how would i the sturctural formula look for this one:

dimethyl-propane:
my guess that it would be like so:
CH3
l
CH2
l
C-CH2-CH3
l
CH2
l
CH3

Is this right?

Please visit the following:

http://images.google.com/images?hl=en&safe=off&as_qdr=all&sa=N&resnum=0&q=%20%22dimethylpropane%22&spell=1&tab=wi

You have written 1,1-diethyl propane. I hope this helps.