0.010 mol of chloral hydrate, CCl3CHO(OH), is dissolved in a pure organic solvent. The resulting solution is made up to one litre exactly. In this solvent, the chloral hydrate dissociates to chloral, CCl3CHO, and water. The chemical reaction for the process is: CCl3CHO(OH)_{(in\,solution)} ⇌ CCl3CHO_{(in\,solution)} + H2O_{(in\,solution)} When the reaction has reached equilibrium the concentration of water in the solution is measured to be 0.0020 M. The equilibrium constant for the reaction at this temperature would be: A. 4.0 × 10⁻⁴ B. 5.0 × 10⁻⁴ C. 0.20 D. 0.25

SSCE VCE Chemistry Measuring Solubility and Concentration: 0.010 mol of chloral hydrate, CC

0.010 mol of chloral hydrate, CCl3CHO(OH), is dissolved in a pure organic solvent - VCE - SSCE Chemistry - Question 6 - 2002 - Paper 1

Question 6

0.010 mol of chloral hydrate, CCl3CHO(OH), is dissolved in a pure organic solvent. The resulting solution is made up to one litre exactly. In this solvent, the chlor... show full transcript

Worked Solution & Example Answer:0.010 mol of chloral hydrate, CCl3CHO(OH), is dissolved in a pure organic solvent - VCE - SSCE Chemistry - Question 6 - 2002 - Paper 1

Step 1

Calculate the change in concentration

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Answer

At equilibrium, the concentration of water is 0.0020 M. For each mole of chloral hydrate that dissociates, one mole of water is produced. Since we started with 0.010 mol of chloral hydrate in 1 L, the initial concentration of chloral hydrate is 0.010 M.

Step 2

Determine the equilibrium concentrations

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Answer

Let the change in concentration of CCl3CHO be represented as 'x'. At equilibrium:

[CCl3CHO] = 0.010 - x
[H2O] = 0.0020 M (given)

Step 3

Write the expression for the equilibrium constant, Kc

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Answer

The equilibrium constant Kc is given by the expression: $K_c = \frac{[CCl_3CHO]}{[H_2O]}$

Step 4

Substitute the equilibrium concentrations into the Kc expression

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Answer

Substituting the known values into the expression: $K_c = \frac{0.010 - 0.0020}{0.0020}$ Now, solve for Kc.

Step 5

Calculate Kc

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Answer

Calculating gives: $K_c = \frac{0.008}{0.0020} = 4.0$ Thus, the equilibrium constant is approximately 4.0 × 10⁻⁴.

Step 6

Identify the correct answer from the options

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Answer

Based on the calculation, the answer corresponds to option B: 5.0 × 10⁻⁴.

0.010 mol of chloral hydrate, CCl3CHO(OH), is dissolved in a pure organic solvent - VCE - SSCE Chemistry - Question 6 - 2002 - Paper 1

Worked Solution & Example Answer:0.010 mol of chloral hydrate, CCl3CHO(OH), is dissolved in a pure organic solvent - VCE - SSCE Chemistry - Question 6 - 2002 - Paper 1

Calculate the change in concentration

Determine the equilibrium concentrations

Write the expression for the equilibrium constant, Kc

Substitute the equilibrium concentrations into the Kc expression

Calculate Kc

Identify the correct answer from the options

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