formulas

Question 1

Relationship between frequency and wavelength

Answer 1

v=c/ƛ

where v=frequency (Hz) c=speed of light (3x10^8ms^-1) and ƛ=wavelength (nm)

Question 2

Relationship between frequency and energy

Answer 2

E=hv

where E=energy (J) h=Planck’s constant (6.626x10^-34 Js) v=frequency

Question 3

Factor of a metre: femto (f)

Answer 3

10^-15

Question 4

Factor of a metre: pico (p)

Answer 4

10^-12

Question 5

Factor of a metre: nano (n)

Answer 5

10^-9

Question 6

Factor of a metre: micro (µ)

Answer 6

10^-6

Question 7

Factor of a metre: milli (m)

Answer 7

10^-3

Question 8

Factor of a metre: centi (c)

Answer 8

10^-2

Question 9

Factor of a metre: deci (d)

Answer 9

10^-1

Question 10

Factor of a metre: kilo (k)

Answer 10

10^3

Question 11

Factor of a metre: mega (M)

Answer 11

10^6

Question 12

Factor of a metre: giga (G)

Answer 12

10^9

Question 13

Factor of a metre: Ångstrom (Å)

Answer 13

10^-10

Question 14

Beer-Lambert Law

Answer 14

A=Ɛcl
where A=absorbance Ɛ=molar absorption coefficient at given l (M^-1cm^-1) c=concentration (M) l=distance light passes through sample (cm)

Question 15

Bronsted-Lowry theory

Answer 15

For every acid there is a conjugate base

Question 16

pH in terms of [H+]

Answer 16

pH=-log10[H+]
acidic solutions: [H+] > 1x10^-7M pH < 1x10^-7M pH >7
neutral solutions: [H+] = 1x10^-7M pH =7

Question 17

equilibrium constant expression for aA + bB = cC + dD

Answer 17

Ka = ([C]^c[D]^d)/([A]^a[B]^b)
If K >1 product favoured
If K <1 reactant favoured

Question 18

pKa in terms of Ka

Answer 18

pKa = -log10Ka

Question 19

Henderson-Hasselbach equation

Answer 19

pH = pKa + log10[base]/[acid]

Question 20

Le Chatelier’s principle

Answer 20

If a reaction mixture at equilibrium is disturbed, reaction occurs in the direction that opposes the change

Question 21

First order rate law for aA + bB = cC + dD

Answer 21

v=k[A]^x[B]^y

Question 22

First order concentration-time equation

Answer 22

ln[A]t=ln[A]o-kt

Question 23

Second order rate law for aA + bB = cC + dD

Answer 23

v=k[A]^2

Question 24

Second order concentration-time equation

Answer 24

1/[A]t = kt+ 1/[A]o

Question 25

First order half life equation

Answer 25

ln2 = kt1/2

Question 26

Second order half life equation

Answer 26

t1/2 = 1/(k[A]o)

Question 27

Arrhenius equation

Answer 27

lnk = lnA - Ea/RT

where A=prefactor Ea=activation energy R=gas constant (8.314Jmol^-1K^-1) T=temp in Kelvin

Question 28

Gibbs free energy

Answer 28

ΔG = ΔH - TΔS
if ΔG > 0 spontaneous
if ΔG < 0 non-spontaneous
if ΔG = 0 equilibrium
G = gibbs free energy (energy available to do work) H= enthalpy (the conversion of potential energy to heat) T = temp in Kelvin S = entropy (molecular disorder)

Question 29

free energy and chemical equilibria

Answer 29

ΔG = -RTlnK
if K > 1 spontaneous
if K < 1 non-sponataneous
if K = 1 equilibrium

Question 30

Boltzmann equation

Answer 30

S = Kb lnW

where S is entropy, Kb is Boltzmann’s constant (1.38x10^-23K^-1) W is the number of ways a state can be acheived

Question 31

First law of thermodynamics

Answer 31

Energy can neither be created nor destroyed but merely converted from one form to another

Question 32

Second law of thermodynamics

Answer 32

In any spontaneous process the entropy of a system and its surroundings always increases

Question 33

third law of thermodynamics

Answer 33

The entropy of a perfect crystal at absolute zero is zero

Question 34

Cell potential

Answer 34

ΔG = -nFE
where n is number of moles of electrons
F is Faraday constant (96485C/mol)
E = cell potential (V)

Question 35

Nernst equation

Answer 35

E = E°cell - (RT/nF)lnQ

Q is the reaction quotient