Organic compounds Flashcards
Functional group
Atom/ group of atoms that give compound its characteristic properties
Homologous series
A series of compounds with the same functional group
Hydrocarbon
Compound of carbon and hydrogen only
Saturated compound
One in which all the C to C bonds are single bonds
Eg. Alkanes
Unsaturated compound
Contains C two C multiple ones
Eg. Alkenes
Molecular formula
Shows the atom and how many of each type there are in a molecule of a compound
Displayed formula
Shows ALL bonds and atoms in a molecule
Shortened formula
Shows the group in sufficient detail that this structure is unambiguous
Skeletal formula
Shows the carbon and hydrogen backbone of a molecule as a series of bonds with any functional groups attached
Empirical formula
Formula of a compound with the atoms of the elements to the simplest integer ratio
Structural isomers
Compounds with the same molecular formula but different structural formulae
Van der waals forces
Dipole - dipole or temporary dipole - temporary dipole interaction between atoms and molecules
Naming organic compounds
Alkanes- A saturated hydrocarbons with single c-c bonds
Alkenes - unsaturated hydrocarbons with C- C double bond
Halogenoalkanes- Hydrogen swapped for a halogen
Alcohols- Compounds containing OH
Carboxylic acids- Contain COOH
prefixes
Meth- 1 number of C
Eth- 2
Prop-3
But-4
Pent- 5
Hex- 6
Hept- 7
Oct- 8
Non- 9
Dec-10
general formula of alkanes
CnH2n+2
general formula of alkenes
CnH2n
how to work out empirical formula from molecular
find simplest ratio
eg. Mr of ethane= C2H6
ratio- 2:6
1:3
Empirical- CH3
The effect of chain length on melting and boiling temperatures
Energy is needed to overcome forces when a substance melts or boils
Hydrocarbons are nonpolar- Electronegativities of carbon hydrogen are similar
Means temporary dipole - temporary dipole van der Waals forces are present between the molecules (Weak intermolecular forces)
The more surface there is in contact, the stronger the forces meaning more energy is needed to overcome the forces and melting- boiling temperatures are higher
The effects of branching on boiling temperatures
more branches- more spherical
Spherical shape means less surface area available for contact
Compared to straight chains where more surface area is available
More branches, lower boiling temp
Less surface contacts between molecules
Means weaker van der Waals forces between molecules and so less energies needed to separate them
The effects of functional groups on boiling temperatures
Molecules that form hydrogen bonds will have a higher boiling temperature than those of a similar size that cannot hydrogen bond
bc hdrogen bonds are he srongest bond
solubility
of compounds
Hydrocarbons cannot dissolve in water because they only form WDW interactions between molecules and are not able to form attractions with polar water molecules
Alcohol and carboxylic acids- Have - 0H groups that can form hydrogen bonds with water. Therefore soluble in water
Solubility decreases as chain length increases Size of the hydrocarbon part of molecule increases and exerts such a large hydrophobic effect that compound is no longer soluble
