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04/30/2018, 02:07 PM | #1 |
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Chemists, mathematicians and wanna be's
Randy's recipe 1 calls for 596 grams baking soda to make 1 gallon. There are 3785 ml in a gallon of water. That would be 37.85 g/100ml water?
This article states that the solubility of baking soda in water is 9.3 g 100ml., or 352 grams. (9.3*37.85) What am I missing? Also, I just weighed 1 cup of baking soda and came up with 264 g equaling 660 g per 2.5 cups, the amount in volume Randy's recipe calls for. And just for further confusion: Self-Rising Flour: 1 cup = 4 ounces = 113 grams. Baking powder: 1 teaspoon = 4 grams. Baking soda: 1/2teaspoon = 3 grams. Butter: 1/2 cup =1 stick = 4 ounces = 113 grams from a google search. teaspoons in 1 cup 48 therefore 96 1/2 teaspoons and at 3 g per 1/2 tsp. we get 720 g in 2.5 cups.
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Gary 180 gallon, 40 gallon sump, 3 250 W MH + 4 80W ATI T5's, MTC MVX 36 Skimmer, Apex controller Aquamaxx T-3 CaRx Current Tank Info: A 2 Barred Rabbitfish, Red Head Salon, Yellow/Purple, McMaster Fairy, Possum, 2 Leopard Wrasses, Kole, & Atlantic Blue Tangs, 2 Percula Clown, 3 PJ and 1 Banggai Cardinalfish , Swallowtail, Bellus and Coral Beauty Angels Last edited by hkgar; 04/30/2018 at 02:54 PM. |
04/30/2018, 06:17 PM | #2 |
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Which weighs more?
A pound of feathers or a pound of beef? The same but different volumes.
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04/30/2018, 10:36 PM | #3 |
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Recipe 1 is baked baking soda, which is sodium carbonate. I have forgotten how much it weights after baking, but noticeably less, and sodium carbonate is much more soluble in water. 660 g is very close to 596 g for our purposes. We'd have to check into your scale's accuracy limits to do much more computation. How has it been calibrated?
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05/01/2018, 04:43 AM | #4 | |
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Quote:
My scale can't be calibrated but 10 nickles weigh 50 g on it. I baked 594 grams for 1 hour at 200 f and mixed into 1 gallon of water and a significant amount still was not dissolved.
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Gary 180 gallon, 40 gallon sump, 3 250 W MH + 4 80W ATI T5's, MTC MVX 36 Skimmer, Apex controller Aquamaxx T-3 CaRx Current Tank Info: A 2 Barred Rabbitfish, Red Head Salon, Yellow/Purple, McMaster Fairy, Possum, 2 Leopard Wrasses, Kole, & Atlantic Blue Tangs, 2 Percula Clown, 3 PJ and 1 Banggai Cardinalfish , Swallowtail, Bellus and Coral Beauty Angels |
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05/01/2018, 06:55 AM | #5 | ||||
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Baking soda is NOT sodium carbonate, it is sodium bicarbonate. But for this discussion molar concentration isn't important so let's not worry about this. As stated in the above-referenced article, if your water was at room temperature, it makes sense that it would not all dissolve... Hope this helps!
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05/03/2018, 07:28 PM | #6 |
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I agree with Hooligan above. Also don't forget when the baking soda is baked it turns to sodium carbonate. Baking the recommended 594 g of bicarbonate turns it into about 335g of sodium carbonate. The carbonate has a solubility of about 22g/100mL. The 335g of carbonate in a gallon is about 8-9 g/100mL, which is well within the room temperature solubility of sodium carbonate.
Long story short, if you try to dissolve 600g of bicarbonate in a gallon you are over the solubility and it will not all stay dissolved at room temperature. Baking the bicarbonate turns it into carbonate which should be easily soluble at room temperature. |
05/03/2018, 10:15 PM | #7 |
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The scale seems okay. I agree that you can dissolve the baking soda by heating. That will convert it to sodium carbonate (effectively), which is why it works. Technically, some of the sodium bicarbonate will dissolve and heating will drive off carbon dioxide, allowing more sodium bicarbonate to dissolve. Do you actually want recipe 2, the low-pH version? That is about half as concentrated, for reasons we've discussed.
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