In a chemical reaction

DH = H products   H reactants
If DH >0, then qp >0
The reaction is Endothermic.
Heat goes from the surroundings into the system.
If DH <0, then qp <0
The reaction is Exothermic.
Heat goes from the system into the surroundings.
An example of an exothermic reaction:
An example from the S&T mining dept:
http://www.youtube.com/watch?v=rdCsbZf1_Ng
http://www.youtube.com/watch?v=CIGJPWAynDQ