DF.3 Flashcards
Alkanes and shapes of molecules
What is crude oil a mixture of?
Different hydrocarbons.
What is the process called that is used to separate the different lengths of hydrocarbons in crude oil?
Fractional distillation.
What type of bonds do carbon atoms form?
Covalent bonds.
How many covalent bonds can each carbon atom form?
4 bonds.
What are hydrocarbons?
Compounds that contain only carbon atoms and hydrogen atoms.
What is shape does a carbon unit have when the carbon forms four bonds with four groups?
Tetrahedral.
What is the formula of a benzene ring?
C6H6.
What are aromatic compounds?
Compounds that contain one or more benzene rings.
What are aromatic compounds generally known as?
Arenes
What is the general structure of a benzene ring?
A flat ring with delocalized electrons, giving it alternating double bonds between carbon atoms.
What are aliphatic compounds?
Compounds that do not contain any benzene rings, they are based on chains of carbon atoms instead.
Hydrocarbons are relatively unreactive, especially alkanes and arenes. How can you change the properties of hydrocarbons?
By attaching modifiers to the hydrocarbon framework.
What are functional groups?
Modifiers that are responsible for the characteristic chemical reactions of molecules.
What are compounds with a hydroxyl group, -OH known as?
Alcohols.
What are compounds with a carbon carbon double bond, C=C known as?
Alkenes.
What is it meant when a hydrocarbon is described to be saturated?
It means that the hydrocarbon contains the maximum number of hydrogen atoms possible, with no carbon carbon double or triple bonds present.
Are alkanes saturated or unsaturated hydrocarbons?
Saturated.
What is the general molecular formula for alkanes?
CnH2n+2, where n is the number of carbon atoms, which can be any whole number.
What are the first four alkanes, with their molecular formula?
- Methane, CH4
- Ethane, C2H6
- Propane, C3H8
- Butane, C4H10
What are the prefixes for organic molecular naming?
- Meth-
- Eth-
- Prop-
- But-
- Pent-
- Hex-
- Hept
- Oct-
- Non-
- Dec-
What suffix indicated a molecule is an alkane?
-ane
What does the prefix indicate for alkanes indicate?
The number of carbon atoms.
What are homologous series?
A series of compounds that are related to each other in structure and properties, e.g. alkanes.
What are molecules said to be when they have the same molecular formulae but different structural formulae?
Structural isomers.
Why are there structural isomers?
Because chains of carbons can be straight or branched. So it is often possible to draw more than one structural formula for a given molecular formula.
What are carbon side groups, sometimes referred to as branches, called?
Alkyl groups.
What is the general formula for alkyl groups?
CnH2n+1
What symbol is often used to represent a alkyl group in organic chemistry?
R
What are the first five alkyl groups and their formula?
- Methyl, CH3-
- Ethyl, C2H5-
- Propyl, C3H7-
- Butyl, C4H9-
- Pentyl, C5H11-
What are systematic names of molecules directly related to?
The full structural formula of the molecule.
What are alkanes with cyclic structures called?
Cycloalkane.
What is the general formula for cycloalkanes?
CnH2n
What prefix is used to name cycloalkanes?
Cyclo-
What state are the first four alkanes in at room temperature?
Gas.
What state are alkanes with n 5-16 in at room temperature?
Liquid.
What state are alkanes with n > 17 in at room temperature?
Solid.
Do alkanes mix well with water?
No, they would form two separate layers.
