 Okay guys, let's try this problem and make it a little harder. How many grams does 1.73 moles of boron weigh? So we know again from the periodic table that the mass of 1 boron atom is 10.811 anu. And we also know that we can approximate 1 mole of boron to equal 10.811 grams. So we just use this conversion factor to figure out this problem. So 1.73 moles per boron, multiplied by the conversion factor, 10.811 grams, divided by 1 mole, and then just multiply 1.73 times 10.811 that equals 18.7 grams. Good job guys.