To aubrey, jona, bahemm, CHE 121 Chap 6 Reviewers Flashcards
State in which there are no observable changes
with time
Equilibrium
Chemical Equilibrium is achieved when:
- Rates of the forward and reverse reactions are equal and
- Concentrations of the reactants and products remain
constant - Dynamic equilibrium
Gibbs energy tends to minimum at?
ΔT = 0, ΔP =0
At constant temperature and pressure:
- ΔGrxn < 0 ; forward rxn spontaneous (Exergonic)
- ΔGrxn > 0 ; reverse rxn spontaneous (Endergonic)
- ΔGrxn = 0 ; rxn at equilibrium (Neither)
A strongly exergonic process can drive a _____ endergonic process
weaker
Based on Law of Mass Action, Equilibrium will
Lie to the right & Favor products if K > 1
Lie to the left & Favor reactants if K < 1
Ways of Expressing Equilibrium Constants
- Heterogeneous equilibria
- Homogeneous equilibria
Applies to reactions in which
reactants and products are in different phases
Heterogenous equilibrium
In heterogeneous equilibrium, the concentration of solids and pure liquids_____in the expression for the equilibrium constant
are not included
Applies to reactions in which all
reacting species are in the same phase
Homogenous equilibrium
How does equilibria respond to pressure?
ΔG = -RT ln K
Defined at a single standard pressure, 1 bar. Therefore, K is independent of pressure. However, equilibrium composition is NOT necessarily pressure-independent.
Two ways to pressurize a gas:
- Vapour plus inert pressurizing gas
-Piston permeable to vapour but not to liquid
Le Chatelier’s principle:
If an external stress is applied to
a system at equilibrium, the
system will adjust itself in order
to minimize the stress
How does equilibria respond to temperature
From Le Chatelier’s principle for a system at equilibrium:
* System will shift in endothermic direction as T increases
* System will shift in exothermic direction as T decreases
Type of reaction in which an increased T favors reactants
Exothermic reactions
Type of reaction in which an increased T favors products
Endothermic reactions
It has the dimensions of amount of substance and is reported in moles, ξ (xi)
Extent of reaction;
Is defined as the slope of the
graph of the Gibbs energy plotted against the extent of reaction:
Reaction Gibbs energy, ΔrG
Note: Delta sign means derivative (Not difference in values)
Condition of Equilibrium
∆rG = 0
The spontaneous direction of reaction lies in the direction of decreasing G. The slope is zero, and the reaction is at equilibrium and spontaneous in neither direction,
Ratio of activities of products and activities of reactants. It is also a combination of activities used
to express the current value of the reaction Gibbs energy.
Reaction Quotient, Q
An equilibrium constant K expressed in terms of activities is called a
Thermodynamic equilibrium constant
Note: Because activities are dimensionless, the thermody-
namic equilibrium constant is also dimensionless.
The degree of dissociation (or extent of dissociation, α) is defined as
The fraction of reactant that has decomposed;
Is the value of the reaction
quotient at equilibrium.
Equilibrium constant
Lastly, complete the statement. Shikata….
ga nai
Believe you can and you’re halfway there - Roosevelt
“When things go wrong, as they sometimes will, When the road you’re trudging seems all uphill, When the funds are low and the debts are high, And you want to smile, but you have to sigh, When care is pressing you down a bit,
Rest, if you must, but don’t you quit. - John Greenleaf Whittier
To Aubrey, Bahem, Jona,
Hinaut naa pa mo ani na cards para mabasahan pa ni. Okay lang pud kung dili na hehe. Hapit na gyud ta sa finish line. Hangak na kaayo pero kung atu lantawun, layo na gyud tag nalakwan sa life. 3rd yearr na tayoo. Wala gyud kuy control sa atu situation runn. If ever naa lang kuy magic, ipapasar nako kita tanann. You are always included sa ako prayers, na makapasar unta tayo no matter unsa ka lisud ang umaabot na problems. Wala ko dira sa inyu physically pero I know makaya na ninyu kay naa kayo tulo kumpleto dira. God bless sa inyuuu tulo. Mas giant pa mo compared sa themo. God bless guys, uncertain kay atu future, but but one thing is for sure, naa ra mi dari para ninyu. You are not alone in this fight. Unsure pa sad kung nakapasar ko, but wala na sad ko mabuhat pero sige lang, come what may. All of the besttt sa inyuu, aubreyyy, jonaaa, bahemmm. Buhaton nako tanan ug ihatag nako ako mahelpp para maka graduate tayo on timee gyudd hantud sa ako makaya, labyuuu
-Abdul :))
