[shubi]

In all practicality E=mc2 does only apply to nuclear reactions.

I would teach kids about the energy transformation in beginning chemistry, so they begin to understand the big picture.

[WildTurkey]

Here are some published guidelines for certain schools/districts for teaching:

"b. Students know the energy release per gram of material is much larger in nuclear fusion or fission reactions than in chemical reactions. The change in mass (calculated by E = mc2) is small but significant in nuclear reactions."

Above: Correct but misleading.

"Energy and mass equivalence
E= MC2
Exception” to E=EC2 (conservation) rule - only holds nuclear reactions sun (fusion), nuclear bomb, nuclear power; not related to combustion or day-to-day situations!"

Wrong!