Question

C₂H₆(g) + O₂(g) --> CO₂(g) + H₂O(g)

(a) Consider the unbalanced equation above. How many grams of O₂ are required to react with 15.0 g of C₂H₆? Use at least as many significant figures in your molar masses as in the data given
g O₂

(b) What mass of CO₂ is produced?
g CO₂

(c) What mass of H₂O is produced?
g H₂O

Answer 1

Molar mass of C2H6,

MM = 2*MM(C) + 6*MM(H)

= 2*12.01 + 6*1.008

= 30.068 g/mol

mass(C2H6)= 15.0 g

number of mol of C2H6,

n = mass of C2H6/molar mass of C2H6

=(15.0 g)/(30.068 g/mol)

= 0.4989 mol

Balanced chemical equation is:

2 C2H6 + 7 O2 ---> 4 CO2 + 6 H2O

a)

mol of O2 required = (7/2)*moles of C2H6

= (7/2)*).4989 mol

= 1.746 mol

molar mass of O2 = 32 g/mol

mass of O2 = number of mol * molar mass

= 1.746 mol * 32 g/mol

= 55.9 g

Answer: 55.9 g

b)

Molar mass of CO2,

MM = 1*MM(C) + 2*MM(O)

= 1*12.01 + 2*16.0

= 44.01 g/mol

According to balanced equation

mol of CO2 formed = (4/2)* moles of C2H6

= (4/2)*0.498869

= 0.997738 mol

mass of CO2 = number of mol * molar mass

= 0.9977*44.01

= 43.9 g

Answer: 43.9 g

c)

According to balanced equation

mol of H2O formed = (4/2)* moles of C2H6

= (4/2)*0.498869

= 0.997738 mol

mass of H2O = number of mol * molar mass

= 0.9977*18.02

= 18.0 g

Answer: 18.0 g