12.1- ALKANES Flashcards
What type of hydrocarbons are alkanes?
saturated
Why are alkanes described as saturated hydrocarbons?
contain only carbon-carbon and carbon-hydrogen single bonds
What are alkanes among reactivity?
among the least reactive organic compounds
What are alkanes used as? (3)
fuels and lubricants and as starting materials for a range of other compounds
What is the main source of alkanes?
crude oil
What is the general formula for alkanes?
CnH2n+2
In what form can hydrocarbons be in?
unbranched chains, branched chains, or rings
What are unbranched chains often called?
straight chains
What is the angle of the C-C-C?
109.5 degrees
As the C-C-C is 109.5 degrees what does this mean?
chains are not actually straight
In an unbranched alkane how many hydrogen atoms are attached to each carbon atom?
each carbon atom has two hydrogen atoms except the end carbons which have one extra
What is the general formula for ring alkanes?
CnH2n
Why do ring alkanes have a general formula of CnH2n?
end hydrogens not required
Where is the alkanes named from?
the root
What does the root of an alkane tell us?
the number of carbon atoms
What does the suffix -ane tell us?
denotes an alkane
What must you first find when naming a hydrocarbon with a branched chain?
must first find the longest unbranched chain
What does the longest unbranched chain of a branched hydrocarbon give?
gives the root name
How are the branches/side chains named?
by prefixes e.g. methyl-, ethyl-, propyl-
What do numbers tell us when naming a branched hydrocarbon?
which carbon atoms has side chains are attached to
What alkanes have no isomers?
methane, ethane and propane
How does the number of possible isomers change depending on the number of carbons in the alkane?
possible isomers increases with the number of carbons on the alkane
What is the polarity of alkanes like?
almost non-polar
Why are alkanes almost non-polar?
because the electronegativites of carbon and hydrogen are so similar
