객관식
Consider the reaction A(aq) ⇌ B(aq) in an equilibrium state where KC < 1. The rate of the reaction A(aq) → B(aq) at equilibrium is 59.9 mol/s. What is the rate of the reaction B(aq) → A(aq) at equilibrium?
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16. Chemical Equilibrium
Intro to Chemical Equilibrium
Multiple Choice
Gaseous hydrogen bromide decomposes at elevated temperatures according to the following equation: 2 HBr(g) ⇌ H2(g) + Br2(g). At a certain temperature, a 2.00 L flask is initially filled only with 0.600 mol of HBr. If the equilibrium concentration of H2 is 0.100 M, what is the value of Kc at that temperature?
A
0.050
B
0.100
C
0.025
D
0.200
검증된 단계별 안내1
Start by writing the balanced chemical equation for the decomposition of hydrogen bromide: 2 HBr(g) ⇌ H2(g) + Br2(g).
Identify the initial concentrations. Initially, the flask contains 0.600 mol of HBr in a 2.00 L flask, so the initial concentration of HBr is 0.600 mol / 2.00 L = 0.300 M. The initial concentrations of H2 and Br2 are both 0 M.
Determine the change in concentration at equilibrium. Since the equilibrium concentration of H2 is given as 0.100 M, and the stoichiometry of the reaction shows that 1 mol of H2 is produced for every 2 mol of HBr decomposed, the change in concentration of HBr is 2 times the change in H2, which is 0.200 M.
Calculate the equilibrium concentrations. The equilibrium concentration of HBr is the initial concentration minus the change: 0.300 M - 0.200 M = 0.100 M. The equilibrium concentration of Br2 is the same as H2, which is 0.100 M.
Use the equilibrium concentrations to calculate the equilibrium constant Kc. The expression for Kc is: Kc = ([H2][Br2]) / ([HBr]^2). Substitute the equilibrium concentrations into this expression to find the value of Kc.
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