[jpc3]

  I need an exothermic reaction that will reach 450F to 500F in around 3 mins at room temperature.  I have tried a couple reactions, such as calcium oxide and water (CaO + H20 --> Ca(OH)2 + 63.7kJ/mol of CaO), but have not had much luck.  Does anyone have ideas or know where I could research this?

Thanks a lot!!

[brb725]

H₂SO₄ has a heat of dissolution of around -88.7 kJ/mol, if I recall correctly. You also have to remember that  Le Chatelier's principle says that as the temperature of the system that the reaction is occuring in increases, the reaction equilibrium will shift to favor the reactants (for an exothermic reaction), so that could cause the reaction to take longer than if heat was removed from the system.

However, I don't think that a dissolution reaction would be your best choice, since water has a fairly high specific heat, and thus will require more energy to heat up, and it also boils at 100C, which could be dangerous if you were creating a solution with a strong acid.

A thermite reaction can cause extremely high temperatures very quickly, but it is also very dangerous, so it probably shouldn't be discussed.