Entropy Video Lessons

Concept

# Problem: Calculate the standard entropy change for the reaction2Mg(s) + O2(g) → 2MgO(s)using the data from the following table: Substance ?H?f (kJ/mol)?G?f (kJ/mol)S? [J/(K?mol)]Mg(s)0.000.0032.70O2(g)0.000.00205.0MgO(s)-602.0-569.627.00Express your answer to four significant figures and include the appropriate units.

###### FREE Expert Solution

We’re being asked to determine the Standard entropy change for the given reaction:

2 Mg(s) + O2(g) → 2 MgO(s)

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.

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###### Problem Details

Calculate the standard entropy change for the reaction

2Mg(s) + O2(g) → 2MgO(s)

using the data from the following table:

 Substance ?H?f (kJ/mol) ?G?f (kJ/mol) S? [J/(K?mol)] Mg(s) 0.00 0.00 32.70 O2(g) 0.00 0.00 205.0 MgO(s) -602.0 -569.6 27.00

Express your answer to four significant figures and include the appropriate units.