Do now; Turn in safety lab New Seats Put Everything away

Separations; Physical or Chemical Change? Mixture  Pure substance? Compound  Elements?

Watch and think… What is happening to the mass? What is happening in terms of energy?

Take out the graphic organizer You will be taking notes in it as I lecture

Laws of Conservation of Matter Matter can not be created or destroyed, only converted from one form to another – Then what happened to the mass in the paper? – Became CO 2 and H 2 O and released into the air! CO 2 + H 2 O

Conservation of Matter If we started with 2 grams of paper and burnt it completely, what is the mass of CO 2 and H 2 O released into the air? – 2 grams If 40 grams of substance A reacts with 20 grams of substance B, how many grams of substance C will be formed? – 60 Grams

Law of the Conservation of Energy Energy cannot be created or destroyed by physical or chemical change, only converted from one form to another – Where did the energy come from? – Where did it go? – What is energy?

What is Energy The ability to do work (using force to move an object a distance) 2 Types of energy – Kinetic – Potential

Kinetic Energy The energy of Motion Anything that moves has kinetic energy

Kinetic Energy; Temperature Temperature is the measure of the average kinetic energy – Atoms, molecules and other particles are all moving and have kinetic energy Higher the Temp, the more kinetic energy

Kinetic Energy; Temperature Scales; Celsius; Based on the freezing and boiling points of water  0 = freezing  100 = boiling

Kinetic Energy; Temperature Scales; *Kelvin; Reset the Celsius scale so that there were no negative numbers – 1 kelvin increase = 1 degree C increase – 0 degrees kelvin = -273 degrees C At 0 kelvins EVERYTHING STOPS MOVING!!

Converting from Celsius to Kelvin Freezing point of water – 0 celsius  K? – 273 kelvin Boiling Point of water – 100 Celsius  K? – 373 Kelvin 293 kelvin  Celsius? – 20 degrees celsius 35 Celsius  Kelvin? – 308

Potential Energy Stored Energy Isn’t doing work right now but has the ability to if released This climber has a lot of potential energy…she’s so high up!

Potential Energy Food has potential energy (that’s why we need to eat it!) Stored in the chemical bonds in the molecules that make up the food

Potential Energy Coiled springs Batteries Objects at a height Magnetism…

Potential Energy: Measurement Can not be directly measured Must be converted to Kinetic energy and measured using a calorimeter Units: Joule (or Kilojoule)

Understanding check; ‘What’s my rule?’ A A boulder resting at the top of a hill A pulled back bow B A comet plummeting towards earth An arrow flying through the air

Back to the paper… Did it absorb or release energy? Where did the energy come from? Where did the energy go? How much energy was released in the reaction?

Heat of Reaction (ΔH) Δ = change (Δt would be change in time…) H = heat Heat always flows from where its hot to where its not

Heat of reaction ΔH During a reaction, energy can change from potential to kinetic or vice versa We have specific vocabulary to describe each Exothermic and Endothermic

Exothermic – Exo = outside – Therm = energy/heat Energy is being released to the outside environment What would happen to the temperature of the outside environment – Increase

Exothermic Heat is being lost…so would ΔH be positive or negative? - ΔH

Exothermic - ΔH Examples; Burning paper Heat pack

Endothermic Endo = internal/inside Therm = energy/heat Heat is flowing from the outside  in What would happen to the temperature of the outside? – It would decrease

Endothermic Energy is being gained, so would ΔH be positive or negative? + ΔH

Endothermic + ΔH Examples: – Cold packs – Melting ice (the ice is absorbing the heat) – Cooking an egg

Put simply… Potential energy  Kinetic energy = Exothermic – Negative ∆H Kinetic Energy  Potential Energy = Endothermic – Positive ∆H

What’s my rule? Battery Stretched rubber band Food Someone at the top of the stairs A projectile flying through the air A spinning yo-yo Someone falling down the stairs

What’s my rule? A camp fire burning Thermite reaction An instant cold pack Food cooking Sort; Freezing Water, Evaporating water

Practice A reaction occurs where the reactants have 70kJ of energy and the products have 50kJ. 1.Was this reaction exothermic or endothermic? 2.Positive or Negative ΔH? 3.If this occurred in water would the temperature increase or decrease? 4.What is the change in energy for this reaction?

Topic 2: Energy Graphic Organizer Lets take a look…

Do now; P of the homework packet (and anything before it that may not be finished) Read p8-10 in the notes packet and fill in Topic 3 graphic organizer