What does the symbol #Delta# in a chemical equation mean?

1 Answer
Jun 10, 2016

It means heat. So you could put something on a hot plate, crank up the temperature... then you'd be carrying out the action indicated by #Delta#.

So you might see something like:

#"NH"_4"NO"_3 stackrel(Delta" ")(->) 2"H"_2"O" + "N"_2"O"#

That would be the decomposition of ammonium nitrate into water and nitrous oxide. The #Delta# then tells you to heat the compound to promote this decomposition.

Another example is the radical halogenation of alkanes:

#"CH"_4 + "Cl"_2 stackrel(Delta" ""or " hnu" ")(->) "CH"_3"Cl" + "HCl"#

In this case, #Delta# still means heat, but for this photochemically-catalyzed reaction, you could have also used UV light, which was indicated by #hnu# since #E = hnu# tends to be used to evaluate the energy of a photon (or a #"mol"# of photons).