Chem – How Energy is Represented in a Chemical Equation Part 1

HOW IS ENERGY REPRESENTED IN A CHEMICAL EQUATION?

Energy can be connected in different ways to a chemical equation. The first and easiest to recognize is when energy is presented in a chemical equation like the examples below.

 

200kJ + N2(g) + 3 H2(g) —-> 2 NH3(g)

Above the energy shown on the LEFT SIDE of the arrow (yield sign) by the number and units 200kJ.  This is an example of a chemical reaction that absorbs energy. In chemistry they call this an ENDOTHERMIC (or ENDERGONIC) reaction.

 

2 H2O(g) —-> 2 H2(g) + O2(g) + 147cal

Above the energy shown on the RIGHT SIDE of the arrow (yield sign) by the number and units 147cal. This is an example of a chemical reaction that releases energy. In chemistry they call this an EXOTHERMIC (or EXERGONIC) reaction.

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