Afuel gas containing 74.0% methane, 12.0% ethane, and 14.0% propane by volume flows to a furnace at a rate of 1450 m3/h at 25.0°c and 210.0 kpa (gauge), where it is burned with 16.0% excess air. calculate the required flow rate of air in scmh (standard cubic meters per hour). you may take the composition of air to be 21.0 mol% o2 and the balance n2.

V=4373.2m³/hr

Explanation:

To calculate volumetric flow rate of the gases

Methane = (74/100)×1450 = 1073m³/hr

Ethane = (12/100)×1450 = 174m³/hr

Propane = (14/100)×1450 = 203m³/hr

Stichiometric equation for gas to complete combustion

CH4 + 2 O2 = CO2 +2 H2O

1m³/hr CH4 requires 2m³/hr O2

1073m³/hr CH4 requires (2×1073)m³/hr O2

1073m³/hr CH4 requires 2146m³/hr O2

C2H6 + 7/2 O2 = 2 CO2 + 3H2O

1m³/hr C2H6 requires 7/2m³/hr O2

174m³/hr C2H6 requires (174×7/2)m³/hr O2

174m³/hr C2H6 requires 609m³/hr O2

C3H8 + 5 O2 = 3 CO2 + 4 H2O

1m³/hr C3H8 requires 5m³/hr O2

203m³/hr C3H8 requires (203×5)m³/hr O2

203m³/hr C3H8 requires 1015m³/hr O2

Total O2 required = 2146+609+1015

Total O2 required = 3770m³/hr

Excess air = 16% × 3770 = 603.2m³/hr

Total flow rate of air = 3770 + 603.2 = 4373.2m³/hr

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