Re: Where does the energy go?

The short answer is: no, the camphor will not burn brighter.  This of
course leads to your second question, "where does the energy go?", and
the answer to that is "nowhere".  Even though it may not appear that
there is any residue from burning the camphor, of course, there really
is.  Imagine having a box from which nothing, no matter, light, heat,
etc., could escape.  Put 10 grams of camphor inside, weight the whole
thing on a mass balance, then burn the camphor and repeat the weighing.
You would find no change, as we would expect from the conservation of
mass/energy.  Remember, that energy and mass are related by E = m c^2,
where E is energy, m is mass, and c^2 is the square of the speed of light,
thus the heat and light generated by burning have mass as well.  Also,
we can use E = m c^2 to deduce that most of the mass remains as some
sort of material product after the burning (smoke,gas, ash).  The reason
for
this is that c^2 is a REALLY big number, and if you converted any
macroscopic quantity of matter completely to energy, you'd blow a sizable
hole in the planet (in any chemical reaction, such as burning, the
amount of mass converted to energy is so small as to be not measurable;
this is not so for nuclear reactions).

So, the gravitational energy gained by carrying the camphor up ten
stories is still there after burning, now held in the products of the
burning.  Let's again consider doing the experiment in the box from
which nothing can escape.  Put the camphor in the box, carry it up
the stairs, and burn the camphor.  The gravitational energy you put
in by going upstairs is still in the box and combustion products.  To
get it back, throw the box out a window (or just carry it back downstairs).
Similarly, you could do the burning at the bottom of the stairs, and
carry it up - the end result doesn't depend on where you actually burn
the camphor.

You might also ask why the camphor doesn't "burn brighter", since it
really does have more energy upstairs than down.  Chemical energy, which
is released during the burning, is really electromagnetic energy stored
in the chemical bonds of the various molecules involved.  The energy
gained by going upstairs is gravitational, and in the universe we
live in today, gravity and electromagnetism are separate forces, so
there is no direct conversion of gravitational to electromagnetic
energy, or vice versa.  There are some subtleties here from quantum
field theory, and of course, one can do the "conversion" via some
intervening mechanical device, but the discussion of such things would
be rather lengthy.