How to solve and round to correct sig figs

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.

In the analysis of hair and fiber samples, which does a compound comparison microscope allow for that a conventional compound microscope does not? a. simultaneous observation b. polarization c. fluorescence d. higher magnification

Flourine is found to undergo 10% radioactivity decay in 366 minutes determine its halflife