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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A reaction is catalyzed by an acid. Is this an example of homogeneous or heterogeneous catalysis?
Describe the difference between positive and negative catalysis.
Describe the effect of a catalyst on the rate of both the forward and reverse reactions in a reversible reaction.
Describe the effect of temperature on the activity of an enzyme catalyst.
Describe the main steps involved in heterogeneous catalysis according to the adsorption theory.
A student adds a catalyst to a reaction mixture and observes that the reaction reaches equilibrium faster. Has the equilibrium constant changed?
A reaction has a rate constant k1 = 2.0 × 10−3 s−1 at 300 K without a catalyst. In the presence of a catalyst, the rate constant increases to k2 = 8.0 × 10−3 s−1 at the same temperature. Calculate the difference in activation energy (ΔEa) between the catalyzed and uncatalyzed reactions. (R = 8.314 J mol−1 K−1)
Consider the following reaction mechanism for the decomposition of ozone:
Step 1: O3 → O2 + O (slow)
Step 2: O3 + O → 2O2 (fast)
A catalyst X is introduced, which reacts with O3 in a new fast step to form an intermediate, lowering the activation energy of the overall reaction. Explain how the presence of catalyst X changes the reaction mechanism and the energy profile diagram.
In the Haber process, which catalyst is used to synthesize ammonia? (1) Iron (2) Platinum (3) Nickel (4) Copper
Which of the following best describes a catalyst? (1) It increases the activation energy of a reaction. (2) It is consumed during the reaction. (3) It provides an alternative reaction pathway with lower activation energy. (4) It changes the equilibrium position of the reaction.
Which of the following is a feature of enzyme catalysis? (1) High specificity (2) High temperature stability (3) Non-selectivity (4) Works only in non-aqueous media
Which of the following is a negative catalyst? (1) Manganese dioxide in H2O2 decomposition (2) Glycerol in the decomposition of H2O2 (3) Iron in Haber process (4) Vanadium(V) oxide in contact process
A catalyst increases the rate of a reaction by _______ the activation energy.
Fill in the blank: In the presence of a catalyst, the activation energy of the forward and reverse reactions is _______.
Fill in the blank: The _______ is the region on an enzyme where the substrate binds and the reaction occurs.
Fill in the blank: The _______ model explains the action of enzymes as catalysts by suggesting that the substrate fits into the active site of the enzyme.
A reaction proceeds faster in the presence of a catalyst. Does this mean the reaction is more exothermic?
A student adds a catalyst to a reaction mixture and observes that the reaction reaches equilibrium faster. Has the equilibrium constant changed?
Does a catalyst get consumed in the overall chemical reaction?
True or False: A catalyst alters the equilibrium constant of a chemical reaction.
