Chapter 14 - Equilibrium

What is equilibrium?

reactants and products exist simultaneously, similar to a seesaw, the reactions are reversible and shift back
and forth from A -> B and A <- B

What happens to weak acids in an equilibrium reaction?

they sometimes separate into ions but sometimes do not

What does equilibrium determine about "insoluble" ionic compounds?

they aren't exactly insoluble however only a little bit of the compound can dissolve

Do you reach equilibrium with strong acids?

no, 100% of the reactants turn into products

Do weak acids reach equilibrium?

yes, not all the reactants convert to products and vice versa, you will some of both, symbolized by a double arrow,
reactants can shift to products and vice versa at any time

How do you use rate laws in equilibrium reactions?

treat both of the reactions as elementary reactions (simple), reactions can be looked at forward or reverse (backward),
however the rates are equal, rearrange the formula to find the equilibrium constant to calculate K

How do you calculate K?

K is calculated from values of chemical A (A + B ⇌ 2C) that can change -> molarity of a solution [A] or partial pressure of
a gas Pa, not solids or liquids because molarity and partial pressure are effected

What is always true about K?

K is always positive, has no units, and changes very easily with changes in T

Are Kp and Kc always equal?

they are only equal if the coefficients are equal

What can you determine about a reaction if K <100 (K is large)

the reaction favors products (there's more products than reactants)

What can you determine about a reaction if K >0.01 (K is small)

the reaction favors reactants (there's more reactants than products)

What is the Haber process?

a process that fixes nitrogen, traditionally has 3 bonds, fixes to 1, is an equilibrium reaction

What is Q?

Q-reaction quotient, Q is similar to K, whether or not the reaction is at equilibrium

What is the difference between Q and K?

Q and K are similar, however Q is when reactions are not at equilibrium, K is when reactions are at equilibrium, Q
returns to K by shifting to the other side of the reaction

What is similar between Q and K?

they are both calculated using the rule products over reactants

How does Q return to K?

Q returns to K by shifting to the other side of the reaction

What happens when Q<K?

reactants shift to products, to make Q (1/1), K (4/1), A shifts to B, A↓ B↑

What happens when Q>K?

products shift to reactants, to make Q (9/1), K (4/1), B shifts to A, A↑ B↓

What is Le Chatelier's Principle?

When a change is imposed on a system at equilibrium, the equilibrium will shift to counteract the change.

What happens when you add A to an equilibrium reaction?

reaction shifts away from A

What happens when you remove A from an equilibrium reaction?

reaction shifts back to A

What happens to a reaction when you heat it?

heating a reaction is like adding energy

What happens to a reaction when you cool it?

cooling a reaction is like removing energy

Where does energy go in an exothermic reaction?

energy goes in the products side, A ⮀ B + Energy

What happens when you heat an exothermic reaction?

reaction shifts, A 🡨 B + Energy

What happens when you cool an exothermic reaction?

reaction shifts, A 🡪 B + Energy

Where does energy go in an endothermic reaction?

energy goes in the reactants side, Energy + A ⮀ B

What happens when you heat an endothermic reaction?

reaction shifts, Energy + A 🡪 B

What happens when you cool an exothermic reaction?

reaction shifts, Energy + A 🡨 B

What happens if you change the gas pressure of reaction A(g) ⮀ B(g).

no effect, changing pressure of a reaction with equal moles doesn't change equilibrium reaction

What happens if you change the gas pressure of reaction A(g) ⮀ 2 B(g).

changing pressure changes equilibrium reaction bc of unequal amount of moles

What happens if you increase the pressure in an equilibrium reaction?

reaction shifts to the side with fewer gas moles (crowded)

What happens if you decrease the pressure in an equilibrium reaction?

reaction shifts to the side with more gas moles (lonely)