Reef Chemistry Question of the Day #279: Ions sticking to calcium carbonate

[Randy Holmes-Farley]

Reef Chemistry Question of the Day #279

Which of the following two ions are least likely to stick to a bare calcium carbonate surface in a reef aquarium?

A. Lithium
B. Magnesium
C. Calcium
D. Strontium
E. Phosphate
F. Nitrate


Good luck!

Previous question of the day:

Reef Chemistry Question of the Day #278: Main components of seawater

Aside from water, what is the highest concentration component of seawater? Don't look it up! Guess if you need to! Possible answers: 1. Sodium 2. Chloride 3. Magnesium 4. Sulfate Good luck! Previous question of the day...

www.reef2reef.com

 

[gbroadbridge]

Reef Chemistry Question of the Day #279

Which of the following two ions are least likely to stick to a bare calcium carbonate surface in a reef aquarium?

A. Lithium
B. Magnesium
C. Calcium
D. Strontium
E. Phosphate
F. Nitrate


Good luck!

Previous question of the day:

Reef Chemistry Question of the Day #278: Main components of seawater

Aside from water, what is the highest concentration component of seawater? Don't look it up! Guess if you need to! Possible answers: 1. Sodium 2. Chloride 3. Magnesium 4. Sulfate Good luck! Previous question of the day...

www.reef2reef.com

A & F

 

[Miami Reef]

I know Nitrate definitely doesn’t stick to calcium carbonate. I’m curious to know the other one, and the reason for why they don’t.

 

[Randy Holmes-Farley]

I know Nitrate definitely doesn’t stick to calcium carbonate. I’m curious to know the other one, and the reason for why they don’t.

One way to think through it, which is a useful approximation for many scenarios like this, is to think about which ions tend to precipitate with one of the ions already on the surface.

 

[Miami Reef]

One way to think through it, which is a useful approximation for many scenarios like this, is to think about which ions tend to precipitate with one of the ions already on the surface.

CaCl2 (aq) + NaCO3 (aq) ———> NaCl (aq) + Ca(CO3)2 (s)

Calcium precipitates when it comes in contact with carbonate. So Calcium?

 

[Miami Reef]

@Randy Holmes-Farley

 

[Randy Holmes-Farley]

And the answer is...

Which of the following two ions are least likely to stick to a bare calcium carbonate surface in a reef aquarium?

A. Lithium
F. Nitrate

Nitrate and lithium won't noticeably stick to calcium carbonate from seawater because they have no strong way of interacting with either calcium or carbonate.

For example, lithium carbonate is quite soluble, as is calcium nitrate.

Ions with a strongly attraction for one another would tend to stick together and tend to have low solubility. Calcium phosphate, strontium carbonate, etc.

 

[AquaKey]

Will that mean dosing calcium carbonate as a DIY Coral Snow alternative wouldn't be advised because it would pull beneficial ions out of the water?

 

[blaxsun]

I failed chemistry, lol.

 

[Pico bam]

Someday this will make sense only nine hundred and ninety-nine more of Randy's articles to go! (I've read alot more than one)

 

[Randy Holmes-Farley]

Will that mean dosing calcium carbonate as a DIY Coral Snow alternative wouldn't be advised because it would pull beneficial ions out of the water?

It will bind ions, but I don't think it is likely to be problematic except possibly for phosphate if it is pretty low to begin with. That's because it is one of the most prevalent to bind, and it starts much lower than most other things that bind.