1. Module 1

1.22. Page 4

Module 1: Lesson 4

Module 1—Thinking Energy

Lesson Summary

 

In Lesson 4 you considered the following questions:

  • What changes occur during a chemical reaction at the particle level?
  • Why do chemical changes and energy changes occur at the same time?
  • What is enthalpy?

You studied both theoretical and empirical aspects of matter and energy changes. You used cartoons and other methods to explain changes in matter and you analyzed data to calculate energy changes. You learned that an enthalpy change is the change in the kinetic and potential energy of a system and that an enthalpy change can be quantified using a calorimeter.

 

Lesson Glossary

 

chemical potential energy: a stored form of energy dependent on the relative positions of particles

 

endothermic: a process that absorbs energy from its surroundings

 

enthalpy: the total kinetic and potential energy in a system

 

exothermic: a process that radiates energy to its surroundings

 

kinetic energy: a form of energy related to the motion of particles

 

Kinetic energy can involve vibration, rotation, or translation within or of a particle. Kinetic energy changes are often observed as a temperature change in matter.

 

kinetic molecular theory: a theory that states that small particles that make up a substance are in continuous motion and collide with each other and objects in their path