The calcium in a 150 mL sample of water from the Ogeechee River at a location near Savannah was determined by precipitating Ca2+ as CaC2O4.H2O (FW=146.115 g/mol). The precipitate was collected by filtration, washed and then ignited [turning the CaC2O4.H2O into CaO (FW=56.079 g/mol)] in a crucible that had an initial mass of 26.4092 g. The mass of the crucible plus CaO was 26.7134 g). What is the concentration of Ca (40.078 g/mol) in the river water in units of part per thousand (ppt) (by mass), assuming the river water has the same density as pure water?