# Problem: “Thermite” reactions have been used for welding metal parts such as railway rails and in metal refining. One such thermite reaction is Fe2 O3(s) + 2Al(s) ⟶ Al2 O3(s) + 2Fe(s). Is the reaction spontaneous at room temperature under standard conditions? During the reaction, the surroundings absorb 851.8 kJ/mol of heat.

###### FREE Expert Solution

Fe2O3(s) + 2 Al(s) ⟶ Al2O3(s) + 2 Fe(s)

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

Step 1: We first need to convert ΔH˚ from kJ to J:

ΔH°rxn851800 J/mol

**heat is released to the surroundings

Step 2: We can use the following equation to solve for ΔS˚rxn:

Note that we need to multiply each S˚ by the stoichiometric coefficient since S˚ is in J/mol • K.

ΔS°rxn = –10.2 J/mol • K

Step 3: Now that we have ΔH˚rxn and ΔS˚rxn, we can now solve for ΔG˚rxn

79% (129 ratings) ###### Problem Details

“Thermite” reactions have been used for welding metal parts such as railway rails and in metal refining. One such thermite reaction is Fe2 O3(s) + 2Al(s) ⟶ Al2 O3(s) + 2Fe(s). Is the reaction spontaneous at room temperature under standard conditions? During the reaction, the surroundings absorb 851.8 kJ/mol of heat.

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