Terms in this set (24)
Reaction Composition Diagrams
As the reaction progresses, the reactants (A+B) produce products (AB)
- A mixture of products and reactants is present until all products are produced
- Only reactants are present at the beginning prior to the reaction starting
What causes a reaction to progress?
When does a reaction essentially "stop"?
When the molecules have reached the lowest energy state and are most stable
- low potential energy state
No further change in composition of molecules
(bonds are constantly broken and reformed)
Contains an Fe^3+ to bind and carry O2 in our circulation, CO has a higher binding affinity for the Fe^3+ (TOXIC)
Hb+Fe^3+-O2 + CO <---->Hb+Fe^3+-CO + O2
- Hb+Fe^3+-O2 is more favorable, reaction needs to be pushed in this direction by having high O2 available
Equilibrium Constant (Kc)
Ratio of products to reactants at the point in which the reaction has stabilized and the forward and reverse reactions are equal
- any coefficients become the exponents in the equation (subscripts are not relevant)
Reaction Quotient (Q)
Ratio of products to reactants at a point during the reaction where equilibrium is not met
- any coefficients become exponents in the equation (subscripts are not relevant)
Comparison of Q and Kc
Compare these two numbers to determine the favored direction of the reaction
Table used to determine the equilibrium concentrations of molecules in a reaction
- reach given is not at equilibrium, but it will reach it and you are interested in determining the concentrations when this occurs
I- Initial Concentration Row (First Row)
Use the given concentrations (or determine the concentrations) of the molecules prior to the reaction reaching equilibrium
- concentration must be in M (mols/L)
C- Change Concentration Row (Second Row)
Determine reaction shift and designate this with x or -x depending on the direction the reaction is going
- coefficients will become coefficients for x (i.e. 2Cl --> 2x change)
- if no product or reactants are present initially, the reaction will shift in the direction to form either one that is missing (i.e. if no products are initially present in a system, the reaction will shift towards the products, +x, decreasing the reactants, -x)
E- Equilibrium Concentrations (Third Row)
Using the initial concentrations, add or subtract the change determined in row 2
- using these equations will give you the equilibrium concentrations (in M, mol/L)
Pressure Equilibrium (Kp)
Same equation as Kc, but the units are in torr (or atm)
Equilibrium Expression for Heterogeneous Solutions
Only molecules capable of changing composition (ions in solution, aq, or gases, g) are used
- pure solids and liquids are left out of the expression
Products favored (forward reaction)
Reactants favored (reverse reaction)
2 reactions with different Kc's that can be combined
If a system is not at equilibrium, are the rates of the forward and reverse reaction equal?
When a reaction is driven away from equilibrium, why does it shift to reach equilibrium again?
The reaction is unstable, because there is extra potential energy
- the reaction wants to become stable and lose the extra energy (go back to equilibrium)
When a stress is added to a system at equilibrium, how does it effect the reaction diagram at that moment?
It will show a change in the reaction represented by an increase or decrease in products/reactants
- can be a sudden change or gradual change
After a reaction is disturbed by a stress, it causes a change to the reaction. If the reaction is left to progress for some time, what happens to the reaction diagram?
It will reach equilibrium again
- the rates of the forward and reverse reactions will be equal (the products and reactants lines will level off)
Large K value
Products are favored and reaction progresses in forward direction
Small K value
Reactants are favored and the reaction progresses in the reverse direction
What is the only change to a system that affects a K value?