The speed of a gas-phase reaction is expressed as K . CA . CB. If the reaction chamber volume is decreased to l/4th of its original size, the resulting reaction rate relative to the initial rate will be _______________ times?
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Answer: B. 16
Explanation
The rate expression is second-order, depending on the product of reactant concentrations CA and CB. Decreasing the chamber volume to one-fourth quadruples the concentration of each reacting chemical species. Squaring this fourfold concentration increase raises the overall reaction rate by a factor of 16. Concentration is defined as moles of solute divided by the total volume of the fluid mixture. Second-order reaction rates scale quadratically with increases in reactant concentration levels. Gas-phase reactor volumes directly influence partial pressures and reactant concentrations inversely.
Compressing gas-phase reactor chambers significantly accelerates bimolecular reaction rates in industry. Safety analyses must account for dramatic rate increases when gas volumes decrease unexpectedly. Optimizing reactor pressure helps chemical plants maximize conversion rates per unit reactor volume. Option A 4 times increase corresponds to a first-order reaction rate dependence on volume. Option C 8 times increase is mathematically inconsistent with quadratic concentration scaling laws. Option D 2 times increase underestimates the concentration magnification caused by volume reduction.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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