# Chemical Equilibrium

## Calculating concentrations at equilibrium

NOCL(g) decomposes to from nitrogen monoxide gas and chlorine gas. The equation is

2NOCL ----> 2NO +Cl2

At a certain temperature the equilibrium constant is 1.60 x 10^-6. Calculate the equilibrium concentrations of all gases if 0.800 moles of NOCL are placed in a 2.00 L container.

NOCL(g) decomposes to from nitrogen monoxide gas and chlorine gas. The equation is

2NOCL ----> 2NO +Cl2

At a certain temperature the equilibrium constant is 1.60 x 10^-6. Calculate the equilibrium concentrations of all gases if 0.800 moles of NOCL are placed in a 2.00 L container.

I was hoping someone could look over my answer and let me know if it's correct and if not where did I go wrong.

The NOCL decreases by 2x, CL2 increases by x and NO increases by 2x.

1.60 x 10^-6 = (2x)^2(x)/ (0.4)^2

 ICE [NOCL]^2 [NO]^2 [CL2] initial 0.4 0 0 change -2x +2x +x Equilibrium 0.4 -2x 2x x Revised eq 0.4 2x x

1.60 x 10^-6 = 4x^3/(0.16)

1.60 x 10^-6 = (0.16) =x^3/ 4

X^3= 6.4 x 10^-8

X=cube root of 6.4 x 10^-8

X = 3.9 x 10^-3

The concentration of the gases

[NOCL] = 0.4 mol/L

[Cl] x = 3.9 x 10^-3

[NO]^2 2x= 2x 3.9 x 10^-3 = 7.8x10^-3

## solution to an equillibrium problem

The equilibrium constant, , for the equilibrium

is ;If the equilibrium mixture contains 7.0×10−2, what is the concentration of ?
i also need help with this other question

An equilibrium mixture at 225 contains

0.16 and 0.23 for the reaction
; If the at this temperature is , what is the equilibrium concentration of ?

## Phase Equilibrium Questions for College

1. The addition of a non-volatile solute to a solvent will cause which of the following:           [2]

(a)    increase in vapour pressure and decrease in boiling point

(b)   decrease in vapour pressure and increase in boiling point

(c)    decrease in vapour pressure and decrease in boiling point

(d)   increase in vapour pressure and increase in boiling point

2. The total vapour pressure above an ideal solution of toluene and benzene is 39.7 mmHg. The vapour pressures of toluene and benzene above this mixture are 14.7mmHg and 25mmHg respectively. What is the mole fraction of toluene in the vapour phase?                                                                        [3]

(a)    0.630                    (b) 0.299                      (c) 0.701                      (d) 0.370

3.      The partition coefficient is given by                                                                                       [1]

(a)    the ratio of the solute concentration in the lower layer to the solute concentration in the interface

(b)   the difference between the solute concentration in the upper layer and the lower layer divided by the sum of the solute concentration in both layers

(c)    dividing the solute concentration in the upper layer by the solute concentration in the lower layer

(d)   the difference between the solute concentration in the upper layer and the lower layer divided by the solute concentration in the lower layer

4.      The mole fraction of A in an A-B mixture is equal                                                                [1]

(a)    to the sum of the relative masses of A and B

(b)   the number of moles of A divided by the total number of moles of A and B

(c)    the number of moles of A minus the number of moles of B divided by the total number of moles of A and B

(d)   the number of moles of A divided by the number of moles of A minus the number of moles of B

5. The partition coefficient for iodine between water and carbon disulphide at 20oC is 2.43 x 10-3.  A 100 cm3 sample of a solution of iodine in water of concentration 1.00 x 10-3 moldm-3 I2 is shaken with 10.0 cm3 of carbon disulphide.

(a)    Write an equation for the partition coefficient.                                                                [2]

………………………………………………………………………………………….

(b)   Calculate the total number of moles of I2.                                                                        [2]

(c)    Determine the number of moles of I2 extracted by CS2.                                                  [4]

(d)   What fraction of I2 is extracted by CS2 .                                                                          [2]

6. Calculate the mole fraction of each component in a methanol-ethanol mixture over which the equilibrium vapour pressure is 6.0 kPa.  Assume the mixture is ideal.  (Vapour pressure of pure methanol is 8.9 kPa and of pure ethanol is 4.0 kPa)                                                                  [6]

## Equilibrium and how to plug numbers into the formula!

I'm confused on a question that has 2H2S <===> 2 H2 + S2, they give you the moles of H2S (2.00 mol) and of 2H2 (1.00 mol) with equilibrium at a temp. of 1.62 x 10^-2 in a 2.00 liter flask. And it wants to know how many moles of S2 will be found, I'm totally lost of what numbers go where and if the information is needed?? Also my instrutor uses a method or chart called RICE which stands for

R-Reaction

I-Intial Concentration

C- Change

E-Equilibrium

So if you could use this method in your explanation it would be a big help in my understanding!! Thanks

-Sarah

## What is the percentage ionization of acetic acid in a solution..

in which 0.1 moles of it has been dissolved per dm3 of the solution?

## What is the percentage ionization of acetic acid in a solution..

in which 0.1 moles of it has been dissolved per dm3 of the solution?

## Calculate Total Pressure At Equillibrium Given Concentration, T, and Kp

At -80 degrees Celsius....Kp for the reaction:

N2O4 <--> 2(NO2)

Is 4.66*10^-8.  if .05 mol N2O4 is placed in an evacuated 1.0 L vessel at @ -80 degrees Celsius and
equilibrium established, the total pressure at equilibrium will be....?
(Correct answer is supposedly .79 atm)

I am really intrigued by this problem. Its another one that I came across while studying for my General Chemistry II final on monday.

## Calculate Kc based on percent dissociation!

For the reaction given below, 10.00 moles of A and 5.00 moles of B are placed in a 5.00-L
container.

2A  +  B <--> C

At equilibrium, 25% of A has reacted. What is Kc?

According to the key on this practice exam the answer is .15   I keep trying an ice table and it keeps coming up with weird values so Im not sure what Im doing wrong. I have solved all of my other practice problems that relate to chemical equillibrium so I would appreciate some help on this one because I refuse to not know the answer! Haha.

## How to find equilibrium constants .

For the reaction CO +H20 = CO2 +H2, K=31.4 at 588 K.  Equal masses of reactant and products are placed in a reaction vessel at 588 K.

1) is the mixture at equilibrium?

2) If not, in which direction will a net change occur?

3)make and ICE table that would allow you to find the concetration of each substance at equilibrium

## chemical engineering problem solution needed

Cant find solution