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For the elementary gas-phase reaction A(g) + 2B(g) → C(g) + D(g), an experiment starts with initial partial pressures p_A = 0.60 atm and p_B = 0.80 atm. If the partial pressure of C becomes 0.20 atm, then the reaction rate compared with the initial rate is
- 1/6
- 1/12
- 1/36
- 1/18
Correct answer: 1/6
Solution
The reaction rate is determined by the change in concentration of the reactants over time. Since the formation of C at 0.20 atm indicates that 0.20 atm of A and 0.40 atm of B have reacted, the initial rate can be calculated based on the initial pressures, leading to a final rate that is 1/6 of the initial rate.
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