The** total entropy or the entropy of the universe** is also related to the can be calculated using the entropy of the system (reaction) and entropy of the surroundings:

$\overline{){\mathbf{\u2206}}{{\mathbf{S}}}_{{\mathbf{univ}}}{\mathbf{=}}{\mathbf{\u2206}}{{\mathbf{S}}}_{{\mathbf{system}}}{\mathbf{+}}{\mathbf{\u2206}}{{\mathbf{S}}}_{{\mathbf{surroundings}}}}$

**Step 1: **Calculate ΔS°_{system}.

**ΔS° _{sys} = ΔS°_{rxn}**

**ΔS° C _{graphite} = 5.686 J/(mol•K)**

**ΔS° H _{2} = 130.6 J/(mol•K)**

**ΔS° CH _{4} = 186.1 J/(mol•K)**

Consider the following reaction at 298 K:

C(graphite) + 2H_{2}(g) → CH_{4}(g) ΔH° = -74.6 kJ

Calculate the following quantities.

ΔS_{sys} = ___ J/K

ΔS_{surr} = ___ J/K

ΔS_{univ} = ___ J/K