Chemical Reaction Mechanisms and Kinetics

Mr. Anderson explains elementary reactions, focusing on collision theory and reaction mechanisms. He discusses unimolecular, bimolecular, and termolecular reactions, emphasizing the importance of energy and orientation in collisions. The video also covers rate laws and the predictability of reaction mechanisms, using examples like radioactive decay to illustrate concepts.

What is necessary for a reaction to occur between two colliding molecules?

• They must be at a high temperature.

• They must be in a liquid state.

• They must have enough energy and correct orientation.

• They must be of the same type.

What is the main focus when studying elementary reactions?

• The pressure of the system

• The temperature of the reaction

• The collision of molecules

• The color of the reactants

Which of the following is an example of a unimolecular reaction?

• Photosynthesis

• Formation of water from hydrogen and oxygen

• Radioactive decay of carbon-14

• Combustion of methane

In a unimolecular reaction, what is the order of the reaction?

• Zero order

• First order

• Second order

• Third order

What is the rate law for a bimolecular reaction involving two different reactants?

• K times the square of the concentration of one reactant

• K times the concentration of both reactants

• K times the concentration of one reactant

• K times the sum of the concentrations of both reactants

What happens to the rate of a bimolecular reaction as the concentration of reactants increases?

• It increases

• It remains constant

• It decreases

• It becomes unpredictable

Why are termolecular reactions considered rare?

• They require three molecules to collide simultaneously with enough energy and correct orientation.

• They involve complex molecules.

• They require a catalyst to proceed.

• They only occur at very high temperatures.

What is a key characteristic of termolecular reactions?

• They are very fast.

• They are very common.

• They are very rare.

• They require a catalyst.

What does stoichiometry help predict in a chemical reaction?

• The energy released

• The color change during the reaction

• The amount of products formed

• The speed of the reaction

Why can't the rate law of a reaction be predicted just by looking at the balanced equation?

• Because it depends on the temperature.

• Because it depends on the color of the reactants.

• Because it depends on the pressure.

• Because it depends on the reaction mechanism.