Join TSR now and get all your revision questions answeredSign up now

AQA GCSE - Unit 3 (P3,B3,C3) New specification papers. Watch

    Offline

    0
    ReputationRep:
    For the Examination Style Questions at the end of B3 in the AQA Nelson Thorns revision guide (page 287), does anybody know the answer to 6b(ii)? It asks you to suggest a reason why the aeration rate in a fermenter for a fungi is one rather than two.
    (Original post by lolface32)
    Well, we are going to be the first set of students to sit the exam, so hopefully low! But then again, people sitting Unit 3 are more than likely smart so I would not count on them being too low
    Remember, the people taking the exam are basically all the people who took unit 2 in January 2013 or June 2013 (except some) so regardless of the grade boundaries you are technically competing against the same people, so if you perform similarly relative to everybody else as you did on your unit two exam then the UMS should reflect this by giving you a similar grade. So you shouldn't worry too much how the grade boundaries go.
    Offline

    0
    ReputationRep:
    (Original post by Last Theorem)
    For the Examination Style Questions at the end of B3 in the AQA Nelson Thorns revision guide (page 287), does anybody know the answer to 6b(ii)? It asks you to suggest a reason why the aeration rate in a fermenter for a fungi is one rather than two.
    Remember, the people taking the exam are basically all the people who took unit 2 in January 2013 or June 2013 (except some) so regardless of the grade boundaries you are technically competing against the same people, so if you perform similarly relative to everybody else as you did on your unit two exam then the UMS should reflect this by giving you a similar grade. So you shouldn't worry too much how the grade boundaries go.
    Not necessarily, take into account they are sitting other exams too, and unit 3 may be harder for some. But these are minor tbh...
    Offline

    3
    ReputationRep:
    What do you reckon the 6-mark questions will be on for b3, c3 and p3?
    Offline

    9
    ReputationRep:
    p3 - Xrays and Ultrasound
    c3 - Bond energies
    b3 - Biogas and biofuel and stuff like that
    IMO
    Offline

    3
    ReputationRep:
    (Original post by Blake-inator)
    p3 - Xrays and Ultrasound
    c3 - Bond energies
    b3 - Biogas and biofuel and stuff like that
    IMO
    A 6 marker on bond energies (How would that work?) If anything, I think It would be on hard + soft water (+ chlorination.).
    Offline

    9
    ReputationRep:
    (Original post by tohaaaa)
    A 6 marker on bond energies (How would that work?) If anything, I think It would be on hard + soft water (+ chlorination.).
    I just named topics i guess water does make more sense
    Offline

    3
    ReputationRep:
    (Original post by tohaaaa)
    Epic Chemistry Questions to munch on:

    1)I have a substance, I preform a flame test on the substance, the colour of the flame is red. Identify the substance present.
    2)Some substances react with sodium hydroxide to form a coloured precipitate, I dissolve an unknown substance into sodium hydroxide and a blue precipitate forms. Identify the substance.
    3)I have the substances: Calcium, Magnesium and Aluminium (III), describe how to use tests to distinguish between these three substances.
    4)Describe and give the result of the test for Sulfate Ions.
    5)I react a substance with Silver Nitrate in the Presence of Dilute Nitric Acid, a Yellow precipitate forms. Identify the negative ion present.
    6)I have an unknown substance, when dilute hydrochloric acid is added to it, the substance fizzes and a gas is given off, describe and give the result of the test to show carbonate ions are present in this substance.

    ENJOY
    1) The substance contains calcium because calcium compounds burn with a brick red flame and lithium compounds burn with a crimson flame.

    2) The blue precipitate of copper hydroxide has formed. This means the compound originally contained Copper ions.

    3) Magnesium, Aluminium and Calcium all dissolve in sodium hydroxide to form white precipitates.

    If the precipitate dissolves in excess NaOH then it contains Aluminium ions.

    If it burns brick red in a flame test as well as producing a white precipitate in NaOH it contained Calcium ions.

    The remaining substance contains magnesium ions.

    4) To detect a sulfate ion dissolve the substance in dilute hydrochloric acid and add barium chloride. A white precipitate of barium sulfate forms if sulfate ions were present in the original compound.

    5) Iodide ions are present. This is because when an iodine compound is dissolved in dilute nitric acid and silver nitrate solution is added, a yellow precipitate of silver iodide is formed.

    6) When you add a dilute acid to a carbonate compound, the gas carbon dioxide is released. This can be detected by bubbling the emergent gas through limewater, turning it cloudy.

    Is that what you were getting at?

    Also, could anyone be so kind as to explain to me the details of how fusarium is fermented to produce mycoprotein? I just never know how much detail we're supposed to know of the process..


    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    (Original post by CD223)
    1) The substance contains calcium because calcium compounds burn with a brick red flame and lithium compounds burn with a crimson flame.

    2) The blue precipitate of copper hydroxide has formed. This means the compound originally contained Copper ions.

    3) Magnesium, Aluminium and Calcium all dissolve in sodium hydroxide to form white precipitates.

    If the precipitate dissolves in excess NaOH then it contains Aluminium ions.

    If it burns brick red in a flame test as well as producing a white precipitate in NaOH it contained Calcium ions.

    The remaining substance contains magnesium ions.

    4) To detect a sulfate ion dissolve the substance in dilute hydrochloric acid and add barium chloride. A white precipitate of barium sulfate forms if sulfate ions were present in the original compound.

    5) Iodide ions are present. This is because when an iodine compound is dissolved in dilute nitric acid and silver nitrate solution is added, a yellow precipitate of silver iodide is formed.

    6) When you add a dilute acid to a carbonate compound, the gas carbon dioxide is released. This can be detected by bubbling the emergent gas through limewater, turning it cloudy.

    Is that what you were getting at?

    Also, could anyone be so kind as to explain to me the details of how fusarium is fermented to produce mycoprotein? I just never know how much detail we're supposed to know of the process..


    Posted from TSR Mobile
    Fusarium is a fungus that produces mycoprotein as it is grown in a fermenter. It is supplied with glucose and mineral ions as well as oxygen as fuel for the Fusarium to respire aerobically. The glucose is formed by using enzymes to digest maize starch.

    Keeping bacteria away: Three things - Sterilise the fermenter with steam, Sterilise the glucose and mineral ions, filter the air supply.

    Temperature maintenence: Jacket of cold water outside of the fermenter, Air bubbles. This is needed because the Fungus releases energy in respiration which could cause enzymes in the fermenter to denature; as well as this the enzymes may not work well because they are not at their optimum temperature.

    That's it really
    Offline

    1
    ReputationRep:
    (Original post by Last Theorem)
    For the Examination Style Questions at the end of B3 in the AQA Nelson Thorns revision guide (page 287), does anybody know the answer to 6b(ii)? It asks you to suggest a reason why the aeration rate in a fermenter for a fungi is one rather than two.
    I have the mark scheme if that helps...
    Offline

    0
    ReputationRep:
    (Original post by Hazwaz7)
    What do you reckon the 6-mark questions will be on for b3, c3 and p3?
    B3 - I think it might be evaluating Dialysis with Kidney Transplant
    C3 - Comparing Mendeleev and Newlands?
    P3 - Either x-rays and ultrasounds or something on transformers

    I'd expect the grade boundaries to be lower than Unit 2 exams. In january we basically only had to focus on those three exams so people obviously did better. I'd guess an A* will be around 46 but it all kinda depends on how the exam is. Did anyone else get lower than expected on unit 2 biology by the way?
    Offline

    0
    ReputationRep:
    (Original post by Farhan96)
    I have the mark scheme if that helps...
    It would be very much appreciated if you could put it up for B3

    An interesting 6 marker for physics could be the method for finding the centre of mass for an irrigular flat shape such as a cardboarde cutout. It is listed on the specification so I'd reccomend knowing it by heart.
    Offline

    3
    ReputationRep:
    (Original post by sneakbo2)
    Fusarium is a fungus that produces mycoprotein as it is grown in a fermenter. It is supplied with glucose and mineral ions as well as oxygen as fuel for the Fusarium to respire aerobically. The glucose is formed by using enzymes to digest maize starch.

    Keeping bacteria away: Three things - Sterilise the fermenter with steam, Sterilise the glucose and mineral ions, filter the air supply.

    Temperature maintenence: Jacket of cold water outside of the fermenter, Air bubbles. This is needed because the Fungus releases energy in respiration which could cause enzymes in the fermenter to denature; as well as this the enzymes may not work well because they are not at their optimum temperature.

    That's it really
    Thank you so much!
    I need to get learning the bacteria and temperature regulation bits...


    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    Is it me or has B3.4(well the opening topics) been overly bulked up in the textbook with stuff that we all probably know from our previous units in Chem and Bio.
    Offline

    1
    ReputationRep:
    (Original post by Last Theorem)
    It would be very much appreciated if you could put it up for B3

    An interesting 6 marker for physics could be the method for finding the centre of mass for an irrigular flat shape such as a cardboarde cutout. It is listed on the specification so I'd reccomend knowing it by heart.
    ii Any sensible suggestion plus explanation e.g.:
    • increased oxygen → increased respiration rate
    (suggestion)
    • less substrate available for making enzyme/toxic product made
    (explanation)
    or
    • more respiration occurs which releases heat (2 marks)
    must mention heat or temperature
    Offline

    1
    ReputationRep:
    (Original post by CD223)
    Thank you so much!
    I need to get learning the bacteria and temperature regulation bits...


    Posted from TSR Mobile
    All of the temperature maintenence stuff i got from past papers, they always bring them up yet it's not in the textbook. That's why learning mark schemes from the past papers as well as the knowledge is what seperates that A* and an A.
    Offline

    3
    ReputationRep:
    Hello everyone, how is everyone feeling for the biology exam which is a week on tuesday? :/
    Offline

    2
    ReputationRep:
    Worried. You want to start the exams on a good note and not start worrying what if and why didn't I.....
    Offline

    3
    ReputationRep:
    (Original post by Captain Anonymous)
    Hello everyone, how is everyone feeling for the biology exam which is a week on tuesday? :/
    I would say that I know practically all the content for the exam, but I'm still not confident because the questions for biology always seem really awkward and weird. I need to do more past papers lol!
    Offline

    3
    ReputationRep:
    did you get the mygcsescience ones?
    Offline

    0
    ReputationRep:
    (Original post by Captain Anonymous)
    Hello everyone, how is everyone feeling for the biology exam which is a week on tuesday? :/
    I'm pumped!
 
 
 
Poll
Which Fantasy Franchise is the best?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.