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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: crichtonracing on April 29, 2009, 02:16:18 PM

Title: Possible Sources of Error
Post by: crichtonracing on April 29, 2009, 02:16:18 PM
After a precipitate forms, it’s filtered, and the mass of the dry precipitate is measured. This information is then used to determine the concentration of ions in the sample. Comment on the accuracy of the test result. Suggest and explain a potential source of error. Any ideas?
Title: Re: Possible Sources of Error
Post by: Borek on April 29, 2009, 03:13:54 PM
You just don't ask. You try, you tell us what you did, we push you in the right direction.
Title: Re: Possible Sources of Error
Post by: crichtonracing on April 29, 2009, 03:51:58 PM

What do you guys think?
Title: Re: Possible Sources of Error
Post by: Lone Proton on April 30, 2009, 12:51:40 AM
  • When the precipitate dries some of it could've dissolved or evapourated in the mixture
  • When measuring the weight, the scale could be off
  • When you filter the precipitate it might not catch everything

What do you guys think?

The precipitate won't dry out or evaporate.
The scale isn't off >.<
The filter does catch everything.

How big was your margin of error? You might have made a mistake getting it from the filter to the weighing station (or to the bunson burner). If not I'd say you made a mathematical error when you "determine the concentration of ions in the sample".

Try again with more details?
Title: Re: Possible Sources of Error
Post by: Apocalypse_6 on April 30, 2009, 04:37:40 AM
Some possible sources of error that happen pretty often

1. Some precipitate may have been left in the beaker or flask during transfer.
2. Depending on the type of filtration system used, precipitate may not have accumulated entirely on the filter paper, but rather on the sides of the filtration apparatus.