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2 O(l) -715.9 2) When solid KI is dissolved in water, a cooling of the mixture occurs because the solution process is endothermic. Explain, in terms of what happens to the molecules and ions, why this mixing occurs spontaneously? 3) Predict the algebraic sign of the entropy change for the following reactions? a) PCl 3 (g) + Cl 2 (g) → PCl 5 ...
In a spontaneous reaction, the formation of products is more favorable. Spontaneity is determined by the overall change in Gibb’s free energy (ΔG), i.e. energy available to do work. A reaction is spontaneous when ΔG° < 0 and is nonspontaneous when ΔG° > 0.
The standard entropy change (Δ Ssystemꝋ ) for a given reaction can be calculated using the standard entropies (Sꝋ ) of the reactants and products. The equation to calculate the standard entropy change of a system is: ΔSsystemꝋ = ΣSproductsꝋ - ΣSreactantsꝋ. (where Σ = sum of)
1. Calculate the change in entropy of a large vat of molten copper when 50 J of energy is removed reversible from it as heat at 1100 °C. 2. Calculate the change in entropy of 1.0 L of water at 0 °C when it absorbs 235 J of energy from a heater.
Worksheet on Entropy and Free Energy. Define entropy in your own words, and list the variables or conditions that you must consider when comparing the entropy of two substances, or when trying to determine the relative change in entropy.
Calculate the change in entropy of the surroundings when water freezes at −10.°C; use ΔHfus(H2O) = 6.0 kJ·mol−1 at −10.°C. Answer: We can expect the entropy of the surroundings to increase when water freezes because the heat released stirs up the thermal motion of the atoms in the surroundings.
The entropy change for a reaction within a system can be calculated by finding the difference between the standard entropies of the products and the reactants: If the entropy change for a reaction is positive, the products are more disordered than the reactants.
