Formula To Calculate Enthalpy Change

Enthalpy Change Formula:

\[ \Delta H = m \times C_p \times \Delta T \]

Enthalpy Change (ΔH):

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1. What is the Enthalpy Change Formula?

The enthalpy change formula (ΔH = m × Cp × ΔT) calculates the heat energy absorbed or released during a thermodynamic process at constant pressure. It's a fundamental equation in thermodynamics and chemistry.

2. How Does the Calculator Work?

The calculator uses the enthalpy change formula:

\[ \Delta H = m \times C_p \times \Delta T \]

Where:

\( \Delta H \) — Enthalpy change (Joules)
\( m \) — Mass of the substance (kg)
\( C_p \) — Specific heat capacity (J/kg·K)
\( \Delta T \) — Temperature change (K)

Explanation: The formula calculates the heat energy required to change the temperature of a given mass of substance by a certain amount at constant pressure.

3. Importance of Enthalpy Change Calculation

Details: Enthalpy change calculations are essential for understanding heat transfer in chemical reactions, designing heating/cooling systems, and analyzing thermodynamic processes in engineering applications.

4. Using the Calculator

Tips: Enter mass in kilograms, specific heat capacity in J/kg·K, and temperature change in Kelvin. All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between enthalpy and heat?
A: Enthalpy is a thermodynamic property that includes internal energy plus pressure-volume work, while heat is the energy transferred due to temperature difference.

Q2: Why is constant pressure important in this formula?
A: The formula ΔH = m × Cp × ΔT is valid only for processes at constant pressure, as enthalpy is defined at constant pressure conditions.

Q3: Can this formula be used for phase changes?
A: No, this formula is for temperature changes without phase transition. For phase changes, use ΔH = m × L where L is latent heat.

Q4: What are typical Cp values for common substances?
A: Water: 4184 J/kg·K, Aluminum: 897 J/kg·K, Iron: 449 J/kg·K, Air: 1005 J/kg·K (at constant pressure).

Q5: How does this relate to chemical reactions?
A: For chemical reactions, enthalpy change represents the heat absorbed or released during the reaction at constant pressure, important for reaction thermodynamics.