8.2 Alkanes Flashcards
what are the properties of organic compounds governed by
The properties of organic compounds are governed by:
- a series of carbon atoms linked together to form a stable, almost completely unreactive framework or molecular skeleton.
- a series of different reactive functional groups which determine the basic “chemistry” of the molecule that are added on to the carbon skeleton.
What gives an organic molecule its properties
The reactive or functional groups give the compound its properties
what are hydrocarbons
The base of all organic compounds are called skeletons, called hydrocarbons, consist of carbon and hydrogen
hydrocarbons are formed when carbon atoms bond with hydrogen atoms. Hydrocarbons are subdivided on the basis of the types of bonds formed between the carbon atoms: single, double, or triple
what are alkanes
Alkanes are hydrocarbons in which the carbon atoms are singly bonded to each other.
They are also called saturated hydrocarbons since they hold the maximum number of hydrogen atoms
what is the simplest hydrocarbon
Methane is the simplest hydrocarbon, CH4, it is a gas at room temp and is highly flammable when combined with oxygen
what is the second simplest hydrocarbon
Ethane is next, C2H6. Ethane is also a highly flammable gas. Natural gas is about 80% methane and 20% ethane. Ethane is made of two methyl groups (CH3) connected through the C-C bond
what are many hydrocarbons used for
Many hydrocarbons are fuel sources and react with oxygen to burn
What affects the boiling point of hydrocarbons
As the number of carbon atoms increases so does the boiling temperature
Boiling points are lower for branched hydrocarbons due to fewer contact points, higher for cycloalkanes because their rigid structure allows more contact between molecules
what are some properties of alkanes
Alkanes are nonpolar and insoluble, they have density between 0.65-0.70 g/ml and so float on water. Lower melting and boiling points compared to other organic compounds
where do methane compounds with 2+ Cl atoms get their names
Methane compounds with two or more chloride atoms are named after their common names and do not reflect structure
what are configurations related to C-C bonds
As groups attach to the c-c single bond they rotate around and their relative arrangements have different conformations
what is the formula for an alkane
The general formula for an alkane is CnH2n+2
what is the ending of all alkane names
All saturated hydrocarbons have a name ending in -ANE
what are two properties of hydrocarbons
- Very unreactive (C-C and C-H bonds are very strong)
- Boiling & melting points increase with number of carbons
