percentage error

how does decreasing the concentration decease the percentage error????

http://www.knockhardy.org.uk/sci_htm_files/08error.pdf

maybe this could help?

thanks a lot .. but it still doesnt answer my question (

well it depends, i don't understand what you mean by concentration.

I need more info, concentration of what?

the question says "the concentration of sodium thiosulfate used to titrate the iodine was changed from 0.100 mol/dm^3 to 0.050 mol/dm^3.. explain whether this change will improve the experimental procedure for measuring the concentration of sulfur dioxide" the markscheme: 1) larger titration reading/.......... 2) so smaller percentage error
ORR
1) smaller mass of sodium thiosulfate used to make solution
2) so greater percentage error in the mass measurment

i dont understand how the concentration is effecting the vulme and mass and thus the percentage error.........

Decreasing the conc means that you will get a larger titre. If your burette measures to the nearest 0.05cm^3. then if your titre was say 10 your percentage error would be (0.05/10 *100) =0.5%, whereas if your titre was 20 then it is now (0.05/20 *100) =0.25%