suppose your surface body temperature averages 90^0 F. How much radiant energy in micrometer would be emitted from your body. Determine the wavelength of maximum energy emission of your body, using Wien's law.

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen