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Enthalpy calculation with Cp

We can calculate the energy difference between two states of different temperature if we know the heat capacities. When the pressure is constant, integration of ({ C }_{ p }) …

Heat of formation at 1000 K

We can calculate the enthalpy changes at temperatures other than reference temperature by taking a reversible detour. Integration of ({ C }_{ p }) over temperature gives the energy changes …

Example 1 : supercooled water

If the system is insulated (adiabatic), -10℃ H({2})O((l)) (supercooled liquid) will be transformed to ice + liquid H({2})O at 0℃. Calculate fraction of ice in the final mixture.       Basis …

T_ P dependence of heat capacity

Heat capacity ♦  Temperature dependence of heat capacity      • (C)(p) usually give as (C)(p)=(a)+(bT)+(cT)−(2)+(dT)(2)      • When phase changes → Heat capacity changes abruptly ♦  Pressure dependence of heat capacity      • …

Summary of Week 1

In this first week, you looked at the definition of the first law of thermodynamics and their physical meaning. The first law is nothing but conservation of energy. The total …

The week ahead

Welcome to Week 2. This week in thermodynamics of energy engineering, we are still talking about the first law of thermodynamics, but we are going be looking at its application …

Heat capacity

In dealing with energy balance equations, we often need to calculate energy change upon temperature change. Heat capacity is the thermal energy required to change the temperature of a material, …

Heat capacity of ideal gases

For ideal gases, the relationship between ({C})({p}) and ({C})({v}) is       ({C})({p}) – ({C})({v}) = ({R}) The ideal gases have specific heat capacities       monoatomic ideal gas ∶  ({C})({v}) = (frac{3}{2}) ({R}), …

Example

We have a box which is adiabatic and closed. Pressure outside of box is constant at P. Inside this box, water at 25 ℃ is contained in a cup located …

Energy balance equation for the open system

In formulating the energy balance equation for the open system, we must consider energy transfer involved with materials in transit. The energy balance equation for the open system is thus …

Types of work

Besides mechanical work, there are several forms of work in thermodynamic systems. In Solid : generally γ(≠)σ   – Solids can support a certain shear stress   – In solids, atoms cannot …

Glossary

Before getting into the world of thermodynamics, we need to understand some basic notions and definitions. ■ System The thermodynamic system is any portion of space or materials defined for …

Energy balance equation for the closed system

As a mathematical interpretation on the first law, we can formulate the conservation of energy concept into equations, called energy balance equation. The first and the most simple formulation is …

Resisting pressure-vacuum

The pressure in mechanical work or P-V work The magnitude of mechanical work or the P-V work is the force F, multiplied by the displacement dx through which the system …