homogenous heterogeneous equilibria n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Homogenous & Heterogeneous Equilibria PowerPoint Presentation
Download Presentation
Homogenous & Heterogeneous Equilibria

Loading in 2 Seconds...

play fullscreen
1 / 9

Homogenous & Heterogeneous Equilibria - PowerPoint PPT Presentation


  • 120 Views
  • Uploaded on

Homogenous & Heterogeneous Equilibria. Homogenous Equilibria  equilibrium conditions for rxns in which all the reactants & products are in the same state eg. 2CO (g) + O 2(g)  2CO 2(g) Heterogenous Equilibria

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Homogenous & Heterogeneous Equilibria' - barto


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
homogenous heterogeneous equilibria
Homogenous & Heterogeneous Equilibria

Homogenous Equilibria

 equilibrium conditions for rxns in which all the reactants & products are in the same state

eg. 2CO(g) + O2(g) 2CO2(g)

Heterogenous Equilibria

 equilibrium conditions for rxns that involve substances in more than 1 state

eg. NH4Cl(s)  NH3(g) + HCl(g)

slide2

 Earlier, we expressed [] as M (for gases)

[] of solids & liquids in a chem. rxn. do not change substantially and so are not included in the equilibrium constant

[solid & liquid]  change during a rxn, left out of Keq

 eg. C(s) + H2O(g) CO(g) + H2(g)

Keq = [CO][H2] .

[H2O]

the reaction quotient
The Reaction Quotient

 It is hard to tell if a rxn. has reached equilibrium

 The “reaction quotient” (Q) is used to determine if a rxn. is @ equilibrium

 Q is calculated like Keq except the []’s are taken @ the time of measurement, not necessarily @ equilibrium

 Thus we can compare the value of Q to the value of Keq to see how the rxn. is progressing

 Rxn. is @ equilibrium when Keq = Q

example
Example:

At 473°C, nitrogen gas is reacted with hydrogen gas to produce ammonia. A measurement was taken as the reaction proceeded and it was found that there was 0.15 M of nitrogen gas, 0.0020 M of hydrogen gas, and 0.15 M of ammonia. Given that the Keq is 0.105, is the reaction at equilibrium?

n 2 g 3h 2 g 2n h 3 g
N2(g) + 3H2(g) 2NH3(g)

temp. = 473°C [NH3] = 0.15 M

Keq = 0.105 [N2] = 0.15 M

[H2] = 0.0020 M

Keq = [NH3]2Q = (0.15)2 .

[N2][H2]3 (0.15)(0.0020)3

= 1.9 x 107

Keq Q this rxn. is NOT @ equilibrium

which direction will rxns proceed to reach equilibrium
Which direction will rxns proceed to reach equilibrium?

Q < Keq

Q is less thanKeq

 denominator is too large and numerator is too small

 too much of reactants, too little of products

 rxn. will proceed to the right (in the direction of products)

slide7

Q > Keq

Q is greater thanKeq

 denominator is too small and numerator is too large

 too much products, too little reactants

 rxn. will proceed to the left (in the direction of reactants)

example1
Example:

COCl2(g) CO(g) + Cl2(g)Keq = 170

At the time of measurement:

[CO] = 0.15 M

[Cl2] = 0.15 M

[COCl2] = 1.1 x 103 M

Is the rxn. @ equilibrium? If not, which direction will it proceed?

slide9

Q = [CO][Cl2] = (0.15)(0.15). = 20.

[COCl2] (1.1 x 103)

Q < Keq thus rxn. is NOT @ equilibrium

 there is too much reactants

 rxn. will shift right in the direction of products