Important Flashcards
(55 cards)
thermo
study of Ecs of chemical reactions
2 rel forms of E in chem
Ek mvmt of m/cs
Ep E stored in chem bonds
wat is most imp Ep storage m/c in all cells?
ATP, which stores E in the ester bonds b/w phos groups
1st law of thermodynamics
law of cons of E
E of the uni is constant
implications of 1st law
E sys decreases, E of rest of universe ( surroundings) increase and vv
2nd law thermo
disorder/ entropy of uni increases
another way to state 2nd law
spont reactions tend to increase disorder of universe
symbols for entropy and change in entropy
S and delS
change in entropy symbols
delS= S fin-S in
if delS is - did the disorder of system increase or decrease
decreased because del S is neg then the system lost entropy
del G =n
del G= delH -T delS
T is temp in K
H enthalpy
del H =n
del H= del E+ P delV
E = bond E of products or reactants of system
P= pressure
V= volume
Given that cell reactions take place in l phase how is H related to E in a cell
H is approx = to E since change in V is approx 0
del G is affected by
increases with increasing del H ( bond E) and decreases with increasing entropy
Given 2nd law of thermo and math def.n of del G which reaction will be favorable, one with decrease in free E or one with increase in free E
favorable rct.ns have del G less than 0
deduced from the 2nd law and equation 1 because second law states increasing is favorable
spont or non spont del G
del G - spont
del G + non spont
dets whether reactants will stay as they are or be converted to products
spont rct.ns
occur without net addition of E have del G less than 0
occur with E to spare
exergonic reactions
rct.ns with - delG
E exits the system
endergonic rct
can only occur if E is added
how are endergonic rct driven in lab and body
in lab : add heat
in body: coupled with exergonic
exothermic rct.ns
rct with - del H
liberate heat
most met.c reactions are exo, that is how homeothermic orgms such as mammals maintain a constant body temp
rct.ns with + v H
require input of heat and are referred to as endothermic
signs of thermo quantities
assigned from the POV of the system not the surroundings or the universe
meaning of - delG
system goes to a lower free E state and syste will always move in direction of lowest free E
