Question

When 27.7 g of acetylene reacts with hydrogen, 25.0 g of ethane is produced. What is the percent yield of C2H6 for the reaction?
C₂H₂(g)+2H₂(g)→C₂H₆(g)

Answer 1

Molar mass of C2H2,
MM = 2*MM(C) + 2*MM(H)
= 2*12.01 + 2*1.008
= 26.036 g/mol

mass of C2H2 = 27.7 g
mol of C2H2 = (mass)/(molar mass)
= 27.7/26.04
= 1.064 mol


Balanced chemical equation is:
C2H2(g)+2H2(g)→C2H6(g)


According to balanced equation
mol of C2H6 formed = moles of C2H2
= 1.064 mol


Molar mass of C2H6,
MM = 2*MM(C) + 6*MM(H)
= 2*12.01 + 6*1.008
= 30.068 g/mol


mass of C2H6 = number of mol * molar mass
= 1.064*30.07
= 31.99 g

% yield = actual mass*100/theoretical mass
= 25*100/31.99
= 78.15 %
Answer: 78.2 %