Not sure I understand the question completely. Economic Class - CEC, FSW. Family Class - Spousal sponsorship. They have completely different rules and application forms.
Can you be more specific with your question? These two are so different. It is like asking what is difference between fried rice and sushi (both has rice on them). The answers could be very short or very long, depending on the context of the answer you need.
If you are applying under the CEC class, it is an economic class application. Doesn't matter if you are single or have a family, it is still economic class.
The "class" of the application refers to the basis under which you qualify for permanent residence. Family class applications qualify on the basis of being a family member of a citizen/permanent residence.