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Flashcards in Chapter 13 Deck (30):
1

equilibrium

-the state where the concentrations of all reactants and products remain constant with time
-this does not mean there is no activity
-there is just no net change
-concentrations of the reactants never go to zero, they’ll just be in small but constant concentrations
-the concentrations of all reactants and products remain constant because forward and reverse reactions rates are equal (molecules react by colliding with one another, and the more collisions, the faster the reaction)

2

equilibrium constant

-Kc or K
-it’s concentration is in molarity (moles /volume)
-its the equilibrium constant at an given constant temperature
-IT DOES NOT HAVE UNITS

3

law of mass action

-if you know something in that form, it equals Kc

4

when writing the equation for equilibrium constant

-do not include solids or liquids because the concentration and molarity is constant
-only include gas, aqueous, and ions

5

if the balanced equation is multiplied by a factor n

-the equilibrium is the original expression raised to the nth power.

6

if the balanced equation is reverse

-the new equilibrium is 1/k of the original equilibrium (look in book)

7

if the balanced equation is multiplied by 1/2

-Kc to the 1/2

8

if k > 1

-favor the products
-more products

9

if k < 1

-favour reactants
-more reactants

10

Kp

-equilibrium constant in terms of partial pressures
-ONLY WRITTEN AS Kp
-Kp = Kc(RT) squared delta n

11

n in Kp = Kc(RT) squared delta n

-number of mol gas products - number of mol gas reactants

12

homogeneous equilibria

-equilibria for systems in the gas phase
-all reactants and products are gases

13

heterogeneous equilibria

-involve more than one phase
-the Kc is only the

14

reaction quotient (Q)

-it is obtained by applying the law of mass action using initial concentrations instead of equilibrium concentrations
-there are three different ways an equilibrium can shift
1. q is equal to k (no shift)
2. q is greater than k (ratio of initial concentrations of products to reactants is too large, shifts to left or consume products and form reactants)
3. q is less than k (ratio of initial concentrations of products of reactants is too small, shift to right or form products and consumes reactants)

15

le chatelier’s principle

-if an change is imposed on an system at equilibrium, the position of the equilibrium will shift in an direction that tends to reduce that change
-if an component is added to an reaction system at equilibrium (at constant T and P or constant T and V) the equilibrium position will shift in the direction that lowers the concentration of that component. If an component is removed,the opposite effect occurs
-the system shifts in the direction that compensate for imposed change

16

three ways to change the pressure of an reactionary system involving gaseous components

-add or remove an gaseous reactant or product
-add an inert gas (one not involved in the reaction)
-change the volume of the container

17

the effect of adding an inert gas

-it increases the total pressure but has no effect on the concentrations or partial pressures of the reactants or products

18

the effect of changing the volume of the container

-concentrations (and thus partial pressures) are changed
-when the the volume is reduce, the system responds by reducing its own volume by decreasing total number of gaseous molecules in the system (equilibrium position will shift toward side of the reaction involving smaller number of gaseous molecules in the balanced equation

19

the effect of an change in temperature

-the value of K changes with temperature
-treat energy as an reactant (in an endothermic process) and predict the direction of the shift in the same way as when and actual reactant or product is added or removed
-treat energy as an product (in an exothermic process) and predict the direction of the shift in the same way as when and actual reactant or product is added or removed

20

how do you treat energy (in an endothermic process) ?

-reactant

21

how do you treat energy ((in an exothermic process)?

-product

22

when the temperature is positive.....

-endothermic

23

when the temperature is negative....

-exothermic

24

adding water (blue)

turns pink

25

adding hydrochloric acid and calcium chloride

turns blue

26

adding silver nitrate

turns pinks

27

heating up solution

turns blue

28

cooling down solution

turns pink

29

endothermic

increased temp ... cause to shift to right and K increase

30

exothermic

increased temp ... cause shift to left and K decrease