Enthalpy Problems

[cindi]

Hi! I was wondering if someone could help me out with 2 questions.

 

The heat of vapourization of a liquid is the energy required to vapourize 1.00g of the liquid at is boiling point. In one experiment, 60.0g of liquid nitrogen are poured into a styrofoam cup contatining 200g of water at 55.3*C (*= the small circle exponent-temperature). Calculate the molar heat of vapourization of liquid nitrogen if the final temperature of the water is 41.0*C

 

I know what equations to use but i don't know what "C" would be (specific heat capacity) or if there would be one cause its in a styrofoam cup -- would it be the heat capacity of water?

 

equation i will use: delta H = mc(delta T) then delta H neut = delta H/nHCI

 

A 200mL sample of 0.862 mol/L HCI is mixed with 200mL of 0.431 mol/L Ba(OH)2 in a calorimeter having a heat capacity of 453 J/*C. The initial temperature of the HCI and Ba(OH)2 solutions is the same at 20.48*C. Given that the heat of neutralization for the process

 

H+ added to OH- ==> H2O

 

is -56.2 kJ, what is the final temperature of the mixed solution?

 

I have no idea how to do this question... How would you solve to get the final temperature?

 

thank so much!

i appreciate any help =D

[UncleAl]

Do you know how to balance a checkbook?

 

You know how much liquid nitrogen was vaporized. You know how much water was in the adiabatic container and how much its temperature changed - without there being a phase transition. Do the obvious and calculate the latent heat of vaporization of nitrogen. (You might also Google BLEVE. )

 

Understand the model instead of eructating its equations like a mindless pre-med. If you expect to memorize science like 200 paintings for the Art final you will be irretrievably lost. Science is process as much as product. One would like to see no art criticism allowed unless its purveyor could do art. Would that ever shake out a lot of crap!