Mark We are doing a project for our automotive class. We are comparing winter and summer blends of gasoline. I have found that butane is the major hydrocarbon in winter blend because it is more volatile (RVP rating of 52 psi). Is this correct? We are making a ball and stick model to show the major component in that winter blend. I am having trouble finding the major hydrocarbon (I think it is a type of FCC gasoline) for summer blend. What hydrocarbon (structural formula) would I use to represent the summer blend gasoline?