C3/C4: Solutions/Equilibrium

Question 1

what is a solute?
- solvent?

Answer 1

• the substance present in a smaller amount
• the substance present in a greater amount

Question 2

what is an aqueous solution?

Answer 2

when a solution has water as the solvent

Question 3

what happens to solubility if temperature is increased for:
- solids in liquids
- gases in liquids

Answer 3

• increases
• decreases (heat released)

Question 4

what happens to solubility if pressure is increased for:
- gases in liquids

Answer 4

increases, gas pushed into solution

Question 5

at equilibrium, the overall ____ of reactants and products is the same and the rate of the____ reaction is equal to the ____ of the ____ reaction

Answer 5

concentration; forward; rate; reverse

Question 6

what is the equilibrium expression?

Answer 6

Ksp = [products]/[reactants]
- solids are not included and coefficients are shown as exponents

Question 7

what has the ability to change Keq?
- K is determined under ____ conditions

Answer 7

temperature
- standard state (298K)

Question 8

what do the following expressions mean:
- Keq < 1
- Keq = 1
- Keq > 1

Answer 8

• rxn favors reactants
• rxn balances reactants and products
• rxn favors products

Question 9

what is the variable for reaction quotient?
- it has the same formula as ____ except it is used when ____

Answer 9

• Q
• Keq; the concentrations do not have to be at equilibrium

Question 10

a reaction strives to reach a state in which Keq = ____

Answer 10

Q, where the rxn is at equilibrium

Question 11

• what happens if Q is less than Keq?
• more than Keq?

Answer 11

• the rxn proceeds in the forward direction
• the rxn proceeds in the reverse direction

Question 12

what is le chatelier’s principle?

Answer 12

a system at equilibrium will try to neutralize imposed change in order to reestablish equilibrium

Question 13

following le chatelier’s principle, what happens if within a rxn we:
- add more of a product
- remove a product
- add more of a reactant
- remove a reactant
- add a catalyst

Answer 13

• shifts left
• shifts right
• shifts right (bc the forward rxn is favored when adding more reactant)
• shifts left
• increases the rxn rate but does not effect equilibrium, no shift

Question 14

following le chatelier’s principle, what happens if within a rxn we:
- change the volume of a container
- change the temperature of the rxn
- what happens in regard to endo and exothermic rxns when temp is increased/decreased?

Answer 14

• if the # of moles on the reactants side is not equal to the # of moles on the products side, the system will react depending on whether volume is increased or decreased. if volume is decreased, the rxn wil favor the side of the rxn with a smaller # of moles. if volume is increased, the rxn favors the side with a greater # of moles
• if temp is increased, the rxn shifts left. if it is decreased, the rxn shifts right
• if the temp is lowered the exothermic rxn is favored, if the temp is raised the endothermic is favored

Question 15

what is molar solubility?

Answer 15

the max amount of solid you can add to 1L of water without precipitation. AKA it describes how to make a saturated solution

Question 16

____ always decreases solubility

Answer 16

common ion effect (when there is the same ion on the reactants and products side)

Question 17

what are the 4 solubility rules?

Answer 17

1. like dissolves like (polar dissolves polar, nonpolar dissolves nonpolar)
2. all group 1 and NH4+ salts are soluble
3. NO3-, ClO4-, and CH3COO- salts are soluble
4. Ag+, Hg2+, and Pb2+ salts are insoluble except when paired with #3

Question 18

what are the 11 common polyatomic anions and their formulas?

Answer 18

CHECK FOLDER

Question 19

what happens when an ionic substance dissolves?

Answer 19

they dissociate into ions

Question 20

what are electrolytes?
- what is a strong electrolyte?
- weak electrolyte?
- nonelectrolyte?

Answer 20

• free ions in a solution
• solutes that dissociate completely
• solutes that remain ion-paired to some extent
• covalent compounds that dont dissociate into ions

Question 21

what is the vant hoff factor for the following:
- ionic bonds
- strong acids/ bases
- covalent bonds
- weak acids/ bases

Answer 21

• greater than 1
• greater than 1
• equal to 1
• equal to 1

Question 22

describe what the following expressions mean in regard to solubility:
- Qsp < Ksp
- Qsp = Ksp
- Qsp > Ksp

Answer 22

• more salt can be dissolved
• solution is saturated
• excess salt will precipitate