Energy – the ability to do work or produce Potential energy
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Energy Energy
Energy – the ability to do work or produce ______ Potential energy – energy due to _____________ of an object Kinetic energy – the energy of motion Energy
The SI unit for energy is the ____________ 1 J = 1 Kgm2 / s2 Another unit of energy that you may be more familiar with is the calorie
1 cal = 4.18 J 1000 calories = 1 Kilocalorie = 1 Calorie Energy Conversions Convert 15,500 joules into Calories Formulas – Kinetic Energy Kinetic energy KE = ____________ KE = kinetic energy (joules) m = mass (must be in Kg) V = velocity (must be in m/s)
Potential Energy PE = __________ PE = Potential Energy (J) m = mass (Kg) g = gravitational constant = 9.8 m/s2 h = height (m) Formulas - Work Work (w) –______________ Force (F) – a push or pull on an object W = mgd = Fd = PE Work and potential energy can be looked at in the same light No distance __________________ Examples
A bowler lifts a 5.4 kg bowling ball 1.6m and then drops it to the ground. How much work was required to raise the ball? Examples How much potential energy does that ball have at this height? If the ball is dropped and we assume that all of the potential energy is turned into kinetic energy, at what velocity will the bowling ball hit the ground? More examples What is the kinetic energy of 1 atom of Ar moving at 650 m/s? 1st Law of Thermodynamics – energy is conserved The law of conservation of energy states that in any chemical reaction or physical process, energy can be converted from one form to another, but it is neither ____________________ 1st Law of Thermodynamics Since energy can neither be gained nor lost, the change in E can be calculated using: DE = Ef – Ei In a chemical reaction i indicates __________ and f indicated ____________ DE DE has 3 parts: A # indicating the _____________ A sign (+/-) indicating the _____________- A unit Thermochemistry Thermochemistry is the study of _______________that accompany chemical reactions and phase changes. In thermochemistry, the __________ is the specific part of the universe that contains the reaction or process you wish to study. Thermochemistry Everything in the universe other than the system is considered the ________________ Therefore, the ____________ is defined as the system plus the surroundings. Relating D E to heat & work The system can exchange energy with its surroundings in 2 ways: _________________ DE =_______ DE = change in energy q = heat
w = work q & w
Don’t forget q & w must have signs In order to get the sign you must look at the system as a box and the surroundings as everything else q & w Anything going INTO the box will be ___ Anything going OUT of the box will be ________ Examples
A system absorbs 140 J of heat from the surroundings and does 85 J of work on the surroundings. Calculate D E. Endothermic & Exothermic Directory: SiSFiles -> Schools Schools -> How were the North, South, and West Different Socially During the Antebellum Period? Schools -> Civil War True/False Schools -> A doll's House Schools -> Maus Prologue, Ch. 1 & 2 Questions Schools -> 1. Revolution Timeline According to the timeline, what major event happened in March 1770, that helped lead to the American War for Independence? 2 Schools -> A raisin in the Sun questions – Act I Schools -> Omam topic #1: The Needs Served by Relationships Download 124.62 Kb. Share with your friends:
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