Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: bakedpotato on October 29, 2017, 02:31:14 AM
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Hi,
I have a project where I have to develop reversal film and the process calls for a bleach solution based on potassium dichromate.
I am trying to figure out how to convert a recipe that uses potassium dichromate crystals. Potassium dichromate is very toxic and I would prefer to manipulate the chemical in a liquid state.
The chemical recipe calls for
1200ml distilled water
70ml 50% Sulfuric Acid
15g potassium dichromate crystals
water to make 1500ml
The available potassium dichromate solution concentrations are:
product#1: 0.1000N ±0.0005N (0.0167M)
and
product#2: 0.200N ±0.001N (0.0333M)
How can I find how much solution(ml) of each of the K dichromate products I will need to make it equivalent to 15g of crystals diluted in ~1430ml of distilled water and 70 ml of acid.
I need to end up with 1,5L of total solution as this is the min size of the bath and maximum size of the storage container.
Any help is welcome!
Thanyou
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Potassium dichromate is very toxic and I would prefer to manipulate the chemical in a liquid state.
While it is definitely toxic, don't panic. I worked with the dichromate in the past. With a minimum precautions and in the case of a single use (ie you will be not working with it on a daily basis for months) it is quite safe. Use gloves, avoid breathing the dust - and it is not a a substance that has tendency to become airborne, just don't throw it in the air. In the case of this particular recipe I would be more careful when measuring and adding the 50% sulfuric acid.
Solutions you have listed
product#1: 0.1000N ±0.0005N (0.0167M)
and
product#2: 0.200N ±0.001N (0.0333M)
are probably quite expensive compared to the solid, as preparing solutions of precisely known concentrations is labor expensive.
That being said - it is a simple dilution, so calculations are rather easy. Just calculate what volume of the available solutions contain 15 g of dichromate, following the usual path - mass -> moles -> volume.
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Thanks for your response Borek.
I will use the crystals as they are cheaper and will take every precaution while manipulating the chemicals.
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Don't get crazy about it - common sense is all you need. Apron, glasses, gloves and working under fume hood (or in open) are perfectly enough.