Why can we not use the Nitrogen that we breath in

What does a particular point on a line of a phase diagram represent? o a. the maximum temperature a substance can exist at without bonds breaking b. the pressure created by the kinetic energy of molecules at a particular temperature c. the melting point or boiling point of a substance at a specific pressure d. the conditions in which temperature and pressure have equal effects on a substance

Asolution contains 225 g of sodium chloride, nacl, dissolved in enough water to make a 0.25 l of solution. what is the molarity of the solution?

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.