Exercise 2 | Chemical Thermodynamics
General Chemistry 3 - Exercise 2
Give the signs of ΔH and ΔS for the following observations:
- the reaction is never spontaneous
- the reaction is spontaneous only at low temperatures
- the reaction is spontaneous only at high temperatures
ΔG = ΔH – TΔS
Spontaneity of reaction if ΔG < 0
- the reaction is never spontaneous:
⇒ ΔG < 0 ⇒ ΔH: (+) and ΔS: (-)
- the reaction is spontaneous only at low temperatures (ΔG ≈ ΔH):
⇒ ΔG > 0 ⇒ ΔH: (-) and ΔS: (-)
- the reaction is spontaneous only at high temperatures (ΔG ≈ – TΔS):
⇒ ΔG > 0 ⇒ ΔS: (+) and ΔH: (+)