Page 1 of 2 12 LastLast
Results 1 to 25 of 40
Like Tree1Likes

Thread: Decarbonation of soft drink

  1. #1
    New Member **Kate**'s Avatar
    Join Date
    Mar 2005
    HSC
    N/A
    Gender
    Undisclosed
    Location
    Australia, not Italy
    Posts
    10
    Rep Power
    10

    Decarbonation of soft drink

    Hi can anyone help me out with this dot point, a breif sketch of the prac is all i need. Thanks

    Identify data plan and perform a first hand investigation to decarbonate soft drink and gather data to measure the mass changes involved and calculate the volume of gas released at 25oC and 100kPa

  2. #2
    Love Addict - Nakashima Dreamerish*~'s Avatar
    Join Date
    Jan 2005
    HSC
    2005
    Gender
    Female
    Posts
    3,712
    Rep Power
    12
    Do you mean a sketch - literally? Because that would just be drawing some scales and a big plastic drink bottle.

    http://www.geocities.com/jamesyscien...c/tae/exp.html

    That should help.
    uai :: 98.20 | b. pharmacy @ usyd | no more chemistry students til '07


  3. #3
    bmc
    bmc is offline
    Cadet
    Join Date
    Jul 2005
    HSC
    2006
    Gender
    Male
    Location
    South of the Border
    Posts
    61
    Rep Power
    10
    Quote Originally Posted by **Kate**
    Hi can anyone help me out with this dot point, a breif sketch of the prac is all i need. Thanks

    Identify data plan and perform a first hand investigation to decarbonate soft drink and gather data to measure the mass changes involved and calculate the volume of gas released at 25oC and 100kPa
    when sketching it draw ur soft drink can on a tripod and gauze mat and with a bunsen. Heating increases the likelihood of all the gas being removed. just include in ur method to weight the can b4 and after heating.

  4. #4
    New Member
    Join Date
    Sep 2005
    HSC
    2005
    Gender
    Female
    Posts
    6
    Rep Power
    9
    Hi Kate

    I did this degassing prac for my chemistry assessment for which i got 19/20

    I have the document (hypothesis, aim, method, conclusion, discussion) saved on my computer. I can send it to you by email if you like

  5. #5
    Junior Member jamesy_1988's Avatar
    Join Date
    Dec 2004
    HSC
    2005
    Gender
    Male
    Location
    Brisbane
    Posts
    114
    Rep Power
    10
    Quote Originally Posted by bmc
    when sketching it draw ur soft drink can on a tripod and gauze mat and with a bunsen. Heating increases the likelihood of all the gas being removed. just include in ur method to weight the can b4 and after heating.
    You have to be really careful when you decarbonate soft drinks using this method as there is a possibility that water may be lost to the atmosphere when it is heated, even just slightly above room temperature.

    The best method of decaqrbonating soft drink i have found is to either shake it until you have a consistent mass or to add a known mass of sodium chloride to the soft drink. Either method works fine and reduces the possibility of experimental error

    Jamesy

    http://www.geocities.com/jamesyscience
    Bachelor Engineering (Chemical) / Bachelor Science (Chemistry) University of Queensland

    www.geocities.com/jamesyscience

  6. #6
    New Member
    Join Date
    Aug 2005
    HSC
    2006
    Gender
    Female
    Posts
    8
    Rep Power
    10

    Re: Decarbonation of soft drink

    what does the sodium chloride actually do?

  7. #7
    wah
    wah is offline
    Cadet
    Join Date
    Sep 2004
    HSC
    N/A
    Gender
    Male
    Posts
    27
    Rep Power
    10

    Re: Decarbonation of soft drink

    There are 3 methods to achieve the aim:

    -heating the soft drink gently such that the evaporation of the water (and other stuff) is at a minimum. This means no boiling of the soft drink.

    -Shake the soft drink

    -Use NaCl to salt it out

    though the first two methods are more common.

  8. #8
    New Member
    Join Date
    Feb 2006
    HSC
    2006
    Gender
    Female
    Posts
    10
    Rep Power
    9

    Re: Decarbonation of soft drink

    i've got the same prac.

    would freezing work? i read in my text book that CO2 is less soluble in ice.
    No trees were harmed in the making or sending of this message. However, a great number of electrons were seriously inconvenienced.

  9. #9
    Love Addict - Nakashima Dreamerish*~'s Avatar
    Join Date
    Jan 2005
    HSC
    2005
    Gender
    Female
    Posts
    3,712
    Rep Power
    12

    Re: Decarbonation of soft drink

    Quote Originally Posted by Tess653
    i've got the same prac.

    would freezing work? i read in my text book that CO2 is less soluble in ice.
    You should never freeze a bottle of soft drink because the solubility of CO2 in ice is very low. So almost all the CO2 is going to come out of solution as the water freezes out, and pack into the small space under the cap. This would cause a significant build-up of pressure, and possibly an explosion.

    However, I suppose if you were to place the drink in the freezer without the lid (or with the lid loosely on), the CO2 could escape from the bottle. But that would certainly take more than one period at school, and you usually have just one lesson to do it.
    uai :: 98.20 | b. pharmacy @ usyd | no more chemistry students til '07


  10. #10
    .
    Join Date
    Oct 2005
    HSC
    N/A
    Gender
    Undisclosed
    Posts
    5,595
    Rep Power
    12

    Re: Decarbonation of soft drink

    I once froze a can of coke in the freezer at home.

    It exploded of course. And I think I heard it.

  11. #11
    New Member
    Join Date
    Feb 2006
    HSC
    2006
    Gender
    Male
    Posts
    2
    Rep Power
    9

    Re: Decarbonation of soft drink

    when adding salt to the soda water, i know CO2 comes out because of a disruption in the equilibrium , but wot exactly does the salt do??????
    does it act as a catalyst???

  12. #12
    Love Addict - Nakashima Dreamerish*~'s Avatar
    Join Date
    Jan 2005
    HSC
    2005
    Gender
    Female
    Posts
    3,712
    Rep Power
    12

    Re: Decarbonation of soft drink

    Quote Originally Posted by femuu
    when adding salt to the soda water, i know CO2 comes out because of a disruption in the equilibrium , but wot exactly does the salt do??????
    does it act as a catalyst???
    I don't know exactly why, but salt causes dehydration, and since water is a reactant, dehydration of the equilibrium will shift it to the left, producing more water and carbon dioxide.

    After thinking about it, I'm guessing that the salt in solution is stopping the water from reacting with the carbon dioxide.

    As you know, when a system is at equilibrium, the rate of the forward reaction is equal to the rate of the backward reaction. That is to say, some carbon dioxide is reacting with water to form carbonic acid. Salts, being ionic substances ionise in solution, so by adding NaCl, you are adding sodium and chlorine ions to the solution. From year 11 you learned that ionic substances dissolve well in water because water as a polar molecule has oxygen being slightly negative and hydrogen being slightly positive. So when NaCl dissolves in water, the positive Na+ is attracted to the negative oxygen atom while the negative Cl- is attracted to the positive hydrogen atom.

    So I'm guessing that when water molecules are "wrapped" in anions and cations, they can't react with carbon dioxide to form carbonic acid. Making a reactant unable to participate in the reaction is as good as removing it. Hence the equilibrium will shift to the left, producing more water and carbon dioxide.

    My best guess.
    Last edited by Dreamerish*~; 22 Feb 2006 at 10:00 PM.
    uai :: 98.20 | b. pharmacy @ usyd | no more chemistry students til '07


  13. #13
    no soup for you (enigma)'s Avatar
    Join Date
    Jul 2005
    HSC
    2006
    Gender
    Male
    Location
    Penrith
    Posts
    269
    Rep Power
    10

    Re: Decarbonation of soft drink

    Quote Originally Posted by femuu
    when adding salt to the soda water, i know CO2 comes out because of a disruption in the equilibrium , but wot exactly does the salt do??????
    does it act as a catalyst???
    apparently the salt reduces the liquids ability (not sure if thats the right word for it) to allow gas to dissolve into it, but im not really sure why. does anyone else know?

  14. #14
    .
    Join Date
    Oct 2005
    HSC
    N/A
    Gender
    Undisclosed
    Posts
    5,595
    Rep Power
    12

    Re: Decarbonation of soft drink

    We don't need to know exactly why the salt causes dehydration, it's not in the syllabus and even someone as knowledgeable as Dreamerish doesn't fully know the answer. I'm not trying to say that we shouldn't find out about these outside questions, but you could ask your chem teacher.

  15. #15
    Loquacious One +Po1ntDeXt3r+'s Avatar
    Join Date
    Oct 2003
    HSC
    2003
    Gender
    Undisclosed
    Posts
    3,530
    Rep Power
    13

    Re: Decarbonation of soft drink

    Quote Originally Posted by Dreamerish*~
    I don't know exactly why, but salt causes dehydration, and since water is a reactant, dehydration of the equilibrium will shift it to the left, producing more water and carbon dioxide.

    After thinking about it, I'm guessing that the salt in solution is stopping the water from reacting with the carbon dioxide.

    As you know, when a system is at equilibrium, the rate of the forward reaction is equal to the rate of the backward reaction. That is to say, some carbon dioxide is reacting with water to form carbonic acid. Salts, being ionic substances ionise in solution, so by adding NaCl, you are adding sodium and chlorine ions to the solution. From year 11 you learned that ionic substances dissolve well in water because water as a polar molecule has oxygen being slightly negative and hydrogen being slightly positive. So when NaCl dissolves in water, the positive Na+ is attracted to the negative oxygen atom while the negative Cl- is attracted to the positive hydrogen atom.

    So I'm guessing that when water molecules are "wrapped" in anions and cations, they can't react with carbon dioxide to form carbonic acid. Making a reactant unable to participate in the reaction is as good as removing it. Hence the equilibrium will shift to the left, producing more water and carbon dioxide.

    My best guess.
    ure kinda right.. but its not a dehydration per say.. because thats a specific physiological effect in medicine rather than the chemical change ure describing..

    time to school the chem tutor

    salting causes.. the diverse ion effect. its 1st yr uni chem.. so its right up ure ally
    http://www.psigate.ac.uk/newsite/ref...em2/p01193.htm

    here has a description.. both a oversimplified and accurate version
    I take no responsibility for this post's content

  16. #16
    Love Addict - Nakashima Dreamerish*~'s Avatar
    Join Date
    Jan 2005
    HSC
    2005
    Gender
    Female
    Posts
    3,712
    Rep Power
    12

    Re: Decarbonation of soft drink

    Quote Originally Posted by +Po1ntDeXt3r+
    ure kinda right.. but its not a dehydration per say.. because thats a specific physiological effect in medicine rather than the chemical change ure describing..

    time to school the chem tutor

    salting causes.. the diverse ion effect. its 1st yr uni chem.. so its right up ure ally
    http://www.psigate.ac.uk/newsite/ref...em2/p01193.htm

    here has a description.. both a oversimplified and accurate version
    I can't say I understood all of it , but thanks for providing an answer.

    Maybe this is why high-school teachers don't bother explaining the reason behind adding salt to aerated drinks.
    uai :: 98.20 | b. pharmacy @ usyd | no more chemistry students til '07


  17. #17
    Chocobo XcarvengerX's Avatar
    Join Date
    Oct 2005
    HSC
    2006
    Gender
    Male
    Location
    Sydney
    Posts
    378
    Rep Power
    9

    Re: Decarbonation of soft drink

    I did this experiment at school laboratory by heating the soft drink. But, the liquid just spurt out uncontrollably...:mad1:
    Achievements:
    No band 6

    ESL - 85
    Mathematics Extension 1 - 85
    Mathematics Extension 2 - 83
    Business Studies - 87
    Chemistry - 88
    Physics - 79

    17 marks difference
    Mathematics Extension 2 (74 - External; 91 - Internal)

    JC DUX of 2006
    2006 NSW UAI= 96.10

  18. #18
    New Member
    Join Date
    Dec 2005
    HSC
    2006
    Gender
    Female
    Location
    Sydney
    Posts
    6
    Rep Power
    9

    Re: Decarbonation of soft drink

    Hey
    ok so some of u might recall helping me during the holidays with some questions i had about the decarbonating soft drink prac....
    one question was about Le Chatelier's Principle and to give a specific example in nature. After hearing many of your opinions about the example in nature, i decided to write about a lake and its acidity. When i got my assessment back, the teacher has taken a mark off me for this, telling me i am wrong because lakes are not acidified (they have a "negligible amount"). I'm just wondering who is correct in this case???

    Also, I used the heating method for the actual prac, where i made a water bath, with the bunsen, tripod, etc. and heated a bottle of soft drink. to compare the mass loss due to evaporation, i also heated a bottle of water at the same time, under exactly the same conditions. The water was my control as i subtracted this mass loss from evaporation to the mass loss of the soft drink to get the mass loss of carbon dioxide. My teacher has taken marks from me saying that this is wrong because it has to be the same drink. I have spoken to my tutor about this (a HSC chemistry teacher) who says i am correct, and also found a past hsc question with the same method as i used, showed my teacher the question and yet i am still wrong.
    is she correct or do i have grounds to appeal??
    An extra 2marks (1 for each of these things) will move my rank from 6th to 1st so it could potentially mean alot if I can get this sorted out.

    Thanks in advance for your help!!
    Any advice is appreciated!
    Eli

  19. #19
    Love Addict - Nakashima Dreamerish*~'s Avatar
    Join Date
    Jan 2005
    HSC
    2005
    Gender
    Female
    Posts
    3,712
    Rep Power
    12

    Re: Decarbonation of soft drink

    Quote Originally Posted by eli_1988_1
    Hey
    ok so some of u might recall helping me during the holidays with some questions i had about the decarbonating soft drink prac....
    one question was about Le Chatelier's Principle and to give a specific example in nature. After hearing many of your opinions about the example in nature, i decided to write about a lake and its acidity. When i got my assessment back, the teacher has taken a mark off me for this, telling me i am wrong because lakes are not acidified (they have a "negligible amount"). I'm just wondering who is correct in this case???
    Are you talking about a buffering solution in lakes? I wouldn't say lakes are "acidified" - some of them have a buffering system which consists of comparable amounts of a weak acid and its conjugate base - in this case, H2CO3 and HCO3-. The equation is:

    H2CO3 + H2O H3O+ + HCO3-

    When acid is added, the concentration of H3O+ is increased. The equilibrium adjusts to this change by shifting to the left to absorb some of it. When base is added, the OH- reacts with H3O+ to form water, removing the H3O+ from the products side of the reaction. Furthermore, the water produced increases the concentration of H2O, which is a reactant. The equilibrium then shifts to the right to absorb the extra water and to produce more H3O+ to replace the loss.

    There is a small amount of the buffer solution in lakes and rivers. I wouldn't say it's negligible, but I think your teacher was talking about something else. Anyhow, a simpler equilibrium reaction in nature would be the carbon dioxide equilibrium. Some carbon dioxide from the atmosphere is dissolved in rain water, resulting in the rain water being slightly acidic, even when there is no atmospheric pollution:

    CO2 + H2O
    H2CO3
    Quote Originally Posted by eli_1988_1
    Also, I used the heating method for the actual prac, where i made a water bath, with the bunsen, tripod, etc. and heated a bottle of soft drink. to compare the mass loss due to evaporation, i also heated a bottle of water at the same time, under exactly the same conditions. The water was my control as i subtracted this mass loss from evaporation to the mass loss of the soft drink to get the mass loss of carbon dioxide. My teacher has taken marks from me saying that this is wrong because it has to be the same drink. I have spoken to my tutor about this (a HSC chemistry teacher) who says i am correct, and also found a past hsc question with the same method as i used, showed my teacher the question and yet i am still wrong.
    is she correct or do i have grounds to appeal??
    An extra 2marks (1 for each of these things) will move my rank from 6th to 1st so it could potentially mean alot if I can get this sorted out.

    Thanks in advance for your help!!
    Any advice is appreciated!
    Eli
    I think your argument is justified. Water has the same boiling point whether it is a pure solution or a mixture - in this case a soft drink.
    uai :: 98.20 | b. pharmacy @ usyd | no more chemistry students til '07


  20. #20
    Magician, and Lawyer. Mountain.Dew's Avatar
    Join Date
    Nov 2005
    HSC
    2005
    Gender
    Male
    Location
    Sydney, Australia
    Posts
    825
    Rep Power
    9

    Re: Decarbonation of soft drink

    Quote Originally Posted by eli_1988_1
    Hey
    ok so some of u might recall helping me during the holidays with some questions i had about the decarbonating soft drink prac....
    one question was about Le Chatelier's Principle and to give a specific example in nature. After hearing many of your opinions about the example in nature, i decided to write about a lake and its acidity. When i got my assessment back, the teacher has taken a mark off me for this, telling me i am wrong because lakes are not acidified (they have a "negligible amount"). I'm just wondering who is correct in this case???

    Also, I used the heating method for the actual prac, where i made a water bath, with the bunsen, tripod, etc. and heated a bottle of soft drink. to compare the mass loss due to evaporation, i also heated a bottle of water at the same time, under exactly the same conditions. The water was my control as i subtracted this mass loss from evaporation to the mass loss of the soft drink to get the mass loss of carbon dioxide. My teacher has taken marks from me saying that this is wrong because it has to be the same drink. I have spoken to my tutor about this (a HSC chemistry teacher) who says i am correct, and also found a past hsc question with the same method as i used, showed my teacher the question and yet i am still wrong.
    is she correct or do i have grounds to appeal??
    An extra 2marks (1 for each of these things) will move my rank from 6th to 1st so it could potentially mean alot if I can get this sorted out.

    Thanks in advance for your help!!
    Any advice is appreciated!
    Eli
    okay...heres my 2 cents

    about le chatelier's principle...when people were talking about its relevance in nature, i think it has implied buffer systems, such as the amount of carbon dixoide in blood, or the amount of a weak acid in wine. yes, i agree that a lake will have some acidity, but i agree with the teacher that it has such a 'neglible amount' that the HSC doesnt factor in such small measures. the HSC always trys to simplify things to make ideas and concepts easier for students to understand. and that does mean sacrificing a degree of needed detail and accuracy. and, there is also the case that some rivers are not always acidic...some are basic, and some are neutral as well.

    about ur decarbonating prac...you do have good grounds for appeal. its ridiculous that ur teacher is rejecting a perfectly valid method...i guess it just wasnt in the scope of what ur teacher taught you, and so, has rejected it.

    but there is one word of advice. sometimes, IN THE HSC -and only in the HSC- for science subjects, it is not wise to always think outside the square.
    Last edited by Mountain.Dew; 9 Mar 2006 at 6:50 PM.
    B Comm/LLB @ USyd (V)


    Yeah, I feel old...as an undergrad. lol.

  21. #21
    New Member
    Join Date
    Feb 2006
    HSC
    2006
    Gender
    Female
    Posts
    2
    Rep Power
    9

    Question Re: Decarbonation of soft drink

    Hey i too have the same prac but mine says "Plan and perform a first-hand investigation to identify a factor that affects the rate of degassing of a soft drink." Im not sure what to do.. please help .. i think i have to do the other stuff too like measure the mass changes and calculate volume of CO2 so if anyone has some handy notes they'd be much appreciated. Thanks (in advance :P)

  22. #22
    Cadet Bractune's Avatar
    Join Date
    Mar 2006
    HSC
    2006
    Gender
    Male
    Location
    Gunnedah
    Posts
    34
    Rep Power
    9

    Re: Decarbonation of soft drink

    Hey Guys, I've got the prac all set out, initial tests confirm that freezing will be the way i do it. I just finished looking at a bottle of soda water with indicator in it that i froze over night...(cap off) Its changed from bright red to pale green with a dark green ring around the top. I read in an earlier post that CO2 was very insoluble in ice. The internet however seems to disagree with me. Can someone...."Cough, cough dreamerish" set me straight is this true and if so why?
    Thanks in advance.

  23. #23
    .
    Join Date
    Oct 2005
    HSC
    N/A
    Gender
    Undisclosed
    Posts
    5,595
    Rep Power
    12

    Re: Decarbonation of soft drink

    The freezing of the soda drink forces all the carbon dioxide out of the aqueous solution, since we know that it's insoluble as the water turns into ice. Therefore the carbon dioxide is released from the solution into the air as a gas:

    CO3(aq) <=> CO3(g)

    Eventually, as the water becomes frozen, virtually all the CO2 will have been converted into gas, meaning the soda drink loses its acidity and therefore its pH will be around 7. I'm assuming you used universal indicator, and pale green indicates an approximate pH of 7. I hope that explains things.
    Last edited by Riviet; 24 Mar 2006 at 10:10 PM.

  24. #24
    Cadet Bractune's Avatar
    Join Date
    Mar 2006
    HSC
    2006
    Gender
    Male
    Location
    Gunnedah
    Posts
    34
    Rep Power
    9

    Re: Decarbonation of soft drink

    Yeah, when it melted but the indicator turned yellow as in pH6. So what happened there? Gas trapped inside the ice? I was thinking of just scrapping it and going with just weighing the bottle taking the lid off and letting it sit for 5 days or something then weighing it again and figuring out the difference.
    I just dont care anymore i've spent so much time trying to get it right i just need something foolproof.
    Thanks again.

  25. #25
    New Member
    Join Date
    Jan 2008
    HSC
    2008
    Gender
    Female
    Posts
    2
    Rep Power
    8

    Re: Decarbonation of soft drink

    Could u send it to me too????!!! i NEED YOU!!! HELP ME!!!
    thanks
    my email is: icansingloud@gmail.com

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •