THERMALDYNAMICS (需全部删改进matter and molecules)

THERMALDYNAMICS (需全部删改进matter and molecules)

1. Kinetic Theory of matter

   • (补充)(or so-called kinetic model) states that all matter is made up of a vary large number of tiny particles (that are arranged differently depending on the phase) which are in continuous motion (Brownian motion & diffusion).
   • particles and Moles: measure of amount of substance
     • mole: (SI unit) a measure of the amount of substance. 1 mole=6.02×10^23 = NA. (n mole)·(NA) = N. (n mole)·(Mr)=(mass)
   • common states
     • Solid: fixed shape & volume, particles are of regular pattern closely pack & arrange in order, vibrating in a fixed position | very strong -EF, IMF
     • Liquid: fixed voulme, particles are of irregular pattern & further apart, move randomly | less strong -EF, IMF
     • Gas: neither fixed shape nor volume, particles are of irregular pattern & widely spaced, move randomly & fast | negligible EF+PE, very weak IMF
   • continuous motion
     • Brownian motion: rmMovement of particles
       • the random movement of particles in a medium due to their collisions with other much smaller particles of the medium.
   • Kinetic Theory of gas
     • (or so-called ideal gas model.)
     • juice: pressure exerts
       • Elastic Collisions: △p=2mu & N2: wall experiencedF=△p/ △t + N3: particles expF → expP=F/ A
         • (principle) particles collide with the wall, momentum changes when velocity changes. as N2 law states force is the rate of change of momentum, wall experience a force. as N3 law states particles experience an equal but opposite force by the wall. 
         • e.g. (this is the theory behind the gas exerts pressure on wall, so if we need to talk about F, P...) if T↑, KE & v ↑, particles collide more frequently, △p↑, F↑.
         • PV=(1/3)(N)(m)(m.s.)
           • N: number of particles in the substance. m: mass of each particles m.s.(mean square speed): mean square speed of the whole particles.
           • r.m.s.(root mean square speed)
             • root mean square speed:  take mean of each squared speeds, then root the mean.
             • (补充)the average velocity can be 0 as particles are in random motion.
             • Maxwell-Boltzmann distribution: distribution of speeds of particles
               • 1. is a distribution showing a range of speeds of particles of the substance. 2. named as two physicians Maxwell and Boltzmann.
       • Equation of state: PV∝nT → PV=(nT)(R)
         • (补充推导)the equation of states refer to the relationship between several thermodynamic constants, pressure, temperature and volume. it combines 3 laws: Boly's law. Charles' law(V∝T). Avogadro's law(V∝n). Hence PV∝nT.Therefore PV=R(nT)
         • (notice) if we gonna study the relationship of pressure against temperature, such a state equation demonstrating nothing but a tool for calculation.  so what we could do is to understant the theory behind this, which related to assumptions behind kinetic model and newton's laws.
         • apply k (Boltzmann's constant)=R/ (NA) → PV=(NT)(k)
           • → KE=(3/2)(k)(T)
             • combine equations of PV=1/3Nm(m.s.) and PV=(NT)k

2. constants of proportionality

   • c (Specific Heat Capacity): E △T of matter / m
     • energy required to change the temperature of matter per unit mass(Specific refers to sth per unit mass).
     • experi. determine c of liquid
       • 5pieces: 1.insulation (insulating substance to reduce external effects), 2.magnetic stirrer (stir liquid for uniform T throughout), 3.electrical heater with seperated circuit, 4.thermometer, 5.known mass liquid
         • 1.measurement: measure mass of that liquid.  initial and final T. current, voltage, time interval. 2.calculations: input energy: E=Pt=IVt. △T=T2-T1. 3.draw a graph of T ∝ t OR E. c=1/ (gradient)(m).
       • Method of mixture: △E1+△E2=0: m1c1(T1-T)=m2c2(T-T2)
         • given known masses of 2 substances at different T are mixed together, recording their final T. one c can be determined if known another c.
       • uncertainties: 1.heat loss to the container 2.heat transfer to surroundings/environments
     • c = E/ △Tm
       • it actually is the constant of proportionality. since E ∝ △T, m,  we can figure out some ratio to make it equal as an equation to use.
       • e.g. thermometer:E=c(△T m) the murcury inside has its own capacitance. when it absorbed energy from outside it changes temperature of murcury of unit mass. hence
   • L (Specific Latent Heat): E △phase / m at constantT
     • energy required to change the phase per unit mass while at constant T. 1.Lf: fusion E from solid to liquid. 2.Lv:vaporisation from liquid to gas.
     • experi.
     • L = E/ m

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