We did an experiment to find the molar heat of fusion for water, by melting ice and recording temperature changes.
We found our results did not match the theoretical values due to our inability to control certain variables, such as energy transfer with the environment.
We then explored the concept of molar heat of fusion:
Students used this template to explore molar heat of vaporisation, next...
The background of the work we are about to get into includes:
COLLISION THEORY
Specifically, we need to be aware that changing temperature has an effect upon the energy of the system. To keep things "fair", we need to compare things at the same temperature (or at a specific temperature).
ENTHALPY CHANGES
One of the key concepts we need to remember from last year is enthalpy change:
This is how I would lay out my answer, allowing me to make a concise conclusion about the polarity of each molecule, so linking my knowledge to my decision about their respective polarity:
Once we have these mastered, we can look at Lewis Structures for polyatomic ions, exceptions to the Octet Rule, and shapes with more 5 and 6 for their Steric Number.