If you take a sample of pure, Filtered sea water at 35 parts per thousand (ppt) salinity and using a lab scale you measure its mass: it weighs 1 kg (=1,000g). If you put your sample over a boiler and evaporate the water completely so that all you have left in the container are the salts that were previously dissolved in the seawater.
How many grams of sodium (Na+) are in the residue?