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Chemistry Questions (1 Viewer)

someth1ng

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Re: Does anyone have detailed notes on these two experiments.

Based on your method, your experiment was NOT reliable because you didn't state that it was repeated and you didn't mention consistency of results.

For accuracy, you might want to compare the masses originally to determine how much CO2 was lost.

"keeping constant temperature maximises the overall yield" is nit necessarily correct - only when at ~37C. This line implied that it was true at any temperature.

For the test of ethanol, I can never understand why you use drops of Br2 on C2H4 because it is a gas, not a liquid. I prefer something like the dehydration of ethanol produces a gas and if this gas is captured and bubbled through bromine water, the bromine water should decolourise.
 

study-freak

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Re: Does anyone have detailed notes on these two experiments.

Based on your method, your experiment was NOT reliable because you didn't state that it was repeated and you didn't mention consistency of results.

For accuracy, you might want to compare the masses originally to determine how much CO2 was lost.

"keeping constant temperature maximises the overall yield" is nit necessarily correct - only when at ~37C. This line implied that it was true at any temperature.

For the test of ethanol, I can never understand why you use drops of Br2 on C2H4 because it is a gas, not a liquid. I prefer something like the dehydration of ethanol produces a gas and if this gas is captured and bubbled through bromine water, the bromine water should decolourise.
Nah.
It's just that reliability can't be assessed - doesn't mean it wasn't.
 

someth1ng

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Re: Does anyone have detailed notes on these two experiments.

Nah.
It's just that reliability can't be assessed - doesn't mean it wasn't.
The dotpoint is "monitor mass changes" which CAN be assessed. Therefore, you need to repeat the experiment and look at the consistency of results (similar mass changes).

ie. Are the mass changes similar if you repeat the experiment (each test)?
 

someth1ng

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Re: Does anyone have detailed notes on these two experiments.

Nah.
It's just that reliability can't be assessed - doesn't mean it wasn't.
The dotpoint is "monitor mass changes" which CAN be assessed. Therefore, you need to repeat the experiment and look at the consistency of results (similar mass changes).

ie. Are the mass changes similar if you repeat the experiment (each test)?
 

study-freak

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Re: Does anyone have detailed notes on these two experiments.

Based on your method, your experiment was NOT reliable because you didn't state that it was repeated and you didn't mention consistency of results.

For accuracy, you might want to compare the masses originally to determine how much CO2 was lost.

"keeping constant temperature maximises the overall yield" is nit necessarily correct - only when at ~37C. This line implied that it was true at any temperature.

For the test of ethanol, I can never understand why you use drops of Br2 on C2H4 because it is a gas, not a liquid. I prefer something like the dehydration of ethanol produces a gas and if this gas is captured and bubbled through bromine water, the bromine water should decolourise.
The dotpoint is "monitor mass changes" which CAN be assessed. Therefore, you need to repeat the experiment and look at the consistency of results (similar mass changes).

ie. Are the mass changes similar if you repeat the experiment (each test)?
Of course you can assess reliability if you repeat the experiment, but his method does not specify this and on this basis, you claimed that his results are unreliable. I'm saying this is incorrect because it simply doesn't make sense to talk about (un)reliability of results without any repetition.

(N.B. I don't like saying 'unreliable experiment' as it's really the result(s) you are talking about)
 

someth1ng

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Re: Does anyone have detailed notes on these two experiments.

I see what you mean now but yeah, I guess you're right. I think it's best to say that the reliability is questionable or something like that.
 

golgo13

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Re: Does anyone have detailed notes on these two experiments.

I thought that reliability is the ability to follow the procedure word for word basically. Unless it's the reliability of the results for which it's arguable to say that it's questionable but to i guess improve on that is to measure it against widely accepted values?
 

nerdasdasd

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I thought that reliability is the ability to follow the procedure word for word basically. Unless it's the reliability of the results for which it's arguable to say that it's questionable but to i guess improve on that is to measure it against widely accepted values?
Reliability is how close all of of the results are . Validity is the ability to follow the procedure .
 
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what's the big deal of ethanol being renewable?



this is put quite bluntly, but it's my question.
 

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Re: ethanol as a reneweable resource?

It allows a renewable source of fuel for the future. At the moment (this day and age) the majority of hydrocarbons are producted from petroleum (i.e. non nenewable). By creating ethanol from renewable sources, such as bacteria or vegetation, it allows for the continued products to be made in the future (i.e. hydrocarbons= plastics)
 

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Re: ethanol as a reneweable resource?

ethanol can be derived from the process of fermentation of glucose ( a non-fossil fuel( petroleum) source), meaning that it is renewable and enviro-friendly.
It can also be derived from the decomposition of bacteria within cellulose or from starch. ( completely natural)

Ethanol is considered renewable as when it is combusted it results in Carbon dioxide and molecules of water which can be used to form glucose by the process of photosynthesis---> fermented by yeast--> ethanol

C2H50H+302-->2CO2+ 3H20

Please note that distillation occurs at the end of the process which requires great amounts of heat energy which come from sources of a non-renewable nature.
so we're using non-renewable sources to make renewable sources...
 
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Re: ethanol as a reneweable resource?

isn't the main point of it being renewable is that it is an infinite resource, what you said falls under the "greenhouse neutral argument"?
 

theind1996

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Re: ethanol as a reneweable resource?

Well ethanol can be produced from glucose which is derived from natural resources.

When plants take in sunlight, they undergo photosynthesis --> glucose is one of the products from photosynthesis --> used for the fermentation process which produces ethanol --> when ethanol combusts, CO2 and H2O are the products --> the CO2 is released into the atmosphere, but the greenhouse effect is negated by the fact that plants take in equal amounts of CO2 and H2O to undergo photosynthesis --> they produce glucose --> repeated cycle of ethanol production.

As a result of all this, ethanol is a renewable fuel as plants can be continuously grown to produce ethanol (since plants won't die out most of the time) and so ethanol can be continuously produced for the future --> hence it is known as a renewable resource.
 

theind1996

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Re: ethanol as a reneweable resource?

haven't heard of this tbh
When ethanol combusts, releases CO2 (which causes the greenhouse effect) --> but this same CO2 is taken in by plants for photosynthesis, so there's no CO2 actually lost to the atmosphere --> greenhouse NEUTRAL.
 

Siddy123

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Re: ethanol as a reneweable resource?

When ethanol combusts, releases CO2 (which causes the greenhouse effect) --> but this same CO2 is taken in by plants for photosynthesis, so there's no CO2 actually lost to the atmosphere --> greenhouse NEUTRAL.
oh right, knew the process just didnt know the terminology.
thanks bro.
 

Siddy123

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Re: ethanol as a reneweable resource?

isn't the main point of it being renewable is that it is an infinite resource, what you said falls under the "greenhouse neutral argument"?
now that i know what greenhouse neutral means...
how does the renewability of ethanol change or differ due to the "greenhouse neutral idea"???
they're unrelated?
 

theind1996

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Re: ethanol as a reneweable resource?

now that i know what greenhouse neutral means...
how does the renewability of ethanol change or differ due to the "greenhouse neutral idea"???
they're unrelated?
You can chuck it in as an extra point regarding its environmental friendliness.
 

Siddy123

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Re: ethanol as a reneweable resource?

You can chuck it in as an extra point regarding its environmental friendliness.
yeah i see that
but girlworldclub addressed the infinite source of renewable ethanol etc... then mentioned greenhouse neutral.
i dont think they relate
 

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