Effecting Reaction Rates

 1) Which of the following is/are true concerning catalysts?

     (a) An enzyme is a catalyst.

     (b) The active site of an enzyme is specific and only binds certain substrates.

     (c) Catalysts increase the rate of a reaction by altering the mechanism thereby increasing the activation energy.

 2) Which of the following changes would not affect the rate of the reaction of cisplatin with water?

Pt(NH₃)₂Cl₂(aq) + H₂O(l) [Pt(NH₃)₂(H₂O)Cl]⁺(aq) + Cl^-(aq)

     (a) Adding a catalyst to the reaction system.

     (b) Using 100 mL of cisplatin and 100 mL of water for the reaction instead of 50 mL of each.

     (c) Using 1.0 M cisplatin in the reaction instead of 0.25 M cisplatin.

     (d) Performing the reaction at 50°C instead of 25°C.

 3) Which of the following is/are true concerning catalysts?

     (a) Most enzymes are highly specific catalysts, so they only act on one or two substrates.

     (b) The active site of an enzyme forms covalent bonds to the substrate.

     (c) When the reacton, 2SO₂(g) + O₂(g) 2SO₃(g), takes place in the presence of NO(g), the rate is increased. This system involves a homogeneous catalyst.

  4) Which of the following changes would not affect the rate of the combustion of coal (carbon)?

     (a) Performing the reaction at 1500°C instead of 29°C.

     (b) Using powdered coal instead of large chunks.

     (c) Using 10 grams of coal instead of 100.

     (d) Using carbon in the form of graphite instead of coal.

 5) Which of the following is/are true concerning catalysts?

     (a) An enzyme-catalyzed reaction is a one step reaction.

     (b) Enzymes are specific because their active site has a specific shape and the active site has specific groups that only participate in certain types of noncovalent interactions.

     (c) Industrial uses of catalysts include emission controls in both cars and power plants.

 6) Which of the following changes would not affect the rate of the reaction of phosphorus with oxygen?

P₄(s) + 5O₂(g) P₄H₁₀(s)

     (a) Using red phosphorus instead of white phosphorus.

     (b) Using 50 g of P₄ instead of 25 g.

     (c) Performing the reaction at 75°C instead of 25°C.

     (d) Adding a catalyst to the reaction.

  7) Which of the following is/are false concerning catalysts?

     (a) When a substrate and enzyme bind, the shape of the active site, the shape of the substrate, or the shape of both may change.

     (b) An inhibitor can bind to an enzyme and prevent it from binding with the substrate.

     (c) When the following reaction, N₂(g) + 3H₂(g) 2NH₃(g) takes place in the presence of solid iron, the iron remains unchanged, but the reaction is faster than without the iron. The iron is a homogeneous catalyst.

  8) Which of the following changes would not affect the rate of the decomposition of calcium carbonate?

CaCO₃ (s) CaO(s) + CO₂(g)

     (a) Using powdered calcium carbonate instead of large chunks.

     (b) Adding a catalyst to the reaction.

     (c) Using 100 grams of calcium carbonate instead of 500 grams.

     (d) Performing the reaction at 350°C instead of 25°C.

 9) Which of the following is/are false concerning catalysts?

     (a) There is a maximum rate for an enzyme-catalyzed reaction.

     (b) The active site is the part of the substrate that interacts with the enzyme.

     (c) Heterogeneous catalysts are often used in industry because they are easily separated from the products.

10) Which of the following changes would not affect the rate of the reaction of cisplatin with water?

Pt(NH₃)₂Cl₂(aq) + H₂O(l) [Pt(NH₃)₂(H₂O)Cl]⁺(aq) + Cl^-(aq)

     (a) Using a 500 mL Erlenmeyer flask for the reaction instead of a 250 mL Erlenmeyer flask.

     (b) Using 0.20 M cisplatin in the reaction instead of 0.10 M cisplatin.

     (c) Performing the reaction at 100°C instead of at 25°C.

     (d) Adding a catalyst to the reaction system.