Being confident in tackling different types of mole calculation is the foundation upon which much of A level chemistry stands – each of these posts takes you through a step by step method (with video) and there are some practice questions as well – what’s not to like?
Reacting mass calculations
The key to reacting mass calculations at A level is to have a foolproof method for setting them out so that as they get more complicated, you can always follow your working and your logic if you get lost.
Percentage yield calculations
Percentage yield is one of many deciding factors in determining whether or not a reaction is economically viable.
Determining the limiting reactant in a reaction
Limiting reactant problems follow on directly from reacting mass calculations. In these questions, you have to figure out which reactant is in excess and which will limit the amount of product formed.
Finding the formula of a hydrated salt
Finding the formula of a hydrated salt is no different than determining the empirical formula of any other compound – we are simply treating water as a stand alone unit in the formula, rather than breaking it down into the elements hydrogen and oxygen.
Determining an empirical formula using combustion analysis
Combustion analysis is a simple technique used to find the empirical formula of a compound – often an organic or carbon based molecule.
Working with concentration
Essentially, you need to be able to work out the concentration of a solution both in mol dm-3 and in g dm-3.
Basic titration calculations
You may have come across titration calculations at GCSE, and this post builds on that knowledge.
The good news is that if you have mastered moles and formulae, this is no different.
Advanced titration calculations
Let me walk you through some of the scarier titration exam questions from recent A level papers, and then there are a couple of practice questions to get your teeth into!
Titration – experimental technique questions
Questions based on carrying out titration and interpreting the results are common both at AS and A level.
You need to be able to describe how to carry out a titration in detail and you also need to be able to explain how errors in carrying out a titration or making up a standard solution would affect the accuracy of calculations based on results from said titration.