Question

In 3.45 mg of boron there are how many of the following?
grams of boron?
moles of boron?
boron atoms?

Answer 1

\[3.45mg \times \frac{1g}{1000mg}=0.00345g\]This is basic dimensional anaysis. You will have better luck on the chemistry site for the other two questions, I think.

Answer 2

moles of boron = .00345/relative atomic mass of boron in grams
for the third part you need to use the number of atoms in 1 mole of born which is
Avogadros Number whose value i cant recall

Answer 3

Moles = Mass(g)/MW
Moles = 0.003.45/10.811
Moles = 0.32

There are 0.00032 moles of Boron in 3.45mg or 0.00345g.

Answer 4

6.02x10 to 23rd power

Answer 5

thanks all of you so much!!!

Answer 6

yw