1. 1 mole of anything contains 6.022x10^23 pieces
d
2. a
3. c, number
5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms
6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br
molar mass = grams / number of moles = g/mole
to find moles = g / molar mass
to find mass = g = molar mass / moles