Energy Changes in Chemical Reactions Quiz

What is the law of conservation of energy?

• Energy can be created but not destroyed
• Energy can be destroyed but not created
• Energy can be neither created nor destroyed
• Energy can be both created and destroyed

In an exothermic reaction, what happens to the temperature of the surroundings?

• It increases
• It decreases
• It remains constant
• It fluctuates randomly

Which of the following is an example of an endothermic reaction?

• Combustion
• Neutralization
• Thermal decomposition
• Rusting

What is the definition of activation energy?

• The total energy released in a reaction
• The minimum energy particles must have to react
• The difference in energy between reactants and products
• The energy needed to break all bonds

In an energy level diagram, where are the reactants typically placed in relation to the products for an exothermic reaction?

• Above the products
• Below the products
• At the same level as the products
• It varies depending on the specific reaction

What does ΔH represent in chemical equations?

• Activation energy
• Reaction rate
• Enthalpy change
• Heat capacity

In bond energy calculations, the energy required to break bonds is considered:

• Positive
• Negative
• Zero
• Variable depending on the bond

Which of the following is true for an endothermic reaction?

• Energy is released to the surroundings
• The products have lower energy than the reactants
• The enthalpy change (ΔH) is positive
• The temperature of the surroundings increases

In the reaction CH₄ + 2O₂ → CO₂ + 2H₂O, how many O=O bonds are broken?

• 1
• 2
• 3
• 4

What is the overall energy change in a reaction equal to?

• Energy to break bonds + Energy to form bonds
• Energy to break bonds - Energy to form bonds
• Energy to form bonds - Energy to break bonds
• Energy to break bonds × Energy to form bonds