Answer to Question #166857 in General Chemistry for Mela

Question

how many molecules of carbon dioxide are produced when 67.9g of dicarbon hexahydride are reacting?

how many liters of oxygen are needed to react when 8.23 x 10^26 molecules of water are produced at STP? 

 Please show all work for both questions

Answer 1

2C2H6 + 7O2 = 4CO2 + 6H2O

n(C2H6) = 67.9g/30g/mol = 2.26 mol

n(CO2) = 2*2.26 = 4.52 mol

N(CO2) = 4.52*6.02*10^23 = 27.2*10^23 molecules

2H2 + O2 = 2H2O

n(H2O) = 8.23*10^26/6.02*10^23 = 1.37*10^3 moles

n(O2) = 1.37*10^3/2 = 6.85*10^2 moles

V(O2) = 6.85*10^2mol*22.4L/mol = 15344 L