Answer the following- what is the dot structure, cross-cross method, molecular mass, compound name, compound formulae for each reactants:
potassium and oxygen,
sodium and sulfur,
calcium and nitrogen, carbon and sulfide, hydrogen and phosphorus?

water at room temperature is flowing through a pipe with pressure taps located 10 ft apart along one section of the pipe, which are connected to a mercury (s=13.6) manometer.

a

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)