OLD‎ > ‎

Term 1, week 10

The focus for the week is to complete the calculation component of the achievement standard. Ask your support teacher to arrange a suitable time. This is a formal test and needs to be supervised. The assessment will have a % composition calculation, emperical and molecular formula calculation, a stoichiometry problem plus you need to be able to calculate the number of moles (n) when you are given the mass, also the concentration of a solution given the mass of solute and the volume of the solution.
  • Do activity 8A in study guide before you do the assessment task.
  • Do assessment task.
  • When the assessment has been done, read p64 to 67 in the study guide. The activity 8B maybe too difficult , I will provide some more instructions in week 1, term 2. I want the titration to be completed hopefully the end of week 2. You may like to play with the animation in the attachments and see if you can do the calculation. I don't think you will get to this stage as it is a short week but you may like to do some reading in the holidays. Mathew i don't expect you to take your books to Katmandu!
  •   c n v
When doing a titration calculation it is very useful to use a table like above. For one solution you will know its concentration (c) and the volume (V) of it used, therefore you can calculate the number of moles (n) by using the formula n=c x V. Next step you look at the balanced chemical equation and see the mole ratio and therefore you can calculate the number of moles in the solution you do not know the concentration of. Last step substitute values into c=n/V to find the concentration.

Maree Pullar,
29 Mar 2012, 14:27