Page 412 - Chemistry eBook

Structural Formula
The structural formula shows us the setup of the molecule.
How to draw the structural formula of a molecule:
1. Find the number of C atoms in the molecule. Draw a chain of the C atoms.
Butane has 4 C’s, so draw: -C-C-C-C-
2. Check out the structural formula example on Reffy, Table Q (p. 7) to see if the molecule has only single bonds (alkanes), a double bond (alkenes) or a triple bond (alkyne). (Alkanes are saturated because they have only single bonds; alkenes and alkynes are unsaturated.)
Butane only has single bonds between all of the C atoms, so it is an alkane.
3. Find the correct number of H’s by applying the general formula for alkanes, CnH2n+2: C4H8+2=C4H10. Butane contains 4 C’s and 10 H’s.
Attach the correct number of ‘H’s to the ‘C’ atoms.
Butane: Each C atom must have 4 lines coming out of it (representing 4 covalent bonds
of 8 valence electrons).
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