Chapter 5 Energy  Energy- "something" an object has if it can do work  Work- force x distance  Kinetic energy- energy of motion KE= 1/2 mv^2  Potential energy- stored energy PE= mgh  Chemical energy- PE stored in compounds w. chemical bonds Units:  Calorie- amount of heat needed to raise the temperature of 1.00 g of water by 1 degree  1 nutritional "Calorie" = 1000 cal = 1 kilocalorie = 1 kcal  Joule- mass x velocity (kg m^2/ sec^2)  4.184 J = 1.00 cal Kinds of energy:  PE increases when objects that attract are separated/ objects that repel are moved closer together  Exothermic- process gives off energy (heat out)  Forming a chemical bond (negative sign dH)  Endothermic- process consumes energy ( heat in)  Breaking a chemical bond (positive sign dH) Reactions:  Thermite Reaction (exothermic) 2Al+ Fe O --> 2 3 Al 2 +3Fe (l)  Step 1 Iron oxide --> 2 Fe + 3O (bonds break= endothermic) 