Journal Entry:

Suppose a reaction is spontaneous at temperatures only below 300K. If the ΔH for this reaction is -18.0 kJ/mol, the value of ΔS for this reaction is closest to which of the following? Assume ΔS and ΔH do not change significantly with temperature.

(A) -60 J/molK

(B) -18 J/molK

(C) -0.0010 J/molK

(D) 18 J/molK

(E) 18000 J/molK

Learning Intentions

• You will learn how to predict the sign of ΔH, ΔS  and ΔG after observing a demonstration of a process or reaction.

• You will learn how to answer FRQs using the appropriate energy equations and supporting your answers with the proper work and explanations.

• You will learn what can be used to make non spontaneous process spontaneous.

Content Standards being covered:

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)

If a chemical or physical process is not driven by both entropy and enthalpy changes, then the Gibbs free energy  change can be used to determine whether the process is thermodynamically favored. (E.K. 5.3.E)

External sources of energy can be used to drive change in cases where the Gibbs free energy change is positive. (E.K. 5.E.4)