given the following info for water specific heat capacity of steam 2.03 j/g degrees calculate the total quanity of heat evolved when 10.0g of steam is condensed,cooled,and frozen to ice at -50 degrees

Answer 1

This is best done in stages. There are just two formulas involved. Remember them.
q1 = heat released on the phase change from vapor (steam) at 100 C to liquid water at 100 C.
q1 = mass steam x heat vaporization. (formula 1)

q2 = heat released on cooling liquid water at 100 C to liquid water at zero C.
q2 = mass water x specific heat water x (Tfinal-Tinitial)[formula 2--not a phase change but moving WITHIN a phase, in this case all liquid].

q3 = heat released on the phase change of liquid water at zero C to solid ice at zero C.
q3 = mass water x heat fusion (formula 1 again except we are freezing it and not condensing it).

q4 = heat released on cooling ice from zero C to -50C. (moving within a phase again)
q4 = mass ice x specific heat ice x (Tfinal-Tinitial) (formula 2 again.)

Total q = sum of individual qs.

Answer 2

A 3.0−L sample of a 6.2M NaCl solution is diluted to 75L .