1 chemical equilibrium chapter 16. objective distinguish between reversible and completion reactions...
TRANSCRIPT
OBJECTIVE• Distinguish between reversible
and completion reactions• Understand Equilibrium• Define/ apply the terms system
and stress to reversible reactions
• Le Chatlier’s Principle
Reversible Reactions
H2 + I2 ↔ 2HI • the products may react back to original
reactants.
• “closed system”: ONLY if all reactant are present
• If one piece is completely gone it has ”gone to competition” and no longer reversible
TWO REACTIONS
• only difference is the Direction
H2 + I2 ↔ 2HI
2HI ↔ H2 + I2
reactants products
Left Right
Examples: Reversible Reactions.
• Unopened Soda
• Breathing
• Rechargeable batteries
• Color changing shirt
Equilibrium
•The state in which a chemical reaction and its reverse reaction occur at the same rate.
8
Reversible ReactionsReversible Reactions
Product conc. increases and then becomes constant at equilibrium
Reactant conc. declines and then becomes constant at equilibrium
Equilibrium achieved
“stressing a system”
• Pick reversible reactions that have different colored products.
•EXAMPLES T –shirt ball
•Stress: done to change the ratio color change means change ratio of two products
Le Chatelier’s Principle
•Anything YOU do (stress) to a reversible reaction, the system reacts in a way to UNDO that change
•Remember there are TWO reactions going in every reversible reaction.
Shifting Equilibrium
• Change Temperature• Change concentration of Cl-
CuCl4 (aq) ↔ Cu+ (aq) + Cl- (aq) + heatLeft: GREEN Right BLUE
•Add Temperature or Cl- : Green/ right•Remove heat or Cl: Blue / Left
Concentration:Amount
ADD reactant or
REMOVE reactant
Will cause opposite results
Science is fun31918
Cu and hydrogen
PressureUsed for gases Easiest way to measure the amount of a gas
Same affect as changing the concentration
17Equilibrium Disk
6C32
Equilibrium systems are
• DYNAMIC (in constant motion)
• REVERSIBLE
• can be approached from either direction
Equilibrium systems are
• DYNAMIC (in constant motion)
• REVERSIBLE
• can be approached from either direction
Pink to blueCo(H2O)6Cl2 ---> Co(H2O)4Cl2 + 2 H2 H22OO
Blue to pinkCo(H2O)4Cl2 + 2 H2O ---> Co(H2O)6Cl2
Le Chatelier’s Principle
• If you ADD reactants , The system will REMOVE reactants by making more products.
• If you REMOVE reactants , The system will ADD reactants by USING (reacting) products.