ANSWER
Power stroke
EXPLANATION
At the power stroke stage, the piston is forced to move down by the expanding gases as both intake valve and exhaust valve are closed.
A spark from the spark plug contributes to ignition of the compressed fuel air mixture to released energy to perform work.
Answer:
-0.050 kJ/mol.K
Explanation:
- A certain reaction is thermodynamically favored at temperatures below 400. K, that is, ΔG° < 0 below 400. K
- The reaction is not favored at temperatures above 400. K, that is. ΔG° > 0 above 400. K
All in all, ΔG° = 0 at 400. K.
We can find ΔS° using the following expression.
ΔG° = ΔH° - T.ΔS°
0 = -20 kJ/mol - 400. K .ΔS°
ΔS° = -0.050 kJ/mol.K
