Can someone name a project i can do for my science fair for 7th grade i need a easy one

Determine the empirical formula of a compound containing 40.6 grams of carbon, 5.1 grams of hydrogen, and 54.2 grams of oxygen. in an experiment, the molar mass of the compound was determined to be 118.084 g/mol. what is the molecular formula of the compound? for both questions, show your work or explain how you determined the formulas by giving specific values used in calculations.

The skeletal system performs a variety of functions that are crucial to maintaining life processes. what function is performed in the bone marrow, but not in the ossified bones of the skeleton? a oxygen transportation c mineral storage b. muscle attachment d red blood cell production

Used the balanced equation 2h2+ o2 - -> 2h2o. if you have 7.2 grams of o2 , how many grams of h2o can you produce ?