1. 16.3 The Effect of Temperature on Spontaneity
Entropy changes in the surroundings are primarily determined by heat flow
Exothermic process increases the entropy in the surroundings
Significance of exothermicity as a driving force depends on the temperature at which the process occurs
The impact of the transfer of a given quantity of energy as heat to or fro the surroundings will be greater at lower temperatures.
Characteristics of Ssurroundings
The sign of Ssurr depends on the direction of the heat flow.
The magnitude of Ssurr depends on the temperature.

2. Driving force provided by the energy flow (heat)
Magnitude of the entropy change of the surroundings
Quantity of heat (J)
Temperature (K) = =

3. Quantity of heat (J)
Temperature (K)
Exothermic process
Ssurr
= +
Quantity of heat (J)
Temperature (K)
Endothermic process
Ssurr
= – H T
Ssurr =

4. Yes if Ssys > Ssurr Yes if Ssurr > Ssys
Suniv
Spontaneity +
Yes – No ?
Yes if Ssys > Ssurr
Yes if Ssurr > Ssys