[helpmeplz]

Hey guys I really need your help on this question. It says

A student measured the molar heat of dissolution to identify an unknown solute.

He recorded the following data:

mass of H2O= 140.0 g
mass of unknown solute: 4.8 g
initial temperature of water: 17.5 C
final temperature of water: 15.5 C

Using the following data, identify the unknown solute:

KNO3: Delta H= 36 Kj/mol
NaNO3: Delta H= 21 Kj/Mol
NaOH: Delta H= -42 Kj/Mol

Please help me out guys, I'm really lost. I dont know whether to use the q= m s delta T as it doesn't appear to work.

[Borek]

q = m s delta T will give you amount of heat, now assume your substance was each one of these listed and calculate its molar heat of dissolution (hint: convert mass to number of moles).