Hi All,
and welcome back to a new term.
Has anyone been asked to supply a sodium dithionite (sodium hydrosulfite) solution as a means for removing oxygen from water prior to photosynthesis and respiration experiments?
We need it for year 7, it is only approved for years 11-12, to be used with caution.
I would love to hear of a safer alternative...
Cheers,
~Robyn
oxygen removing solution
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ELIZABETH
- Posts: 233
- Joined: 02 Jun 2006, 10:00
- School: O'Connor Catholic College
- Suburb: Armidale
- State/Location: NSW
Re: oxygen removing solution
Hi Robyn,
A much easier alternative is to boil the water vigorously for about 5 mins immediately before use then cool it - no mess, no chemicals.
Liz
A much easier alternative is to boil the water vigorously for about 5 mins immediately before use then cool it - no mess, no chemicals.
Liz
Re: oxygen removing solution
Hi All,
A great method to de-oxygenate water or other gas containing liquid is to use a Ultrasonic Agitator. Essentially it is a shallow rectangular "deep Fryer" that contains water. When you turn the instrument on, it agitates the liquid using ultrasonic waves.
But some schools may not have this particular piece of equipment.
Cheers,
Robb.....
A great method to de-oxygenate water or other gas containing liquid is to use a Ultrasonic Agitator. Essentially it is a shallow rectangular "deep Fryer" that contains water. When you turn the instrument on, it agitates the liquid using ultrasonic waves.
But some schools may not have this particular piece of equipment.
Cheers,
Robb.....
Dr Robert Crosdale. MRACI. NSS. NSSA. NASA.
Ph.D (Chem), Post Grad Ph.D (Physics), M.Ed, B.Sc (Hons), Dip. Appl. Sc. (Chem)
Lake Munmorah High School.
University of New England.
University of New South Wales.
University of Newcastle.
To understand the Universe from our perspective, we need to look towards our own backyard first for answers.
** AD ASTRA PER ASPERA - SEMPER EXPLORO **
Ph.D (Chem), Post Grad Ph.D (Physics), M.Ed, B.Sc (Hons), Dip. Appl. Sc. (Chem)
Lake Munmorah High School.
University of New England.
University of New South Wales.
University of Newcastle.
To understand the Universe from our perspective, we need to look towards our own backyard first for answers.
** AD ASTRA PER ASPERA - SEMPER EXPLORO **
Re: oxygen removing solution
No we do not have this contraption, but boiling the water is brilliant. If I store in in airtight container fiiled to the top, that should work well.
thanks Lada
thanks Lada
Re: oxygen removing solution
G'day all,
I am very in favour of the boiling water technique but our teachers are very sceptical.
Can you give me more details? How long did you boil it and how soon after it cooled did you use it? We need it (the oxygen free water) to turn methylene blue clear.
Thanks,
~Robyn
I am very in favour of the boiling water technique but our teachers are very sceptical.
Can you give me more details? How long did you boil it and how soon after it cooled did you use it? We need it (the oxygen free water) to turn methylene blue clear.
Thanks,
~Robyn
Re: oxygen removing solution
If you boil water to remove oxygen you will need to contain it so oxygen can not ingress back in ie. pour the just boiled water into a flask which you fill to the top so that when it is stoppered there is little or no air above the water while it cools.
Another way is to sparge water with oxygen free nitrogen gas (most school labs may not have nitrogen bottles)
Another way which I used to use when home bottling whiite wine was to add ascorbic acid. Ascorbic acid will scavenge dissolved oxygen. Oxygen dissolves to about 2x10-5 Molar in water, so I used to add ascorbic acid in order to make the wine 10-4Molar with respect to ascorbic acid. This gives about a five times excess over oxygen.
Before using this technique however you would need to be sure the excess ascorbic acid does not interfere with the processes you are studying.
Another way is to sparge water with oxygen free nitrogen gas (most school labs may not have nitrogen bottles)
Another way which I used to use when home bottling whiite wine was to add ascorbic acid. Ascorbic acid will scavenge dissolved oxygen. Oxygen dissolves to about 2x10-5 Molar in water, so I used to add ascorbic acid in order to make the wine 10-4Molar with respect to ascorbic acid. This gives about a five times excess over oxygen.
Before using this technique however you would need to be sure the excess ascorbic acid does not interfere with the processes you are studying.
