![Page 1: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/1.jpg)
TOPIC: ENERGYDo Now:
![Page 2: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/2.jpg)
All physical & chemical changes are accompanied by change in energy
The chemistry of energy changes is known as Thermochemistry!
![Page 3: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/3.jpg)
Stability and Energy
• If energy is high, stability is low
• If energy is low, stability is high
![Page 4: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/4.jpg)
Energy: Ability to do WorkThe SI unit for an energy
measurement is called the Joule (J)
EXAMPLE: 1 Joule = amount of energy required to lift a golf ball 1 meter
![Page 5: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/5.jpg)
Other Energy Units: calorie, Calorie, BTU’s
1 calorie = 4.18 Joules
1 Calorie = 1000 calories = 1 kilocalorie
NOTE: When your body breaks down food, these reactions give off heat – which is measured in calories (That’s why your food is labelled in calories)
![Page 6: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/6.jpg)
Law of Conservation of Energy
• Energy is neither created nor destroyed in ordinary chemical or physical change, rather it can be converted from one form to another
Energy before = Energy after
- potential to kinetic - radiant to electric- electric to heat - chemical to kinetic- chemical to electrical
![Page 7: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/7.jpg)
(Not a complete list!)
Energy
Mechanical – large enough to see
Kinetic Potential
Non-mechanical – too small to see
Chemical Heat Light Electrical Nuclear
![Page 8: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/8.jpg)
Kinetic Energy (KE) – energy of motion
• KE = ½ x Mass x Velocity2 = ½ mV2
• KE depends on how heavy and how fast
Kinetic Molecular Theory: the atoms and molecules making up substances are in constant motion
![Page 9: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/9.jpg)
Potential Energy (PE): energy of position; stored energy of matter
EXAMPLESstaplerRubberband
![Page 10: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/10.jpg)
• When Potential energy is released from matter it becomes kinetic energy
![Page 11: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/11.jpg)
Energy in Chemistry=
chemical energy
heat energy
![Page 12: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/12.jpg)
Chemical Energy
• energy stored in bonds
• Bonds are stable• You need energy to break bonds• Energy is released when bonds are formed
![Page 13: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/13.jpg)
EXOTHERMIC If the overall energy in a chemical
reaction is negative (meaning energy is released) = the rxn is
exothermicenergy (heat) is given off =
exothermic EXO - energy leaves system (exits)
![Page 14: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/14.jpg)
Environment
System
Energy
Exothermic RxnTemperature of environment
Temperature of system
![Page 15: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/15.jpg)
ENDOTHERMIC If the overall energy in a chemical
reaction is positive (meaning energy is absorbed) = the rxn is
endothermic
energy (heat) is absorbed = endothermic
Endo - Energy enters system (enter)
![Page 16: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/16.jpg)
Environment
System
Energy
Temperature of environment
Temperature of system
ENDOTHERMIC
![Page 17: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/17.jpg)
Energy of Universe is conserved
Universe
EnvironmentEnvironment
System
Energy
Energy can move between the system and the environment
![Page 18: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/18.jpg)
Calorimeter: an insulated devise used for measuring the amount of heat absorbed or released during a chemical or physical change
![Page 19: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/19.jpg)
“universe” is contained in Styrofoam cup
“environment” is water****
“system” is whatever put in water
Energy lost = Energy gained
Difficult to monitor “system”Easy to monitor “environment” (water)
Energy lost/gained by environment = Energy gained/lost by system
![Page 20: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/20.jpg)
Calorimetry
10 grams of NaOH is dissolved in 100 g of water & the temperature of the water increases from 22C to 30C
• was dissolving process endothermic or exothermic
• how do you know?
Exothermic – temperature of environment ↑
![Page 21: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/21.jpg)
Heat EnergyHeat: energy that is in the process of
flowing from warmer object to a cooler object
Symbol for heat energy = Q or q
The amount of heat required to raise the temp. of 1 gram of water 10C = a calorie
![Page 22: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/22.jpg)
The amount of heat transferred depends on 3
things
Temperature changeMass of substanceSpecific Heat of substance
![Page 23: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/23.jpg)
Specific Heat• The amount of heat required
to raise the temp of any given substance by 10C
• Symbol = c
• Specific heat = a physical constant
• unique for each pure substance
Found in Table B
![Page 24: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/24.jpg)
Calculating Heat Transferred
Q = mCT
Simple system: •pure substance in single phase •calculate heat gained or lost using:
Q = amount of heat transferredm = mass of substanceC = specific heat capacity of the substance.T = temperature change = Tfinal – Tinitial
![Page 25: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/25.jpg)
Calorimetry problem from before
10 grams of NaOH is dissolved in 100 g of water & the temperature of the water increases from 22C to 30C
• We already said it’s exothermic – now we can actually calculate the amount of heat energy released
Energy lost by NaOH (system) = Energy gained by
water (environment)
Environment
Energy
![Page 26: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/26.jpg)
• What’s happening when NaOH dissolves?
Add H2O
NaOH close together, not interacting
Na+ and OH- ions pulled apart & interacting with H2O
![Page 27: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/27.jpg)
Q = mCTQ = energy (joules)M = mass (grams)C = specific heat capacity (Table B)T = temperature change = Tf - Ti
Q = ?M = Well, temp change was for water, so want mass of water
m = 100 gC = specific heat capacity (Table B) = 4.18 J/gKT = temperature of water increased from 22C to 30C
30C -22C = 8C = T
![Page 28: TOPIC: ENERGY Do Now:. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!](https://reader036.vdocument.in/reader036/viewer/2022062407/56649d985503460f94a8308c/html5/thumbnails/28.jpg)
Q = mCT
• Q = (100 g)(4.18 J/gC)(8C)
• Q = 3344 Joules