3.3.1 Introduction to Organic Chemistry Flashcards
Define General Formula
An algebraic formula that can describe any member of a family of compounds
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Define Empirical formula
Simplest ratio of atoms of each element in a compound
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Define Molecular formula
Actual number of atoms of each element in a molecule
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Define Structural Formula
Shows the atoms carbon by carbon + attached hydrogens & functional groups
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Define Skeletal Formula
Shows the bonds of the carbon skeleton ONLY + any functional groups
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Define Displayed Formula
Shows how all the atoms are arranged and all the bonds between them
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What is the functional group for alkanes?
C—C
What is the functional group for alkenes?
C=C
What is the functional group for alcohols?
C—OH
What is the functional group for haloalkanes?
C—halogen
What is the functional group for aldehydes?
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What is the functional group for ketones?
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What is the functional group for carboxylic acids?
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What is the functional group for nitriles?
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What is the functional group for amines?
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What is suffix for alkenes?
-ene
What is suffix & prefix for alcohols?
-ol & hydroxy-
What is the prefix for haloalkanes? (4x)
- fluoro-
- chloro-
- bromo-
- iodo-
What is the suffix for aldehydes?
-(an)al
What is the prefix & suffix for ketones?
oxo- & -(an)one
What is the suffix for carboxylic acids?
-(an)oic acid
What is the suffix for nitriles?
-(anen)nitrile
What is the prefix & suffix for amines?
-(yl)amine & amino-
What is the general formula for alkanes?
CnH2n+2
(n = 1,2,3 etc.)
What is the general formula for alkenes?
CnH2n
(n = 1,2,3 etc.)
What is the general formula for alcohols?
CnH2n+1OH
(n = 1,2,3 etc.)
What is the general formula for carboxylic acids?
CnH2n+1COOH
(n = 0,1,2 etc.)
What is the general formula for haloalkanes?
CnH2n+1X
(n = 1,2,3 etc.)
(X = F, Cl etc.)
What is the general formula for primary amines?
CnH2n+1NH2
(n = 1,2,3 etc.)
What is the general formula for aldehydes?
CnH2n+1CHO
(n = 0,1,2 etc.)
What is the general formula for ketones?
CmH2m+1COCnH2n+1
(m & n = 0,1,2 etc.)
Name 5 features of a homologous series
- Chemically similar / react in same way
- Each successive member differs by CH2
- Same general formula
- Same functional group
- Gradation in physical properties or specified trend
What effect does the length of the carbon chain have on chemical reactivity of the functional group?
Has little effect
What affects the physical properties (e.g. melting/boiling point & solubility) of carbon molecule?
The length of carbon chain
In general: small molecules are ___ and larger ones are ____ + _____
gas & liquids + solids
Why does the length of the carbon chain affect physical properties?
Melting/boiling points increase by small amounts as no. of C in chain increases ∵ intermolecular forces increase
How does chain branching generally affect melting points and why?
- Reduces melting points
- ∵ less surface area (molecules pack together less well) & weaker van der Waals forces
Hydrogen ring molecules have prefix of ____
‘cyclo’
What are isomers?
Molecules that have the same molecular formula but their atoms are arranged differently
Name 2 type of isomers
Stereoisomers & structural isomers
What are structural isomers?
Have same molecular formula but different structural formulas
Name 3 types of structural isomers
- Chain Isomers
- Positional Isomers
- Functional Group Isomers
What is a chain isomer?
- Same molecular formula
- Hydrocarbon chain is arranged differently
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What is a positional isomer?
- Compounds with same molecular formula
- But different structures due to different positions of the same functional group on
- The same carbon chain
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What are functional group isomers?
- Same molecular formula
- Have the same atoms but have different functional groups
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What are stereoisomers?
(Where 2 or more) compounds with the same structural formula but with atoms arranged differently in space
_____ show E/Z Isomerism
Alkenes
The atoms connected to the C=C double bonds _____ rotate around them like they can around single bonds
Cannot
What causes the type of stereoisomerism called E/Z isomerism?
Restricted rotation around the (planar) C=C double bond
Explain how alkenes show E/Z isomerism
- Alkenes have restricted rotation around their C=C double bonds
- & if both of the double-bond carbons have different functional groups attached to them = get 2 stereoisomers (E/Z isomerism)
Where are the same groups situated in (cis) Z-isomer?
Either both above or both below double bond
(matching groups are on ‘ze zame zide’)
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Where are the same groups situated in (trans) E-isomer?
Same groups positioned across the double bond
(matching groups are ‘enemies’)
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What rules do we use to identify whether a molcule with a C=C bond, surrounded by 3 or 4 different functional groups, is a E- or Z- isomer?
Use the Cahn-Ingold-Prelog (CIP) priority rules
Describe how we use the CIP rules to identify a E-/Z-isomer
- Identify the groups directly bonded to each of the C=C carbon atoms
- Assign a priority by finding the atom with the highest atomic number - this given the highest priority
- If higher priority groups = same side of molecule = Z-isomer OR if higher priority groups = different sides of molecule = E-isomer
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CIP rules: What do you do if the atoms directly bonded to carbon are the same?
Look at next atom in the groups to work out which has the higher priority
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Why is the IUPAC system used for naming organic compounds?
It’s the agreed international language of chemistry so it allows scientific ideas to be communicated across the globe more effectively
What are mechanisms?
Diagrams that break reactions down into individual stages
What reaction do mechanisms show?
How molecules react together
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What do curly arrows show?
How electron pairs move around in reactions
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As electrons are _____ _____, they move from areas of high ______ _____ to more _____ ____ areas
As electrons are negatively charged = move from areas of high electron density to more positively charged areas
(e.g. pair of electrons = attracted to carbon atom at positive end of a polar bond)
Explain how free radicals form?
- Sometimes a covalent bond may break in such a way that 1 electron goes to each atom that originally formed the bond
- These fragments of original molecule have an unpaired electron = called free radicals
Free radicals are extremely ____
reactive
How are free radicals represented?
By a dot
(e.g. CH3• = methyl radical)
What is the functional group of an ester?
-COO
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State the name of CH3CH=CHCH2OH
But-2-en-1-ol