Titanium(IV) chloride can be made from titanium(IV) oxide as shown in the equation. TiO₂(s) + 2C(s) + 2Cl₂(g) → 2CO(g) + TiCl₄(l) ΔHf = -60.0 kJ mol⁻¹ Some entropy data are shown in Table 3. Table 3 | Substance | TiO₂(s) | C(s) | Cl₂(g) | CO(g) | TiCl₄(l) | |---------------|---------|-------|--------|-------|----------| | S° / J K⁻¹ mol⁻¹ | 50.2 | 5.70 | 223 | 198 | 253 | Use the equation and the data in Table 3 to calculate the Gibbs free-energy change for this reaction at 989 °C. Give your answer to the appropriate number of significant figures. Use your answer to explain whether this reaction is feasible.

A-Level AQA Chemistry Energetics: Titanium(IV) chloride can be mad

Titanium(IV) chloride can be made from titanium(IV) oxide as shown in the equation - AQA - A-Level Chemistry - Question 5 - 2017 - Paper 1

Question 5

Titanium(IV) chloride can be made from titanium(IV) oxide as shown in the equation. TiO₂(s) + 2C(s) + 2Cl₂(g) → 2CO(g) + TiCl₄(l) ΔHf = -60.0 kJ mol⁻¹ Some entrop... show full transcript

Worked Solution & Example Answer:Titanium(IV) chloride can be made from titanium(IV) oxide as shown in the equation - AQA - A-Level Chemistry - Question 5 - 2017 - Paper 1

Step 1

Calculate ΔS for the reaction

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Answer

To find the change in entropy, ΔS, we can use the equation:

$ΔS = S_{products} - S_{reactants}$

Calculating for the given reaction:

$ΔS = [2(198) + 253] - [50.2 + 2(5.70) + 2(223)]$

Calculating the values:

For products: $2(198) + 253 = 396 + 253 = 649$
For reactants: $50.2 + 2(5.70) + 2(223) = 50.2 + 11.4 + 446 = 507.6$

Thus,

$ΔS = 649 - 507.6 = 141.4 \, J \, K^{-1} \, mol^{-1}$

Step 2

Calculate Gibbs free-energy change (ΔG)

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Answer

The Gibbs free-energy change is calculated using the following equation:

$ΔG = ΔH - TΔS$

Where:

ΔH = -60.0 kJ/mol = -60000 J/mol (convert to Joules)
T = 989 °C = 1262 K (convert to Kelvin by adding 273)
ΔS = 141.4 J K⁻¹ mol⁻¹ (calculated previously)

Now substitute the values into the equation:

$ΔG = -60000 - (1262)(141.4)$

Calculating:

$= -60000 - 178,880.8 = -238,880.8 \, J/mol$

Converting to kJ:

$ΔG = -238.9 \, kJ/mol$ (to three significant figures)

Step 3

Explain feasibility of the reaction

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Answer

The reaction is feasible since the Gibbs free-energy change, ΔG, is negative. A negative ΔG value indicates that the reaction will proceed spontaneously under the given conditions. Therefore, this reaction is thermodynamically feasible.

Titanium(IV) chloride can be made from titanium(IV) oxide as shown in the equation - AQA - A-Level Chemistry - Question 5 - 2017 - Paper 1

Worked Solution & Example Answer:Titanium(IV) chloride can be made from titanium(IV) oxide as shown in the equation - AQA - A-Level Chemistry - Question 5 - 2017 - Paper 1

Calculate ΔS for the reaction

Calculate Gibbs free-energy change (ΔG)

Explain feasibility of the reaction

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