-
Finished your HSC? Check out our University Discussion, Non-School forums or help out next year's HSC students! -
YOU can help the next generation of students in the community! Share your trial papers and notes on our Notes & Resources page
Fermentation of glucose(sugar) (1 Viewer)
- Thread starter gadbil
- Start date
~*HSC 4 life*~
Active Member
- Joined
- Aug 15, 2003
- Messages
- 2,411
- Gender
- Undisclosed
- HSC
- N/A
i posted this in yr 11 forum, but here we go again!
you prepare a glucose solution by mixing water, glucose and yeast together and put it in a conical flask. Then you weigh this and record its mass. Now, what will happen is the yeast will catalyse the fermentaton reaction and covert glucose into ethanol, releasing carbon dioxide gas--> therefore mass is lost. At my school we put a cotton bud to seal off the conical flask, because that way it allowed carbon dioxide to leave the flask, but avoided oxygen going into the flask (you need to have an absence of oxygen ie an ANAEROBIC environemt for fermnetation). You may also connect a tube from the conical flask to a beaker of limewater, to confirm that the gas produced is C02 (it will go milky if present). You leave this for about a week at about 37 degrees and weigjh it every day, recording mass changes. Yous hould notice the mass decreases.
C6H1206 (aq) --zymase--> 2CO2 (g) + 2C2H5OH (aq)
you prepare a glucose solution by mixing water, glucose and yeast together and put it in a conical flask. Then you weigh this and record its mass. Now, what will happen is the yeast will catalyse the fermentaton reaction and covert glucose into ethanol, releasing carbon dioxide gas--> therefore mass is lost. At my school we put a cotton bud to seal off the conical flask, because that way it allowed carbon dioxide to leave the flask, but avoided oxygen going into the flask (you need to have an absence of oxygen ie an ANAEROBIC environemt for fermnetation). You may also connect a tube from the conical flask to a beaker of limewater, to confirm that the gas produced is C02 (it will go milky if present). You leave this for about a week at about 37 degrees and weigjh it every day, recording mass changes. Yous hould notice the mass decreases.
C6H1206 (aq) --zymase--> 2CO2 (g) + 2C2H5OH (aq)
currysauce
Actuary in the making
YOU SIR ARE A GOD!
one more thing, at our school we have to teest for ethanol with potassium permanganate, how do i do that?
one more thing, at our school we have to teest for ethanol with potassium permanganate, how do i do that?
~*HSC 4 life*~
Active Member
- Joined
- Aug 15, 2003
- Messages
- 2,411
- Gender
- Undisclosed
- HSC
- N/A
someone pm'd me a qu regarding fermentation i thought i might post it here, its just some additional info which might come in handy
q. how do we extract ethanol from this sugar solution?
you just use distillation, and do it several times to increase pruification- keeping in mind that ethanol will be maximum about 15% in concentration, because as the reaction continues and ethanol is produced, it poisons the yeast catalyst being used in the reaction, hence the reaction stops and ethanol production ceases.
q. how do we extract ethanol from this sugar solution?
you just use distillation, and do it several times to increase pruification- keeping in mind that ethanol will be maximum about 15% in concentration, because as the reaction continues and ethanol is produced, it poisons the yeast catalyst being used in the reaction, hence the reaction stops and ethanol production ceases.
Xayma
Lacking creativity
- Joined
- Sep 6, 2003
- Messages
- 5,953
- Gender
- Undisclosed
- HSC
- N/A
But the maximum concentration one can get from distillation is 95% ethanol solution this is the reason it is most commonly used.
This is as the ethanol forms an azeotrope, with a boiling point just below that of ethanol. This azeotrope acts effectively as one chemically meaning it will all boil away.
This is as the ethanol forms an azeotrope, with a boiling point just below that of ethanol. This azeotrope acts effectively as one chemically meaning it will all boil away.
~*HSC 4 life*~
Active Member
- Joined
- Aug 15, 2003
- Messages
- 2,411
- Gender
- Undisclosed
- HSC
- N/A
what i meant was 15% conc before distillation
and ive got no idea about this azeotrope stuff
and ive got no idea about this azeotrope stuff
currysauce
Actuary in the making
lol me again
3 questions
1. what are hazardous materials in this prac?... for safety thing? limewater, potassium permanganate and yeast?
2. do you measure mass changes in the control setup?
3. what can i do for the control!!!??
no glucose, no yeast... lower temp.!!! AHHH!!
lol
3 questions
1. what are hazardous materials in this prac?... for safety thing? limewater, potassium permanganate and yeast?
2. do you measure mass changes in the control setup?
3. what can i do for the control!!!??
no glucose, no yeast... lower temp.!!! AHHH!!
lol
jackanator87
fff
- Joined
- Aug 25, 2004
- Messages
- 32
- Gender
- Male
- HSC
- N/A
anyone here from macquire uni??
read my title.
read my title.
1. what are hazardous materials in this prac?... for safety thing? limewater, potassium permanganate and yeast?
limewater is a mild base can splash into eyes
yeast is not toxic
no idea about potassium permanganate never used that
2. do you measure mass changes in the control setup?
yes, you measure the weight before and after
3. what can i do for the control!!!??
nothing really, make sure the lid on the burning little jar thing (looks bit like a lantern) when you measure make sure lid is off when your measure it before and after
also removing the carbon residue on the cloth
im assuming your upto burning the ethanol and checking nrg output
limewater is a mild base can splash into eyes
yeast is not toxic
no idea about potassium permanganate never used that
2. do you measure mass changes in the control setup?
yes, you measure the weight before and after
3. what can i do for the control!!!??
nothing really, make sure the lid on the burning little jar thing (looks bit like a lantern) when you measure make sure lid is off when your measure it before and after
also removing the carbon residue on the cloth
im assuming your upto burning the ethanol and checking nrg output
hsc 4 life: because yeast dies up on more than 15% conc of ethanol...so no further fermentation can take place...
safety, well, look at the glass wear (breakable), potentially, the glass wear may impode if stoppered... yeast is not toxic, yet the waste produced is...
control: same amount/conc of glucose used, same amount of yeast used, temp/pressure ...
safety, well, look at the glass wear (breakable), potentially, the glass wear may impode if stoppered... yeast is not toxic, yet the waste produced is...
control: same amount/conc of glucose used, same amount of yeast used, temp/pressure ...
technically the yeast isnt dead, its just 'drunk' and wont spread any further, but if you very soon remove the ethanol and keep on going it should be fine, but i think obviously if you starve it of glucose for awhile they die