Is boiling water until salt remainds a chemical or physical?

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

Which symbol can be used to indicate the pressure at which a chemical reaction is carried out? 25°c 2 atm pa

Iron (fe) reacts with copper sulfate (cuso4) to form iron (ii) sulfate. in this reaction, cu2+ gains electrons to form cu. which statement is true about this reaction? fe(s) + cuso4(aq) → feso4(aq) + cu(s)