(TG) Heat and the Stoichiometric Method

* I know that these two topics were taught several weeks apart, but I want to keep the blog updated, and 1 post is simpler than 2.

ENERGY (in kJ's)

• Often times in chemistry you will get a chemical reaction that is either: EXOTHERMIC, or ENDOTHERMIC. These words may seem complicated but really they just mean, releasing heat (exo) and absorbing heat (endo)
• Whenever you see these in a formula (ie. NaBr + I = NaI + Br + 234kJ) all you have to do is treat the kJ's like another element.
• Since energy will only appear on one side of the equation you dont even have to balance it
• Whenever using energy pretend as if there is the coefficient of "1" infront of it

Now lets look at an example:

How much energy is released when 2.0 mol of I is used up?

2NaBr + I(2) = 2NaI + Br(2) + 345kJ

2.0 x 1/2 = 1 x 345 = 345kJ