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hissingnoise
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| Quote: | | . . . also a shed is not a real problem, being more than just new to chemistry and attempting to boil it down in a steel pot on a gas flame and
fogging up an 12 room big house. |
Jeeez! That sure stimulates my cough reflex ─ 'hope your soft furnishings remain unaffected . . .
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blogfast25
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I like this bit:
If you can't gas them with H2SO4 off gases, try ammonia!
Do you run a 'little chemical house of horrors', or something?
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blogfast25
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I've just checked my hot plate and it creeps slowly up to 300 C, hot enough for 95 % H2SO4 ('in theory'), so I'm actually going to boil down about 20
ml of 70w% H2SO4 to as far as I can bear it. And determine acid strength by titrometry. Need some decent weather though, right now it's threatening to
rain...
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aga
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What is this 'rain' that you speak of ?
Is it an element ?
Where can i buy some ?
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HgDinis25
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blogfast25, are you kidding me? Inventing new kinds of evidence?
Let me ask you, if you have two people, one is defending hypothesis A and the other is defending hypothesis B. You don't have a way to check it by
yourself. Then comes a very respeced person, specialized in the field, that says that hypothesis A is the correct one. It, however, only gives a
brief explanation. Are you saying that, in your mind, hypothesis A wouldn't get a few points of consideration, perhaps making you considering it as
true?
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blogfast25
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HgDinis25:
You're making several reasoning errors:
1) NR isn't 'specialised in the field'. He carried out the experiment but didn't provide evidence for the 95 + assertion.
2) Experts get things wrong too. There's a term for invoking experts: 'appeal to authority fallacy'.
3) That A would get a few points of consideration would only tell of my credulity, not that A is actually true. It's not about 'considering it as
true' but whether it IS true or NOT.
And what constitutes an 'expert': why is NR more of an expert (in your eyes) than SCWack?
aga:
I'll send you some but it'll cost you! And it might be a bit acidic too...
[Edited on 7-5-2014 by blogfast25]
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HgDinis25
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Quote: Originally posted by blogfast25  | HgDinis25:
You're making several reasoning errors:
1) NR isn't 'specialised in the field'. He carried out the experiment but didn't provide evidence for the 95 + assertion.
2) Experts get things wrong too. There's a term for invoking experts: 'appeal to authority fallacy'.
3) That A would get a few points of consideration would only tell of my credulity, not that A is actually true. It's not about 'considering it as
true' but whether it IS true or NOT.
aga:
I'll send you some but it'll cost you! And it might be a bit acidic too... |
Actually, there's this thing called the Authority Argument. It isn't always a fallacy. Since you brought it up, let me explain something to you.
In order to be valid, an Authority Argument must comply to the following requirements:
- The specialist must indeed be a specialist in the given field;
- There mustn't be controversy between specialists;
- The specialist mustn't have personal interestes;
- The argument mustn't be weaker than a refuting argument.
The video of nurdrage comply to the four requirements, in my personal view.
I do, however, agree that withou evidence, we can't really be that 100% sure, and that "experts" do get things wrong. However, it is still an
argument. And when two points are being discussed, it is of importance to use. I'm not saying that it has the same importance as an experimental proof
argument, I'm saying that it has some importance.
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aga
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| Quote: Originally posted by HgDinis25 | | Let me ask you, if you have two people, one is defending hypothesis A and the other is defending hypothesis B. You don't have a way to check it by
yourself. Then comes a very respeced person, specialized in the field, that says that hypothesis A is the correct one |
My response to that situation would be that I Don't Know.
If i had to Act with that information, i would set teams 1,2,3 down route A, and team 4 on route B.
Team 5 would be set to find out if there were another possibility, which did not rely on routes A or B.
'Follow the Leader' seems OK, but doesn't do Lemmings much good.
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HgDinis25
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haha I love your team routes example. I was thinking pretty much like that when I was writing the thing.
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blogfast25
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"[...] in my personal view."
Says it all: i.o.w. it's a belief system.
Testimony by people like NR is a form of evidence but it's rather weak because he provides no proof of his assertion.
[Edited on 8-5-2014 by blogfast25]
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blogfast25
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Here’s the first part of my experiment.
12 g of water and 28 g (15 ml) of conc. H2SO4 were loaded into wide necked 200 ml Erlenmeyer. This makes a concentration of about 70 w%. Both the
flask and its content were weighed to 0.1 g.
The flask was then heated on an electrical plate on maximum setting (about 300 C):
Boling started shortly after start of heating and was gentle and without fuming. Clearly steam was coming off.
5 minutes (measured) later boiling had ceased altogether and the first fumes started coming off, at first only lightly:
Fumes became thicker and thicker though. It’s clear that without fume hood this cannot be done safely inside: the furmes are very choking.
And then it started raining, at first almost nothing, so I got a large umbrella to protect the experiment and hoping to weather it but then a bit
more, and more, you get the picture. So for electrical reasons the run had to be stopped, about 25 minutes into it.
I allowed the flask to cool down to about 70 C, then weighed it: it had lost 14.6 g weight.
The flask has now been covered with quadruple cling film, ready for titration, hopefully tomorrow.
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CHRIS25
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(you've got weeds on your patio)
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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Zyklon-A
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Maybe, but 300°C isn't really enough if we want to see what the highest concentration possible is by boiling.
I guess I could give it a go. My hot plate get over 460°C in ~ 5 minutes.
I can almost melt aluminum on it, the highest it can get is about 620-640°C.
[Edited on 8-5-2014 by Zyklonb]
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blogfast25
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Zb:
From Wiki:
Boiling point: 337 °C (639 °F; 610 K) When sulfuric acid is above 300 °C (572 °F), it will decompose slowly
Although nearly 99% sulfuric acid can be made, the subsequent loss of SO3 at the boiling point brings the concentration to 98.3% acid. The 98% grade
is more stable in storage, and is the usual form of what is described as "concentrated sulfuric acid." Other concentrations are used for different
purposes.
Trust me, if you'd seen what I’ve seen (and smelled!) you really don’t want to go much above 300 C. Destroying part of the acid to get an extra 1
% is folly. These super high concentrations are achieved via Oleum I believe.
By all means have a shot. But only if you can measure final concentration… otherwise it will only contribute to the general confusion and
disagreement.
C25:
It's no laughing matter! Damn nuisance, weeds...
[Edited on 8-5-2014 by blogfast25]
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HgDinis25
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| Quote: Originally posted by blogfast25 |
"[...] in my personal view."
Says it all: i.o.w. it's a belief system.
Testimony by people like NR is a form of evidence but it's rather weak because he provides no proof of his assertion.
[Edited on 8-5-2014 by blogfast25] |
All knowledge is beliefe. In your last sentence you defendend my point.
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blogfast25
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But some beliefs are superior to others. Evidence based belief systems are better than faith based belief systems.
[Edited on 8-5-2014 by blogfast25]
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blogfast25
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The titration results are in.
About 1 g of the concentrated acid was weighed accurately and diluted to 250.0 ml in a volumetric flask.
Three 20.0 ml pipetted aliquots were titrated with 0.1 N NaOH of known titre, using phenolphtalein as indicator. Three identical titration volumes
were obtained and calculated to 97.4 w% H2SO4.
A simple density determination (using a 10.0 ml measuring cylinder and 0.01 g scales) gave a density value of 1.84, in accordance with the % value.
So it appears that concentrating dilute H2SO4 by open kettle boiling is possible to at least 95 – 97 w% (allowing for measuring error). I don't know
whether even higher values can be achieved.
I think in practical terms one can stop perhaps 15 – 30 minutes after fuming starts, to get that indicated range of w% H2SO4.
[Edited on 8-5-2014 by blogfast25]
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HgDinis25
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blogfast25, Of course, evidence based beliefes are what I believe we all follow here.
Nice report. Now we have the proof. But let me ask you the following, and please don't take this personally. I'm just stating an hypothesis, one I
believe almost false, so don't take this in the wrong way.
How does that post of yours serve as proof? We don't know if you're telling the truth or not. You don't state explanations you are merely discribing
facts. People can lie about facts. How is your post any different from Nurdrage's video? We believe in you because you are seen as an "expert" in the
fiel and as trustworthy. So, wouldn't your report be in the same level as Nurdrage's video?
Now leaving matters aside, I think it has been well established that concentrating Sulfuric Acid works by this method.
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blogfast25
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HgDinis25
Nice comments that go to the heart of what is evidence and what is proof.
The answer is simple. I provided an experimental set up that anyone can follow and replicate. I'm fully confident that any bona fide experimenter will
find as I found.
In short, you don't have to believe me but should perform your own experiment to prove me wrong, should you be that way inclined. That's how it works.
No offence taken. Skepticism is at the heart of the scientific method.
The experiment would gain much in value by others confirming its results, independently.
[Edited on 8-5-2014 by blogfast25]
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HgDinis25
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blogfast25, Indeed the main difference is that you give an experimental setup that can prove your hypothesis. We can only get "real" proof (and I say
"real" because defining what's real proof isn't as simple as it migh appear) when experimenting or seing an experiment and then theorize an
explanation (or the other way around). That's how Synthetic a Priori Judgment works, the basis of science.
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S.C. Wack
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How much of the missing 2.6 grams was sulfuric acid? Recall that what started all this before y'all turned it into something else is the fumes.
[Edited on 8-5-2014 by S.C. Wack]
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aga
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Goats.
What you really need for weeds is Goats.
I'll give this a try tomorrow with the lead sulphate + SiC contaminated acid i got.
Do you use an erlenmeyer rather than a straight beaker in order to try to 'keep' some SOx in the pot ?
I'll try it with a conical flask, a straight beaker and an open tapered pot (pyrex measuring jug) and see if it makes any difference.
Why can't some (if not all) of the SOx be directed back through the boiling liquid ?
Would that not raise the resulting conc. even if by just a little ?
[Edited on 8-5-2014 by aga]
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HgDinis25
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aga, problem is seperating the Sulfur Oxides from the water. Condensing is not an option because the gases would dissolve in the water condensing.
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aga
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You're right.
I've just been pondering on what SO2 and SO3 actually *do* in the water vapour.
First thought is fractionation, but still pondering.
I kinda agree with SC Wack's point that SOx is lost - seems wasteful and crude.
[Edited on 8-5-2014 by aga]
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blogfast25
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| Quote: Originally posted by S.C. Wack | How much of the missing 2.6 grams was sulfuric acid? Recall that what started all this before y'all turned it into something else is the fumes.
[Edited on 8-5-2014 by S.C. Wack] |
How am I supposed to know that? At a guess: 100 %.
WE have turned this into something else??? See, I kind of expected that response from you. Read the thread again and stop trying to back
pedal: you lost this argument, plain and simple. It was your (justified) scepticism among other things that made me run the experiment. It turns out
that concentrating dilute H2SO4 to 95 - 98 w% with open pot boiling is not problematic, as stated by plenty 'how to?' guides.
Aga: the Erlenmeyer shape somewhat prevents splattering droplets from the boil leaving the flask. That's why I chose it over a plain beaker. A beaker
covered with an hour glass or similar would have been better but a bit slower.
[Edited on 9-5-2014 by blogfast25]
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