<p>It gets hot because the enthalpy of solvation is negative..but I think its a physical process, not a chemical reaction</p>
<p>H20+CaCl2>2HCl+CaO(s)</p>
<p>ok thnx, I will ask my teacher today,
I must know this, because this experiment will be 10 percent of my final exams grade:S</p>
<p>man on fire, are you sure thats the reaction? I am almost positive that CaCl2 is an ionic solid that is very soluble in water.</p>
<p>I just done the experiment, It becomes very hot with water</p>
<p>yeah..cuz the enthalpy of solvation is negative. but i still think the process is a physical process, not a chemical reaction because its just cacl2 ionizing in water.</p>
<p>Yeah youre right, it isn't a chemical reaction, it's the Ca2+ who breaks off the h2o-roster, and therby causing lot of energy, what comes out as heat</p>