The Kinetic Theory

The Particle Model (Year 9) and the Collision Theory (Year11) are both important in understanding why reactions and phase changes occur. We are about to learn about factor that control the rate of reaction, but first we had to revisit these key ideas from previous years:

Bond Enthalpy

Bond enthalpy is the amount of energy required to break one mole of a particular bond. As bond breaking requires energy, these values are always exothermic.

Calculating Enthalpy Change

We do experiments using calorimeters to find enthalpy changes. The change in temperature of the solution is translated into an energy change for the water component of this solution. This is then inferred to be the equal (but opposite) value for the energy change for the reactants. This can then be used to calculate the enthalpy change.

Enthalpy Change Diagrams

We were asked to do the same for an endothermic reaction. For homework, we have to read pp140-142 and attempt #2, p144 in Beginning Chemistry.

Molecular Polarity

The last part of this unit is about molecular polarity. We combine the ideas of bond polarity and shape to predict and justify molecular polarity.

Here is the blog post etc. from last year: