The combustion of acetylene in the presence of excess oxygen yields carbon dioxide and water:

2C2H2 (g) + 5O2 (g) �¨ 4CO2 (g) + 2H2O (l)

The value of ĢSo for this reaction is __________ J/K.

I can't decipher the f+cents mark but I assume you want to calculate So for the reaction at 25 C. Look in your book at the thermodynamic tables and find So for each material. Then (sum So products)-(sum So reactants) = So reaction.

To determine the value of ∆So (standard entropy change) for a reaction, we can use the standard entropy values (∆So) for the reactants and products.

First, we need to find the standard entropies (∆So) of each compound involved in the reaction. These values can be obtained from reference tables or online databases. For this reaction, we have:

∆So (C2H2) = 200.9 J/K (per mole)
∆So (O2) = 205.0 J/K (per mole)
∆So (CO2) = 213.6 J/K (per mole)
∆So (H2O) = 188.7 J/K (per mole)

Next, we can determine the ∆So for the reaction by using the stoichiometric coefficients of the balanced equation. According to the reaction:

2C2H2 (g) + 5O2 (g) �¨ 4CO2 (g) + 2H2O (l)

The overall change in entropy (∆So) can be calculated using the formula:

∆So = Σn∆So(products) - Σm∆So(reactants)

Where Σn and Σm represent the total moles of products and reactants, respectively.

∆So = [4 × ∆So(CO2)] + [2 × ∆So(H2O)] - [2 × ∆So(C2H2)] - [5 × ∆So(O2)]

∆So = [4 × 213.6 J/K] + [2 × 188.7 J/K] - [2 × 200.9 J/K] - [5 × 205.0 J/K]

After performing the calculations, we find:

∆So = 854.4 J/K + 377.4 J/K - 401.8 J/K - 1025.0 J/K

∆So = -194.8 J/K

Therefore, the value of ∆So (standard entropy change) for this reaction is -194.8 J/K.

To find the value of ΔSo (change in entropy) for the given reaction, we need to subtract the sum of the molar entropies of the reactants from the sum of the molar entropies of the products.

The equation for calculating ΔSo is as follows:

ΔSo = Σ nSo(products) - Σ mSo(reactants)

Where:
n = stoichiometric coefficient (number of moles) of each compound in the balanced chemical equation
So = molar entropy

For the given reaction:
2C2H2 (g) + 5O2 (g) → 4CO2 (g) + 2H2O (l)

The molar entropies of the reactants and products are as follows:
So(C2H2) = X J/K (not given)
So(O2) = Y J/K (not given)
So(CO2) = Z J/K (not given)
So(H2O) = W J/K (not given)

Using the equation above, the ΔSo value can be calculated by considering the stoichiometric coefficients:

ΔSo = (4 * So(CO2) + 2 * So(H2O)) - (2 * So(C2H2) + 5 * So(O2))

However, since the molar entropies (So) of the reactants and products are not provided in the question, it is not possible to calculate the exact value of ΔSo.