# Problem: For the reaction 2CH4(g)→C2H6(g)+2H2(g) calculate ΔG∘rxn at 25 °C.Express your answer using one decimal place.Standard Thermodynamic Quantities for Selected Substances at 25 °C   Substance      ΔH∘f(kJ/mol)      S∘(J/mol⋅K)      CH4(g)   −74.6   186.3   C2H6(g)   −84.68   229.2   H2(g)   0   130.7   N2(g)   0   191.6   NH3(g)   −45.9   192.8   N2H4(g)   95.4   238.5   NO(g)   91.3   210.8   O2(g)   0   205.2   KCl(s)   −436.5   82.6   KClO3(s)   −397.7   143.1

###### FREE Expert Solution

$\overline{){\mathbf{\Delta G}}{{\mathbf{°}}}_{{\mathbf{rxn}}}{\mathbf{=}}{\mathbf{\Delta H}}{{\mathbf{°}}}_{{\mathbf{rxn}}}{\mathbf{-}}{\mathbf{T\Delta S}}{{\mathbf{°}}}_{{\mathbf{rxn}}}}$

For this problem, we need to do the following steps:

Step 1: Calculate ΔH˚rxn.

Step 2: Calculate ΔS˚rxn.

Step 3: Use ΔH˚rxn and ΔS˚rxn to calculate for ΔG˚rxn.

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###### Problem Details

For the reaction 2CH4(g)→C2H6(g)+2H2(g) calculate ΔG∘rxn at 25 °C.

Standard Thermodynamic Quantities for Selected Substances at 25 °C

 Substance ΔH∘f(kJ/mol) S∘(J/mol⋅K) CH4(g) −74.6 186.3 C2H6(g) −84.68 229.2 H2(g) 0 130.7 N2(g) 0 191.6 NH3(g) −45.9 192.8 N2H4(g) 95.4 238.5 NO(g) 91.3 210.8 O2(g) 0 205.2 KCl(s) −436.5 82.6 KClO3(s) −397.7 143.1