There are two simple method to determine that. The 'high-tech" way is to look up the densities of the organic solvent and your compound before you come to the lab and make it part of your prelab. Aqueous solutions have a density around 1 g/mL. Most organic non-halogenated solvents like esters, ethers, hydrocarbons have densities lower than 1 g/mL (solvent table). Halogenated solvents are usually significantly heavier than water.

The other possibility is a simple test in the centrifuge tube. Place your mixture in there and add some drops of water. Which layer increses in volume?