## Enthalpy and Entropy

Arman M 1A
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Joined: Wed Nov 14, 2018 12:23 am
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### Enthalpy and Entropy

What is the difference between enthalpy and entropy?

105114680
Posts: 60
Joined: Fri Sep 28, 2018 12:23 am

### Re: Enthalpy and Entropy

Enthalpy is heat released or absorbed in chemical reactions and physical changes. Entropy, on the other hand, is needed to describe the likelihood of a system being in a particular state. The textbook refers to entropy as a measure of disorder within a system, although Dr. Lavelle has decided to avoid this terminology and instead describes it as the number of accessible microstates. Energy and matter tend to disperse to increase the microstates available to them and thus any spontaneous change (a change in a system that is not driven by external forces) results in a positive change in entropy (an increase). Hope this cleared things up a bit!

Cynthia Aragon 1B
Posts: 47
Joined: Mon Apr 09, 2018 1:38 pm

### Re: Enthalpy and Entropy

Enthalpy, is denoted by he symbol 'H' and refers to the measure of total heat content in a thermodynamic system under constant pressure. It is calculated in terms of change, i.e., ∆H = ∆E + P∆V(where E is the internal energy). The SI unit of enthalpy is joules (J).
It can be defined as the total energy of a thermodynamic system that includes the internal energy.

Entropy, is denoted by the symbol 'S' which refers to the measure of the level of disorder in a thermodynamic system. Its measured as joules per kelvin (J/K) and it is calculated in terms of change, i.e., ∆S = ∆Q/T (where Q is the heat content and T is the temperature).
It is a thermodynamic property that is defined as a measure of the number of specific ways in which a thermodynamic system can be arranged.