IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: zbzbzb25 on May 20, 2009, 12:58:57 pm
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ASALAMOALAIKUM WARAHMATULLAHI WABARAKATUHU WAMAGHFIRATUHU
n hi!
which apparatus is most suitable for producing ethanol by fermentation?
A- a conical flask with cotton wool at its mouth containing sugar sol and yeast,not being heated
B-a conical flask with a bung containing sugar sol and yeast,being heated
C-a conical flask with sugar sol and yeast, being heated and no cotton wool or bung with steam escaping
D- a conical flask placed in a tray of ice,the conical flask contains sugar sol and yeast (no bung or cottonwool)
this is qn no. 40 from 0620 november 1999
mark scheme says (A)
but i thnk it shud be (B)
Thanks
JAZA KALLAH KHAIR
ALLAH HAFIZ
FIAMANALLAH
Take care
bye
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i agree with u, in the revision guide i use, the diagram shows a bung and an air lock
hope i helped :)
By the way loved the beginning and ending of ur post ;)
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i think it actuallly is A as if it is heated da yeast would be killed...and b4 da ethanol is made it would be of no use thn...hope this helps
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i agree with u, in the revision guide i use, the diagram shows a bung and an air lock
hope i helped :)
By the way loved the beginning and ending of ur post ;)
bung and an airlock IS needed but if da thing is heated the yeast would die...
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i agree with u, in the revision guide i use, the diagram shows a bung and an air lock
hope i helped :)
By the way loved the beginning and ending of ur post ;)
bung and an airlock IS needed but if da thing is heated the yeast would die...
ya, so its not A, cause A says that cotton wool is used :-\
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the co2 escapes...
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the co2 escapes...
isnt that why we have an airlock ?? for the CO2 to escape?
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the co2 escapes...
isnt that why we have an airlock ?? for the CO2 to escape?
air LOCK is dere so oxygen doesnt anter or else ethanol would oxidise....or we would get sumthing else [ethanoic acid i think]
but not ethanol
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the co2 escapes...
isnt that why we have an airlock ?? for the CO2 to escape?
air LOCK is dere so oxygen doesnt anter or else ethanol would oxidise....or we would get sumthing else [ethanoic acid i think]
but not ethanol
enter*
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the co2 escapes...
isnt that why we have an airlock ?? for the CO2 to escape?
air LOCK is dere so oxygen doesnt anter or else ethanol would oxidise....or we would get sumthing else [ethanoic acid i think]
but not ethanol
The airlock is used to allow CO2 out and prevent O2 and bacteria entering the fermentation jar, thus allowing anaerobic respiartion to occur.
why is the cotton needed? and where is it placed?
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the co2 escapes...
isnt that why we have an airlock ?? for the CO2 to escape?
air LOCK is dere so oxygen doesnt anter or else ethanol would oxidise....or we would get sumthing else [ethanoic acid i think]
but not ethanol
The airlock is used to allow CO2 out and prevent O2 and bacteria entering the fermentation jar, thus allowing anaerobic respiartion to occur.
why is the cotton needed? and where is it placed?
A- a conical flask with cotton wool at its mouth containing sugar sol and yeast,not being heated...it says at its mouth...and i think its used for letting co2 escape
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I guess its B bcuz uu doo need to heat the yeast till
30 degree celcius
bcuz below that its inactive n more then that its destroyed
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but temperature isnt specified
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the question says: which apparatus is most suitable for producing ethanol by fermentation?
my text book and notes say that CO2 escapes from the airlock, no cotton wool is mentioned
are u sure its cotton wool ?? :-\
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yea
which means its room temperature
w8 it should be 18-20 degree
so yea now it make sence why it is A
with heat
bcuz room temperature is 24 degree
n soo it fermentatrion will carry on
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my book says air lock allows the bubbles of co2 to escape BUT doesnt allow th air to get in
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my book says air lock allows the bubbles of co2 to escape BUT doesnt allow th air to get in
ya, same here !!
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yea
which means its room temperature
w8 it should be 18-20 degree
so yea now it make sence why it is A
with heat
bcuz room temperature is 24 degree
n soo it fermentatrion will carry on
so it is A...air lock is used soctht oxygen doesnt get in or we would not get ethanol
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and cotton is used to let the co2 escape
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yup it is A
bcuz heat is not required
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alrighty then,
too bad the person who asked the question isnt here,
Thanks for the help guys ;) +REP to both of u
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haha he will hopefully read thw whole thing n understand it
thanx for the +rep:D
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alrighty then,
too bad the person who asked the question isnt here,
Thanks for the help guys ;) +REP to both of u
Thanks!
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;D and i thought i waz bad in chemistry!!!!;D
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haha he will hopefully read thw whole thing n understand it
thanx for the +rep:D
no one +REP me :'(
lol, just joking :P
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haha he will hopefully read thw whole thing n understand it
thanx for the +rep:D
no one +REP me :'(
lol, just joking :P
u got da answer rong... ;D