Introduction to Organic Chemistry Flashcards
What is a molecular formula? (1 mark)
⦾ Actual no. of atoms of each element in compound (1)
What is a structural formula? (2 marks)
⦾ Arrangment of atoms carbon by carbon (1)
⦾ with attached hydrogens + functional groups (1)
e.g. ⦾ Ethane: CH3CH3
⦾ Pen-1-ene: CH3CH2CH2CHCH2
What is a displayed formula? (2 marks)
⦾ All atoms arrangment (1)
⦾ and all bonds between them (1)
What is an empirical formula? (1 mark)
⦾ Simplest whole no. ratio of atoms of each element in compound (1)
What is a general formula? (1 mark)
⦾ Algebraic formula that can describe any member of a family of compounds.
What is a skeletal formula? (3 marks)
⦾ Shows bonds of carbon skeleton (1)
⦾ (and) non-carbon atoms (1)
⦾ H + C atoms that are part of main C chain not shown (1)
⦾ Vertices are Cs
What is a homologous series? (4 marks)
Series of molecules with: ⦾ Same functional group (1) ⦾ Same general formula (1) ⦾ React similarly (1) ⦾ Increase in bp.s as chain length increases (1)
Explain alkanes fully? (5 marks)
⦾ CnH2n+2 (1) ⦾ End in: -ane (1) ⦾ Only H + C (1) ⦾ Each C atom has 4 SINGLE BONDS (1) ⦾ SATURATED (1)
Explain halogenoalkanes fully? (3 marks)
⦾ Similar to Alkanes EXCEPT (+) 1 H atoms replaced with HALOGEN atom (1)
⦾ Prefix: fluoro-, chloro-, bromo- or iodo- (1)
⦾ Even replace all Hs with halogen atom (1)
Explain cycloalkanes fully? (5 marks)
⦾ Ring of C atoms with 2 Hs attached to each C (1)
⦾ CnH2n (1)
⦾ Still saturated (1)
⦾ cyclo- (1)
⦾ -ane (1)
⦾ e.g. 3 Cs needed to make ring so CYCLOPROPANE is smallest cycloalkane - C3H6
Explain branched alkanes fully? (4 marks)
⦾ Alkane that doesn’t have all C atoms in 1 straight chain (1)
⦾ Main (longest) C chain + (+) 1 Cs coming off main chain (1)
⦾ Branches - ALKYL groups (1)
⦾ CnH2n+2 (1)
What does the ‘3’ in 3-ethylpentane mean? (1 mark)
⦾ branch is on the 3rd C along main chain (1)
Explain alkenes fully? (5 marks)
⦾ HC with (+)1 C=C (1)
⦾ CnH2n (1)
⦾ Cs of C=C only bonded to 3 atoms each rather than max of 4 (1)
⦾ So they can form another bond so they’re UNSATURATED (1)
⦾ (makes them) reactive (1)
- The general formula CnH2n only applies to alkenes with… (1 mark)
⦾ …exactly 1 C=C bond (1)
Explain alcohols fully? (4 marks)
⦾ -OH group (1)
⦾ CnH2n+1OH (1)
⦾ -ol (1)
⦾ React to give alkenes (1)
Explain aldehydes fully? (3 marks)
⦾ End of C chain has: O ll - C - H (1) ⦾ R-CHO (R is alkyl group) or an H atom (1) ⦾ -al (1)
Explain ketones fully? (3 marks)
⦾ C=O bond except its in middle
O
ll
R' - C - R' (1)
⦾ R + R' are alkyl groups which may/may not be the same (1)
⦾ R - CO - R' (1)Explain carboxylic acids fully? (3 marks)
⦾ Contain functional group:
O
ll
- C - OH (1)
⦾ -oic acid (1)
⦾ R-COOH (1)What does Nomenclature mean? (1 mark)
⦾ Naming organic compounds (1)
Why is the IUPAC system more benficial? (2 marks)
⦾ Scientific ideas communicated across the globe more effectively (1)
⦾ Easier for scientists to get on with testing each other’s work + either support or dispute new theories (1)
How do you name straight-chain alkanes? (3 marks)
- 1st: no. of C atoms in molecule (1)
- 2nd: “-ane” (1)
- e.g pentane (5 C atoms) (1)
How do you name branched alkanes? (3 marks)
- no. of C atoms in longest chain + work out stem (meth-, eth-, prop-, but-) (1)
- Name side chains - according to no. of C atoms they have + which C atom they’re attached to (1)
- If there’s (+) 1 side chain in molecule, place them in alphabetical order. i.e. but- before eth- groups (1)
⦾ e.g. 2-methylbutane. 3-ethyl-2-methylpentane
How do you name cycloalkanes? (4 marks)
- Same name as straight chain alkane but with cyclo- (1)
- If alkyl group attached, add alkyl prefix (1)
- If there’s (+) 1 alkyl group, make the numbers as low as possible (1)
- Alkyl that alphabetically 1st goes on the C (1)
⦾ e.g. 1-ethyl-3-methyl-cyclopentane
How would you name other functional groups? (3 marks)
- Stem is longest C chain containing functional group (1)
- Prefixes + suffixes come from functional groups as well as any alkyl side chains (1)
- If you need to use no. to show the position of the functional group, give the C which the functional group attached lowest no. possible (1)
How do you name alkenes? (2 marks)
⦾ Find stem no. (1)
⦾ -ene (1)
If there’s more than 1 functional group, you have to work out which one has the highest priority.
What is the priority list? (1 mark)
Highest priority: 1. Other functional groups 2. Alkenes 3. Alkyl groups 4. Halogens Lowest priority: (1) Stem of name comes from longest C chain containing the main functional group. Number Cs so main functional group has the lowest number possible. e.g. 3-chloropropan-1-ol e.g. 4-chloro-2,2-dimethybutanal e.g. pent-4-e-2-one
- What are structural isomers? (2 marks)
2. What are the 3 types?
- ⦾ (Compounds with the) same molecular formula but (1)
⦾ different structural / displayed / skeletal formula (1) - ⦾ Chain isomers (1)
⦾ Position isomers (1)
⦾ Functional group isomers (1)
Explain what chain isomers are? (2 marks)
⦾ Same functional groups (1)
⦾ but different arrangement of C skeleton (1)
⦾ Some straight chains + others are branched in different ways.
Explain what position isomers are? (1 mark)
⦾ Functional group of molecule in different position of C chain (1)
Explain what functional group isomers are? (1 mark)
⦾ Different arrangment of same molecular formula (1)
⦾ so molecule has different functional group
Explain what stereoisomers are? (2 marks)
⦾ (Compounds / molecules with) the same structural formula (1)
⦾ with atoms / bonds / groups arranged differently in space (1)
OR atoms / bonds / groups with different spatial arrangements
Give a type of stereoisomerism? (1 mark)
⦾ E-Z isomerism (1)
Explain E-Z isomerism? (3 marks)
⦾ Limited rotation around C=C (1)
⦾ E - (German for apart) opposite + apart (diagonal) (1)
⦾ Z - (German for together) together + same side (horizontal) (1)
Explain Cahn-Ingold-Prelog (CIP) Priority Rules?
2 marks
⦾ Atom/group on each side of C=C with higher Ar/Mr given higher priority (1)
⦾ Determine E or Z isomerism (1)
Br Cl What is the type of isomerism shown in this
l l molecule? (3 marks)
C = C
l l
F H
⦾ Br has higher Ar than F - Br is higher priority (1)
⦾ Cl has higher Ar than H - Cl is higher priority (1)
⦾ Therefore Z isomer (1)
What do curly arrows show? (1 marks)
⦾ movement of e- (1)
