Equilibrium

Question 1

Dynamic Equailibrium

Answer 1

State which no observable changes at the macroscopic level but there is a constant change at particle level
- rate of forward and reverse reactions are equal
- concentrations of reactant and product remain constant

Question 2

3 conditions for equilibrium to occur

Answer 2

• reaction must be reversible
• system must be closed (no matter can escape)
  Note: important - need a control variable, easier to assess when system is separated from surroundings
• conditions of temperature and pressure are constant

Question 3

3 types of equilibrium

Answer 3

• Phase Equilibrium - between different physicalstatus
• Solubility Equilibrium - between solute and solventin saturated solution
• Chemical Equilibrium

Question 4

Percent Yield

Answer 4

equalibrim/ stoichiometrically x 100
< 50% reactants favoured
>50% products favoured
=50% quantitative - one way reaction

Question 5

Law of Mass Action

Answer 5

• large # of small units acting randomly by themselves can have larger pattens (UHS students in hallway)
• applies to all chemical equilibria
• can be stated mathematically

Question 6

Equilibrium Constant Expression

Answer 6

K = products ^ coefficient / reactant ^ coefficient

Question 7

Limitations of Equilibrium

Answer 7

• gases and ions aqueous solution can change concentrations
• liquids and soilds cannot change concentrations therefore are not added in the K expression

Question 8

What is Quotient Q? And whats its purpose?

Answer 8

• Q describes reaction not at equilibrium
• to figure out the direction a reaction will go to reach equilibrium
  Q < K – shifts right - reaction make more product
  Q > K – shifts left - reaction make more reactants
  Q = K – no shift

Question 9

Le Chatelier’s Principle

Answer 9

whenever a system at equilibrium is subjected to a stress then the equilibrium will shift in a direction to relieve that stress

Question 10

What are the possible stresses a reaction may experience?

Answer 10

• Changing concentration
• Changing Volume
• Changing Pressure
  Note:
  increase Volume = decrace Pressure – least mole
  decrease Volume = increase Pressure – more mole
• Changing Temperature
• Adding catalyst or inert gas (no effect / shift)

Question 11

Solubility

Answer 11

quantity of substance that dissolves to form a saturated solution

Question 12

Molar Solubility

Answer 12

of moles of solute that dissolves to form a liter of saturated solution

Question 13

Gram Solubility

Answer 13

mass in grams of the solute that dissolves to form a liter of saturated solution

Question 14

Ksp (solubility product)

Answer 14

the equilibrium constant for the equilibrium between an ionic solid and its saturated in solution, expresses the extent of the dissociation

Question 15

Bronsted - Lowry Theory

Answer 15

Acid is proton donor, Base is proton acceptor

Question 16

Strong Acids and Bases

Answer 16

Acids:
HCIO4 , HI, HBr, HI, HNO3

Bases:

Question 17

what is Neutralization Reaction?

Answer 17

reaction in which acid and base react in an aqueous solution to produce a salt and water

Question 18

Hydrolysis and what ions don’t hydrolyze

Answer 18

• reaction of a salt with rather to form an acidic or basic solution
  Don’t hydroyze
• Group 1
• Halogens (fluorine is the exception)
• conjugates of strong acid and strong base

Question 19

Amphiprotic

Answer 19

• substance that can both donate and accept protons
• “protic” refers to hydrogen ions either being donted or accepted
• ex: Water, HS04-

Question 20

Amphoteric

Answer 20

• a substance which can act as either acid or a base but a proton exchange is not required
• All amphiprotic substances are also amphoteric - but the reverse isn’t true
• ex: Lewis Theory of Acid and Base _ not dependant on hydrogen but on the charges