Question

Partial pressures question?

2A ----> B...At a given temperature and total pressure of 1.2 atm the partial pressures of an equilibrium mixture for the rxn are Pa=.6 atm and Pb=.6 atm. After a disturbance the system regains equilibrium with a total pressure of 1.5 atm. What is the partial pressure of A?

I know the first answer is 1.7

The next answers are supposed to be PB= .81 and PA=.69

Answer #1

For the first set of equilibrium pressures:

Kp = (0.6 atm) / (0.6 atm)^2

Kp = 1.667 atm-1

All we know about the second set of equilibrium pressures is that
Kp will remain constant at a given temperature. If the nature of
the "disturbance" adds A or B to the mixture, we can find pA after
a new equilibrium has been reached. I'll solve the case for "adding
B." As it turns out, the case of "adding A" would result in the
same final equilibrium pA (I won't show the work for this here, but
this case could be solved similarly to what I'll do below).

Suppose x atm of B are added to the mixture. To reach equilibrium,
some of B (y) would have to get converted to A (by Le Chatelier's
principle):

Kp = (0.6 + x - y) / (0.6 + 2y)^2

Since the total pressure has to be 1.5 atm,

(0.6 + x - y) + (0.6 + 2y) = 1.5 atm

1.2 + x + y = 1.5 atm

x = 0.3 - y

Kp = (0.6 + (0.3 - y) - y) / (0.6 + 2y)^2

1.667 = (0.9 - 2y) / (0.6 + 2y)^2

6.667y^2 + 6y - 0.3 = 0

By quadratic equation:

y = [-6 + sqrt(6^2 - 4*6.667*(-0.3))] / (2*6.667) (the "negative"
answer would make no sense here)

y = 0.0475

pA = 0.6 + 2y

pA = 0.6 + 2(0.0475)

pA = 0.695 atm

Consider the following reaction: A(g)⇌2B(g) Find the equilibrium
partial pressures of A and B for each of the following different
values of Kp. Assume that the initial partial pressure of B in each
case is 1.0 atm and that the initial partial pressure of A is 0.0
atm. Make any appropriate simplifying assumptions. Kp=1.8 Find Pa
and Pb.

Consider the following reaction:
A(g)⇌2B(g)
Find the equilibrium partial pressures of A and B for each of the
following different values of Kp. Assume that the initial
partial pressure of B in each case is 1.0 atm and that the initial
partial pressure of A is 0.0 atm. Make any appropriate simplifying
assumptions.
Kp= 1.6×10−4,Kp=
1.6×105,
Kp= 1.6×10−4 Pa, Pb= needed
Enter your answers numerically separated by a comma. Express
your answers using two significant figures.

A mixture of three gases (Ar, Ne, and CO2) has a total pressure
of 1.2 atm. If the mixture of gases is composed of 25.0 g of each
gas, what is the partial pressure of Ne?

please answear each question
1)At equilibrium, ________.
a)the rates of the forward and reverse reactions are equal
b)the value of the equilibrium constant is 1
c)all chemical reactions have ceased
d)the rate constants of the forward and reverse reactions are
equal
e)the limiting reagent has been consumed
2)The equilibrium-constant expression depends on the ________ of
the reaction.
a)
stoichiometry
b)
mechanism
c)
the quantities of reactants and products initially present
d)
temperature
e)
stoichiometry and mechanism
3)Given the following reaction...

Suppose the total pressure in a bottle of soda water before it
is opened is 40 psig
(http://hypertextbook.com/facts/2000/SeemaMeraj.shtml) and that the
gas mixture is 75% CO2 and 25% other gases. The temperature is
10°C. The Henry’s Law constant is 0.104x104 atm.
a) If the system is in equilibrium, how much CO2 is dissolved in
the soda? (For this problem,ignore reactions between the CO2 and
the water.) I know the answer is about 6500 mg/L but I'm
having trouble finding the...

Suppose the total pressure in a bottle of soda water before it
is opened is 40 psig
(http://hypertextbook.com/facts/2000/SeemaMeraj.shtml) and that the
gas mixture is 75% CO2 and 25% other gases. The temperature is
10°C. The Henry’s Law constant is 0.104x104 atm.
a) If the system is in equilibrium, how much CO2 is dissolved in
the soda? (For this problem,ignore reactions between the CO2 and
the water.) I know the answer is about 6500 mg/L but I'm
having trouble finding the...

1- Acetone (1) and Methanol (2) form
an azeotrope boiling at 55.7oC at 1 atm pressure, with a
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Coefficients for the system.
2- Perry (Table 13-1) quotes the following x,y,T data for
Acetone (1) and Methanol (2) at 101.3 kPa total pressure. Estimate
the van Laar constants A12 & A21.
T/oC
64.65
61.78
59.60
58.14
56.96
56.22
55.78
55.41
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56.21
x1
0
0.091
0.190
0.288
0.401
0.501
0.579...

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