Wednesday 29 June 2016

Enthalpy Calculations - Enthalpy of Formation and Hess's Law

USING ENTHALPIES OF FORMATION



USING HESS'S LAW



The following is how we could use Hess's Law to solve the same problem as used for showing using Enthalpies of Formation:

Wednesday 22 June 2016

Molar Heat of Fusion

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...

Tuesday 21 June 2016

Energy Recap

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:

Thursday 16 June 2016

Intermolecular Forces

Today, we had the following tasks:

  • Reading pp93-4; 96 in Continuing Chemistry
  • Graphng task pp95-6 in Continuing Chemistry
  • Homework sheets (Lewis structures etc.)



Friday 10 June 2016

Lewis Structures and Shapes - Level 3




EXAMPLE QUESTION


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:

Wednesday 8 June 2016

Lewis Structures and Shapes - Level 2 Recap

We need to remember how to draw Lewis Dot Diagrams:



Then, we need to understand the shapes that molecules (and polyatomic ions) can be:

https://figures.boundless.com/10397/full/vsepr-geometries.png

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.