help please, chem question!?

Question

if 18.0 L at STP of ethane gas C2H6 reacts with an excess of oxygen gas, how many liters of CO2 (carbon dioxide) are produced at STP?

A 36.0L

B 18.0L

C 9.00 L

D 1.24 L

thanks :DD

Answer 1

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C2H6 + 7/2 O2 ----> 2 CO2 + 3 H2O

1 mole C2H6 ---> 2 moles CO2..right?

but since this is a gas..and P and T is constant...

PV = nRT

n = V x (P/RT) = constant x V...

in other words.. we can read the coefficients of the balanced equation as

1 mole C2H6 ---> 2 moles CO2..right

and

1 liter C2H6 ---> 2 liter CO2

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18.0 L C2H6 x (2 L CO2 / 1 L C2H6) = 36.0 L CO2

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