F325 - Rates, Equilibrium and pH Flashcards
Describe zero order.
The rate is unaffected by changing the concentration in A.
What is the rate of reaction?
The change in concentration of a reactant or product per unit time.
Change in conc/time
Describe first order.
Proportional to the increase in concentration.
Eg increase of 3 then increase of 3.
Describe second order.
Increases proportional to the square of the concentration.
Eg concentration increases by 3.
Rate increases by 9.
What does a half life graph look like for first order?
Constant half life.
Describe a zero order Half life graph.
Half life decreased with time at a constant rate.
Describe a second order half life graph.
1/x
What changes Kc?
Temperature
What does a Kc value of 1 indicate?
Equilibrium is halfway between reactants and product
What does a Kc above 1 suggest.
Product favoured, shifts to the right.
When the forward reaction is endothermic how does Kc increase?
As temperature increases so does Kc.
What is Kc?
Products/reactions
Why is a Brønsted-Lowry acid and base?
Acid: any substance for which a proton can be removed.
Base: any substance that can remove a proton from an acid.
What is an alkali?
A base that dissolved in water forming OH- ions.
What is an acid base conjugate pair?
A pair of two species that transform into each other by gain or loss of a proton.
What is pH?
-log[H+]
What I [H+]?
10^-pH
What is a strong and weak acid?
Strong completely dissociates in water.
Weak partially dissociates in water.
In a strong acid what does H+ equal?
[H+]=[HA]
What does [H+] equal in weak acids?
[H+]=[A-]
Describe Kw in water, acidic and alkaline solutions.
Water H+=OH-
Acid H+>OH-
Alkaline H+<OH-
What is Kw?
[H+][OH-] both (aq)
1 x 10^-14
What is a buffer solution?
A mixture that minimises pH changes on addition of small amounts of acid or base.
How is a buffer solution made?
A mixture of a weak acid and it’s conjugate base.
Describe the action of a buffer solution HA.
HA ~ H+ + A-
When H+ is added A- reacts and eq shift to the left removing the H+ ions.
When OH- is added H+ react and eq shifts to the right.
What is equivalence point?
The point in a titration at which the volume of one solution has reached exactly the volume of the second solution.
