PowerPoint Presentation

2/10/2014What is the law of conservation of mass?

So what do you think the law of conservation of ENerGY is?Todays GoalI can use chemical and physical changes to recognize chemical reactions.Todays PlanDiscuss the Law of Conservation of EnergyLab Conclusions

*Review on Tuesday**Chemistry Test Wednesday

Write down the underlined phrases and 1 example of each type of energyEnergyEnergy = Ability to do work;Energy = A source of useable power

What are the six different types of energy?Mechanical: Energy from motion (or position)What types of things have mechanical energy?

Other types of energyChemical: Energy that is storedWhat has chemical energy?

Other types of energyThermal: Energy from heat!What has thermal energy?

Other types of energyElectrical and Electromagnetic: Energy from charges (electrons).What has electric or magnetic energy?

Other types of energyNuclear: energy from atoms.

Converting EnergyMrs. Gardner ran 3 miles last night. What kind of energy is running?Running = Movement = Mechanical Energy!Where did Gardner get the energy to run?Food = Stored energy = Chemical Energy!Where did the food get its stored energy?Sun = heat = Thermal Energy!We traced this pathway BACKWARDSbut understand that all energy starts with the sun!

SunGives off heat which is Thermal EnergyPlantMakes Fruit that is full of Chemical EnergyBirdChews the fruit using Mechanical Energy

FruitFood gets stored as Chemical Energy in the bird

BirdFlies using Mechanical EnergySweat and HeatReleased to atmosphere through Thermal Energy

EnginePistons start pumping creating Mechanical Energy

BatteryUses stored Chemical Energy to ignite the engine

KeyTurned to on position using Mechanical Energy

FootPresses gas pedal using Mechanical Energy

GasolineReleases stored Chemical Energy into the engineCarDrives to the mall using Mechanical EnergyChemical reactions need energy to happenThat energy cannot disappear

Remember the Law of Conservation of EnergyExothermic reaction: a change that releases heat.

EXothermic = ExitFeels Hot

Endothermic reaction: a change that requires (or absorbs) heat.

ENdothermic = Enter(Feels Cold)Photosynthesis is an endothermic reaction (requires energy input from sun)

Measuring HeatreactionreactionExothermic reaction, heat given off & temperature of water risesEndothermic reaction, heat taken in & temperature of water dropsExamplesRunning: Motion energy changes into heat energySinging: Motion energy changes into sound energyCooking: Chemical energy and heat energy change into chemical energyLaw of Conservation of energyHow to make a reaction happen fasterEverything is made of particles.

The more these particles run into each other, the faster the reaction.Chemical Reactions occur because particles are moving

Increasing temperatureBy increasing the temperature, you are adding more energy to the particlesAdding more energy makes the particles move fasterThe more candy you give middle school students, the more active they becomeAdding energy to a liquid makes the particles move faster to become a gasThere are ways to make particles hit each other more2. Increasing surface areaBy increasing the surface area, you are creating more places for particles to hit each otherThere are ways to make particles hit each other more

Surface Area

If the particles are going fast enough to react, the next step is to allow it to react with as much material as it can. 23An inhibitor is a substance that slows down or stops a chemical reaction

Examples:Antibiotics stop the reaction needed for bacteria to make cell wallsPreservatives in food slow down the process of going badInhibitor