1. What is Molar Heat Capacity at Constant Pressure?

Definition: Molar Specific Heat Capacity at Constant Pressure (Cp) of a gas is the amount of heat required to raise the temperature of 1 mol of the gas by 1 °C at constant pressure.

Purpose: This calculator determines Cp for linear molecules based on their atomicity using theoretical relationships from kinetic theory.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( C_p \) — Molar heat capacity at constant pressure (J/K·mol)
• \( N \) — Atomicity (number of atoms in the molecule)
• \( [R] \) — Universal gas constant (8.314 J/K·mol)

Explanation: The formula accounts for translational, rotational, and vibrational degrees of freedom in linear molecules.

3. Importance of Cp Calculation

Details: Knowing Cp is essential for thermodynamic calculations involving heat transfer, energy balances, and process design in chemical engineering.

4. Using the Calculator

Tips: Enter the atomicity (number of atoms in the molecule) - for example, 2 for O₂ or 3 for CO₂. The value must be ≥ 1.

5. Frequently Asked Questions (FAQ)

Q1: Why is this specific to linear molecules?
A: Linear molecules have different rotational degrees of freedom than nonlinear ones, affecting their heat capacity.

Q2: What's the atomicity of common molecules?
A: O₂ = 2, CO₂ = 3, C₂H₂ = 4, etc. Count all atoms in the molecular formula.

Q3: How does temperature affect Cp?
A: This simple model assumes moderate temperatures where vibrational modes aren't fully excited.

Q4: What's the difference between Cp and Cv?
A: Cp is at constant pressure, Cv at constant volume. For ideal gases, Cp = Cv + R.

Q5: Can I use this for nonlinear molecules?
A: No, nonlinear molecules have a different formula: Cp = (((3×N)-3)×[R]) + [R].