Which option yields the maximum heat of combustion?
Show answer Hide answer
Answer: D. C2H6
Explanation
Ethane has a longer carbon chain with more carbon and hydrogen bonds than methane or hydrogen. Additional chemical bonds in ethane release the maximum heat of combustion per mole when oxidized. Larger hydrocarbon molecules store more chemical bond energy, increasing total combustion heat release. Heat of combustion measures the total energy released when a specific amount of fuel is burned. Ethane is a saturated paraffin hydrocarbon gas found naturally in association with petroleum deposits. Molecular structure dictates the amount of oxygen required and heat liberated during oxidation.
Petrochemical industries utilize ethane as a primary feedstock for producing ethylene and plastics. Fuel gas heating values scale directly with the carbon and hydrogen content of constituent molecules. Combustion calculations rely on accurate heats of combustion for designing efficient heating equipment. Hydrogen has a lower heat of combustion per mole because it contains only two atoms per molecule. Carbon monoxide has a single carbon-oxygen bond, yielding much less heat of combustion than ethane. Methane contains fewer carbon-hydrogen bonds than ethane, resulting in a lower molar combustion heat.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Which fuel possesses the maximum gross calorific value?
Show answer Hide answer
Answer: D. Oil refinery gas
Oil refinery gases contain light hydrocarbons that provide very high gross calorific values. Refinery off-gases feature concentrated hydrocarbon fractions yielding superior combustion heat outputs. High proportions of sa...
Q2. Which substance exhibits the highest flame propagation velocity?
Show answer Hide answer
Answer: A. H2
Hydrogen has a very low molecular weight and high thermal diffusivity, giving it fast flame speed. Rapid molecular mobility allows hydrogen-air mixtures to propagate combustion flames extremely quickly. Low density and h...
Q3. Identify the fuel gas that is denser than air ?
Show answer Hide answer
Answer: A. Blast furnace gas
Blast furnace gas contains a high proportion of heavy carbon dioxide and nitrogen, making it dense. Triatomic and diatomic heavy molecules increase the molecular weight above the average weight of air. Density calculatio...
Q4. Which parameter evaluates the binding/agglutinating characteristics of coal?
Show answer Hide answer
Answer: B. Caking index
The caking index is a standard laboratory parameter used to evaluate binding and agglutinating coal traits. Determining the caking index reveals how well softened coal binds inert material during heating. Standardized ca...
Q5. Which fuel reaches the highest calorific value?
Show answer Hide answer
Answer: C. Anthracite
Anthracite has the highest carbon content and lowest volatile matter among all coal types. High fixed carbon concentration in anthracite maximizes the thermal energy released during combustion. Advanced geological metamo...
Q6. Identify which of the following constitutes a rich fuel gas?
Show answer Hide answer
Answer: C. Refinery gases
Refinery gases are rich in low-molecular-weight hydrocarbons like propane and butane, classifying them as rich. High concentrations of saturated hydrocarbon gases give refinery off-gases superior heating values. Rich fue...