Catalysts and Energy Diagrams

The video tutorial explains exothermic reactions, focusing on their potential energy diagrams. It describes how energy is released, resulting in a negative Delta H, and how the diagram appears downhill. The tutorial also covers the components of the diagram, including reactants, products, and the activated complex. It explains activation energy for both forward and reverse reactions and discusses the role of catalysts in lowering activation energy without affecting the overall enthalpy change.

What does the term 'exothermic' imply about a reaction?

• Heat is constant.

• Heat is absorbed.

• Heat is released.

• No heat change occurs.

In an exothermic reaction, what is the sign of Delta H?

• Positive

• Zero

• Negative

• Undefined

How does the potential energy diagram of an exothermic reaction appear?

• Downhill

• Uphill

• Circular

• Flat

What does the highest point on a potential energy diagram represent?

• Catalyst

• Activated Complex

• Products

• Reactants

Which line on the diagram represents the potential energy of the reactants?

• No line

• Top line

• Middle line

• Bottom line

What happens to the activation energy when a catalyst is added?

• It becomes zero.

• It increases.

• It decreases.

• It remains the same.

Does adding a catalyst change the starting and ending points of a reaction?

• No, neither changes.

• Only the ending point changes.

• Only the starting point changes.

• Yes, both change.

How does a catalyst affect the overall heat of reaction (Delta H)?

• It makes Delta H zero.

• It increases Delta H.

• It decreases Delta H.

• It does not affect Delta H.

What is one benefit of using a catalyst in a reaction?

• It increases the reaction time.

• It lowers the activation energy.

• It raises the temperature.

• It changes the reactants.

Which of the following is NOT affected by the addition of a catalyst?

• Delta H

• Reaction rate

• Reaction pathway

• Activation energy