Open Question
The reaction H2(g) + I2(g) ⇌ 2 HI(g) has ∆H = -2.2 kcal/mol (-9.2 kJ/mol). Will the equilibrium concentration of HI increase or decrease whenH2 is removed?
15. Chemical Equilibrium
Le Chatelier's Principle
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The following data was collected for the following reaction at equilibrium
2 A (g) + 3 B (g) ⇌ C (g)
At 25 oC K is 5.2 x 10-4 and at 50 oC K is 1.7 x 10-7. Which of the following statements is true?
a) The reaction is exothermic.
b) The reaction is endothermic.
c) The enthalpy change, ΔH, is equal to zero.
d) Not enough information is given.
A
The reaction is exothermic.
B
The reaction is endothermic.
C
The enthalpy change, ΔH, is equal to zero.
D
Not enough information is given.
Verified step by step guidance1
Identify the given data: The equilibrium constant K at 25°C is 5.2 x 10^-4, and at 50°C, it is 1.7 x 10^-7.
Understand the relationship between temperature and the equilibrium constant: If K decreases with an increase in temperature, the reaction is exothermic. If K increases with an increase in temperature, the reaction is endothermic.
Analyze the change in K: The equilibrium constant decreases from 5.2 x 10^-4 at 25°C to 1.7 x 10^-7 at 50°C, indicating that the reaction favors the reactants more at higher temperatures.
Apply Le Chatelier's Principle: A decrease in K with an increase in temperature suggests that the reaction releases heat, thus shifting the equilibrium towards the reactants to counteract the added heat.
Conclude based on the analysis: Since the equilibrium constant decreases with an increase in temperature, the reaction is exothermic.
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