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

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

    Offline

    5
    ReputationRep:
    Hi guys, I'm trying to find information on the social and economical advantages and disadvantages of alcohols, carboxylic acids and esters. If anyone could help me on this I would very much appreciate it. Thanks in advance!
    Offline

    2
    ReputationRep:
    (Original post by a123a)
    Hi guys, I'm trying to find information on the social and economical advantages and disadvantages of alcohols, carboxylic acids and esters. If anyone could help me on this I would very much appreciate it. Thanks in advance!
    You don't need to know much about the economic and social advantages and disadvantages of alcohols, carboxylic acids and esters, and any question on this subject will likely provide you with some information to interpret. However, some important points to remember are:

    - Alcohols, carboxylic acids and esters can be used in many ways in foods, drinks and as fuels

    - Alcoholic drinks and solvents can be abused which can lead to health and social problems

    - Biofuels offer an alternative to fossil fuels and help with problems of diminishing resources and climate change

    - However, some of the crops used for the production of biofuels require the use of agricultural land which could be used to grow food
    Offline

    3
    ReputationRep:
    So what we know is that this exam is out of 60. But does anybody have a rough idea of what an A* will be ? Obviously I'm not expecting a definitive answer as nobody knows but is there a trend from maybe Unit 1 ?

    If somebody could estimate what 91 UMS, 95 UMS & 99 UMS you are a star !
    Offline

    3
    ReputationRep:
    91 about 46
    95 about 50
    99 about 54
    Offline

    3
    ReputationRep:
    please note that they are only guesses :P
    Offline

    1
    ReputationRep:
    revision game anyoneee?
    Offline

    0
    ReputationRep:
    (Original post by sneakbo2)
    revision game anyoneee?
    sure, you start
    Offline

    0
    ReputationRep:
    (Original post by Captain Anonymous)
    please note that they are only guesses :P
    Will we be doing the first sitting of these exams? If so, they may be lower :eek:
    Offline

    1
    ReputationRep:
    hmm okay

    B3 - 4 problems caused by Deforestation
    Offline

    0
    ReputationRep:
    (Original post by sneakbo2)
    hmm okay

    B3 - 4 problems caused by Deforestation
    1) Disruption of habitats, less biodiversity
    2) Increase of C02 levels in atmosphere
    3)Increasing levels of methane
    4) Less carbon dioxide taken in

    How does a hydraulics system work?
    Offline

    1
    ReputationRep:
    (Original post by lolface32)
    1) Disruption of habitats, less biodiversity
    2) Increase of C02 levels in atmosphere
    3)Increasing levels of methane
    4) Less carbon dioxide taken in

    How does a hydraulics system work?
    Ahh can't remember this. Pressure is transmitted equally in all parts of the liquid. In the case of pistons, one piston has a higher surface area than the other, although the pressure transmitted is the same in both pistons. Using the formula P=F/A we can see that pistons are useful as they are a efficient way of increasing force, because as the area increases, so does the force exerted. :confused:

    Give 3 problems associated with having an artificial heart.
    Offline

    0
    ReputationRep:
    (Original post by sneakbo2)
    Ahh can't remember this. Pressure is transmitted equally in all parts of the liquid. In the case of pistons, one piston has a higher surface area than the other, although the pressure transmitted is the same in both pistons. Using the formula P=F/A we can see that pistons are useful as they are a efficient way of increasing force, because as the area increases, so does the force exerted. :confused:

    Give 3 problems associated with having an artificial heart.
    Yep, that is perfect!

    Artificial hearts may have risk of infection during surgery
    Will need to be constantly supplied with battery power
    Valves in the artificial hearts can easily be worn (something like this)
    Offline

    0
    ReputationRep:
    (Original post by Captain Anonymous)
    91 about 46
    95 about 50
    99 about 54
    Too low compared to the boundaries we had
    Offline

    3
    ReputationRep:
    (Original post by NightStrider)
    Too low compared to the boundaries we had
    What would you say the boundaries be ? Again, this is purely guess work
    Offline

    1
    ReputationRep:
    (Original post by Midnight1811)
    What would you say the boundaries be ? Again, this is purely guess work

    I personally think the boundaries will be high. Everyone knows their stuff now, the retakes for module 1s were all low possibly because alot of d/c grade students who probably got a free retake from their school were retaking which pulled it down. The module 3s are also the easiest in my opinion and there isnt that much to learn, therefore lots of people are gonna be scoring very high. Just look at the C2 boundaries, it was the same thing there. Thats why instead of worrying about grade boundaries, get 60/60 raw marks.
    Offline

    0
    ReputationRep:
    (Original post by Midnight1811)
    What would you say the boundaries be ? Again, this is purely guess work
    50s across the board
    Offline

    3
    ReputationRep:
    50's across the board are ridiculous, I would say around mid-high 40's
    Offline

    3
    ReputationRep:
    Could somebody please explain to me all the details we need to know about switch mode transformers for P3? Its a small topic that we really rushed in class and its been bugging me ever since...


    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    (Original post by CD223)
    Could somebody please explain to me all the details we need to know about switch mode transformers for P3? Its a small topic that we really rushed in class and its been bugging me ever since...


    Posted from TSR Mobile
    Switch transformers work at a higher frequency (around 50kHz to around 200kHz) than normal transformers do, which means that they can be smaller and lighter (since the higher the frequency the more energy they carry). it also makes them useful for chargers and power supplies for laptops/computer.

    As well as this, switch transformers are also more efficient because when no load (like your phone, for example) is plugged in, then the switch transformer (in this case, your charger) uses little energy, so they save on energy costs.
    Offline

    3
    ReputationRep:
    (Original post by Graviton-Pulse)
    Switch transformers work at a higher frequency (around 50kHz to around 200kHz) than normal transformers do, which means that they can be smaller and lighter (since the higher the frequency the more energy they carry). it also makes them useful for chargers and power supplies for laptops/computer.

    As well as this, switch transformers are also more efficient because when no load (like your phone, for example) is plugged in, then the switch transformer (in this case, your charger) uses little energy, so they save on energy costs.
    Thank you so much! I swear I've learnt more from that overview than in lesson haha.


    Posted from TSR Mobile
 
 
 
Poll
Which pet 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.