Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
chem 120 review
thermodynamics...entropy and such...
| Question | Answer |
|---|---|
| extensive property | dependent on the size of the system if the system gets larger, then the value gets larger |
| state | complete specification of the system properties or variables (e.g. P, V, n, and T) to know the state is to know everything there is to know about the system |
| intensive property | independent of system size |
| mols (n) | extensive so if we wanna make a property intensive, well just divide it by mols to make it intensive |
| Pressure (P) | intensive think of the two rooms with the connected door |
| Volume (V) | extensive |
| Gas constant (R) | intensive |
| temperature (T) | intensive b/c d=m/v aka extensive/extensive and that's intensive |
| mass | extensive |
| energy (U) | extensive |
| enthalpy | H extensive; a property of the system |
| entropy | S property of the system |
| energy | the capacity of a system to do work (or produce heat) J calorie, kilocalorie (Calorie), |
| thermal energy | kinetic energy associated with the random motion of atoms and molecules |
| enthalpy | H = U+PV extensive thermodynamic state function in J or kJ |
| entropy | S microscopic def: the logarithm of the number of microstates available to a system in a given macrostate AKA A MEASURE OF DISORDER (high entropy high level of disorder) (im eating dis order) |
| spontaneous | broader def might eventually occur on its own (possibly, maybe) this may occur if you give it enough time,,,but that time could be beyond the age of the universe possible rxn moves in the natural aka spontaneous direction |
| nonspontaneous | will NEVER EVER occur on its own you have to do work for this process to happen impossible |
| what does spontaneity tell us about rate of a rxn | nothing it says nothing about rate rate is controlled by chemical kinetics |
| is the first law of thermodynamics sufficient in predicting spontaneity | hell nah first law cannot predict spontaneity but it can determine whether a process is endo vs exothermic |
| can we tell spontaneity purely based off of if a process is exo vs endo thermic | no some endothermic processes are spontaneous and some exothermic processes are nonspontaneous |
| endothermic | ΔH>0 |
| exothermic | ΔH<0 |
| spontaneous processes tend to be accompanied by | dispersal of matter and/or energy AKA MORE ENTROPYYYYYYYY |
| dispersal of matter and/or energy | tends to favor spontaneity think about it, if you release mass of a gas, it'll disperse (natural direction) but you'll have a hard time putting it all back together how it was (it'd take a lot of......work....) |
| what are the 2 factors that tend to affect spontaneity | energy and mass specifically, their distribution |
| micro vs macro states | for one macro state there are many ways microscopically your system can get there aka microstates are the combinations to get a certain outcome (macrostate) this is so genetics. microstates are the genotypes and macrostates are the phenotypes |
| distribution | group of energetically equivalent microstates |
| how do you determine the most probably distribution (macrostate) | |
| what determines the entropy of a system | the number of microstates corresponding to a certain macrostate |
| what defines a macrostate | thermodynamic variables like temperature pressure and volume |
| spontaneous processes associated with what level of entropy | HIGH levels of entropy greater entropy= more disorder= cant get your ducks in a row = cant do as much work = don't need to if its spontaneous = so more entropy associated with spontaneity |
| dispersal of matter ___ entropy | increases |
| few microstates | small entropy spontaneity less probable |
| many microstates | large entropy spontaneity more probable |
| first law of thermodynamics | the total internal energy of the system and surrounding is a constant (internal) energy is neither created nor destroyed energy gained by system is lost from surroundings and vise versa ΔU total = ΔU (system) +ΔU surroundings = 0 and ΔU= - ΔUsurr |
| second law of thermodynamics | spontaneous change causes an increase in the total entropy (system + surroundings) entropy can only increase, never decrease |
| third law of thermodynamics | a perfect crystal at 0K has an entropy of 0 *sets a baseline/bottom value for doing entropy calculations* whats the lowest possible entropy you could have because only 1 microstate is available then, no more because nothing can move |
| S^o | standard (absolute) entropy entropy of a pure substance at 1 atm |
| what does the circle/not mean | constant pressure, specifically 1 barr aka 1 atm |
Created by:
user-1759191