What is the percent of phosphorus by mass in phosphoric acid, H3PO4?
Use 1.008 g/mol for the molar mass of hydrogen, 16.00 g/mol
for the molar mass of oxygen, and 30.97 g/mol for the molar
mass of phosphorus.

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the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.