Recent content by pollycampos

Thank you, I didn't know how to use the LaTeX :-p

Ohh but I have found a pdf file talking about it https://chemicalparadigms.wikispaces.com/file/view/15.2+Lattice+enthalpy.pdf, but it gave only this reason :-p

Oh yes, I think I should write that in my homework :-p Is there another reason for the experimental value be different from the theoretical? I have to write 2 reasons.

Thank you a lot, Infinitum :smile: The radius information was given by my teacher's book, so I guess it isn't wrong...:rolleyes: I thought the results should be very close, because MgF2 is a very ionic solid, no?

So I added 86 + 116 = 202, and the result is: http://img546.imageshack.us/img546/1336/quinooo.jpg It's still kind of far away from the experimental result (-2962 kJ/mol), no? Or is this result right? Thank you in advance, Infinitum :biggrin:

Homework Statement Calculate the theoretical lattice energy for MgF2 (Born-Landé equation) Ionic radius Mg+2 (coordination number 6) = 86 pm Ionic radius F- (coordination number 3) = 116 pm Madelung constant = 2.408 n = 7 Homework Equations The Attempt at a Solution I'm...

Oh yes, my bad :-p But anyway, I can't find the heat of formation :frown:

Homework Statement What is the heat released by the complete combustion of 22.4x10^3 litres of FeTiH2 - a fuel used in hydrogen cars -, producing liquid water? Homework Equations ΔH°(reaction) = ΔH°f(products) - ΔH°f(reactants) The Attempt at a Solution 1 mol FeTiH2 - 22,4 L (STP)...