I'm stumped on two chemistry questions:



1) Determine the mass of 1.00 * 10^23 molecules of ethane (30 g/mol)

a) 6.04 * 10^46 grams

b) 5 grams

c) 3.01 * 10^24 grams

d) 2.01 * 10^45 grams





2) How many molecules of ethane (30 g/mol) are in 60 grams of the substance?

a) 3.61 * 10^25 molecules

b) 2.989 * 10^-21 molecules

c) 1800 molecules

d) 1.20 * 10^24 molecules





Can someone explain how these problems are done and give the correct answer? Thanks a lot :)