Which is not true regarding the effects temperature changes have on a system at chemical equilibrium?
a) A temperature increase favours the endothermic reaction.
b) A temperature decrease favours the exothermic reaction.
c) An increase in temperature increases Keq in an endothermic system.
d) An increase in temperature increases Keq in an exothermic system.
e) All of the above are true.
e) All of the above are true.
None of the statements are incorrect regarding the effects of temperature changes on a system at chemical equilibrium.
are you sure?
Apologies for the mistake in my previous response. The correct answer is:
c) An increase in temperature increases Keq in an endothermic system.
In an endothermic reaction, an increase in temperature will shift the equilibrium towards the reactants, since heat is considered a reactant in the reaction. Thus, increasing the temperature will decrease the value of Keq. Therefore, statement c is not true.
What is the correct answer?
The correct answer is:
c) An increase in temperature increases Keq in an endothermic system.
To determine which statement is not true regarding the effects of temperature changes on a system at chemical equilibrium, let's analyze each option:
a) A temperature increase favors the endothermic reaction.
When the temperature is increased, according to Le Chatelier's principle, the equilibrium will shift in the direction that consumes heat. Endothermic reactions absorb heat, so increasing the temperature will favor the endothermic reaction. This statement is true.
b) A temperature decrease favors the exothermic reaction.
Similarly, when the temperature is decreased, the equilibrium will shift in the direction that produces heat. Exothermic reactions release heat, so decreasing the temperature will favor the exothermic reaction. This statement is true.
c) An increase in temperature increases Keq in an endothermic system.
The equilibrium constant, Keq, is a constant value at a given temperature. It does not change with changes in temperature. The concentration of reactants and products can change, but Keq remains constant. Therefore, this statement is not true.
d) An increase in temperature increases Keq in an exothermic system.
Similar to the previous statement, Keq does not change with changes in temperature. Therefore, this statement is also not true.
e) All of the above are true.
Since statements c and d are not true, option e cannot be correct.
Therefore, the correct answer is:
c) An increase in temperature increases Keq in an endothermic system.