Chemical Equilibrium

Equilibrium Worksheet and Assignment

Practice Quiz on Le Chatlier’s Principle

If for a chemical reaction the equilibrium constant Kc is found to be 156. However Qc the concentration is 34. In which direction will the equilibrium shift.

 
 
 
 

What will happen if we take away some nitrogen (N2) for this system in equilibrium.

Q1 LechatliersPrinciple

 
 
 
 

Identify the most essential condition for a system to attain equilibrium

 
 
 
 

What will happen to the equilibrium position if we add some hydrogen to this system in equilibrium?

Q1 LechatliersPrinciple

 
 
 
 

If an inert gas is added to a system in equilibrium, in which direction will the equilibrium shift.

 
 
 
 

For a given reaction the equilibrium constant Kc is 256. If the concentration quotient Qc is 500, in which direction will the equilibrium shift?

 

 
 
 
 

Adding a catalyst to a system in equilibrium will shift the equilibrium

 
 
 
 

What would happen if we add some heat to this system in equilibrium.

Q1 LechatliersPrinciple

 
 
 
 

What would happen if we add some ammonia (NH3) into this system that has achieved equilibriumQ1 Le Chatliers Principle

 
 
 
 

Question 1 of 9

 

Videos on Equilibrium

Topics for Test – Chemical Equilibrium

  • Chemical Equilibrium
  • Graphs representing systems in equilibrium
  • Homogeneous equilibrium
  • Heterogeneous equilibrium
  • Dynamic equilibrium
  • How to write equilibrium concentration expressions for heterogeneous equilibrium
  • What does the magnitude of Kc or Keq tell you
  • Equilibrium constant for reactions with 2 or more elementary steps
  • Multiplying an equation by a coefficient ‘n’ changes Kc to Kc raised to n
  • When Kc = 1 what does it mean?
  • Application of Le Chatliers principle on systems in equilibrium
  • Shift in equilibrium when there is a [concentration] change
  • Shift in equilibrium when concentration is changed by changing volume
  • Shift in equilibrium when an inert gas is added to the reaction mixture
  • Shift in equilibrium when products are removed from the closed equilibrium system
  • Shift in equilibrium when the number of moles of reactants and products are not equal for gaseous system
  • Shift in equilibrium when heat is added or removed in an exothermic or endothermic reaction
  • Shift in equilibrium and catalyst for a reversible reaction
  • Problems – When the equilibrium expression is a perfect square
  • Problems – When K is very very small (applying 100th rule)
  • Problems – When the equilibrium expression is not a perfect square and the use of quadratic equation
  • Problems – When a stress is applied to a system in equilibrium (Le Chatliers principle) new concentration of reactant or product
  • Entropy – definition and prediction based on state of matter, temperature of reactants and products, # of moles of reactants and products
  • Spontaneous reactions
  • Gibbs Helmoltz equation and free energy
  • What is the significance of free energy?
  • What are the conditions for spontaneity of chemical reactions
  • Calculation of Kc from free energy ΔG = -2.303 RT log Kc, ΔG = ΔH – TΔS
  • Temperature at which a system attains equilibrium DG and equilibrium when value = 0
  • ΔG and equilibrium when value < 0 = -ve
  • ΔG and equilibrium when value > 0 = +ve
  • ΔG = 0 the system is in equilibrium.
Solubility Product Topics for Test (This may be a separate test)
  • Equilibrium of sparing soluble salts
  • Solubility product constant Ksp
  • Determination of Ksp from molar solubility
  • Ion product Vs Solubility product
  • Determining molar solubility from Ksp
  • Common ion effect, qualitative explanation and calculation
  • Predicting precipitation, problems
  • Selective precipitation of halides, sulfides, hydroxides, metals
  • Application of knowledge of Ksp
  • Use of complex ion formation in qualitative analysis
  • Separation of metal ions using Ksp
Test Outline
  • Multiple choice questions
  • Short Answers
  • Problems
Types of problems on the test
  • Determination of Kc or determination of Concentration using Kc and ICE table
  • Problems involving Perfect square or quadratic equation
  • Manipulation of Equilibrium constant expression
  • Predicting shift in equilibrium – LeChatliers Principle
  • Calculating and comparing Qc and Kc or Keq and predicting shift in equilibrium
  • Solubility product expressions (Heterogenous equilibrium)
  • Selective precipitation and use of Qsp and Ksp for predicting precipitation problems are also involved, application of selective precipitation.
  • Determination of molar solubility from Ksp, predicting precipitation when solutions are mixed – Calculation involved.
  • Commonion effect definition with an example.
  • Spontaneity definition, conditions for a reaction to become spontaneous use ΔG and the three possibilities.
  • Determination of equilibrium temperature or predicting at what temperature a system will attain equilibrium.
  • Use of equilibrium temperature to calculate entropy, enthalpy or T Problems
  • Problems based on the equation ΔG = -RTlnKc or ΔG = -2.303RTlogKc

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