Exploring Exothermic and Endothermic Reactions

This lesson covers the differences between exothermic and endothermic reactions, explaining how exothermic reactions release energy, often as heat or light, while endothermic reactions absorb energy. Real-life examples of both types of reactions are provided. The lesson also introduces the concepts of enthalpy and entropy, explaining how they relate to energy changes and disorder in reactions. Students are encouraged to understand these concepts to differentiate between the two types of reactions.

What is an exothermic reaction?

• A reaction that absorbs energy

• A reaction that releases energy

• A reaction that only releases light

• A reaction that neither absorbs nor releases energy

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Which hint helps you remember what an endothermic reaction is?

• Endo means energy exits

• Exo means energy enters

• Endo means energy enters

• Exo means energy exits

Tags

NGSS.HS-PS1-4

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

• Evaporation

• Burning wood

• Baking bread

• Photosynthesis

Tags

NGSS.HS-PS1-4

What happens when you mix acid in water?

• The solution becomes colder

• The solution becomes warmer

• The solution remains the same temperature

• The solution freezes

Tags

NGSS.HS-PS3-4

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

• Mixing acid in water

• Dissolving salt in water

• Freezing water

• Rusting

What is enthalpy a measure of?

• Energy in surroundings

• Light in a system

• Heat in a system

• Randomness

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

In an exothermic reaction, what happens to entropy in the surroundings?

• It becomes zero

• It decreases

• It remains the same

• It increases

What is the difference between enthalpy and entropy?

• Enthalpy measures heat, entropy measures randomness

• Enthalpy measures light, entropy measures heat

• Enthalpy measures energy, entropy measures light

• Enthalpy measures randomness, entropy measures heat

In an endothermic reaction, what happens to enthalpy?

• It decreases

• It remains the same

• It increases

• It becomes zero

Tags

NGSS.HS-PS1-4

What happens to the surrounding area when ice melts?

• It loses energy and feels colder

• It gains energy and feels warmer

• It gains energy and feels colder

• It remains the same temperature

Tags

NGSS.HS-PS3-4