atomic mass of carbon is 12.01, we can also say that one mole of carbon atoms, or the number 6.02 times 10 to the 23rd carbon atoms, both are equal to 12.01 grams. If you take carbon and you put it on a laboratory scale and weigh out 12.01 grams, then you know that you have one mole of carbon. Next up, we want to determine how can we find the molar mass of a compound rather than a single element. We know that if we want to determine the molar mass of an element, we just have to look at the periodic table and find that atomic mass value. But if we want to find the molar mass of a compound, we've got to take it one step further. In order to do this, we have to multiply the molar mass of each element in the compound and we're going to multiply that by the subscript for that element and then we're going to add the results. So if I were to ask a problem, like what is the molar mass of this compound here called calcium chloride or CaCl2, we can answer this problem in three steps. The first step is we need to determine the molar mass of each element present in the compound. Calcium chloride here contains two different elements. It contains calcium, it contains chlorine. The molar mass of calcium is equal to 40.1 grams. This comes directly from the periodic table and the atomic mass under calcium is 40.1. Next up, we need to determine the molar mass of chlorine. The molar mass of chlorine is 35.5 grams. Come straight from the periodic table as well. The second step, once you determine the molar mass of each element present in your compound, is to multiply each molar mass value by the number of that particular element that's present in the compound. So in this case, we'll start with calcium. The formula tells us that there's only one calcium and a molecule of calcium chloride. That comes from the fact that there is no subscript next to calcium. No subscript implies that there's one. So one molecule or one atom of calcium multiplied by 40.1 grams is equal to 40.1 grams. Now what about chlorine? You look here, chlorine has a subscript of two indicates there's two chlorines for every one calcium. So we're going to multiply two chlorine by the molar mass of chlorine, which is 35.5 and that equals 71.0 grams. The second step is completed. The third and final step is to simply add the results together. By adding 40.1