# Chem1BTest2

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1. Equilibrium constant expression for aA + bB ↔ cC + dD
• K = K1/K-1 = [C]c[D]d/[A]a[B]b
• Product favored: K has large value
• Reactant favoried: K has a small value
• Note - Pure solids and liquids aren't included in equilibrium constant expression
2. Effect on equilibrium constant if equation is reversed? A coefficient is added? You add equations together?
• Reversed: Kbackward = 1/Kforward
• Coefficent: Knew = Knoriginal
• Addition: Knew = K1 x K2
3. Relationship between Kp and Kc
• KP = Kc x (RT)Δn
• Δn = moles gas products - moles gas reactants
• note - Kp always given in atm
4. Reaction Quotient?
• same as equilibirum constant, but at ANY concentration.
• Can be compared with equilibrium constant to determine how reactants/products will change
• Q>K - [reactants] increase and [products] decrease
• Q<K - [reactants] decrease and [products] increase
• Q=K - [reactants] and [products] do not change
• If rxn has only reactants Q = 0, only products Q = ∞
5. Explain the simplification step and method of approximations
• Simplification: assume x is very small and eliminate x from equation (+x, -x). Solve equation. If x is less than 5% of the largest initial concentration then the answer is correct.
• Method of approximations: if x is not smaller than 5% of the largest initial concentration then input the number you got into the equation. If the new answer is not less than 5% of the largest initial concentration then input the number you just got into the equation, repeat until less than 5%!
6. Effect of adding/removing reactants, gas volume changes, and temperature shifts
• Adding a reactant / removing a product: rxn ---->
• Adding a product / removing a reactant: rxn <-----
• When volume is reduced equilibrium favors side w/ fewer moles (gases)
• When volume is increase equilibrium favors side w/ more moles (gases)
• Temperature: determine exothermic/endothermic. Write heat into the equation (exo - heat as product, endo - heat as reactant). Consider temperature change as a change to heat within the equation. EXAMPLE - endothermic heat increases forces equilibrium ---->
 Author: victimsofadown ID: 105384 Card Set: Chem1BTest2 Updated: 2011-09-30 13:12:30 Tags: Chem1BTest2 Folders: Description: Chem1BTest2 Show Answers: