What sections should I include in the Project Description section of my NSF grant proposal? I am a Ph.D. student, and I am writing my first proposal to the U.S. National Science Foundation (NSF) for a research grant in the field of chemistry.

One thing that I have found very confusing is the format of my written proposal.  Specifically, what sections should I include?

The U.S. NSF distributes a very detailed (76 pages) set of guidelines (The National Science Foundation Proposal and Award Policies and Procedures Guide: Part I - Grant Proposal Guide, available in PDF here).  Section IIC2 is about "Sections of the Proposal," but this section only enumerates the following sections that I should include:


a. Cover Sheet
b. Project Summary
c. Table of Contents
d. Project Description
e. References Cited
f. Biographical Sketches
g. Budget
h. Current and Pending Support
i. Facilities, Equipment, and Other Resources
j. Special Information and Supplementary Documentation
k. Appendices


It seems that the Project Description -- at least from the intellectual merit and broader impacts perspective -- will contain the "meat" of my proposal; the Project Description has a 15 page limit.  It is here, I think, that I will discuss my plan of work, the scientific rationale, and the methods that I will apply.  I should also discuss the related work in the literature in this section.  Finally, I should discuss broader impacts of the proposed work.  

But, beyond this, the NSF Guidelines do not seem to be all that specific about sections or section headings within the Project Description section.  Am I free to make my own sections/section headings within the Project Description section?  For example, could I make a section "Previous experimental work," followed by a section "Previous theoretical work," followed by a section "Proposed model description," and so on and so on?  These section headings would be quite specific to my proposed work and the chemical system that I propose to investigate.  Thanks for your time.
The NSF doesn't specify any rules on what goes into the project description, but each community has its norms and expectations. If you wish to get a good review, it's probably a good idea to understand the norms and standards of your community.

In general, what you should do is find peers in the area that have written proposals for this program and look at what are standard templates (and isn't your advisor involved in this ? In my corner of the NSF, students can't be lead PIs on proposals). 

From the sound of it, you haven't seen too many examples of proposals (successful or otherwise), and I'd strongly recommend that being your first step. If that's not possible, talk to faculty within your department (again, where's your advisor ?) to get help.