[Avodah] The Burning of the Golden Calf

[Joshua Meisner]

R' Moshe Y. Gluck wrote:
> That said, I'm not sure that the Ibn Ezra's words work with this. Quote (Ibn
> Ezra Ha'aruch, from MHK's Toras Chaim Chumash): Ki Yeish Davar She'yusam
> B'eish Im HaZahav U'm'yad Y'sareif V'yi'yeh Shachor Ul'olam Lo Yashuv Zahav.
> The first part sounds like it is something that happens either
> instantaneously or close to it, and the last phrase makes it sound that this
> causes some reaction in the whole piece

The only way that a metal can undergo a chemical change (as opposed to
a physical phase change such as melting) is if something comes in
contact with the metal atoms to make them react.  In order for
interior atoms to change, therefore, either they have to be brought to
the surface or the reacting molecule (e.g., sulfur) has to be brought
to them.  Although it is possible for sulfur to diffuse through solid
metal, it would take a *long* time - and possibly even longer to
dissolve through a layer of copper sulfide.  You bring a good point,
though, that the passuk implies that grinding was not an essential
part of the burning. So... I don't know.

>- if it were just tarnish then why would he say that it never becomes
gold again?

Barring methods such as that described by RMM to chemically remove
tarnish, it does never become gold again.  Physically rubbing a
tarnished object doesn't change it back to metal, it merely removes
the outer layer, something that would not be possible if we're dealing
with a fine powder (unless one grinds it moreso).

R' Mikha'el Makovi wrote:

> A strong acid would just dissolve the gold into a salty solution. By salt I
> don't mean table salt, but rather salt in the sense of a metal and nonmetal
> ionically bonded.
>
> For example:
>
> Sulfuric acid + gold
> H2SO4(aq = water) + 2Au
> H2SO4(s = solid) + H2O + 2Au
> SO4 (-2 charge) + 2H(+1 charge) + H2O + 2Au
> SO4 (-2) + H2 (gas) + H2O + 2Au(+2 charge)
> Au2So4 (aq) + H2 (gas)

No, it wouldn't (That's what led me to suggest that it must be
something else in the eigel that was doing the reacting).  Gold is so
resistant to chemical attack that even H2SO4 won't do it.  A reagent
commonly used to dissolve gold is aqua regia, a solution of
concentrated nitric acid and hydrochloric acid, in which (acc. to
Wikipedia) the nitric acid produces a very small number of gold ions
which react with the chlorine ions from the hydrochloric acid to
produce chloraurate ions, so that little by little, the system is
thermodynamically driven towards a dissolution of the gold.  Sodium or
potassium cyanide also works.  Either way, though, the dissolution of
gold requires truly vicious chemicals that were not likely to have
been utilized more than a few centuries ago - and at any rate, would
produce only a clear solution, not a scorched solid, as you mentioned.

Joshua Meisner