some qns (1 Viewer)

[sven0023]

In carrying out a titration prac, what sort of errors are there?

"Give possible sources of error that could contribute to inaccuracies in determining the concentration of your standard solution and discuss briefly how these sources of error could be eliminated or minimized."

hmm i'm not sure what to write, so far its

improper rinsing of the flasks; how to fix: rinse conical flask / volumetric flask with distilled water and rinse burette, pipette with soln they are about to measure..


hmm any other ideas? thanks//

 

[Ragerunner]

Your up to titration already?

You got to be kidding me? hahha

I'd say that you ensured all the standard solution was dissolved properly in the beaker. And continuously adding water to the break and puring it into the flask to remove any remains.

Perform the experiment a numerous amount of times and get the average.

If you want to be more exact say parallax error. i.e. the reading of the burette may not have been at the right level each time you did it.

Don't add too much indicator. The indicator itself can have an effect on the concentration.

 

[sven0023]

yeah thx

what about like saftety considerations

lol, i wish it was just all maths and calcuation problems etc, i hate this kind of theory

 

[Ragerunner]

Not much safety consideration is needed except maybe saying that because acid is used you should take more care in case any of it gets on you.

 

[sven0023]

yeah i said something along the lines of spilling a few drops of water on the acid is highly exothermic (in the case of HCl anyway) and the water will boil rapidly and volitily spit etc, wear goggles

 

[sven0023]

one more thing, conq chem (p148) says "the equivilence point is sometimes called the end point" but written in my notes I have

"The equivalence point is the point in the titration where all of the original acid has just completely neutralized the entire original base or vice versa. The chemical point at which there is no excess of either original acid or base. The endpoint is the point at which the indicator changes color. (The aim in a volumetric analysis is to align the endpoint and equivalence point as close as possible)"

 

[Ragerunner]

Your definition is more accurate. The textbooks say that because technically those 2 points should be very close together. Unless you performed a really bad titration.

But make sure you know the difference. They could throw in a question to differentiate between them.

 

[spice girl]

Originally posted by sven0023
yeah i said something along the lines of spilling a few drops of water on the acid is highly exothermic (in the case of HCl anyway) and the water will boil rapidly and volitily spit etc, wear goggles

hahaha....u need conc acid for that to happen. if the acid is so concentrated it's syruppy, then u start worrying

which reminds me of the time i had a bit of conc HCl and i was going to drench it with cold water, but since someone was using hot water on the tap before, hot water came out and heaps of HCl vapour got up my nose.....euck

otherwise, just wear goggles in case u make a mess and it flies into your eyes...

 

[ND]

Originally posted by spice girl
if the acid is so concentrated it's syruppy, then u start worrying

At what concentration does this begin to occur?

 

[spice girl]

Originally posted by ND
At what concentration does this begin to occur?

about 10M prolly...

 

[~Dreamer]

make sure you write something about having adequete amount of indicator too see when end point has been reached