28-30 Flashcards Preview

PR - Big book > 28-30 > Flashcards

Flashcards in 28-30 Deck (32):
1

reaction intermediates don't pile up; when confronted by a slow step, they go in the reverse direction

Catalysts are not mentioned, either. Catalysts can be modified during a reaction, but return to original state at the end (CATALYST = REGENERATED)

2

three factors that influence rate

LOWER activation energy (via catalyst)
MORE CONCENTRATED reactants
HIGHER temperature

TEMPERATURE influences rate constant, k; does NOT change Ea (!IMPORTANT)

3

Catalyst == Ea

NOT G, H, or S

4

rate constant k

rate / [A]^a [B]^b

5

equillibrium

generation of product is the same as generation of reactants (rate = reverse_rate)

DYNAMIC equilibrium

6

K_a, K_b, K_s

all equilibrium constants

K_eq is a constant at a given temperature

TEMPERATURE INFLUENCES K_eq

7

K_a, K_b, K_s

all equilibrium constants

K_eq is a constant at a given temperature

TEMPERATURE INFLUENCES K_eq

K_sp is the solubility (salt) product constant

8

reaction quotient

Q - same as K_eq but fluctuates

Q > Keq, reverse reaction is favored
Q < Keq, forward reaction is favored

le Chatelier's principle is related to Q

9

pressure and le Chatelier's equation

see which side has more moles of gas

increased pressure = reduced volume = favors the fewer moles

PRESSURE CAUSES REACTIONS TO CONDENSE

10

reaction quotient

Q - same as K_eq but fluctuates

Q > Keq, reverse reaction is favored
Q < Keq, forward reaction is favored

le Chatelier's principle is related to Q

Q = K_eq, reaction is at equilibrium
∆G = 0, reaction is at equilibrium

you can also calculate Q by [Partial pressure A]^a / [Partial pressure B]^b

11

temperature and le Chatelier's equation

if the product is heat, then reducing temperature favors the forward process

likewise, adding heat shifts left

"LOWERING TEMPERATURE favors the exothermic reaction, raising temperature favors endothermic"

CHECK TO SEE ∆H and add heat to the equation

12

hydration

when solvent is water, it is hydration and aqueous

solvent is higher in proportion than solute

13

strong electrolyte = good conductor of electricity

covalent bonds = nonelectrolytes

14

ionizability factor (i)

tells us how many particles are dissociated in solution

glucose i =1
nacl i=2

15

phase solubility rules

1. solubility of solids in liquids increases with temperature
2. solubility of gases in liquids decrease with increasingly temperature
3. gases dissolve better under high pressure

16

solubility of a gas

Solubility = kP

k, Henry's law
P, partial pressure of gas above the liquid

17

K_sp

K_sp = [Mg2+][OH-]^2

leave Mg(OH)2 out because it is a solid

equilibrium = rate at which ions go into solution same as precipitation

18

Q_sp and Ksp

K_sp is when the solution is SATURATED

if Q_sp is greater than K_sp, then salt will precipitate

19

common ion effect

hydroxide is added, will shift another chemical balance

20

complex ion formation

creating a complex ion with Lewis base (NH3) takes away a ion from solution, driving forward the propensity of solid salt to exist as ions in solution

21

complex ion formation

creating a complex ion with Lewis base (NH3) takes away a ion from solution, driving forward the propensity of solid salt to exist as ions in solution

22

polyprotic acids and amphoteric substances

HCO3- is both a base and acid = amphoteric

23

the relationship between [H3O+] and [OH-]

K_w is always 10^-14 (autoionization)

K_w increases with increasing temperature

adding acid will shift the equation to the left, decreasing [OH-]

[OH-] = K_w/[H3O+]

24

pOH and pH always equal for acid-base conjugate pair

14 (based on K_w)

25

p

NEGATIVE LOG

"peeing under a (-) log"

26

acid-base conjugate pair

KaKb = 10^-14
pKa + pKb = 14

27

LEWIS acid and base

ACID - electron RECEIVER
BASE - electron donor

A lewis acid causes another molecule to give up an Hydrogen

H+ is a conjugate acid, because it ACCEPTS OH-

OH- donor = BASE

28

strength of acid

strong = completely dissociates, HIGH K_a value

HI, HBr, HCl

HClO4, H2SO4, HNO3

29

strength of base

K_b

Group 1 hydroxides
Group 1 oxides
Ba(OH)2, Sr(OH)2, Ca(OH)2, "CAlifornia has StRong BAses"

Metal amides (NaNH2)

conjugate acid has NO acidic properties

30

a 0.01 M solution of HCl is what pH

0.01 moles / L

pH = -log(0.01) = 2

31

K_a

[H+][CN-] / [HCN] = x^2 / (starting amount)

32

Neutralization

equimolar strong acid + strong base = neutral pH

weak acid + weak base = variable pH (not neutral)

weak acid or base + strong base/acid (equimolar) = complete neutralization

H+ + OH- -> H2O + heat

ALL equimolar neutralization reactions go to completion