Wednesday, December 6, 2017 0

I've just taught this topic and thought it was worth sharing my ideas as to how I introduced the topic and concept of equilibrium. Firstly, something worth considering before you launch into the topic is when do you teach it? In my opinion it needs to go after energetics. This is because some of the concepts need a good understanding of exothermic and endothermic reactions before one can decide on the effect of temperature on the position of equilibrium. It could ...

Friday, November 24, 2017 0

Equilibria can be a tricky concept to understand. In order to understand it, you need a good idea of reversible reactions and then a good idea of a dynamic equilibria. So, what is a reversible reaction? Put simply, it is a reaction in which products can be turned into reactants, but reactants can also be turned back into products. This can be shown using the ⇌ symbol: Reactants ⇌ Products For example, ammonium chloride will thermally decompose into ammonia and hydrogen chloride gases, but these gases will ...

Wednesday, June 6, 2012 0

If you read my post yesterday you would have found that I would be writing a few articles on Archer John Porter Martin and Richard Laurence Millington Synge. Well the link between the Queen's diamond Jubilee and these biochemists is that they won the Nobel Prize for Chemistry in 1952 - the year the Queen came to the throne1 (I am sure you all got this link - didn't you?!) What did they win the Nobel prize for? It was partition chromatography. More ...

Friday, May 18, 2012 0

You can use these numbers when you introduce a 'Maxwell Boltzman' distribution curve. Picture a gas (say, air) at 15 oC What is the average (mean) speed of the particles in this gas? I bet you can't guess.... It is a staggering 450m per second! That said, what is the average (mean) straight line path that these molecules move without colliding? An unbelievably small 5 x 10 -7 cm! (not even metres!) So how many times does this mean that these particles collide (on average) ...