ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: cootcoot on June 10, 2008, 04:44:25 pm
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Question 1
A 20.0 mL sample of acid is delivered to a laboratory for analysis. The identity of the acid,
and its concentration, is not known. The 20.0 mL sample is made up to the mark with water in
a 250 mL volumetric flask.
25 mL aliquots are then titrated against 0.05 M sodium carbonate, Na2CO3 solution. Methyl
red is chosen as the indicator and a sharp transition occurs at an average titre of 15.6 mL.
a. Calculate the number of mole of Na2CO3
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1 mark
b. Complete the table, showing possible concentrations of the acid.
If the acid is: concentration of diluted acid concentration of original acid
Monoprotic
Diprotic
triprotic
3 marks
how does one do part b may i ask?
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Try writing out equations using common monoprotic/diprotic/triprotic acids as your acid, for example HCl, H2SO4 and H3PO4. Then you can find the mole ratios and then find the concentrations.
Hope that helps! I might post a better solution later when I have time xD
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ahhh,i see. it did help!
thanks for that!
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yeah, i cocked question up too... and I had all the skills to do it too