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What is the key difference between a catalyzed and uncatalyzed reaction mechanism?
Catalyzed: New pathway with lower activation energy, often multiple steps. | Uncatalyzed: Typically has a high-energy transition state, leading to a slow reaction.
How does the activation energy ($E_a$) differ between catalyzed and uncatalyzed reactions?
Catalyzed: Lower $E_a$ due to an alternate reaction pathway. | Uncatalyzed: Higher $E_a$, requiring more energy for the reaction to proceed.
Compare the number of steps in catalyzed vs. uncatalyzed mechanisms.
Catalyzed: Often involves multiple steps with lower energy barriers. | Uncatalyzed: May involve fewer steps, but with a higher energy barrier.
What is a catalyst?
A substance that speeds up a chemical reaction without being consumed, by providing an alternate reaction pathway with a lower activation energy. It is consumed in one step and then regenerated in a later step.
What is activation energy ($E_a$)?
The minimum energy required for a reaction to occur.
What is the role of a catalyst regarding activation energy?
Catalysts lower the activation energy ($E_a$) of a reaction.
What is the role of a catalyst regarding enthalpy (ฮH)?
Catalysts do not change the enthalpy (ฮH) of a reaction.
How are catalysts represented in chemical equations?
Catalysts are written above the reaction arrow in chemical equations, not as reactants or products.
What is the effect of a catalyst on the rate of a reaction?
It speeds up the reaction.
What is the effect of lowering the activation energy ($E_a$)?
More molecules have enough energy to react, thus speeding up the reaction.
What is the effect of a catalyst on the equilibrium of a reaction?
It affects the rate at which equilibrium is reached, but does not change the position of the equilibrium.
What is the effect of a catalyst binding to reactants?
It orients them more favorably for a reaction or lowers the activation energy.
What is the effect of $V_2O_5$ on the reaction $2SO_2(g) + O_2(g)
ightleftharpoons 2SO_3(g)$?
It acts as a catalyst, providing an alternate pathway and lowering the activation energy, thus speeding up the reaction.