Streamwatch sodium chloride help

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rosiegbh
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Joined: 05 Feb 2008, 08:27
Job Title: SAO/Lab Assistant
School: Wyndham College
Suburb: Quakers Hill
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Streamwatch sodium chloride help

Post by rosiegbh »

Hi again,

I have a Yr 11 class conducting a streamwatch prac over this term. A standard sodium chloride solution has been supplied with the kit but it is not calibrating properly. It is called Conductivity standard 12.9mS/cm of sodium chloride and the teacher wants me to make up another solution.

Does anyone know what mS/cm of sodium chloride is and how to make it up? :?

Rosemary
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lada
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Joined: 29 Jun 2006, 10:00
State/Location: NSW

Re: Streamwatch sodium chloride help

Post by lada »

Hi Rosemary,
just looked it up for you.
1ppm TDS=0.00156mS/cm
1mS/cm=640ppm TDS

You need 12.9mS/cm, so you will need 8256 ppm(mg/L of salt.)
Not sure if 1ppm of TDS is equal to 1ppm of NaCL, but I think it is. So you will need 8.26g of NaCL in 1 L of distilled water.

Hope this makes sense.
Lada :coffee:
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rosiegbh
Posts: 100
Joined: 05 Feb 2008, 08:27
Job Title: SAO/Lab Assistant
School: Wyndham College
Suburb: Quakers Hill
State/Location: NSW

Re: Streamwatch sodium chloride help

Post by rosiegbh »

Thanks Lada you're an angel. :wub:

Rosemary
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