then why does water become hot when u dissolve NaOH in it and cold when u dissolve urea or NH4CL {ammonium chloride} in it
2006-12-28 02:15:40 · 3 answers · asked by lets rock 2 in Science & Mathematics ➔ Chemistry
Dissolving is an entropy driven process. The enthalpy can either be positive or negative. The ions in the solid are being separated (endothermic) and then solvated (usually exothermic) so it depends on which of these two processes is dominant to give either a cooling or warming.
2006-12-28 06:09:47 · answer #1 · answered by deflagrated 4 · 0⤊ 0⤋
because from the point of view of thermodynamics there is a heat of solvation which is the amount of heat absorbed or released on dissolving one mole of solute in a solvent ,dissolving of NaOH in water(reaction called hydration) is exothermic while the other reaction is endothermic.
2006-12-28 03:03:52 · answer #2 · answered by gogo 2 · 0⤊ 0⤋
Thease are exothermic & endothermic chemical reactions.
2006-12-28 02:42:25 · answer #3 · answered by deepak57 7 · 0⤊ 0⤋