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Energetics Chemistry - Enthalpy change calculations

Energetics Chemistry - Enthalpy change calculations

Flyer24

Hi guys, could any chemists help me with knowing when to use a plus or minus sign for enthalpy calculations. I invariably get the correct number but struggle with knowing when to use the +/- for the calculation.

Reply 1

11huxleya

A really good tip my teacher gave me was that if the end value you calculated was, for example, 56 Kj/mol-1 then the surrounding environment has gained 56 kj/mol-1 so the system has lost 56kj/mol so the end answer would be -56 kj/mol-1

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