This page provides exercises in the use of the Born-Haber cycle to determine lattice energies of ionic compounds. When you press "New Problem", a window will open with a set of thermochemical data related to an ionic compound. One enthalpy will be missing. Most of the time, the missing heat will be the lattice energy, but, occasionally, it will be another term. Regardless, determine the value of the missing heat, enter it and press "Submit". Results appear in the main window. There are a number of very important rules:
Signs are very important.
Be very careful with your calculations. The data is presented in such a fashion that all answers calculated should be integers.
The page creates and calculates the lattice energy fresh each time. We're fairly certain that the algorithms that do this perform properly, but bug reports are most welcome.
To remove the possibility of your "answering" the questions by merely looking in a reference book, the thermodynamic values the page presents have been very slightly altered from the literature values. In most cases, the change is less than 1%. Nonetheless, the only way to get the correct answer is to do a proper Born-Haber analysis of the data provided.