Question

Use the standard entropy data in Appendix G to determine the change in entropy for each of the following reactions. All the processes occur at the standard conditions and 25 °C.

a) MnO₂()⟶Mn()+O₂()

b) H₂()+Br₂()⟶2HBr()

c) Cu()+S()⟶CuS()

d) 2LiOH()+CO₂()⟶Li₂CO₃()+H₂O()

e) CH₄()+O₂()⟶C(,graphite)+2H₂O()

f) CS₂()+3Cl₂()⟶CCl₄()+S₂Cl₂()

Answer 1

To find the standard entropy change for reactions, use standard molar entropy values for products and reactants, subtract the reactants' sum from the products' sum, and make sure the reactions are under standard conditions at 25 °C.

Step-by-step explanation:

To determine the standard entropy change for each reaction, we can use standard entropy values for the reactants and products which are typically found in Appendix G of a chemistry textbook. The change in entropy (ΔS°) for a reaction can be calculated using the equation:

ΔS° = ΣS°(products) - ΣS°(reactants)

Where ΣS°(products) is the sum of the standard molar entropies of all products and ΣS°(reactants) is the sum of the standard molar entropies of all reactants.

A change in entropy indicates the degree to which the randomness or disorder of a system changes during a chemical reaction. All calculations for the change in entropy assume the reaction occurs under standard conditions and at 25 °C.