The internal energy possessed by combustion products is ____________________ relative to that of the reactants?
Show answer Hide answer
Answer: B. Less
Explanation
Exothermic combustion reactions release substantial thermal energy to the surrounding environment during chemical conversion. Energy conservation dictates that the total internal energy plus released heat must remain constant overall. Products possess lower internal energy because chemical bond energy converted into sensible heat escaped. Internal energy is a thermodynamic state function representing the microscopic energy stored within a system. Exothermic reactions have a negative enthalpy of reaction at constant pressure and temperature conditions. Combustion transforms high energy chemical bonds of reactants into lower energy stable combustion products.
Power plant boiler design requires accurate enthalpy balances to calculate steam generation rates correctly. Thermodynamic modeling helps engineers predict flame stability and exhaust gas heat recovery potentials. Understanding energy states ensures safe operation of high pressure combustion reaction pressure vessels. Option more incorrectly assumes combustion absorbs energy rather than releasing it to surroundings. Option equal violates the fundamental thermodynamic principle of exothermic chemical energy release. Option depends on state incorrectly suggests exothermic reactions could somehow increase internal energy levels.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Natural gas heating value is primarily driven by the presence of __________________?
Show answer Hide answer
Answer: D. CH4
Natural gas consists predominantly of methane which possesses a high standard specific heat of combustion. Higher concentrations of methane directly elevate the gross calorific value of any standard fuel gas. Other minor...
Q2. Peak adiabatic flame temperatures occur when fuels burn accompanied by ______________________?
Show answer Hide answer
Answer: D. Theoretically required amount of oxygen
Using pure oxygen at stoichiometric proportions removes all inert nitrogen which otherwise absorbs thermal energy. The theoretical amount ensures complete fuel oxidation without excess gas carrying away valuable sensible...
Q3. Forced draft holds the primary advantage over natural draft in that____________________?
Show answer Hide answer
Answer: D. All A., B. & C.
Mechanical fans in forced draft systems provide precise pressure control independent of atmospheric weather conditions. Higher gas velocities achieved through mechanical fans allow much smaller chimney heights for disper...
Q4. High temperature carbonization of coal primarily yields__________________?
Show answer Hide answer
Answer: A. Coke
High temperature carbonization drives off all volatile gases, leaving behind a fused carbon residue. This solid carbon residue forms a strong, porous cellular structure known commercially as metallurgical coke. Process p...
Q5. Flue gas analysis using an Orsat apparatus absorbs components in the respective sequence of_______________________?
Show answer Hide answer
Answer: A. CO2, O2, CO
Potassium hydroxide solution selectively absorbs carbon dioxide gas in the first analytical absorption pipette. Pyrogallol solution absorbs molecular oxygen gas during the second stage of the chemical analysis. Cuprous c...
Q6. The ratio comparing peak adiabatic flame temperatures in air versus pure oxygen is always___________________?
Show answer Hide answer
Answer: B. < 1
Nitrogen in atmospheric air absorbs a large fraction of the chemical energy released during combustion. Pure oxygen combustion lacks this inert diluent gas, resulting in vastly superior peak flame temperatures. Dividing...