Reef Central Online Community

Home Forum Here you can view your subscribed threads, work with private messages and edit your profile and preferences View New Posts View Today's Posts

Find other members Frequently Asked Questions Search Reefkeeping ...an online magazine for marine aquarists Support our sponsors and mention Reef Central

Go Back   Reef Central Online Community > General Interest Forums > The Reef Chemistry Forum
Register Blogs FAQ Calendar Mark Forums Read

Notices

User Tag List

Reply
Thread Tools
Old 04/30/2018, 03:07 PM   #1
hkgar
Registered Member
 
hkgar's Avatar
 
Join Date: Oct 2002
Location: Dewitt MI
Posts: 4,513
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.


__________________
Gary


180 gallon, 40 gallon sump, 8 ATI T5's, MTC MVX 36 Skimmer, Apex controller Reef Octopus CaRx

Current Tank Info: 2 Barred Rabbitfish, Red Head, Yellow/Purple, Hoevans, Possum, 2 Leopard Wrasses, Kole, Purple & Atlantic Blue Tangs, Matted Filefish, 2 Percula Clown, 4 PJ Cardinals, Swallowtail Angel

Last edited by hkgar; 04/30/2018 at 03:54 PM.
hkgar is offline   Reply With Quote
Old 04/30/2018, 07:17 PM   #2
Vinny Kreyling
Registered Member
 
Vinny Kreyling's Avatar
 
Join Date: Nov 2002
Location: Miller Place, NY
Posts: 5,497
Which weighs more?
A pound of feathers or a pound of beef?
The same but different volumes.


__________________
250 gallon mixed reef, 2 Reefbreeder's Photon V 2, RD 3 Speedy 80 Watt, DAS EX-3 Skimmer, MTC mini cal, 2-3/4" Sea Swirls, Aquacontroller & 4 Tunze pumps.
Vinny Kreyling is offline   Reply With Quote
Old 04/30/2018, 11:36 PM   #3
bertoni
RC Mod
 
Join Date: Mar 2002
Location: Mountain View, CA, USA
Posts: 87,407
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?


__________________
Jonathan Bertoni
bertoni is offline   Reply With Quote
Old 05/01/2018, 05:43 AM   #4
hkgar
Registered Member
 
hkgar's Avatar
 
Join Date: Oct 2002
Location: Dewitt MI
Posts: 4,513
Quote:
Originally Posted by bertoni View Post
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?
105.9888 g/mol Sodium carbonate weight, but I have no idea what a mol is?

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.


__________________
Gary


180 gallon, 40 gallon sump, 8 ATI T5's, MTC MVX 36 Skimmer, Apex controller Reef Octopus CaRx

Current Tank Info: 2 Barred Rabbitfish, Red Head, Yellow/Purple, Hoevans, Possum, 2 Leopard Wrasses, Kole, Purple & Atlantic Blue Tangs, Matted Filefish, 2 Percula Clown, 4 PJ Cardinals, Swallowtail Angel
hkgar is offline   Reply With Quote
Old 05/01/2018, 07:55 AM   #5
Hooligan
Registered Member
 
Join Date: Apr 2003
Location: Avon Lake, Ohio
Posts: 62
Quote:
Originally Posted by hkgar View Post
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?
I believe you made an arithmetic mistake here. I get 15.75g/100ml water. ((596/3785) * 100).

Quote:
Originally Posted by hkgar View Post
This article states that the solubility of baking soda in water is 9.3 g 100ml.
This article supports that figure and also tells me that if you raise the water temperature to 60C you'd be able to dissolve 16.5g (a bit more than we need) in that 100ml. Not sure if this is acceptable for your purposes...

Quote:
Originally Posted by hkgar View Post
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.
I wouldn't worry too much about conversions in an article about baking - I'd guess they'd be approximate at best.

Quote:
Originally Posted by hkgar View Post
105.9888 g/mol Sodium carbonate weight, but I have no idea what a mol is?

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.
Sounds like your scale is accurate.

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!


__________________
Mark
Hooligan is offline   Reply With Quote
Old 05/03/2018, 08:28 PM   #6
Mr. Wiggles
Registered Member
 
Join Date: Jun 2010
Location: Chapel Hill, NC
Posts: 189
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.


Mr. Wiggles is online now   Reply With Quote
Old 05/03/2018, 11:15 PM   #7
bertoni
RC Mod
 
Join Date: Mar 2002
Location: Mountain View, CA, USA
Posts: 87,407
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.


__________________
Jonathan Bertoni
bertoni is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -6. The time now is 09:43 PM.


TapaTalk Enabled

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2018 Axivo Inc.
Use of this web site is subject to the terms and conditions described in the user agreement.
Reef CentralTM Reef Central, LLC. Copyright 1999-2014
User Alert System provided by Advanced User Tagging v3.3.0 (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.