Question

Ethane, C2H6, burns in oxygen. 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) What mass of O2, in grams, is required for complete combustion of 23.8 g of ethane? What is the total mass of products expected from the combustion of 23.8 g of ethane?

=_________g O2

Total mass of products = _______g

Answer 1

1)

Molar mass of C2H6,

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

= 2*12.01 + 6*1.008

= 30.068 g/mol

mass of C2H6 = 23.8 g

molar mass of C2H6 = 30.068 g/mol

mol of C2H6 = (mass)/(molar mass)

= 23.8/30.068

= 0.7915 mol

Balanced chemical equation is:

2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g)

According to balanced equation

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

= (7/2)*0.7915

= 2.7704 mol

mass of O2 = number of mol * molar mass

= 2.7704*32

= 88.7 g

Answer: 88.7 g O2

2)

use conservation of mass:

total mass of products = total mass of reactants

= 23.8 + 88.7

= 112.5 g

Answer: 112.5 g