Unit 8 - Relating how much to how many- Stoichiometry Part 2

As these peanuts are reacting with air they are also releasing their chemical energy to the surroundings. In this case, the water above is being heated by the energy released by th epeanuts. Is it possible to quantify the amount of energy released for every mole of peanut that reacted? Can this be done for every reaction whether it is exothermic or endothermic?



Equations representing chemical reactions can also relate numbers of particles (molecules or formula units) to volumes of gases, solutions and to the change in chemical potential energy.

Molar volumes of gases and molar concentrations of solutions are analogs to molar mass used in the previous unit. They enable one to relate how much of a measured quantity to how many particles are involved. The chemical potential energy involved in a reaction is proportional to the number of particles involved. It may be included as a term in the balanced equation for a reaction and treated in the same manner as reactants and products in the BCA table. DH is used as our best approximation of the change in Ech or Ei.


Dr. Michael M. Krop High School







Unit 8 Materials


m r . m o n t e r o . c o m




SCUBA diving tanks are filled with air at high pressure. What happens to the air pressure as the air is consumed by the diver? Is it possible to relate amount of air to pressure? How does is the volume of the gas change as the air is consumed?

Above the gas tanks we can see the ocean. The ocean is a complex solution of water and many ionic solids. Sodium chloride is the most abundant compound. How many moles of sodium chloride can be found in a liter of sea water? in other words, what is the molarity of NaCl in the sea?