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Chemistry Revision
Unit 1

Key Words

Acids and Bases

Nomenclature and Isomerism in Organic Chemistry

Aromatic Chemistry

Amines

Amino Acids

Polymerisation

Organic Synthesis and Analysis

Structure Determination

Chromatography

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Acids, bases and buffers

Defining an acid

An acid is a substance that can donate a proton (H+ ion)
A base is a substance that can accept a proton (H+ ion)

Ionisation of water

Water is slightly ionised, and this becomes an acid base reaction where one water molecule donates…

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This doesn't mean that the water is acidic as the H+ has the same concentration of -OH so is
neutral

Working with the pH scale

Finding [H+] from pH
o pH = -log[H+]
pH= 3.00
Therefore, 3.00 = -log[H+]
o So, - 3.00 = log[H+]
Anti log of this, 10-3.00…

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[Start] 1.00 0.00 0.00

[ m] 1.00 - [CH3COO-] [CH3COO-] [CH3COO-]

For this we assume that the degree of dissociation is that small that 1.00 - [CH3COO-] 1.00
2
[H+]
o Ka = 1.00

[H+] =
K W ×[HA] = 4.12 x 10-3moldm-3
pH = -log 4.12 x 10-3moldm-3 =…

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From the equation, number of moles of H2SO4 = 0.5 number of moles of NaOH
So number of moles of H2SO4 = 15.0 × 1000 B


o Therefore B = 0.00667moldm-3

Choices of indicators for titrations

Equivalence point is where the volume at which exactly the same number of moles…

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Therefore pKA = pH

Buffer Solutions

Buffers are solutions that can resist changes of acidity or alkalinity, when small amounts of acid or alkali are added to them
their pH remains almost constant
o Buffers are designed to keep the concentration of H+ and -OH almost unchanged
They are based…

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o The same equilibrium reaction acts to buffer the acidity of
soils
o There are buffers in everyday products such as detergents and shampoos to prevent these substances becoming too
acidic or too alkaline and damage fabric, skin or hair
Calculations on buffers
o A buffer consists of 0.100moldm-3 Ethanoic…

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Nomenclature and isomerism in organic chemistry

Naming organic compounds

Roots
o -ane means no double bonds
E.g. ethane
o -ene means there is a double bond
E.g. ethane
o -yne means there is a triple bond
E.g. propyne
Functional groups

Family Formula Suffix/ Prefix Example
Alkenes RCH=CH2 ene Propene

Alkynes…

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There are two types
o E-Z isomerism
o Optical isomerism
E-Z isomerism
o Two substituent's may either be on the same side (Z) or on opposite sides (E)
There are no isomers around a single bond as they can rotate around this
There is restricted rotation around a double bond…

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Synthesis of optically active compounds

A racemic mixture is produced from optically active compounds generating a 50:50 mixture of two optical isomers
o The synthesis of 2-hydroxypropanoic acid (lactic acid)
Stage 1




Stage 2




Optical isomers in the drug industry
o Some drugs are optically active molecules
Many drugs work…

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