How would the problems created by an ice storm, differ for people living in a rural area
compared with an urban area?

A,) cause a & b are equal & both gives 180°

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