Keq is the equilbrium constant Ksp is the solubility constant They are related in that Ksp is a type of Keq, but Ksp only deals with how soluble something is under specific conditions. Keq is alot more general, and is usually used to designate what a reaction looks like at equilibrium (ie: max.
Equilibrium Constants
Equilibrium is a state of balance between products and reactants. When the rate of the forward reaction is equal to the rate of the reverse reaction, the concentrations of products and reactants remain constant. Every reaction is striving to reach equilibrium.
Le Chatelier's Principle : if equilibrium is disturbed (eg. if product or reactant concentrations are altered), the direction of the reaction will shift to restore the state of equilibrium.
Equilibria are reflections of Le Chatelier's Principle. If we begin a reaction with only the reactants, they will readily form products. As the concentration of the products increases, the rate of the reverse reaction increases. As the concentration of reactants decreases, the rate of the forward reaction decreases. Eventually the reaction rates will cancel each other out, and there will be no net change in the concentration of reagents.
Omg fortune free slots coins. The Equilibrium Constant(Keq) describes the ratio of products to reactants in a state of equilibrium.
- Some reactions have a big Keq. When these reactions reach equilibrium, there will be a lot of product, and little reactant left.
- Some reactions have a small Keq. Don't expect these reactions to produce much product.
- See that the Keq for the reverse reaction will be the reciprocal of the forward reaction.
Strong acids and bases dissociate with large equilibrium constants.
Explains the relationship between ΔG and Keq for a reaction and illustrates calculations involving these two parameters. To calculate a milliequivalent (mEq) you have to have two pieces of information: The mass of the substance in question and the molar mass (or molecular weight) of that substance. You must also be able to identify its valence from its molecular formula, as this determines ion number in solution. The cell potential and free energy example shows how to calculate free energy of a redox reaction. If ΔG = 0:, solve for E cell 0 = -nFE cell E cell = 0 V This means, at equilibrium, the potential of the cell is zero. The reaction progresses forward and backward at the same rate, meaning there is no net electron flow. Let's now examine how to calculate equlibrium concentrations of cyclohexane conformers. Before beginning it must be clear that the A values (in Kcal!) are related to the equlibrium constant in the following manner: A =-DG x o = RT lnK eq; and Keq is is the equlibrium constant of a group going from axial to equitorial (a favored shift).
We use a specific type of equilibrium constant when describing the dissociation reactions of acids and bases. Recall the equation for the dissociation of an acid:
The Keq of this reaction is given by. We call it Ka, the Acid Dissociation Constant
Likewise, the equilibrium constant for a base dissociation is given by Kb, its Base Dissociation Constant. The best video maker app for pc.
The Dissociation Constant determines the strength of the Acid or Base
Strong vs weak Acids
Here is a list of many acids along with their Ka values. The top three on the list would be considered strong acids – they will essentially dissociate completely. Most acids are weak, though two weak acids can vary greatly in Ka.
Most important difference between strong and weak acids: once the reaction reaches equilibrium, strong acids will be dominantly in the conjugate base form. Weak acids will exist as a mixture of the original acid and the conjugate base form.
For simplicity, the strength of the acid will often be given as pKa. pKa represents the same information as Ka except its logarithmic scale eliminates the need for exponential notation. This simple equation converts between Ka and pKa.
Using these equations, see how a large pKa denotes a very weak acid. Bases have very large pKa
Bases use Kb and pKb as measurement of how favorably they accept protons (basicity). Kb works exactly like ka. A small Kb means equilibrium highly favors conjugate acid formation, indicating a strong base. A larger Kb indicates a weak base that will partially form conjugate acid and partially remain in its base form.
General Note: A stronger acid or base will produce a weaker conjugate. A weaker acid or base will produce a stronger conjugate.
Summary
How To Calculate Keq In Chemistry
Here is an example of an acid base reaction. The Keq is 1.8e-5
Do we start with an acid or a base?
NH3 (ammonia) is a base. This is clear because the products include its protonated form NH4 (ammonium). We see it is acting like a base and accepting a proton from water.
The conjugate acid is ammonium. In the reverse reaction, ammonium acts as an acid and hydroxide acts as a base. Ammonium donates a proton to hydroxide.
How To Calculate Keq From Concentrations
Find Kb for ammonia: This would simply be the given Keq for the reaction. Kb is just the Keq of a specific type of reaction between a base and water. Kb = 1.8e-5. Ammonia is a weak base.
Find Ka of conjugate acid. https://omrevl.over-blog.com/2021/02/adobe-premiere-cs6-help.html. This is would equal the Keq of the reverse reaction. The Keq of the reverse reaction is the reciprocal of the the forward reaction. Ka = 1/Kb = 5.6e-10. Mitsubishi cp9800dw drivers for mac. Since ammonia is a base of moderate strength (though defined as ‘weak'), see how its conjugate acid is is very very weak. This makes sense because if the conjugate acid were stronger, the reverse reaction would be more favorable, causing the forward base reaction to become less favorable.
Convert Ka and Kb to pKa and pKb.
Megabucks las vegas payout. pKb = 4.75 pKb = 9.25
Note: pKa + pKb = 14.0
After reading this you should be able to:
- make a prediction about the properties of a molecule by looking at its pKa value.
- label the acid, base, conjugate acid, and conjugate base in a reaction
- Use Keq to determine concentrations of reagents.
