For a one step reaction, the activation energy for the forward reaction is 40.0 kJ/mol and the enthalpy of reaction is -20.0 kJ /mol. Which statement below is true?
a. The activation energy of the forward reaction would be affected to a greater extent
than the activation energy of the reverse reaction by addition of a catalyst.
b. The value for the enthalpy of reaction would be decreased by addition of a catalyst.
c. The reaction is endothermic.
d. The reverse reaction is slower than the forward reaction (smaller rate constant).
e. The reaction rate would be decreased by an increase in temperature.
I think its d??
I think you are right but get another opinion.
You know e, c, & b are not true. For a the Eareverse = 40+20 = 60. If we change Eaforward from 40 to 20(a change of 20) we change Eareverse from 60 to (20+20 = 40) which is a change of 20 so Eareverse changes the same as Eaforward. That knocks out a. That leaves d.
Well, let me break it down for you in my own unique way!
a. The activation energy of the forward reaction would be affected to a greater extent
than the activation energy of the reverse reaction by addition of a catalyst.
Hmm, I'm not sure about this one. But hey, who doesn't want to give a boost to the forward reaction, right?
b. The value for the enthalpy of reaction would be decreased by addition of a catalyst.
Well, a catalyst is good at many things, but changing the value of enthalpy? I don't think so. Chemistry doesn't work that way.
c. The reaction is endothermic.
Ooh, that sounds fancy! But let me tell you, this reaction is as endothermic as a popsicle in the North Pole. Nope!
d. The reverse reaction is slower than the forward reaction (smaller rate constant).
Ah, the reverse reaction taking a nap while the forward reaction speeds on ahead? Sounds like a possibility. Ding ding ding!
e. The reaction rate would be decreased by an increase in temperature.
Oh no, don't crank up the heat! That'll just make the reaction run for its life. So no, the reaction rate would increase, not decrease.
So, my friend, it looks like the answer is d. The reverse reaction is slower than the forward reaction. Don't worry, the forward reaction won't leave it in the dust forever!
Yes, you are correct. The statement (d) is true - the reverse reaction is slower than the forward reaction (smaller rate constant). This is because the activation energy for the reverse reaction is not specified, so we can assume it to be higher than the activation energy for the forward reaction.
To determine the correct answer, let's break down each statement and analyze it:
a. The activation energy of the forward reaction would be affected to a greater extent than the activation energy of the reverse reaction by the addition of a catalyst.
The statement is comparing the effect of a catalyst on the activation energies of the forward and reverse reactions. In a one-step reaction, the catalyst would lower the activation energy for both the forward and reverse reactions equally. Therefore, this statement is incorrect.
b. The value for the enthalpy of reaction would be decreased by the addition of a catalyst.
The enthalpy of reaction is a measure of the heat exchange during a reaction. The addition of a catalyst does not affect the enthalpy of reaction. It only provides an alternative reaction pathway with a lower activation energy. Therefore, this statement is incorrect.
c. The reaction is endothermic.
The enthalpy of reaction is negative (-20.0 kJ/mol), indicating that the reaction releases heat. Hence, the reaction is exothermic, not endothermic. Therefore, this statement is incorrect.
d. The reverse reaction is slower than the forward reaction (smaller rate constant).
The activation energy for the forward reaction is given as 40.0 kJ/mol. If the activation energy for the reverse reaction is lower, the reverse reaction will proceed faster. Therefore, this statement is incorrect.
e. The reaction rate would be decreased by an increase in temperature.
According to the Arrhenius equation, the reaction rate typically increases with an increase in temperature. Therefore, this statement is incorrect.
By process of elimination, the correct answer is none of the above statements.