Unit 8 Thermodynamics & Gibbs

SEE BELOW FOR VIDEO TUTORIALS ON HOW TO USE/APPLY HESS'S LAW! Scroll to the bottom half for info for Tuesday's quiz (MAY 16).

Learning objectives:

• • Define enthalpy and entropy and describe the relationship between them.

  • Describe at the molecular (or atomic) level three different ways heat is transferred.

  • Compare and contrast endothermic and exothermic reactions in terms of energy.

  • Calculate the enthalpy change in a system.

  • Use bond energies for reactants and products in a chemical reaction to determine if a reaction is exothermic or endothermic (aka - calculate the enthalpy of a reaction)

    • Watch this video to review how:

Where do bond energy values come from: (Also explains the relationship between bond length and bond energy)

STUDY THIS PICTURE TO REMEMBER THE RELATIONSHIPS BETWEEN THESE VALUES:

OTHER VIDEOS FOR THIS UNIT:

Hydrogen Cars: https://www.youtube.com/watch?v=JA4TYSST2I4

How fuel cell vehicles work: https://www.youtube.com/watch?v=tajigZ2e6tQ

Understand our labs a little better with this video on Calorimetry:

CALCULATING ENTHALPY USING MANY STEPS:

USING GIBB'S FREE ENERGY EQUATION:

Learning Target for next quiz: May 16th

• • Use the equation to calculate Gibb's Free energy and determine if a reaction is going to occur spontaneously or not.

  • Describe how entropy and enthalpy values can help you predict the spontaneity of a reaction (know which one is H and which is S).

  • Describe how an increase in temperature can actually cause a chemical reaction to stop!

  • State the general rules of the first two laws of Thermodynamics (watch this video link: https://www.youtube.com/watch?v=8N1BxHgsoOw

What is this equation and how is it used? Watch this short Bozeman Science video for the run-down or for review:

Now look at how you actually use Gibb's free energy: