• Characteristics of equilibrium,
• Calculation of the equilibrium constant or concentration
• ICE model
• Le Chatelier's Principle
• Haber's Process
• Effects of heat, pressure, concentration changes and catalysts on the equilibrium
• Solubility products
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| 409758828 | Characteristics of equilibrium | occurs in reversible reactions, there is no nt change in concentrations of reactants and products, forward and reverse rates are the same | |
| 409758829 | equilibrium constant | K=[C]^c[D]^d/[A]^a[B]^b | |
| 409758830 | reactant quotient | the ratio of the right side over the left if the system is not at equilibrium | |
| 409758831 | Value of reactant quotient and how the system shifts to restore equilibrium | If Q | |
| 409758832 | ICE models | Equilibrium constants and concentrations can often be deduced by carefully examining data about initial and equilibrium concentrations | |
| 409758833 | Le Chatelier's Principle | when a system in chemical equilibrium is disturbed by a change in temp, pressure, or concentration, the system shifts in equilibrium composition in a way that tends to counteract this change of variable. in other words, if conditions at which equilibrium habe been established change, the position of equilibrium is effected. | |
| 409758834 | stress | a change imposed on an equilibrium system | |
| 409758835 | Effect of change in temperature on equilibrium | an increase in temperature causes equilibrium to shift in direction of endothermic reaction | |
| 409758836 | When temperature is decreased: | equilibrium position shifts toward the exothermic direction | |
| 409758837 | Effect of change in pressure on equilibrium(gases only) | an increase in pressure causes equilibrium to shift in direction that has fewer # of moles. | |
| 409758838 | Example of production of ammonia and increasing pressure | N2 (g) + 3 H2 (g) <--> 2NH3 (g) H =-92 kJ mol-1 (An increase in pressure results in a an decrease in N2 and H2 and an increase in NH3) | |
| 409758839 | Effect of change in reactants or products | equilibrium responds in such a way so as to diminish increase. substances on same side of arrow respond in opposite directions. substances on opposite side of arrow move in same direction. | |
| 409758840 | Example of production of ammonia and increasing reactants | N2 (g) + 3 H2 (g) <-->2NH3 (g) An increase in [N2 ] results in a decrease in N2 and H2 and an increase in NH3 | |
| 409758841 | Effect of catalyst on equilibrium | -has no effect on position of equilibrium. or Kc -catalysts affect both the forward and reverse directions equally. -a catalyst does not change the concentrations but reduces the time required for the system to come to equilibrium. | |
| 409758842 | Kc for reverse reactions | Kc'=1/Kc=Kc^-1 | |
| 409758843 | homogenous equilibria | reactions are all in the same physical phase | |
| 409758844 | If K>>1 | reaction is said to go to completion/equilibrium lies to the right/favors products | |
| 409758845 | If K<<1 | then the reaction had hardly taken place at all/equilibrium lies to the left/favors reactants | |
| 409758846 | Kc is not altered by | the addition/removal of products/reactants, change in pressure, or the addition of a catalyst | |
| 409758847 | If product is removed | equilibrium is shifted to the right. more of the reactants will react to replace it. | |
| 409758848 | Increasing [product] | shifts equilibrium to the left | |
| 409758849 | in a reaction where reactants are colorless and products are brown, what happens when pressure is increased? | initially darkens the solution, then equilibrium shifts to the left(where there are less molecules, to counteract effect of pressure change on equilibrium) and solution becomes lighter. explanation: it broke down colored products to create colorless reactants | |
| 409758850 | in a reaction where reactants are colorless and products are brown, what happens when pressure is decreased | Initially lightens the solution, then equilibrium shifts to the right (more molecules) and becomes darker | |
| 409768335 | Highest yield of ammonia in haber-bosch process is produced using | high pressures(favors less molecules), low temperatures (favors exothermic reaction | |
| 409768336 | But the economic way to increase rate of haber-bosch process is: | high temperature, high pressure, with catalyst | |
| 409768337 | 3 reasons for Haber's choice of raising temperature: | 1)low temp=slow reaction 2)the catalyst used has an optimum operating temp 3)ammonia can be condensed, N2 and H2 are reused and not wasted, so low yield is a small concern | |
| 409768338 | reasons for Haber's choice of pressure | high pressure already favors production, and for kinetic reasons. but higher pressure reaction vessels are very expensive, so decision is made by balancing the high initial costs against eventual profit of increased yield | |
| 409821955 | homogeneous equilibrium | all in the same phase | |
| 409821956 | heterogeneous equilibrium | one or more species in a different phase | |
| 409821957 | if a pure solid or pure liquid is involved in a heterogenous equilibrium, its concentration- | is not included in the equilibrium constant expression | |
| 409821958 | solubility product constant, Ksp | product of concentrations of the ions involved in a solubility equilibrium, each raised to their coefficient | |
| 409821959 | common ion effect | the solubility of a slightly soluble ionic compound is lowered when a second solute that provides a common ion is added to the solution |
