How many molecules of CO2 can be formed from 139.1g of C2H6

Question

the equation for this question is 

 

C2H6+ O2 —> H2O + CO2 

which when balanced i believe is 

2C2H6 + 7O2 —> 6H2O + 4CO2

Answer 1

139.1 g C2H6 x 1 mole/30 g = 4.637 moles

4.637 moles C2H6 x 4 mol CO2/2 mol C2H6 x 6.02x1023 molecules CO2/mol CO2 = 5.583x1024 molecules CO2