# How does an exothermic reaction change the entropy of the surroundings?

##### 2 Answers

Jul 29, 2015

when we say that entropy always increases we refer to an isolated system and the entropy of the system and the environment, and for the formation of water, where entropy appears to decrease, we refer only to the system

However, in this case it is the entropy of the environment increases due to the heat yielded by Δ H = T Δ S

Samb Δ Δ = H / T = 484 kJ / 298 K = 1624 J / K, much higher than 88.9 J / K earned by the system

Δ = Δ Stot Samb Ssist + Δ = Δ H / T + Δ Ssist

Multiplying both sides by T

Stot Δ T = T + Δ -Δ Hsist Ssist

And calling Δ = G - T Δ Stot

We find the equation of Gibbs

Δ Δ G = H - T Δ S