How many moles are in 97.2 grams of boron?

Answer 1

To do this, you need to know the atomic weight of the element you're dealing with, found on any Periodic Table. The atomic weight is the mass in grams of the element in one mole - this will provide you with a conversion factor. So take the measurement in grams and divide it by the atomic weight to convert to moles. Really what you're doing is multiplying the number by 1 mole, and dividing it by the equivalent of one mole, the atomic weight. That's the thought process behind unit analysis and how you get your "units to cancel".
In this case, the answer is about 8.99 moles B.

Answer 2

To find the number of moles in 97.2 grams of boron, you need to divide the mass given by the molar mass of boron. The molar mass of boron is approximately 10.81 g/mol. Therefore, 97.2 grams of boron is equal to 97.2/10.81 ≈ 8.98 moles.