7 equilibrium Flashcards

1
Q

in a dynamic equilibrium?

A

the rate of the forward reaction is the SAME as the rate of the backward reaction in a CLOSED system
and the conc of reactants and products is CONSTANT

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2
Q

graph of reaching equilibrium from reactants and from products

A

curved line up like an r + curved line down like an L until both cross and are constant
– reactants form products until eq

conc of reactants incr, conc of products decr

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3
Q

closed vs open system

A

closed: no reactant can escape the mixture

open: some is lost to surroundings (so the reaction is technically not reversed)

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4
Q

in an equilibrium expression, is reactants/prod or prod/reactants?

A

prod/reactants

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5
Q

in an equilibrium expression, the coefficient is?

A

added as a power of the conc

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6
Q

in an equilibium expression, what is not included from the chemical equation?

A

SOLIDS!!! NO SOLIDS

WE FUCKING HATE SOLIDS ok when you think abt it the particles cant rearrange so

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7
Q

what is Kc dependent on?

A

temperature

so at a fixed temp Kc is a constant

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8
Q

when Kc > 1,

A

equilibium shifts to the right,
more products

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9
Q

Kc for
N2 + 3 H2 == 2NH3
vs (doubled)
2N2 + 6H2 == 4NH3

A

the first Kc to the POWER of 2 is the new Kc

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10
Q

calculating Kc for the reverse equation? hwo does this affect the Kc

A

reverse Kc = 1/og Kc

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11
Q

what is the reaction quotient

A

ratio of products and reactats for a reaction that has NOT YET reached equilibrium

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12
Q

what does the size of the reaction quotient tell us

A

how far a reaction is from equilibiurm

which direction the reaction proceeds

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13
Q

what is the position of equilibrium

A

refers to the relative amts of products and reactants in an equilibrium mixture

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14
Q

what is Le Chatelier’s principle

A

says that if a CHANGE is made to a system at DYNAMIC EQUILIBRIUM,
position of equilibrium MOVES to minimise this change
(not required to quote but must APPLY)

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15
Q

increase in reactants conc effect on equilibrium

A

shifts RIGHT (= more product)

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16
Q

effects of increase in pressure on equilibrium

A

shifts in direction that produces SMALLER number of molecules of gas

17
Q

effect of incr temperature on equilbirum shift

A

equilibrium moves in the ENDOTHERMIC direction to reverse the change

change in H = +
means forward is favoured (endo)

18
Q

effect of catalyst on forward and backward reactions

A

incr rate EQUALLY
= reach equilibirum FASTER

19
Q

is the equilibrium constant affected by changes to reactant/product concentration???

A

NOOOOOOO
but the opposite reaction is favoured until equilibrium is restored

20
Q

does change in pressre affect Kc?????

A

NOOOO
its only changes the POSITION of equilibrium

21
Q

do temp changes affect equilibrium constant

A

of COURSE they do
Kc increases with an endothermic reaction (+)

22
Q

is Kc or position of equilibium affected by change in concnetration

23
Q

chemical equaiton for the Haber Process

A

N2 (g) + 3H2 (g) <==> 2NH3 (g)

24
Q

given the eqn for the haber process, N2 (g) + 3H2 (g) <==> 2NH3 (g)

how will increasing nitrogen amt affect:
1. position of equilibium
2. amount of ammonia
3. amount of hydrogen
4. Kc

A
  1. right
  2. incr
  3. decr
  4. unchanged

new equilibrium would be higher than original

25
what do [ ] mean in Kc calculations
the conc of the chemical in mol/dm3
26
what is the chemical formula of ethanoic acid
CH3COOH
27
how to deduce units for Kc
subsitute the units for the concs into the equation and cancel out if its like mol/dm3 divided by mol/dm3 then yeah no units
28
equation for Gibbs free energy change? (section 1 data booklet)
gibbs free energy change = -(gas constant)(temp in K) ln(equilibium constant)
29
what are the units for Gibbs free energy change and R (gas constant)?
G --> kJ / mol R --> J /K/mol = one value needs to be adjusted by 1000
30
when equilibrium constant > 1, gibbs free energy change?
ΔG < 0
31
when Kc = 0, gibbs free energy change?
ΔG = 0
32
a negative ΔG value means the reaction is (spontaneous/non-spontaneous)
spontaneous!
33
as ΔG becomes more negative the forward reaction is? the value of the equilibium constant?
forward favoured Kc increases
34
to find Kc from lnKc = 1.77?
lnKc = 1.77 Kc = e ^ 1.77