[Korokian]

I am lost on what do it. Please help.

When a 4.25-g sample of solid ammonium nitrate dissolves in 60.0g of water in a coffee-cup calorimeter (Figure 1.15), the temperature drops from 22.0C  to 16.9C .  Calculate the  change in enthalpy (in kJ/mol NH4NO3) for the solution process

q=mC(change in temp)

m=64.25g
C=4.18J/gK
change in temperature= 5.1 K

q= (64.25)(4.18J/gk)(5.1K)
  = 1369.6815

1369.68 x 1K/1000J x

is my work right up to that point?
what comes next how do i get into mols?

[Borek]

What is molar mass of ammonium nitrate?

[sdekivit]

you don't need to take mass 64,25 g, but from water: 60 g.

--> the enthalpy calculated with Q = c * m * delta T is then for 4,25 gNH4NO3 dissolved.

Thus you need then to convert that to kJ / mol NH4NO3

[Korokian]

i figure it out thx borek