Monday, September 24, 2018

Calculating Entropy Changes

If you stick some clean reactive metal, like magnesium, into an aqueous solution of hydrochloric acid... Hey presto! Bubbles of hydrogen gas! This gas production is a dead giveaway that the entropy of the system has increased.
But what if all the reactants and products are soluble in water and the entire chemical process occurs in aqueous solution. Has the entropy of the system increased or decreased?
Thankfully, chemists have a tool they can use to make quantitative predictions about the changes in entropy of a chemical system (ΔS). This tool is called the Standard Absolute Entropy (S°), and we have just added a new tutorial, game, test and exam to help you understand what this is and how it can be used.
AUS-e-TUTE Members should log-in to access the new resources under the heading "Thermodynamics".
If you are not already an AUS-e-TUTE there is a "free-to-view" tutorial currently available at https://www.ausetute.com.au/entropychange.html