Can anyone tell me how to use Titration equations??? I'm Lost!?

Question

I am studying Forensic science and we are using these equations to identify reactants to 2.46Kg Aluminium Oxide and how much reactants was used to create an explosive. This would enable us to check with stores for possible suspects.

Answer 1

The equations you will probably need to use are (sorry don't know how to format the text on Answers):

1. number of moles is equal to the mass of the substance in grams divided by the relative formula mass.

2. number of moles is equal to the concentration of the solution multiplied by the volume in cubic decimetres (if your volume is cubic cm you need to divide it by 1000 to make equation work)

You don't give your figures so there isn't much else I can say to help. However, you can calculate the number of moles of aluminium oxide (Al2O3) by using equation 1. above.

If you have a chemical equation for the reaction you need to use it to work out the ratio of Al2O3 reacting.(If you do not have one, you'll need to write one).

Once you've done that you should be able to work out the rest.

Answer 2

Titration is generally based upon reverse identification. That is to say, you have to find how much of your titrant you used to calculate how much of your analyte is present. Can you post the equations? Or perhaps you can check wikipedia for titration of Aluminium Oxide.

Answer 3

Be careful as the above answer is true for cases when stoichiometry is 1:1

Usually for titrations you use normality and chemical equivalents, not moles.

You have to post more details so that we can help.

Answer 4

First write out the equation of the reaction and work out the stoichiometry:

e.g NaOH +HCl ---> NaCl + H2O 1:1 stoichiometry

Moles of NaOH = moles of HCl

but 2NaOH + H2SO4 -----> Na2SO4 + 2H2O - 2:1 stoichiometry

2 moles of NaOH react with one mole of H2SO4. 2 x moles of NaOH = moles of H2SO4

So work out the number of moles of your known (aluminium oxide). moles = mass (g)/ MWt. (g/mol).

You get the molecular weight by adding the atomic masses.
Al2O3 ((2*MWt Al) + (3* MWt O) )

This gives you the number of moles of your unknown if it is a 1:1 reaction if it isn't you need to multiply or divide by the number you worked out earlier.

You then need to calculate the mass:

Mass (g) = moles (mol) x MWt (g/mol)