Chemistry: Moles Problems?

Question

6.0 * 10^23 "things" = 1.0 mole

How many particles are equal to 4 moles?

ANSWER: 2.4 * 10^24

Am I correct or not?

Thanks so much in advance!

If you had one billion pencils, how many moles would this be?

ANSWER: (1.0 * 10^9) / (6.0 * 10^23)

Answer 1

Right - you know how many molecules or formula units are in 1 mole. Multiply avogadros' by 4.

(6.0 x 10^23)(4) = 2.4 x 10^24 This is correct although 6.02 x 10^23 is more accurate. I checked it this way too and both answers were the same.

(1.0 x 10^9)/(6.0 x 10^23) = 1.7 x 10^-15 moles. It would be even better to find the element(s) in the pencils and divide by Avogadros' # to get moles.