Chapter 17_1 Equilibruim Completed

7/27/2019 Chapter 17_1 Equilibruim Completed

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Chapter 17

lesson 1A state of dynamic balance



Tug of war



H2 + O2 H2O

H2 + O2 H2O

What is the difference between the 2

reactions ?



What is the differencebetween the reactions ?

1) H2 + O2 H2O

2) H2 + O2 H2O

3) H2 + O2 H2O



Homogenous and heterogeneousequilibrium



Tell whether each is ahomogenous or a heterogeneouseq

1)H2O(aq) H+(aq) + OH-

(aq)

2)PbCrO4 (s) Pb2+(aq) + CrO42-(aq)

3)Zn (s) + 2 H+(aq) Zn2+

(aq) + H2 (g)

4)N2O4 (g) 2 NO2 (g)

5)Zn (s) + 2 H+(aq) Zn2+

(aq) + H2 (g)



The equilibrium between reactants andproducts is described by an equilibrium

constant. For the balanced reaction:aA + bB cC + dD

The equilibrium constant, Keq is defined as:

[C]c [D]d

Keq =P/R =

[A]a [B]b



Rules for writing equilibrium constant

1) solids and liquids are cancelled

2) products over reactants

3) coefficients become powers .



Write the equilibrium expression



3) coefficients become powers

1)H2O(l) H+(aq) + OH-

(aq)







2)PbCrO4 (s) Pb2+(aq) + CrO42-(aq)







3)Zn (s) + 2 H+(aq) Zn2+

(aq) + H2 (g)



PCl5 (g) PCl3 (g) + Cl2(g)

1) is this reaction reversible ?why

2) is it at equilibrium ?why

3) is it homogenous or heterogeneous ?why

4) write keq expression .



Continued 17.1Chemical equilibrium



What describes a reaction thathas reached equilibrium?



Conditions of equilibrium

1. reactants and products must be

present 2. closed container should be used

3. temperature is constant



Find Keq for the following reaction

N2 (g) + O2 (g) 2NO (g)

Write Keq :

Find Keq if [N2]=0.2M , [ O2]=0.3M and

[NO]=0.6M



Values of Keq :

1.

2.

3.



At equilibrium

solids and liquids are notconsideredgases and aqueous are considered



C10 H 8 (s) C 10 H 8 (g)

1. write Keq :

Find Keq when [ C10H8]=1M



Consider the reaction

Fe O (s) + CO (g) Fe (s) + C O 2 (g)

1. write Keq :

Calculate Keq when 2 moles of CO

produce 2 moles of CO2 in a 2L container.



Write the chemical equation

that has the equilibriumconstant Keq =[CO]2[O2]

[CO2]2



PCl5(g) PCl3(g)+Cl2 (g)

If [ PCl 3] = 0.55 M and [PCl5]=0.135,Keq=2.24

Find [ Cl2]



At which temp is theconcentration of products the

greatest ?

Temp 263 k 273 k 373 k

Keq 0.025 0.5 4.5

Chapter 17_1 Equilibruim Completed

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