01Flat lines on heating curves
During melting or boiling, temperature stays constant: added energy overcomes IMFs instead of increasing KE.
Vaporization takes much more energy than fusion because particles must fully separate.
02Notebook box
q = n·ΔH_fus or n·ΔH_vap on plateaus; q = mcΔT on slopes.
Worked example: Melting 2.0 mol ice (ΔH_fus = 6.01 kJ/mol) needs 12.0 kJ.