Reef Chemistry Question of the Day #47 Ion Abundance

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,861
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
Reef Chemistry Question of the Day #47

The second most abundant ion in seawater is:


A. Sodium
B. Chloride
C. Magnesium
D. Sulfate
E. Calcium
F. Water

Good luck!























.
 

H2O

Well-Known Member
View Badges
Joined
Jun 5, 2010
Messages
846
Reaction score
28
Location
Brooklyn NY
Rating - 0%
0   0   0
Lol a lot of funny scientist on here read the question the answer is D
 

DFW

Active Member
View Badges
Joined
Sep 11, 2014
Messages
446
Reaction score
16
Location
Fort Worth, Texas
Rating - 0%
0   0   0
A!!!!!! There is more chloride by percentage in sea water than there is sodium.
 
Last edited:
OP
OP
Randy Holmes-Farley

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,861
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
And the answer is...A. Sodium

Water isn't an ion, so it doesn't count.

Then the order of abundance of ions in seawater by weight is:
(the order of some of them changes slightly when shown as number of ions rather than weight, with sulfate dropping below magnesium, but sodium is still second). :)


Species...............Concentration milligrams per liter (mg/L)
Cl- (chloride) ...............19,000
Na+ (sodium) ...............10,500
SO42- (sulfate) .............2700
Mg2+ (magnesium) .........1280
Ca2+ (calcium) ................412
K+ (potassium) ................399
HCO3- (bicarbonate) .......110
Br- (bromide) ...................67
CO32- (carbonate) ...........20
Sr2+ (strontium) ...............7.9
B(OH)3 + B(OH)4- (borate)..5 (as Boron)
F- (fluoride) .....................1.3
Organics ..........................1 to 2
Everything else combined (except dissolved gasses) ...Less than 1


This has more:

http://reefkeeping.com/issues/2005-11/rhf/index.php
 
Last edited:
OP
OP
Randy Holmes-Farley

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,861
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
I would also add that by number, sodium is a lot closer to chloride, but chloride is still first.

Here are those values (right hand column of the table below):
http://www.chemistry-reference.com/images/transparencies/Composition of Seawater.jpg

Composition of Seawater.jpg
 

reggaedrummin

Active Member
View Badges
Joined
Aug 8, 2014
Messages
273
Reaction score
1
Location
San Francisco
Rating - 0%
0   0   0
I understand that mg/l is a weight measurement, but I assumed that ppm was a volume measurement. Am I correct? It doesn't change anything in terms of this question, I just want to understand better.
 
OP
OP
Randy Holmes-Farley

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,861
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
I understand that mg/l is a weight measurement, but I assumed that ppm was a volume measurement. Am I correct? It doesn't change anything in terms of this question, I just want to understand better.

Well, ppm (parts per million) could be a pure volume measurement if you are referring to liquids (like microliters per liter = ppm; might be used for ethanol in water, for example), but for anything where one is solid and the other liquid (or both are solids), it is always a weight based measurement, such as mg/kg (milligrams per kilogram), which is close to, but not exactly the same as, mg/L (milligrams per liter) for water solutions.

Mae sense?
 

reggaedrummin

Active Member
View Badges
Joined
Aug 8, 2014
Messages
273
Reaction score
1
Location
San Francisco
Rating - 0%
0   0   0
Well, ppm (parts per million) could be a pure volume measurement if you are referring to liquids (like microliters per liter = ppm; might be used for ethanol in water, for example), but for anything where one is solid and the other liquid (or both are solids), it is always a weight based measurement, such as mg/kg (milligrams per kilogram), which is close to, but not exactly the same as, mg/L (milligrams per liter) for water solutions.

Mae sense?
Yes...and in other news, my understanding of measurements was wrong. Thanks Randy! I always learn something from these quick informational posts. I wish there was a way to subscribe to your posts
 

Mastering the art of locking and unlocking water pathways: What type of valves do you have on your aquarium plumbing?

  • Ball valves.

    Votes: 71 53.0%
  • Gate valves.

    Votes: 68 50.7%
  • Check valves.

    Votes: 34 25.4%
  • None.

    Votes: 30 22.4%
  • Other.

    Votes: 9 6.7%

New Posts

Back
Top