1. What is Equilibrium Constant due to Pressure?

Definition: The equilibrium constant (K_p) expresses the ratio of product partial pressures to reactant partial pressures at equilibrium, with each raised to the power of their stoichiometric coefficients.

Purpose: This calculator determines K_p for reactions involving gas-phase dissociation based on the degree of dissociation and total pressure.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( K_p \) — Equilibrium constant (mol/m³)
• \( \alpha \) — Degree of dissociation (0 to 1)
• \( P_T \) — Total pressure (Pascal)

Explanation: This formula applies to reactions where one molecule dissociates into two (like A ⇌ 2B). The degree of dissociation (α) represents the fraction of molecules that have dissociated.

3. Importance of Equilibrium Constant

Details: K_p helps predict the extent of a chemical reaction at equilibrium and is crucial for understanding reaction thermodynamics and kinetics.

4. Using the Calculator

Tips: Enter the degree of dissociation (between 0 and 1) and total pressure in Pascals. The degree must be less than 1 to avoid division by zero.

5. Frequently Asked Questions (FAQ)

Q1: What does the degree of dissociation represent?
A: It's the fraction of reactant molecules that have dissociated into products at equilibrium (0 = none, 1 = complete dissociation).

Q2: Why is there a 4 in the numerator?
A: The 4 comes from the stoichiometric coefficients in the equilibrium expression for a 1:2 dissociation reaction.

Q3: What units should I use for pressure?
A: The calculator uses Pascals (Pa), but any consistent pressure unit would work as long as K_p units match.

Q4: Can α be exactly 1?
A: No, α=1 would make the denominator zero, which is mathematically undefined. Complete dissociation is approached as α→1.

Q5: How does temperature affect K_p?
A: K_p is temperature-dependent (via the van't Hoff equation) but this calculator assumes constant temperature.