How many atoms are in 2.00 moles of Li?

Question

just need some help, thank you in advance!

Answer 1

Hi, Maria,

I think I can help you with this one. A mole is defined as the number of atoms whose total mass equals the the atomic mass of a given element in grams. It was traditionally defined as the number of carbon atoms in 12.0 grams of C-12, but now it is simply expressed as 6.02214076 X 10²³ "units" of a substance - this could be atoms, molecules, ions, or others. In this case, the question was related to the number of atoms in 2.00 moles of Li (or lithium). The answer is simply 2.00 moles x 6.02214076 X 10²³ atoms/mole so that's 12.04428152 x 10²³ atoms, or using proper scientific notation, 1.204428152 x 10²⁴ atoms.

'Hope that helps!

Chris

P.S. For extra credit, that particular value (6.02214076 X 10²³) is also known as Avogadro's number - you can read a bit more about that here: https://en.wikipedia.org/wiki/Avogadro_constant.