Chemistry question on mass

Question

How to figure out the mass of 1.92 x 10^23 atoms of helium? Can’t figure out how to place this problem to work it out.

Answer 1

hi there! this is a 2 part conversion question. you will need the atomic mass of Helium and Avogadro's number. so first thing we want to do it convert from atoms to moles, to do this we divide by Avogadro's number.

1.92 x 10^23 atoms He/6.02x10^23 atoms He=0.319 mol He

now that we have moles, we can convert to grams using the atomic mass which we can find on the periodic table (4.003 amu). if this was a compound instead of an element, you would use the molar mass where you add up the atomic masses. to convert to grams you have to multiply the moles.

0.319 mol He x 4.003 g He= 1.277 g He

hope this helps!