Energy

 Cooks the food we eat  Propels vehicles that transport us  Allows photosynthesis to occur to start the food chain  Energy from burning fuels heats or cools the classroom  Allows you to think and write  Cells are factories that run on energy derived from the food we eat

 The ability to do work or produce heat  Potential energy vs. kinetic energy – 2 basic forms  Potential energy – energy of position  Kinetic energy – energy of motion  Ex. Roller coaster

 Contain both kinetic and potential energy  Kinetic energy – directly related to constant random motion of particles – prop. To temp.  Potential energy depends on composition – chemical bonds, arrangement of atoms, etc.

 Energy can be neither created nor destroyed, it can only be converted from one form to another.  1 st Law of thermo.

qq  Energy flowing from a warmer object to a cooler object.  As energy flows, change in temperature  Calorie – energy needed to raise one gram of water one º C.  When your body breaks down sugars and fats to form carbon dioxide and water, these reactions generate heat energy that can be measured in calories.  SI unit is the joule which equals calories.

 1J= calories, then one calorie equals…  Joules.  1 nutritional calorie = kcal  Pg. 492 practice problems  The specific heat of any substance is the amount of heat required to raise the temperature of one gram of that substance by one degree Celsius.  So, for water, that’s 4.184J/g · º C

 Cp = q. m x ∆T Cp = specific heat q = heat absorbed or released by substance m= mass ∆T = change in temperature

 The relationship between heat and specific heat…  q=c ·m·ΔT  q total =q water + q material  or  c water ·m water ·ΔT water = c material ·m material ·ΔT material  Table pg. 492

 Pg. 495 #’s 4-6

 (Sounds like…?)  Is an insulated device to measure the change in heat during a chemical reaction.