Water-Soluble Plastic

I buy boxes of dishwasher detergent containing plastic bags filled with the detergent. I place these bags straight into the dishwasher. When the dishes are clean and I remove them from the machine there is no trace of either detergent or the plastic bag that held it.

What happened to the plastic bag?

Can plastic dissolve in water?

Find out in the December 2018 edition of AUS-e-NEWS, AUS-e-TUTE's free, quarterly, newsletter for chemistry students and teachers. 

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Gibbs Free Energy of Formation

You can use standard enthalpy change (ΔH°) and standard absolute entropy (S°) data to calculate the change in Gibbs free energy (ΔG°) for a chemical reaction or physical change using the equation:

 ΔG° = ΔH° - TΔS°

... OR ....
you can use tables of values for the standard Gibbs free energy of formation of compounds (ΔG_ƒ°).
For a chemical reaction or physical change:

reactants → products 

ΔG° = ΣΔG_ƒ°(products) - ΣΔG_ƒ°(reactants)

If you would like to understand where this comes from and how it can be applied solve problems in chemistry, visit our new tutorial Standard Gibbs Free Energy of Formation Calculations

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