Laboring in the vineyard of physical chemistry

Benjamin Widom1

  • 1Department of Chemistry, Cornell University, Ithaca, New York 14853-1301, USA. bw24@cornell.edu

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What is Physical Chemistry?01:23

What is Physical Chemistry?

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The cell is chemically composed of water, organic molecules and inorganic ions.
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The polarity of the water molecule and its resulting hydrogen bonding makes water a unique substance with special properties that are intimately tied to the processes of life. Life originally evolved in an aqueous environment, and most of an organism’s cellular chemistry and metabolism occur inside the aqueous contents of the cell’s cytoplasm. Special properties of water are its high heat capacity and heat of...
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Thermodynamics: Chemical Potential and Activity

The effective concentration of a species in a solution can be expressed precisely in terms of its activity. Activity considers the effect of electrolytes present in the vicinity of the species of interest and depends on the ionic strength of the solution. The activity of a species is expressed as the product of molar concentration and the activity coefficient of the species.
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