module 5 physical chem

Question 1

acid

Answer 1

proton donor

Question 2

base

Answer 2

proton acceptor

Question 3

conjugate acid base pairs

Answer 3

HA + OH –> H2O + A
HA & A acid base pair 1
OH- & H2O acid base pair 2

Question 4

basic equations

Answer 4

acid + metal –> salt + hydrogen
acid + oxide –> salt + water
acid + carbonate –> salt + CO2 + water
acid + hydroxide –> salt + water

Question 5

pH equation

Answer 5

pH = -log[H+]
[H+] is concentration of H+ atoms

Question 6

[H+] equation

Answer 6

[H+] = 10-pH
10 to the power of -pH

Question 7

Diluting pH

Answer 7

X10 everytime to drop down pH
1 –> 2 X10

Question 8

Ka expression

Answer 8

Ka= [H+] [A-]
[HA]
Ka= [H+]2
[HA]

Question 9

Ka equation

Answer 9

Ka= 10-PKa

Question 10

PKa equation

Answer 10

-log(Ka)

Question 11

working out [H+] conc with Ka

Answer 11

[H+] = Ka x [HA]

Question 12

Kw

Answer 12

ionic product of water
1 x 10-14

Question 13

working out [H+] in alkali

Answer 13

you are given OH conc (overall conc)
[H+] = 1 X 10-14 / [OH-]
then put into pH equation (-log[H+] )

Question 14

working out [H+] in alkali
method 1

Answer 14

you are given OH conc (overall conc)
[H+] = 1 X 10-14 / [OH-]
then put into pH equation (-log[H+] )

Question 15

working out [H+] in alkali
method 2

Answer 15

you are given OH conc
put into equation POH = -log[OH-]
then do 14 - POH = pH

Question 16

Rate of reaction definition

Answer 16

change in conc of reactant or a product per unit time

Question 17

Ways to measure rate of chemical reaction

Answer 17

Volume of gas production
Measure loss in mass
Measure increase in mass
Measure colour change

Question 18

Zero order reaction (conc&rate)

Answer 18

changing the concentration of the reactant has NO affect on rate of reaction
(straight horizontal line on graph)

Question 19

First order reaction (conc&rate)

Answer 19

Rate of reaction is directly proportional to the conc of the product
-doubling conc doubles rate
1:1
Straight diagonal line through origin

Question 20

Second order reaction (conc&rate)

Answer 20

Rate of reaction will equal concentration squared
2:1
Curved horizontal line up

Question 21

Rate constant K

Answer 21

Rate = K [A][B][C]
constant that links the rate of reaction with conc
concentration has powers depending on order

Question 22

Overall order

Answer 22

All orders added together
Indices

Question 23

Zero order (conc&time)

Answer 23

Half life decreases over time
straight diagonal line downwards on graph

Question 24

first order (conc&time)

Answer 24

Half life is constant over time
Downwards curve on graph

Question 25

Second order (conc&time)

Answer 25

Half life increases over time
Steep downwards curve on graph

Question 26

Calculating rate constant from half life

Answer 26

K = ln2 / t 1/2

Question 27

Clock reaction

Answer 27

Chemical reaction where one of the chemical products initially has a low conc but gradually increases with time
-amount of time it takes for mixture to change colour

Question 28

Rate determining step

Answer 28

The slowest step in the reaction mechanism of a multistep reaction
step with largest activation energy

Question 29

Creating a multi step reaction

Answer 29

compounds in the rate equation must be in the first step of the multi step reaction

Question 30

Maxwell boltzman curve

Answer 30

higher temp = higher proportion of molecules with activation energy

Question 31

Arrhenius equation

Answer 31

K = Ae to the power of -Ea/RT
e = 2.718
A = pre exponential factor
R = gas constant 8.312
T = temp (kelvin)
Ea = activation energy

Question 32

Rearranged arrhenius equation

Answer 32

K = -Ea/R x 1/T + lnA

Question 33

Arrhenius equation with graph

Answer 33

Y = M X + C
lnk = -Ea/R 1/T + lnA

Question 34

Kc

Answer 34

used to calc the exact position of equilibrium
1 equal lies halfway
greater than 1 equilibrium lies to right
less than 1 equilibrium lies to left
Kc = [products]
[reactants]

Question 35

Practical techniques used to study equilibrium

Answer 35

-Colorimetry
-Titration

Question 36

homogenous

Answer 36

where all reactants and products are in the same state eg all (g)

Question 37

heterogenous

Answer 37

where products and reactants are in different states
Kc equations don’t include solid and liquid states