Module 7
1. Module 7
1.6. Page 4
Module 7—Principles of Chemical Equilibrium
Lesson Summary
In Lesson 1 you considered the following questions:
- What is equilibrium?
- What is happening in a system that is in equilibrium?
- How can you determine whether a system is open or closed?
You learned that equilibrium is defined as a system having constant properties and appearing not to change. There are two main types of equilibrium: static equilibrium and dynamic equilibrium. In a dynamic equilibrium there is a balance between two opposing processes, the forward and reverse reactions, both occurring at the same rate. You also learned to differentiate between a closed system and an open system.
You applied your newly acquired knowledge to identify examples of equilibrium systems. As you work through Module 7 you will continue to examine these systems to describe their other attributes, and you will consider how these attributes are similar in all equilibrium systems.
Lesson Glossary
closed system: a system that is separated from its surroundings by a definite boundary so that energy can enter and leave the system but matter cannot
dynamic equilibrium: the idea that there is a balance between two opposing processes (forward and reverse) occurring at the same rate
The balance between the forward and reverse processes maintains the system’s appearance of constant properties, in spite of change that has occurred internally.
equilibrium: the state of a closed system in which the system does not appear to change
For a chemical system, physical properties, like colour, remain constant and concentrations of substances within the system do not change.
macroscopic: can be observed with the unaided eye or other senses
microscopic: cannot be observed with the unaided eye or other senses
open system: a system in which both matter and energy can enter and leave the system
static equilibrium: the idea that forces on an object are opposing and equal
The object remains constant because no changes are happening internally.