2C_H. + 702 — 400, + 6H2O How many moles of oxygen (O2) are required to produce
45.8 g of water (H20)?

Balanced Eqn

2

C

2

H

6

+

7

O

2

=

4

C

O

2

+

6

H

2

O

By the Balanced eqn

60g ethane requires 7x32= 224g oxygen

here ethane is in excess.oxygen will be fully consumed

hence

300g oxygen will consume  

60

⋅

300

224

=

80.36

g

ethane

leaving (270-80.36)= 189.64 g ethane.

By the Balanced eqn

60g ethane produces 4x44 g CO2

hence amount of CO2 produced =

4

⋅

44

⋅

80.36

60

=

235.72

g

and its no. of moles will be  

235.72

44

=5.36 where 44 is the molar mass of Carbon dioxide

hope this helps