2007-06-05 03:46:28 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
A blank is usually used in something like spectroscopy - you'll often see this in UV/vis spectroscopy - but is used in other places too. Basically, you want to measure the properties of your sample, not of the other stuff that's around (solvent, container, etc.). But if you can only measure the properties of your sample and the other stuff together, you need to find out how much of it is from the sample and how much is from the other stuff. So you run a blank to see how much the other stuff is contributing. For example, if you were trying to see how much light is absorbed by a sample in water, you would run a blank to see how much light is absorbed by the water (and the container) and subtract that absorption from that of your sample + water + container (which is what you can actually measure). This will give you the absorption of just the sample.
2007-06-05 03:56:26 · answer #1 · answered by Anonymous · 1⤊ 0⤋
A blank in chemistry is the equivalent of zeroing. For example when you zero an scale or a balance so that you will be given the exact weight of the object placed on it next. You are giving the test instrument a starting zero point.
2007-06-05 10:52:15 · answer #2 · answered by gene n 1 · 0⤊ 0⤋
Additionally, it is a sample that is treated just like any other, but does not have the substance you are testing for or analyzing. In spectrophotometry, a blank is a sample that has the solvent and everything else in the reaction mixture, but not the substance that absorbs light. In titrations, it is usually the solvent without the compound being titrated.
2007-06-05 10:57:07 · answer #3 · answered by hcbiochem 7 · 0⤊ 0⤋
It's the result you get from running your instrument with no sample.
2007-06-05 10:55:14 · answer #4 · answered by not gh3y 3 · 0⤊ 0⤋