Question

you are given a sample containing 0.70 moles of a substance. How many molecules are present in the sample of the substance is benzene C6H6

Answer 1

1 mole benzene -------------- 6.02 x 10²³ molecules
0.70 moles benzene --------- ( molecules benzene )

molecules benzene = 0.70 x ( 6.02 x 10²³ ) / 1

molecules benzene = 4.21 x 10²³ / 1

= 4.21 x 10²³ molecules of benzene

hope this helps!