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bfesser
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To be honest, the lectures are quite dull. I had a hard time sitting through all three consecutively, partly because I'm already familiar with the
material. I forced myself to watch them, because it's Linus Pauling, and he's like a deity in chemistry. There are plenty of exciting and
interesting chemistry videos on YouTube, though. We even have some resident 'YouTubers' on this board. The important thing is, even if you get
frustrated and confused, don't get discouraged. We're always here to help.
<a href="http://www.rigb.org/" target="_blank">The Royal Institution</a> <img src="../scipics/_ext.png" /> puts out some fantastic
videos:
<iframe sandbox width="560" height="315" src="//www.youtube.com/embed/ti_E2ZKZpC4" frameborder="0" allowfullscreen></iframe>
[Edited on 7/19/13 by bfesser]
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woelen
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A good way to kill insects without destroying external features of them is by immersing them in a mix of air and SO2. Chlorine is too aggressive and
bleaches colors and destroys delicate features (e.g. the very fine dust-like material on the wings of butterflies or the very delicate mesh of
dragonflies' wings).
I agree with endimion17 that there is nothing wrong with experimenting with insects. Even if you accidentally kill one instance of an endangered
species, then I do not believe that that will have much impact. Indeed, environmental changes, pollution, large scale introduction of new predators
(e.g. a foreign insect running loose in its new ecosystem), it is that kind of things which endanger species.
If people get aroused by maiming or killing animals, then they are sick and then of course it is bad, but such people need treatment anyway. I do not
have the impression that our OP is such a type of person.
At the moment I am experimenting with ants. I read that boric acid is toxic for insects, while only being marginally toxic for mammals and birds. I
have tissue paper balls in my garden at the moment, soaked with solutions of boric acid and a lot of sugar in water. These balls are very popular
among the ants in my garden  . Tens of ants are sitting on each ball, absorbing
the sweet fluid. The workers absorb the syrup and take the syrup to their queens and these queens are killed. It looks like all coordination is left
when the queen dies. All the ants just live for their own, they do not cooperate anymore. They spread out over the entire area, walking around
erratically. After a week or so, I hope the ants will be gone. This is just an experiment of mine, trying to avoid the use of nasty toxins, which must
be sprayed on the floor on the paths where the ants are walking. I do not really kill the individual ants, I destroy their 'society'.
Another interesting side observation: Boric acid dissolves in a strong solution of sugar very well, much better than in plain water.
[Edited on 19-7-13 by woelen]
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bbartlog
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Offtopic now of course, but Boeseken and Vermaas did a bunch of work with polyols (especially diols) and boric acid back in the 1930s. For example: http://onlinelibrary.wiley.com/doi/10.1002/recl.19320510106/...
So your observation on sugar and boric acid doesn't surprise me.
The less you bet, the more you lose when you win.
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bfesser
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Quote: Originally posted by woelen  | A good way to kill insects without destroying external features of them is by immersing them in a mix of air and SO2.
. . .
Even if you accidentally kill one instance of an endangered species, then I do not believe that that will have much impact. Indeed, environmental
changes, pollution, large scale introduction of new predators (e.g. a foreign insect running loose in its new ecosystem), it is that kind of things
which endanger species. |
Since everyone continues to drag this thread off topic, I'll throw in my 2¢
again. I don't mean to insult anyone, but it seems that a lot of this discussion has been mere speculation. <strong>woelen</strong>, I'm
only quoting you because it's the latest post and it's well written; take it as a compliment.
First, a killing jar is an acceptable way to kill insects for study and preservation, but lepidoptera are soft-bodied (lack exoskeletons common in
other insects) and can be killed simply by a quick <a href="http://butterflywebsite.com/articles/tamu/mountbutter.html"
target="_blank">pinch</a> <img src="../scipics/_ext.png" /> of the thorax. As I understand it, the pressure surge causes aneurysm in
the 'brain' and <a href="http://kids.britannica.com/comptons/art-53026/Although-the-types-of-moths-and-butterflies-are-numerous-and"
target="_blank">hearts</a> <img src="../scipics/_ext.png" />, resulting in instantaneous death. As far as I'm aware, this method is
preferred by professionals and collectors, as it's efficient and doesn't damage the wings. Granted, the technique is harder to learn than using a
killing jar.
Second, I strenuously disagree with the view that killing even a single instance of an endangered butterfly is no big deal. There are some butterfly
species which are currently stable, but whose habitats are limited to perhaps only a few square kilometers in alpine meadows. The numbers of
individuals of these species is obviously quite low, and killing even a single member can have a huge impact on the whole. If even a handful of
collectors were to collect just one specimen each, these species would go extinct. I'm not arguing that pollution, climate change, and invasive
species aren't factors, but they often don't compare to the threat posed by 'innocent' human curiosity.
Finally, there are certainly cases where climate change and pollution <em>are</em> the major factors contributing to a species being
endangered (e.g. <em><a href="http://en.wikipedia.org/wiki/Apollo_(butterfly)" target="_blank">Parnassius apollo</a></em>
<img src="../scipics/_wiki.png" /> & acid rain), but let's not downplay the detrimental effect that one careless individual can have.
[personal note]
I'm very passionate about this issue, because my parents instilled in me a great respect for nature, and lepidoptera in particular. My father has
collected butterflies since he was very young, and has taught me much on the subject. He has quite a collection by now, as you might imagine. Some
of the specimens are of species which are now considered endangered solely because of over-collection in earlier decades. He is very diligent in
never collecting or purchasing specimens of endangered species.
Once it's pinned behind glass, you can't put it back.
[Edited on 7/19/13 by bfesser]
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PickledPackratParalysis
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I'm pretty sure boric acid is in the product Terro that kills ants... wait... I looked it up and it was Borax. I don't know if there's a difference.
But yeah, it works.
Back to gasses... I had a 'friend', he was kind of a jerk but I overheard him saying something about mixing the toilet cleaner 'the Works' with
aluminum foil to make an explosion. Being naturally inquisitive, I tried it, but it didn't work. Maybe the Works contains sodium hydroxide which would
create hydrogen on contact with aluminum foil and that is what causes the explosion. I also tried making a rocket out of a water bottle full of pure
hydrogen from electrolysis. When I activated the 'launcher' (steel wire short circuited attached to long pieces of copper wire attached to race car RC
battery... which gets so hot the steel wire turns orange and melts), nothing happened other than the wire getting really bright and melting inside the
water bottle. I take it that pure hydrogen doesn't combust on its own, then? How would I know how much to mix it with air to make the rocket work? If
I tip the bottle, the H<sub>2</sub> would all float out the top, wouldn't it?
I since room-pressure hydrogen doesn't have very high density, I take it that it would not be 'too' dangerous if I DID get it to ignite, wouldn't it?
<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: merged
sequential posts; subscript]
[Edited on 2.8.13 by bfesser]
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Hexavalent
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Firstly, please don't double post.
| Quote: Originally posted by PickledPackratParalysis | | I'm pretty sure boric acid is in the product Terro that kills ants... wait... I looked it up and it was Borax. I don't know if there's a difference.
But yeah, it works. |
And yes, there is a difference. Boric acid is H3BO4, whereas borax is disodium tetraborate,
Na2B4O7.
Moreover, you can convert disodium tetraborate into boric acid by adding a strong acid to a hot solution of the former; the reaction proceeds because
the equilibrium shifts to the right due to the formation of a weaker acid.
[Edited on 19-7-2013 by Hexavalent]
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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chemcam
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Yes, they are related but there is a difference. Borax is Sodium Tetraborate, a sodium salt of Boric acid.
---
In regards to the second post,
You sound very k3wl, try to word your
posts a little better find out what specifically is in whatever product you mention. And by the way, they both make H2.
2 Al + 2 HCl → 2 AlCl + H2
2 Al + 2 NaOH + 6 H<sub>2</sub>O → 2 Na[Al(OH)<sub>4</sub>] + 3 H2
[Edited on 7-19-2013 by chemcam]
<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>:
subscript/superscript]
[Edited on 2.8.13 by bfesser]
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bbartlog
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H<sub>3</sub>BO<sub>3</sub>
The less you bet, the more you lose when you win.
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Hexavalent
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You're right, 'twas a typo.
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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Endimion17
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I love the Royal Institution videos. I remember spending one entire night just watching those lectures. 
| Quote: Originally posted by woelen | | A good way to kill insects without destroying external features of them is by immersing them in a mix of air and SO2. Chlorine is too aggressive and
bleaches colors and destroys delicate features (e.g. the very fine dust-like material on the wings of butterflies or the very delicate mesh of
dragonflies' wings). |
SO2 also bleaches some organic dyes, so I wouldn't rely on that.
The vastly superior compound for almost instant killing is hydrogen cyanide. The insects die very, very quickly, and they don't twitch. They stay in
their normal pose and there's no muscle tissue contraction and damage. But HCN is the last resort for an amateur. It's just too poisonous. It's made
in situ, by putting few drops of a strong, nonvolatile acid like sulphuric acid, on a crystal of alkali cyanide below the inert bed in the jar and
then it's covered. The gas concentration is not high, but sufficient to quickly turn off the "power button" on an insect, and it could kill a careless
person indoors.
The usual chemicals used instead of it are acetone, chloroform and ethyl acetate. Also ether, but its volatility and flammability makes it a
nonpopular choice. Dilluted chloroform vapours bathed in sunlight will yield phosgene, so that's also unpleasant.
Acetone makes them twitch, so it has limited usage.
Ethyl acetate is known to leave a soft tissue as it doesn't precipitate the proteins appreciably, but you have to keep them inside the jar until you
put them in a fixer if you want such effect. If you put them out, they become brittle.
Fixing is best with 70% ethanol if you need the sample for DNA analysis, or 4% formaldehyde if you just want to determine the species.
They also die more slowly inside ethyl acetate so, althought it's just the reflexes and other basic neuromuscular activity, it's kind of painful to
watch, especially to unexperienced people and children. The insects just flutter or trash around like crazy and sometimes get damaged.
| Quote: | | I do not really kill the individual ants, I destroy their 'society'. |
That's so delightfully evil on a grand scale.
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Acidum
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So, killing butterflies is wrong, and killing ants and even entire ant colonies is ok? Well, then I must be really weird dude... Thinking that
caterpillars are pest and ants are useful... Silly me...
Although I like the idea of controlled eradication of entire colony with such simple and ingenious approach (yes, psycho I am), I really think that
killing entire ant society is way non necessary and just plain wrong...
PS. Microscale gas chemistry is excellent web site!
...and then I disappeared in the mist...
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woelen
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After some refinements (see below) the sugar/boric acid method really works. The day before yesterday we had many ants in our garden, much more than
the usual amount, but they were moving in all directions and did not show their usual patterns (normally they move along certain tracks). Now, two
days later, we hardly have any ants in our garden anymore. No more sand is moved upwards from under the cobble stones. So, I think the coordination
indeed is lost totally and they simply walked away, spreading over the area around our garden.
I had to refine the method a little bit to have optimal effect. We have a competitor in our garden, which attracts many ants and hence makes them less
interested in my brew. The competitor is formed by a set of sunflowers in our garden and ants like to go up along the stem, all the way to the flowers
and absorb the sticky stuff in the heart of the flowers. What I did is take some tissue and wet this with the sugar/boric acid mix and loosely wrap
this around the stem of the plants which have the biggest flowers, appr. 10 cm above the soil just above the side-stems of leaves, such that the
tissue does not fall towards the ground. Ants moving upwards have to cross this sweet spot and indeed, many ants do not go up anymore and simply
remain at the tissue absorbing the sweet liquid and after some time go down again. I made things extra sweet by mixing in a little amount of fruit
syrup, such that the liquid not only has a sweet taste, but also has a sweet smell.
My first idea was to wet the flowers themselves a little with a solution of boric acid, but I decided not to do that, because besides the ants also
bees, bumblebees and hoverflies are visiting the flowers and I do not want to poison these. With the tissue wrapped around the stem 10 cm above the
soil, the only poisoned animals will be the ants.
You have to wet the tissue every day with some drops of water (just make them soft and sticky, not wet through). If they become totally dry, then ants
simply walk over and do not stop absorbing the sugar.
I like this method because it does not introduce any nasty stuff in the garden, it only affects ants and not other insects and it is non-toxic for
people, pets and birds.
[Edited on 21-7-13 by woelen]
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plante1999
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"it is non-toxic for people"
Tell that to the (female) pharmacist I bought boric acid from. I had a speech of like 15 minute about its "toxicity" and its "proper" use. Then I had
to signe something and she put a note in my medical folder ha ha.
I never asked for this.
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blogfast25
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| Quote: Originally posted by plante1999 | "it is non-toxic for people"
Tell that to the (female) pharmacist I bought boric acid from. I had a speech of like 15 minute about its "toxicity" and its "proper" use. Then I had
to signe something and she put a note in my medical folder ha ha. |
Funny thing is, most of these 'pharmacists' in the UK seem to be 15 year old girls in uniform and on a work experience! Working knowledge of
chemistry? Basically zero. The closest they've ever been to a qualified chemist is making instant coffee for the senior pharmacist in charge... 
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Tdep
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Thank god for that at points though, at least I can charm my way through teenage attendants when buying all the chemicals I can.
An experienced chemist would definitely sense i'm up to something other than the intended use of the products.
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bfesser
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Thread Split
23-7-2013 at 10:27 |
sargent1015
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Actually, it is more like B(OH)3. It is not an acid in the Arrhenius sense of the term.
B(OH)3 + H2O --> B(OH)4 + H+
It really is a clever reaction when you think about it like that. Formulas like these are... beautiful
[Edited on 2-8-2013 by sargent1015]
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