What is the percent of phosphorus by mass in phosphoric acid, H3PO4

If we compare and contrast electromagnetic waves with sound waves, all but one statement is true. that is a) sound waves require a medium to travel while electromagnetic waves do not. b) electromagnetic waves can travel through the vacuum of space while sound waves cannot. c) electromagnetic waves must have a medium in which to travel, but sound waves can travel anywhere. eliminate d) sound waves must bounce off of matter in order to travel while electromagnetic waves do not require matter to be present.

Tell me the iupac name of the following compounds:

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit