Formula Used:
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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.
The calculator uses the formula:
Where:
Explanation: The formula accounts for translational, rotational, and vibrational degrees of freedom in linear molecules.
Details: Knowing Cp is essential for thermodynamic calculations involving heat transfer, energy balances, and process design in chemical engineering.
Tips: Enter the atomicity (number of atoms in the molecule) - for example, 2 for O₂ or 3 for CO₂. The value must be ≥ 1.
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].