Magnesium+ acid: how to calculate energy given off

[jwaterman]

I would like to be able to calculate the energy given off when magnesium reacts with nitric or ethanoic acid (Joules or Kcals). Could you please show me how to work out the energy given off for any mass of magnesium and acid?

[Iodide]

You should be able to take the temperature of the resulting solution and factor in the specific heat of water and the container. I don't know, that's a pretty crude way. Maybe you were looking for a more professional method?

[jwaterman]

Thanx iodide, but I was looking for a way in which you could calculate it without having to conduct the experiment. Isn't it possible to work out how much energy is given off in any exothermic reaction without conducting the experiment :? ?

[RobJim]

I think you need to find the bond energies within the reactant molecules and compare them with the bond energies within the product molecules. Subtract them and it will tell you what the energy change was. You should be able to find the bond energies in the CRC Handbook.