1. Module 1

1.20. Page 2

Module 1: Lesson 4

Module 1—Thinking Energy

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Kinetic Molecular Theory

 

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 with objects in their path

 

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.

 

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

All matter is made of tiny particles. The kinetic molecular theory states that small particles that make up a substance are in continuous motion and collide with each other and with objects in their path. Motion associated with particles can involve more than collisions.

 

Read the bulleted lists under “Heat Transfer and Enthalpy Change” at the bottom of page 487 in the textbook to review the kinds of motion that are associated with a particle’s kinetic energy and the associations between particles that involve chemical potential energy.

 

Try This
 
Chemical Potential and Kinetic Energy

 

TR 1. By hand or digitally, prepare cartoons that depict the different kinds of energy matter can have. Save your work in your course folder and submit a copy to your teacher.

 

Read

 

enthalpy: the total kinetic and potential energy in a system

The sum of the kinetic and potential energies in a system is called enthalpy. A system’s enthalpy cannot be measured directly but can be determined indirectly by comparing the change in enthalpy of the products relative to the reactants.

 

In Lesson 3 you used a calorimeter to measure energy changes that were the result of changes involving matter. How does the energy change for a process measured using a calorimeter relate to an enthalpy change?

 

Read page 488 in the textbook to learn more.

 

Try This
 
Energy Measured in a Calorimeter

 

TR 2. Write a paragraph to respond to the question in the Read activity above: how does the energy change for a process measured using a calorimeter relate to an enthalpy change? Save your response in your course folder and submit a copy to your teacher.

 

TR 3. Can you recall any other assumptions that are made in the design of a calorimeter or in interpreting the data collected from the calorimeter? How do these assumptions make it possible to measure the enthalpy change of a process that occurs within a calorimeter? Make sure you save a copy of your answers to these questions in your course folder as they will help you complete the next activity.

 

Read

 

Read page 489 and work through “Sample problem 11.1” and “Communication example 2” in the textbook.