1. Give reasons for your choice. 2. Give reasons for rejecting other options
6. In a chemical reaction at constant temperature,
the addition of a catalyst
A increases the value of the equilibrium
constant.
B increases the fraction of molecules with more
than a given kinetic energy.
C decreases the energy released in the
chemical reaction.
D provides an alternative reaction mechanism
with a lower activation energy.
E increases the rate at which the molecules
collide with one another.
A is false. Adding a catalyst increases the rate of reaction but not the equilibrium.
D is true. That's exactly what a catalyst does.
What is your take ton the others.
To determine the correct answer and explain the reasons for choosing it, we can analyze each option and eliminate the incorrect ones:
A) The addition of a catalyst increases the value of the equilibrium constant: This statement is not accurate. A catalyst does not affect the equilibrium constant of a reaction, which depends only on the stoichiometry and temperature.
B) The addition of a catalyst increases the fraction of molecules with more than a given kinetic energy: This statement is also not correct. A catalyst does not change the distribution of kinetic energy among the molecules. It lowers the activation energy required for the reaction to occur, but it does not change the energy distribution.
C) The addition of a catalyst decreases the energy released in the chemical reaction: Again, this statement is incorrect. A catalyst does not affect the energy difference between reactants and products or the energy released in the reaction. It only provides an alternative pathway with a lower activation energy.
D) The addition of a catalyst provides an alternative reaction mechanism with a lower activation energy: This statement is accurate. A catalyst lowers the activation energy required for the reaction to proceed by providing an alternative reaction pathway. This allows more reactant molecules to have sufficient energy to surpass the lower activation energy barrier and participate in the reaction.
E) The addition of a catalyst increases the rate at which the molecules collide with one another: This statement is incorrect. A catalyst does not affect the frequency or rate of molecular collisions. It only increases the rate at which collisions result in a successful reaction by lowering the activation energy barrier.
Based on this analysis, the correct answer is D. The addition of a catalyst provides an alternative reaction mechanism with a lower activation energy.
To eliminate the other options, we consider the role of a catalyst in chemistry - it increases the rate of a reaction by lowering the activation energy, but it does not affect the equilibrium constant, energy released, kinetic energy distribution, or collision rate.