Chemical Reaction Rates and Catalysts

The video tutorial covers chemical reactions, focusing on physical and chemical changes, collision theory, and factors affecting reaction rates such as surface area, concentration, temperature, pressure, and catalysts. It includes examples and experiments to illustrate these concepts, emphasizing the importance of each factor in influencing the speed and outcome of reactions.

What is the main difference between a physical change and a chemical change?

• A physical change creates new substances.

• A chemical change is easily reversible.

• A physical change does not produce new substances.

• A chemical change does not involve energy changes.

According to collision theory, what is necessary for a chemical reaction to occur?

• Reactant particles must be in a liquid state.

• Reactant particles must be at a high temperature.

• Reactant particles must be in a gaseous state.

• Reactant particles must collide with sufficient energy.

How does increasing the surface area of a solid reactant affect the rate of reaction?

• It increases the rate of reaction.

• It has no effect on the rate of reaction.

• It only affects reactions in gaseous states.

• It decreases the rate of reaction.

What happens to the rate of reaction when the concentration of a reactant is increased?

• The rate of reaction remains the same.

• The rate of reaction decreases.

• The rate of reaction becomes unpredictable.

• The rate of reaction increases.

In the experiment with magnesium and hydrochloric acid, what was the effect of using a more concentrated acid?

• The total volume of gas produced decreased.

• The reaction rate increased.

• The reaction rate remained the same.

• The reaction rate decreased.

How does temperature affect the rate of a chemical reaction?

• Increasing temperature increases the rate.

• Increasing temperature has no effect.

• Increasing temperature stops the reaction.

• Increasing temperature decreases the rate.

What is the effect of increasing pressure on the rate of reaction involving gases?

• It increases the rate of reaction.

• It only affects reactions in liquid states.

• It has no effect on the rate of reaction.

• It decreases the rate of reaction.

What role does a catalyst play in a chemical reaction?

• It increases the activation energy required.

• It decreases the rate of reaction.

• It provides an alternative pathway with lower activation energy.

• It is consumed in the reaction.

Which of the following is a common example of a catalyst?

• Calcium carbonate

• Sodium chloride

• Manganese(IV) oxide

• Water

What is a unique feature of biological catalysts or enzymes?

• They work best at high pH levels.

• They are not affected by temperature.

• They are not specific to any reaction.

• They are protein molecules.