Energy Changes in Chemical Reactions Quiz

What is the primary difference between exothermic and endothermic reactions?

• Exothermic reactions absorb heat, while endothermic reactions release heat.
• Exothermic reactions release heat, while endothermic reactions absorb heat.
• Both types of reactions release heat.
• Both types of reactions absorb heat.

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

• Photosynthesis
• Combustion of gasoline
• Dissolving ammonium nitrate in water
• Melting ice

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

• It increases.
• It decreases.
• It remains the same.
• It fluctuates.

Which of the following statements best describes the first law of thermodynamics?

• Energy cannot be created or destroyed, only transformed.
• Energy can be created from nothing.
• Energy is always lost in chemical reactions.
• Energy can be destroyed in a closed system.

What happens to the energy of the reactants in an exothermic reaction?

• It increases.
• It decreases.
• It remains constant.
• It fluctuates.

Which of the following processes is endothermic?

• Burning wood
• Respiration
• Dissolving salt in water
• Photosynthesis

During an exothermic reaction, what is the relationship between the energy of the products and the energy of the reactants?

• Products have higher energy than reactants.
• Products have lower energy than reactants.
• Products have the same energy as reactants.
• Energy is irrelevant in this context.

Which of the following best describes a characteristic of endothermic reactions?

• They release energy in the form of heat.
• They require energy input to proceed.
• They occur spontaneously without energy input.
• They are always faster than exothermic reactions.

What is the role of activation energy in chemical reactions?

• It is the energy released during a reaction.
• It is the energy required to initiate a reaction.
• It is the energy that products have after a reaction.
• It is irrelevant to the reaction process.

In a chemical reaction, if the enthalpy change (ΔH) is negative, what type of reaction is it?

• Endothermic
• Exothermic
• Isothermal
• Equilibrium