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Propane is burned completely with excess oxygen. The product gas contains 24.5 mole%
Chapter 4, Problem 4.90(choose chapter or problem)
Propane is burned completely with excess oxygen. The product gas contains \(24.5 \text { mole } \% \mathrm{CO}_{2}, 6.10 \%\) \(\mathrm{CO}, 40.8 \% \mathrm{H}_{2} \mathrm{O} \text {, and } 28.6 \% \mathrm{O}_{2} \text {. }\)
(a) Calculate the percentage excess \(\mathrm{O}_{2}\) fed to the furnace.
(b) A student wrote the stoichiometric equation of the combustion of propane to form \(\mathrm{CO}_{2}\) and CO as
\(2 \mathrm{C}_{3} \mathrm{H}_{8}+\frac{17}{2} \mathrm{O}_{2} \longrightarrow 3 \mathrm{CO}_{2}+3 \mathrm{CO}+8 \mathrm{H}_{2} \mathrm{O}\)
According to this equation, \(\mathrm{CO}_{2}\) and CO should be in a ratio of 1/1 in the reaction products, but in the product gas of Part (a) they are in a ratio of 24.8/6.12. Is that result possible? (Hint: Yes.) Explain how.
Questions & Answers
QUESTION:
Propane is burned completely with excess oxygen. The product gas contains \(24.5 \text { mole } \% \mathrm{CO}_{2}, 6.10 \%\) \(\mathrm{CO}, 40.8 \% \mathrm{H}_{2} \mathrm{O} \text {, and } 28.6 \% \mathrm{O}_{2} \text {. }\)
(a) Calculate the percentage excess \(\mathrm{O}_{2}\) fed to the furnace.
(b) A student wrote the stoichiometric equation of the combustion of propane to form \(\mathrm{CO}_{2}\) and CO as
\(2 \mathrm{C}_{3} \mathrm{H}_{8}+\frac{17}{2} \mathrm{O}_{2} \longrightarrow 3 \mathrm{CO}_{2}+3 \mathrm{CO}+8 \mathrm{H}_{2} \mathrm{O}\)
According to this equation, \(\mathrm{CO}_{2}\) and CO should be in a ratio of 1/1 in the reaction products, but in the product gas of Part (a) they are in a ratio of 24.8/6.12. Is that result possible? (Hint: Yes.) Explain how.
ANSWER:Step 1 of 3
Combustion reaction
Compounds containing carbon and hydrogen are called hydrocarbons. These compounds can be burned in oxygen to form carbon dioxide and heat. Therefore, they are called fuels. The reaction of hydrocarbons with oxygen is called combustion, and the two types of combustion are complete combustion and incomplete combustion.
When hydrocarbons are burned in excess oxygen, the products formed are carbon dioxide, water vapour, and heat. This reaction is called complete combustion. Complete combustion of fuel causes maximum energy release and is the cleanest combustion because soot is not formed.
Incomplete combustion of hydrocarbons occurs in a limited supply of oxygen. The possible products are carbon monoxide or soot (carbon) instead of carbon dioxide, depending on the amount of oxygen present. These reactions produce less energy, and incomplete combustion products are highly toxic.