# Kinetics and equilbria

• Created by: Sopha8
• Created on: 02-04-15 16:18
What is rate of reaction and how do you calculate it? How do you calculate the rate constant?
change in amount of reactants and products per unit of time. Rate=k (A) (B) k=Rate/(A) (B)
1 of 13
Explain the rate determing step
Slowest rate step in a series of steps, it determines the overall rate. Reactants from rate equation or something thats dervied from it will be in the rate determining step
2 of 13
How do you work out the equilibrium constant of a reversible reaction?
Kc=(D) (E) / (A) (B) or products/ reactants
3 of 13
What can affect the value of Kc and how?
:
4 of 13
Define a Bronsted-Lowry acid and base
acid=proton donor base=proton acceptor
5 of 13
Whats the equation for the ionic product of water? How could you use it to work out the pH of a) water b) strong base?
1.Kw= (H+) (OH-) 2. a) Kw for water =(H+)squared so (H+)= Kw then pH equation b) (H+) of strong base=Kw/(OH-) then pH equation
6 of 13
What is the pH equation? How can you arrange it to work out H+ concentration?
1.pH=-log (H+) 2.(H+)=10
7 of 13
How do you calculate the pH of a) strong monoprotic acids b)strong diprotic acids c)weak acids
a) (H+)=concentration of acid as fully disscoaites, then use pH equation b) (H+)=2x concentration of acid then pH equation c) Ka=(H+)(A-)/(HA) all H+ come from acid so Ka=(H+) /(HA) so (H+)= Ka(HA) then pH equation
8 of 13
Sometimes pKa is used when Ka is to larger number to manage, how do you convert between the two?
pKa=-Log (Ka) or Ka=10
9 of 13
How can you calculate the pH of a mixture?
1.calculate mols of both using n=c X v (/1000 if v in cm3) 2. subtract lowest from highest to find out which is in excess 3.if strong acid) c=n/total volume then pH equation or strong base) c=n/total v then (H+)=Kw/(OH-) then pH equation
10 of 13
What is a buffer?
a solution which resists changes in pH when small amounts of an acid or base is added
11 of 13
Write equautions to explain how an acidic and basic buffers works
:
12 of 13
What is the simple equation used when working out the pH of an acid buffer? what happens if a small amount of a)alkali or b)acid is added
(H+)=Ka X (acid)/ (salt) then pH equation a) calcuate mols of alkali by n=c X v, take value away from (acid), add to (salt) then use original equation again b)mols of acid, take from (salt) add to (acid) then first equation
13 of 13

## Other cards in this set

### Card 2

#### Front

Explain the rate determing step

#### Back

Slowest rate step in a series of steps, it determines the overall rate. Reactants from rate equation or something thats dervied from it will be in the rate determining step

### Card 3

#### Front

How do you work out the equilibrium constant of a reversible reaction?

### Card 4

#### Front

What can affect the value of Kc and how?

### Card 5

#### Front

Define a Bronsted-Lowry acid and base