The heat developed by the combustion of 1m3 of ethane (c2h6, taken at 25 degrees and 1 atm) is used to decompose calcium carbonate to calcium oxide and carbon dioxide. Calculate the mass of calcium oxide that is obtained. H°f CO2 = - 393.5
H°f H2O = - 285.8
H°f CaCO3 = - 1206
H°f CaO = -635
H°f C2H6 = - 83.8

Answer
a) 6.04 kg
b) 20.12 kg
c) 18.86 kg
d) 10.57 kg
e) 14.56 kg

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o