Chemical Equillibrium

Question 1

All chemical reactions tend toward an_________ between __________ & _________.
The equilibrium is established because chemical reactions are ___________
- they can occur in ____ directions.
Consider the __________ of N2O4: N2O4(g) -> 2NO2 (g). The ________ reaction is also possible: 2NO2(g) -> N2O4 (g). Where N2O4 is ________ and NO2 is _____-___. To represent this reaction we then write : N2O4(g) -> <- 2NO2(g)

Answer 1

All chemical reactions tend toward an equilibrium between reactants & products.
The equilibrium is established because chemical reactions are reversible
- they can occur in both directions.
Consider the decomposition of N2O4: N2O4(g) -> 2NO2 (g). The reverse reaction is also possible: 2NO2(g) -> N2O4 (g). Where N2O4 is colourless and NO2 is brown-red. To represent this reaction we then write : N2O4(g) -> <- 2NO2(g)

Question 2

1. Dynamic equilibrium – a _______ state in which __ ___ change takes place
   because the _____ and _______ reactions are occurring at the _____ ____
   i.e. rate (forward) = rate (reverse)
2. __________-______ rxn – when products are favored at equilibrium. We say:
   “equilibrium lies to the _____”

________-_____ rxn – when reactants are favored at equilibrium. We say:
“equilibrium lies to the ____”

A reaction will always ____ (__________) _______ its
equilibrium, and the position of the equilibrium is always the ____ for particular conditions.

Answer 2

1. Dynamic equilibrium – a (terminal) state in which no net change takes place
   because the forward and reverse reactions are occurring at the same rate
   i.e. rate (forward) = rate (reverse)
2. Product-favored rxn – when products are favored at equilibrium. We say:
   “equilibrium lies to the right”

Reactant-favored rxn – when reactants are favored at equilibrium. We say:
“equilibrium lies to the left”

A reaction will always tend (spontaneously) towards its
equilibrium, and the position of the equilibrium is always
the same for particular conditions.

Question 3

Ok so there’s 2 graphs on slide 7 and it basically says that if we start

Answer 3

If we start with equal amounts of the reactants in H2(g) +I2 -><- 2HI (g). The reactants and products are both going to cross and product will be way up since its being produced twice as fast as reactants . But if we start with the corresponding amount of product, then we are not going to cross and we are going to start high with the product and gradually adjust to the react

Question 4

aA + bB -><- cC + dD
Write a corresponding equilibrium constant expression?

IF the concentrations are values at equilibrium, the value of the equilibrium
constant expression is the equilibrium constant?

Answer 4

Products->([C]^c [D]^d ) / Reactions->([A]^a [B]^b)

Kc = ([C]^c [D]^d )/ ([A]^a [B]^b)
C in the k = here is the use of concentration in the expression

This value is independent of the starting conditions and will vary only with temperature

Question 5

IF the concentrations are any instantaneous values (regardless of whether the
reaction is at equilibrium) the value of the equilibrium constant expression is
known as a ______ ______:

Values for equilibrium constants and reaction quotients are always unitless.

Answer 5

Qc = ([C]^c [D]^d ) / [A]^a [B]^b)
Reaction quotient

Question 7

For gases;

Answer 7

For Gases
For thermodynamic reasons (see in Topic 6) equilibrium constant expressions
for gas phase reactions are defined in terms of partial pressures, Pi.

Question 8

So for gas phase reactions :

Answer 8

K