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here is the same slide from the end of that last segment and
I've used the red numbers to indicate how we number that compound at the bottom
because its parent chain is not drawn just horizontally all the atoms
in a straight line
but your rules tell us to find the longest sequence of carbons and let that
be the basis of how we name it. so that's why this one at the bottom is named as a
pentane because i can
count out five carbons in sequence instead of just four
and i can even do that with the stick figure over here
and so the two methyl groups are substituents hanging off of what's a
five carbon chain
so that's something to look out for when you are trying to put names with the
structures that are already drawn out for you
the rest of the slides just kind of hit some highlights about properties
theory behind bonding in alkanes
the alkanes up through four carbons are gases at room temperature
once you get to five or six carbons or more they tend to be liquids, and gasoline,
as it says here, is a mixture of things with around five to twelve carbons
they all certainly will burn and can be used as fuel
and some of the alkanes we've just been looking at, their structures they naturally
occurr in things like gasoline
in chemistry we came to separate them out one compound at a time
but as it says here, all of this kind of comes from crude oil and the
different boiling points allow
fractions to be separated
ultimately each alkane can be individually isolated in this manner
properties of alkanes
for the liquids they don't mixed with water very well. that's because they are
nonpolar unlike water
and they don't react in a whole lot
as it says at the bottom you can burn these alkanes easily enough but other
types of chemical reactions, they are resistant to
although we will certainly see later on that they can be made to react
under certain circumstances
and their boiling points are a way to compare them not only to distinguish
truly different molecules but this graph shows that the number of carbons in
an alkane
correlates to predictable boiling point it's not exactly a straight line but it
certainly is a smooth curve. the boiling point goes up in a predictable manner as
you add carbons
the rest of these slides starting with this one, I don't ask you much about
this type of bonding theory on our tests but did this here to indicate to you
that if you're taking any
standardized test based on organic chemistry
then hybridization of orbitals is usually something that's a part of those and so
there's a few slides here and further discussion in your book. but i'll leave
that to you