Energy Changes in Chemical Reactions

The video tutorial explains energy level diagrams, focusing on exothermic and endothermic reactions. It covers how to identify and calculate activation energy and delta H, providing practical examples to illustrate these concepts. The tutorial emphasizes the importance of correctly labeling diagrams to avoid losing marks.

What is the primary purpose of an energy level diagram?

• To show the speed of a reaction

• To determine the color of the products

• To illustrate the energy changes during a reaction

• To calculate the mass of reactants

In an exothermic reaction, how does the energy level of the products compare to the reactants?

• Higher than the reactants

• Unrelated to the reactants

• Equal to the reactants

• Lower than the reactants

What does a negative delta H indicate in an exothermic reaction?

• Energy is constant

• Energy is released

• Energy is absorbed

• No energy change

In an endothermic reaction, what happens to the energy level of the products compared to the reactants?

• It fluctuates

• It increases

• It decreases

• It remains the same

What does a positive delta H signify in an endothermic reaction?

• Energy is constant

• No energy change

• Energy is released

• Energy is absorbed

How is activation energy represented in an energy level diagram?

• As a horizontal line

• As the base of the curve

• As a vertical line

• As the peak of the curve

If the activation energy is 800 kJ/mol and the initial energy is 200 kJ/mol, what is the final energy?

• 200 kJ/mol

• 600 kJ/mol

• 800 kJ/mol

• 1000 kJ/mol

What is the formula to calculate delta H in a reaction?

• Initial energy - Final energy

• Activation energy - Final energy

• Initial energy + Activation energy

• Final energy - Initial energy

What is the significance of the hill in an energy level diagram?

• It represents the speed of the reaction

• It indicates the color change

• It shows the activation energy required

• It marks the end of the reaction

Why is it important to label the axes in an energy level diagram?

• To clarify the energy changes

• To indicate the time taken

• To show the direction of the reaction

• To mark the temperature