Heat+&+Temperature

= = =Heat & Temperature= = = = = Chapter 13. = = Temperature and Kinetic Theory = =



= = Basically everything is composed of little things called atoms, and these atoms can speed up and slow down based on a lot of things like temperature. = = Solids have attractive forces that keep molecules in a somewhat fixed position, they almost oscillate in place. Liquids have a more rapid movement, and gases have very high speeds which move in a sporadic direction. = = A temperature could be defined as the relative hotness or coldness an object is. But remember relative is the key word, because we think of fire being hot, but the air around us is actually passes its boiling point. So RELATIVE = = A lot of ways to measure temperature, Americans are just special and we use Fahrenheit, but in all conversions we need it Celsius. So we can say some degree Celsius equals 5/9(degree Fahrenheit - 32). Most of the time it'll be giving in some bizarre unit since Mr. Pflaumer likes to watch us squirm. = = The next biggest thing is thermal equilibrium, where there is no heat being transferred between objects. Then theres this weird zeroth law where if a=b and b=c then well you guessed it a=c. We are talking about same temperature FYI. = = In the beginning we said that temperature affects the speed of the molecules, well that is true but it also affect the length.( we calculate materials with finite length). = = So the change in length can be expressed by Delta L equals coefficient of linear expansion X initial length X delta Temp. Change in volume can also be expressed by the same formula with beta for the coefficient of volume expansion. = = Boyle' Law = Volume goes up, pressure goes down = = Charles's Law= Volume goes up, temp goes up = = Gay lussac's law= pressure goes up, temp goes up = =

= = There's this other cool thing for gasses called ideal gas law =PV=nRT, remember it's ideal and were not cool enough to real gases. It is all an approximation. = = We normally calculate in kelvin which is 273.15 + degrees Celsius. = = STP is 273 K and 101300 Pa. = = Avogadro's Number 6.022 x10^23 so now we can say PV=NkT with boltzmann's constant 1.38x10^-23. = = Since we have movement we also have kinetic energy which the average transitional kinetic energy can be expressed by KE=1/2mv^2 and KE=3/2kT = = Vrms= sqroot 3kT/m = = and theres this thing called diffusion, but no worries. = = Chapter 14. = = HEAT

= = Heat can be transferred from two objects, and it flows from warm to cold, since well because we don't have a temperature of cold, its just the absence of heat kind of like light and dark. What is dark? the absence of light OK i think we got it = = Well how do we express heat, well mainly in calories of joules, so one calorie is the amount of heat required to increase the temp of 1 gram of water by 1 degree Celsius and obviously you can convert that to other stuff like kcal's and stuff because well physics is pain. 4.186 joules= 1 calorie = = Ideal gases(monatomic-which is one atom…) have some internal energy represented by U=3/2NkT. Internal energy of ideal gases is I-N-D-E-P-E-N-D-E-N-T (yes you know what that means, and yes like the song i do know a rap song) of pressure and volume = = Amounts of heat affects temperature of objects differently and each of them has some proportionality constant called specific heat=c. = = heat transfer Q=mass x specific heat x change in temp This is a fairly important equation. = = We use a calorimetry for a number measurement of heat transfer. The Q=mcat is for things changing temperature amongst one heat, so to change temperature one needs to use latent heats and all that good jazz. = = So all heats have heat of fusion, which is given in amount to change one kg of a substance from a solid to liquid. Yes in kg's but it could be given in some other unit, so it is very vital that you make sure your units are in order if you know what i mean. = = There is also a heat of vaporization which is amount to change 1 kg of liquid to gas. If the opposite function occurs energy is given off and it is negative. Now we can say the heat required to change states is Q=mL. where L is all that latent heat. So for conclusion we just add or subtract all the Q=mcat and Q=mL to find the total energy required to get to the destination. = = Types of Heat transfer = = There is a heated argument between the true types of heat transfer, esteemed physicists have been arguing about this for years 3 or 2? Well let's go with 2 = = First there is Conduction/ Convection which is basically some heat transfer that can be totaled by Q/T=kAdeltaT/l. = = high k values means it is a good conductor of heat, while low is well you got it. = = Radiation- basically no medium, electromagnetic waves to transfer energy. Q/T= esigmaAT^4 = =

= =

= =

= =

= =