A failure

[scotty]

I have been usung 1 teaspoon of .1 sufite solution in place of campden tablets as well as for the acid testing.
I decided to make my own .1 solution fron sodium metabisulfate crystals.


i found the symbol for the compound to be Na2S2O6
than i went to the periodic table and came up with the folowing.
NA2=2X22.989= 45.978
S2 = 2X32.06 = 64.12
O6= 6X15.999= 95.994
FW(formula weight)=206.92


the molar solution formula is


FW X % of solution desired = GRAMS/ONE LITRE


.1 X 206.92 = 20.6 grams/litre to make a .1 solution


I scaled it down to 5 grams for 250 mililiters


I have a gunpowder scale and graduated beakers but it didnt worh.


I used the bottle of .1 solution i have in my inventory and it worked fine.






Can any one find the time to check my wprk and tell me what i did wrong.


I do it to learn no other reason.
I never had chemistry in school

Edited by: scotty

 

[masta]

<DIV =O vape="_x0000_s1026">
<DIV style="mso-line-spacing: '100 20 0'; mso-margin-left-alt: 216; mso-char-wrap: 1; mso-kinsoku-overflow: 1">n
<DIV style="mso-line-spacing: '100 20 0'; mso-margin-left-alt: 216; mso-char-wrap: 1; mso-kinsoku-overflow: 1">10% stock solution can be made up by adding enough water to 100 grams of K-meta or Na-meta to make up a total volume of 1 liter (100 grams / 1000 mls * 100 = 10%)
<DIV style="mso-line-spacing: '100 20 0'; mso-margin-left-alt: 216; mso-char-wrap: 1; mso-kinsoku-overflow: 1">nMix two ounces of K-meta with water to obtain a total of 19 fluid ounces and you have a 10% solution. Dilute one part of your 10% solution with 7 parts water, and you have the recommended 1.25% sulfite solution for sanitizing equipment and bottles.
<DIV style="mso-line-spacing: '100 20 0'; mso-margin-left-alt: 216; mso-char-wrap: 1; mso-kinsoku-overflow: 1">nOne teaspoon of the 10% solution is about 5ml and one tablespoon about 15ml.
<DIV style="mso-line-spacing: '100 20 0'; mso-margin-left-alt: 216; mso-char-wrap: 1; mso-kinsoku-overflow: 1">nOne ml in one gallon adds 15ppm of Free SO2
<DIV style="mso-line-spacing: '100 20 0'; mso-margin-left-alt: 216; mso-char-wrap: 1; mso-kinsoku-overflow: 1">
<DIV style="mso-line-spacing: '100 50 0'; mso-margin-left-alt: 216">

 

[scotty]

I thought that would be a molar solution and therefore we can not use percentages when mixing a solid with a liquid.


Please correct me if i am wrong.

 

[PeterZ]

Sodium metabisulfite is Na2S2O5. I keep things simple by rounding off. Na = 23 x 2 = 46, S = 32 x 2 = 64, O = 16 x 5 = 80. Thus, the formula weight of Na-meta is 46 + 64 + 80 = 190. A 1 Molar soultion would be 190g/L. A 0.1 Molar solution would be 19g/L or 4.25g/250ml.

Since you have a powder scale calibrated in grains Avoirdupois (gr), we need to convert. 1 lb is 7000 gr, and also 453 grams (g). So, (4.5g/453) x 7000 = 70 gr/250 ml to make a 0.1M solution. (actually 69.536gr, but who's counting)

 

[Waldo]

Huh

!!!!!!Edited by: Waldo

 

[smokegrub]

PeterZ's computations are right on the money!

 

[scotty]

I believe my computations were close enough. then if it didint work, ill guess that i mixed it incorrectly. I'll try again. If it still doesnt work, ill just buy the stuff from now on and brood over my failure.

Ill read some more chemistry books also


Thanks all for the input especially


WaldoEdited by: scotty

 

[bovinewines]

Scotty I'm right there with ya! I'm struggling with all of these calculations myself.
If I ever get a handle on it and start to understand it, I'm going to put together a cheat sheet...sort of a "chemistry for dummies".....

 

[scotty]

Scotty I'm right there with ya! I'm struggling with all of these calculations myself.
If I ever get a handle on it and start to understand it, I'm going to put together a cheat sheet...sort of a "chemistry for dummies".....

Well it seems my calculations were correct yet the solution didnt work for the acid test. My bottle od .1 solutuin worked.


I really cant understand it unless i mixed things in correctly.


I spend a lot of time making notes on conversions etc.




maybe ill compile my info and we can see if it has any value.