Journal Entry:

Which of the following combinations of enthalpy and entropy changes accurately describes the combustion of wood into CO_{2 (g)} and H₂O _(g) in a campfire?

(A) ΔH>0,  ΔS>0
(B)  ΔH<0,  ΔS<0
(C)  ΔH>0,  ΔS<0
(D)  ΔH<0,  ΔS>0

Learning Intentions

• We will learn how to use representations and models to predict the sign and relative magnitude of the entropy change associated with chemical or physical processes.

• We will learn how to predict whether or not a physical or chemical process is thermodynamically favored by determination of the signs of both ΔH and ΔS.

• We will learn how to calculate ΔS for given reactions

Closing Task:

You can calculate ΔS for given reactions

Content Standards being covered:

Entropy is a measure of the dispersal of matter and energy. (E.K. 5.E.1) 

Some physical or chemical processes involve both a decrease in the internal energy of the components under consideration and an increase in the entropy of those components. These processes are necessarily "thermodynamically favored".(E.K. 5.E.2)