In this example, we convert from the mass of a compound to the mass of an element within the compound. Our problem reads, "What is the mass of carbon in 15 grams of glucose, C6H12O6?" We'll start our dimensional analysis with 15 grams of glucose. We can convert from the mass of glucose to moles of glucose using the molar mass. In one mole of glucose, we have six moles of carbon atoms, 12 moles of hydrogen atoms, and six moles of oxygen atoms. We can plug in the molar mass of each element from the periodic table, and we'll get the molar mass of glucose, which is 180.156 grams per mole. In our dimensional analysis, we want grams of glucose on the bottom so it cancels our previous units. Then we can convert from moles of glucose to moles of just carbon using the chemical formula: there are six moles of carbon in every mole of glucose. Our last step is to convert from moles of carbon to grams of carbon. From the periodic table, one mole of carbon is 12.01 grams. Completing our calculation, we get 6 grams of carbon in 15 g of glucose.