Examples of the equilibrium position in the following topics:
-
- Catalysts speed up the rate of a reaction, but do not have an affect on the equilibrium position.
- Recall that for a reversible reaction, the equilibrium state is one in which the forward and reverse reaction rates are equal.
- In the presence of a catalyst, both the forward and reverse reaction rates will speed up equally, thereby allowing the system to reach equilibrium faster.
- However, it is very important to keep in mind that the addition of a catalyst has no effect whatsoever on the final equilibrium position of the reaction.
- To reiterate, catalysts do not affect the equilibrium state of a reaction.
-
- A bond can be modeled as two balls connected by a spring: stretching or compressing the spring initiates a back-and-forth motion with respect to the equilibrium positions of the balls.
- Measured bond lengths are the distance between those unperturbed, or equilibrium, positions of the balls, or atoms.
- Even though the bond vibrates, equilibrium bond lengths can be determined experimentally to within ±1 pm.
- Any stretch or compression of the spring will initiate oscillations of the atoms with respect to their equilibrium (unperturbed) positions.
- The minimum energy occurs at the equilibrium distance r0, which is where the bond length is measured.
-
- Chemical equilibrium is the state in which the forward reaction rate and the reverse reaction rate are equal.
- The result of this equilibrium is that the concentrations of the reactants and the products do not change.
- This is the point at which the system has reached chemical equilibrium.
- While there are various factors that can increase or decrease the amount of time it takes for a given system to reach equilibrium, the equilibrium position itself is unaffected by these factors.
- For instance, if a catalyst is added to the system, the reaction will proceed more quickly, and equilibrium will be reached faster, but the concentrations of both A and B will be the same at equilibrium for both the catalyzed and the uncatalyzed reaction.
-
- What would happen to the equilibrium position of the reaction if an inert gas, such as krypton or argon, were added to the reaction vessel?
- The effect of temperature on equilibrium has to do with the heat of reaction.
- Recall that for an endothermic reaction, heat is absorbed in the reaction, and the value of $\Delta H$ is positive.
- Therefore, increasing the temperature will shift the equilibrium to the left, while decreasing the temperature will shift the equilibrium to the right.
- Our heat of reaction is positive, so this reaction is endothermic.
-
- The equilibrium constant K can be calculated using the Nernst equation.
- Thus, zinc metal will lose electrons to copper ions and develop a positive electrical charge.
- The cell equilibrium constant, K, can be derived from the Nernst equation:
- The cell potential is zero at equilibrium (E=0), and Q (the reaction quotient) can now be designated as the equilibrium constant K.
- Calculate the equilibrium constant, K, for a galvanic cell using the Nernst equation
-
- Equilibrium constants can be used to calculate the concentrations of reactants and products that will be present at equilibrium.
- Similarly, we designate +2x as the change in concentration for NO, but it's positive because it's being produced.
- Knowing the initial concentration values and equilibrium constant we were able to calculate the equilibrium concentrations for N2, O2 and NO.
- The equilibrium concentration is the sum of the initial concentration and the change, which is derived from the reaction stoichiometry.
- Calculate the concentrations of reaction components at equilibrium given the starting concentrations and the equilibrium constant
-
- Changes in temperature shift the equilibrium state of chemical reactions; these changes can be predicted using Le Chatelier's Principle.
- Changes in temperature can affect the equilibrium state of a reversible chemical reaction.
- The effect of changes to the equilibrium state can be predicted using Le Chatelier's Principle.
- Reactions with positive enthalpies—those that absorb heat from their surroundings—are known as endothermic.
- Evaluate the effect of temperature on the equilibrium state of a chemical reaction
-
- The equilibrium constants for homogeneous and heterogeneous solutions need to be calculated differently.
- The equilibrium constants for reactions that contain substances that are all in the same phase, and reactions that contain substances in different phases, need to be calculated differently.
- The equilibrium constant K for a given reaction is defined as the ratio of the products of a reaction to the reactants, measured at equilibrium.
- The reaction quotient measured at equilibrium is the equilibrium constant K.
- The equilibrium constant K is simply [Br2], with the concentration of the pure liquid Br2 excluded.
-
- The equilibrium constant is an expression that gives the ratio of reactants and products at equilibrium.
- This constant is known as the equilibrium constant.
- The larger the value of the equilibrium constant, the more the reaction proceeds to completion.
- The progress of an equilibrium reaction can be visualized.
- The equilibrium constant,denoted by K, is the ratio of products to reactants at equilibrium.
-
- Just as for the equilibrium constant, the reaction quotient can be a function of activities or concentrations.
- If Q < Keq, the reaction will move to the right (in the forward direction) in order to reach equilibrium.
- If Q > Keq, the reaction will move to the left (in the reverse direction) in order to reach equilibrium.
- Eventually, the concentrations become constant; at this point, the reaction is at equilibrium.
- The equilibrium constant, Keq, can be expressed as follows: