Chapter 15 part 2
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- The equalibrium constant allows us to predict what 2 things
- 1. the direction in which a reaction mixture will proceede 2. calculate the concentrations of rcts and prods when equal. is reached
- What is the reaction quotient?
- the resulut of substituting product concent or PP into an Keq expression (Q)
- What does it mean when 1. Q>Keq and 2. Q<Keq?
- 1.The reaction achieves equal. by forming more reactants 2. Visa versa
- When does the reaction quot. equal the Keq?
- at equalibrium
- What is LeChatelier's principle?
- If a system at equal. is disturbed by a change in T, P, or Concentration of one of the components, the system will shift its equal. position to counteract the effect
- What are three ways a chem equal can be disturbed?
- adding a rct or prod, changing the P, changing the T
- A system at equal. is in what kind of state?
-
Dynamic: the forward and reverse proccess are occuring at equal rates
system is balanced - How can a system reduce its pressure to return balance (return to equal)?
- reduce the total nimber of gas molecules
- What occurs by reducing the volume of a gaseous equalibrium mixture?
- causes the system to shift in the direction that reduces the number of moles of gas. (conversly increasing volume causes increase gas molecules)
- What effect do pressure-volume changes have on the value of Keg?
-
The do not have any effect as ling as the T remains constant
They DO change the PP of gaseous substances - Changes in the Concentrations or PP Cause what?
- A shift in the equalibrium without changing the value of the Keq
- How can the total Pressure of a rxn be changed without changing the volume?
- Adding a gas that is not involved with the equalibrium.
- When temp is increased in a endothermic what happens to the equalibrium
-
the equalibrium shifts to the right in the direction of the products, Keq increases.
(Heating an exothermic causes a shift to left) - Cooling a Endothermic reaction has what effect on the equal.?
-
shift to the left, decreasing Keq
(cooling an exothermic causes a shift to the right) - What does a catalyst do?
- Lowers the activation barrier betwwen reactants and products. (activation e is lowered in both forward and backward reactions, increases both reaction rates)
- Overall, what does a catalyst do?
- increases the rate of which equalib. is achived. Does not change the composition of the equal mixture
- How are Catalysts important economically
- make it possible to more repidly obtain equal at lower T