Catalysis in Chemical Reactions
Chemistry ⇒ Chemical Kinetics and Equilibrium
Catalysis in Chemical Reactions starts at 11 and continues till grade 12.
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Describe the effect of a catalyst on the rate constant (k) of a reaction.
Describe the lock-and-key model of enzyme catalysis.
Describe the role of a catalyst in a chemical reaction in terms of activation energy.
Describe the term 'catalyst selectivity'.
A reaction has an activation energy of 80 kJ/mol. In the presence of a catalyst, the activation energy is reduced to 50 kJ/mol. By what amount has the activation energy decreased?
A reaction proceeds much faster in the presence of a catalyst. Does the catalyst alter the final amount of products formed at equilibrium? (Yes/No)
A certain reaction is catalyzed by a solid metal surface. If the surface becomes covered with product molecules, the reaction rate decreases significantly. Explain this observation in terms of catalysis.
Consider the following reaction mechanism:
Step 1: A + B ⇌ C (fast equilibrium)
Step 2: C + D → E (slow, rate-determining step)
A catalyst X is introduced, which provides an alternative pathway:
Step 1: A + X → AX (fast)
Step 2: AX + B → C + X (fast)
Step 3: C + D → E (slow)
Explain how the presence of catalyst X affects the overall rate law and the reaction mechanism.
A reaction is catalyzed by an acid. What type of catalysis is this? (1) Homogeneous (2) Heterogeneous (3) Autocatalysis (4) Enzyme catalysis
Which of the following best defines a catalyst? (1) A substance that increases the rate of a chemical reaction without itself undergoing permanent chemical change (2) A substance that decreases the rate of a chemical reaction and is consumed in the process (3) A reactant that is used up during the reaction (4) A product formed at the end of the reaction
Which of the following is a characteristic of a good catalyst? (1) High selectivity (2) High cost (3) High toxicity (4) Low surface area
Which of the following is a common catalyst used in the Contact process for the manufacture of sulfuric acid? (1) Iron (2) Vanadium(V) oxide (3) Platinum (4) Nickel
Fill in the blank: Enzymes are __________ catalysts.
Fill in the blank: In the Haber process, the catalyst used is __________.
Fill in the blank: The minimum energy required for a reaction to occur is called the __________ energy.
Fill in the blank: The process by which a catalyst becomes less effective due to the accumulation of reaction products on its surface is called __________.
A catalyst is not consumed in a chemical reaction. (Yes/No)
A reaction proceeds much faster in the presence of a catalyst. Does the catalyst alter the final amount of products formed at equilibrium? (Yes/No)
True or False: A catalyst can increase the yield of products at equilibrium.
True or False: Catalysts are always specific to a particular reaction.
