Metals expand when heated. if gold is heated, what will happen to its density?

The gold will not expand get thiker in lava Lite and breaks down and then as you cool it down it

They are all decomposition reactions.

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.