Chemistry 30

FAQ | Formulas & Tables | Glossary | Home | Lab Storage | Site Map
Thermodynamics: Unit Index | Practice Problems | Assignments | Student Lab | Research Ideas | Teacher Resources

 

Kinetics: Unit Index | Practice Problems | Assignments | Student Lab | Research Ideas | Teacher Resources
Equilibrium: Unit Index | Practice Problems | Assignments | Student Lab | Research Ideas | Teacher Resources
Solutions: Unit Index | Practice Problems | Assignments | Student Lab | Research Ideas | Teacher Resources
Acids & Bases: Module Index | Practice Problems | Assignments | Student Lab | Research Ideas | Teacher Resources
Redox Reactions: Module Index | Practice Problems | Assignments | Student Lab | Research Ideas | Teacher Resources

 

subglobal7 link | subglobal7 link | subglobal7 link | subglobal7 link | subglobal7 link | subglobal7 link | subglobal7 link
subglobal8 link | subglobal8 link | subglobal8 link | subglobal8 link | subglobal8 link | subglobal8 link | subglobal8 link

Thermodynamics

3.1a Some Comments about Units

A Reminder:

Remember that there are different ways to express fractions. You should be comfortable seeing units in any of the alternate forms. For example:

J

K·mole
=
J · K-1·mol-1
return to notes

Another important note about the units

When we are concerned with S, the units are J · K-1·mol-1 or
J
K·mole
    
But with ΔS the units become just J·K-1 or
J

K
   
Why the difference? S always refers to one mole of a specific substance - element or molecule. ΔS refers to a change in entropy for an entire system (all reactants and products). We are no longer talking about one mole of any specific, individual substance, but rather by how much the entire system has changed. This was true for ΔH as well - heat of formation, ΔH°f refers to one mole of a specific substance, whereas the heat of reaction, ΔH, refers to the change undergone by the entire system.

 

Credits | Central iSchool | Sask Learning | Saskatchewan Evergreen Curriculum | Updated: 22-May-2006