[cuongt]

determining the end point in a titration is a random error right e.g. the end point of the titration was hard to spot and too much of the substance in the burrete was delivered. and a systematic would be the experimental conditions e.g. if there was air blowing towards the weighing device when trying to measure an a certain amount of Na₂CO₃

[english]

Titration error or inidicator error is systematic in nature.

It's what we call a personal or judgmental error.

[xiankai]

the end point of the titration was hard to spot

this is a human error in judging the colour change and hence is a random error like you said.

if there was air blowing towards the weighing device

will the air be blowing all the time? if it will then it will be a systematic error, if not it will be a random error.

[enahs]

the end point of the titration was hard to spot

this is a human error in judging the colour change and hence is a random error like you said.

That is not random error. Random error you can not modify your experiment to adjust for; this can be adjusted for.

This is systematic error. Things that can be done to adjust for it. Such as. Change concentration of indicator. Change solvent of indicator (can have a major effect). Place a solid white or black background behind the flask to better see the color change (choice of white or black depends on the color change expected). Change the lighting. Get a lab partner with better vision in this respect to help.


Random error you can not adjust for, only handle with statistics.

[cuongt]

the end point of the titration was hard to spot

this is a human error in judging the colour change and hence is a random error like you said.

That is not random error. Random error you can not modify your experiment to adjust for; this can be adjusted for.

thanx for all the replies.

so if its not a random error wat type of error is it systematic or not neither?

[english]

so if its not a random error wat type of error is it systematic or not neither?

Re-read my post and enah's post.  It's systematic.

[xiankai]

That is not random error. Random error you can not modify your experiment to adjust for; this can be adjusted for.

a random error also has inaccurate results. this is due to experimental data which does not have an even spread. human judgement of the colour change falls into this area. random error does not merely mean you cannot modify your experimental set-up, it could also mean you choose not to modify it. in the end u're relying on the human sense of sight in the end, which itself should qualify as a random error. the steps that you listed as improvements could probably reduce the error, but not eliminate it.

Random error you can not adjust for, only handle with statistics.

you're right, but see my above paragraph.

also, systematic errors have a precision error, due to a fixed variable change. just like the zero error in the vernier calipers, the zero error on the measuring balance. this is an absolute error that can be adjusted for, providing you know where the source of error is.

[enahs]

That is not random error. Random error you can not modify your experiment to adjust for; this can be adjusted for.

. in the end u're relying on the human sense of sight in the end, which itself should qualify as a random error. the steps that you listed as improvements could probably reduce the error, but not eliminate it.

I agree that using the human eye to notice the end point would fall under random error. However, he said "the end point of the titration was hard to spot". That is mostly systematic; with some random error thrown on top.
I say mostly because there are a tremendous number of things that can be done to reduce that indecisiveness of the end of titration before then factor of the human eye takes place.


Or you could just UV-Vis your sample and rule out the eye all together!


But with the above said, the answer to his question, I would still say systematic. As based on basic chemistry there are 100's of things that can be adjusted to improve an indicator endpoint color-change titration accuracy. And based off of personal experience and general chemistry knowledge, those will have much more sever effects on the error before the human eye factor comes into play, in my opinion (unless you happen to be color blind).

[xiankai]

However, he said "the end point of the titration was hard to spot".

here the error is in the inability of the human eye to judge the end point accurately, since it was 'hard' to spot. anything before the human eye factor comes into play relates to other errors, like the pipette delivering a wrong volume of titre being a systematic error.

those will have much more sever effects on the error before the human eye factor comes into play, in my opinion

those will be systematic errors, indeed.