1

Chemistry / Re: In this reaction How many electrons carbon anion has?

« on: Today at 16:53:53 »

H⁺ has no electrons (just one proton--this reaction is a "protonation")
There are a total of 10 electrons in CH₃^– (6 from the C atom, 1 for each of the 3 H atoms, and 1 extra electron for the negative charge.) Two of these electrons form the inner "core" of the carbon atom (a full 1s orbital), and the remaining 8 electrons are all in the "valence." We can think of there bing 2 electrons in each of the 3 C-H bonds, and another 2 electrons as a lone pair on C.

When the H⁺ comes close to the electrons in the lone pair, it will be attracted electrostatically, and will get closer and closer until it is trapped and "bonded." The product molecule, CH₄ is neutral and has 10 electrons (the proton didn't bring any electrons with it.) The mechanism can be represented by a single curved and double-headed arrow, pointing from the lone pair of the methyl anion (CH₃^– and going to the proton (H⁺).

2

Chemistry / Re: How many protons and electrons of C and Cl are in this compound?

« on: Today at 15:38:18 »

Every H atom has 1 proton and 1 electron
Every C atom has 6 protons and 6 electrons
Every Cl atom has 17 protons and 17 electrons

These are all conserved when the atoms come together to form (neutral) molecules.

3

Physics, Astronomy & Cosmology / Re: Can we switch an electrode on and off?

« on: 16/07/2019 21:46:50 »

It's not that it doesn't require energy. It just isn't really "wasting energy" if it's being used to do work...

4

General Science / Re: Which is the best Science gift to present someone?

« on: 16/07/2019 14:54:14 »

I would imagine the hive mind could help on this, but we will be more effective if you can first answer these questions:
What's your price range, how fast do you need it, and do you know what this relative likes more specifically than "science"?

5

Chemistry / Re: Will a solution of 60% Glycerine to 40% H2O Thicken over time?

« on: 16/07/2019 03:03:03 »

I suspect that in the case of a glycerol-water mixture, whatever hydrogen bonded structure is most stable will form very quickly (within a few seconds of thorough, turbulent mixing?)

No idea if this is accurate, but it looks reasonable, and may be of interest: http://www.met.reading.ac.uk/~sws04cdw/viscosity_calc.html

Glycerol will absorb water out of the air, and increase dramatically in volume, becoming less viscous as well (on a humid day, one must clean up small spills of glycerol immediately, or be confronted with an expanding puddle...)

What else was added? (It may actually be quite crucial to the thickening observed.) Small amounts of boric acid, sulfuric acid, or acrylate esters can cross-link glycerol, causing it to become more viscous.

6

Plant Sciences, Zoology & Evolution / Re: What is the chirality of the nautilus shell?

« on: 15/07/2019 14:33:30 »

What does "chiral" mean? Well, it's a term I first learned in O-chem used to describe shape, but it's not limited to chemistry.

Yes, chirality is usually encountered in the context of chemistry, but it is a generalized concept that applies to all shapes (in spaces of all dimensions, but then thee definitions need to be more specific).

For 3D shapes which can rotate freely in 3D space, any object that has an "improper rotation" symmetry is not chiral, and any object that lacks one is chiral. Improper rotation is the combination of a rotation of a fraction of a turn and a reflection through the plane which is perpendicular to the axis of rotation.

Ultimately what it means is: if two objects are mirror images of each other, then they are either identical to each other and achiral, or they are chiral.

7

Question of the Week / Re: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?

« on: 15/07/2019 14:22:30 »

Well... the easiest way is if there are obvious landmarks that allow one to recognize whether the sun is in the East or West.

I would also expect there to be subtle but detectable differences in the images, because sunrises and sunsets aren't exactly the same. When sunrises occur, it is much colder than when sunsets occur, so the corresponding differences in atmospheric properties might induce some very small changes in how the light disperses.

8

Plant Sciences, Zoology & Evolution / Re: What is the chirality of the nautilus shell?

« on: 11/07/2019 15:40:27 »

It appears to me that a whole nautilus shell has mirror plane symmetry, and is therefore achiral.

However, if one were to cut a nautilus shell perfectly in half along its mirror plane, then each of the halves would be unique and mirror images of each other, (chiral enantiomers).

Any slice or defect that would disrupt the mirror symmetry of the shell would result in chirality.


Note that snail shells lack this mirror plane, and are chiral: https://en.wikipedia.org/wiki/Gastropod_shell

9

Chemistry / Re: what is 'heavy water' - can you swim in it ?

« on: 01/07/2019 04:46:32 »

The differences between D₂O and H₂O are pretty subtle. The density of pure D₂O is about halfway between that of pure H₂O and that of the water in the Dead Sea. And, last I checked, boats work in the Dead Sea (https://igoogledisrael.com/saving-the-dead-sea/)

In addition to being slightly denser than normal water, heavy water has a higher melting point and higher boiling point, higher viscosity, lower surface tension, and higher heat of formation.
https://en.wikipedia.org/wiki/Heavy_water

As correctly pointed out by ylide (a long time ago), one of the primary differences is that chemical reactions in which the rate determining step involves the motion of H atoms or ions will be slower if instead is it D atoms or ions that must move. Also, the nuclear properties are quite different. H nuclei have a spin of 1/2, while D nuclei have a spin of 1 (influencing NMR or MRI signals). H atoms will readily capture neutrons, while D atoms are less likely to do so (which is why heavy water is used in nuclear reactors).

10

Geek Speak / Re: What is longest random computer password that can be resolved?

« on: 01/07/2019 01:38:17 »

What is longest random computer password that can be resolved?

0000000000000000000000000000000000000000000000000000000000000000000000000000000000000001

11

Chemistry / Re: Chemistry Images: a chemical's point of view...

« on: 27/06/2019 15:42:42 »

A bunch of Nickel (II) complexes coming together to say happy Pride Month!

IMG_9287.JPG (845.76 kB . 3308x1417 - viewed 327 times)

12

Chemistry / Re: Making aluminum powder using angle grinder and aluminum profiles from windows?

« on: 26/06/2019 19:50:18 »

indeed. Thanks Bored!

13

Chemistry / Re: Making aluminum powder using angle grinder and aluminum profiles from windows?

« on: 26/06/2019 19:35:40 »

I would recommend having a class D fire extinguisher on hand

I wouldn't.
It might lull you into a false sense of security.
You might, for example, think it will extinguish a thermite fire; (spoiler alert- it won't)

The appropriate fire control strategy for use of thermite is " do not allow anything combustible anywhere near a thermite reaction unless you are prepared to sacrifice it."
People, in this context, are combustible.

Fair enough. And yes, nothing can reliably extinguish thermite once started.

Essentially anything other than sand, glass, and concrete can be considered flammable under these situations. However, I would still recommend having the class D extinguisher on hand any time one is handling powdered aluminum.

14

Physics, Astronomy & Cosmology / MOVED: Do you think sports is sciencee?

« on: 26/06/2019 18:32:32 »

This thread can now be found in the "Just Chat" subforum: https://www.thenakedscientists.com/forum/index.php?topic=77243.0

15

Chemistry / Re: Making aluminum powder using angle grinder and aluminum profiles from windows?

« on: 26/06/2019 05:07:10 »

Aluminum powder is not particularly expensive, unless you want the really small particle sizes needed for making pyrotechnics or explosives. A quick web search shows I could get 250 grams for $15, plus shipping... I can't imagine it would be that different where you are.

250 grams is more than enough to get into trouble with. But be VERY careful, thermite is serious stuff!!! It gets so hot that it produces molten iron as it goes, and can inflict an incredible amount of damage to property and/or body in a very short amount of time. Improperly prepared thermite mixtures can also explode, showering molten and burning metal everywhere. I would recommend having a class D fire extinguisher on hand (and doing a lot more research) before playing with this stuff.

16

The Environment / Re: Why do we see beauty in nature?

« on: 23/06/2019 15:11:16 »

By default if anything attract human eyes it is considered as a beautiful thing. And by this way the sunrise, sunset, dark green forest, flowers, Animals and some other things definitely will attract humans and so it is very beautiful.

I don't know about that. There are several things that will attract the human gaze that are more considered horrifying than beautiful. As in, "I couldn't look away from the gruesome scene."

Also, it is often true that simple beauty is easily overlooked. Only when someone is in the right frame of mind, with their focus drawn the right away can the image/view be properly enjoyed.

17

Chemistry / Re: How can I precipitate silicon from an acidic solution at room temperature?

« on: 22/06/2019 23:09:49 »

8M NaOH solution

That makes much more sense!

Perhaps you would want to neutralize with a more concentrated acid (neutralizing 8 M NaOH with 2 M HCl, would also result in a roughly fivefold dilution). You could cool the alkaline Si-containing solution in an ice bath and add concentrated HCl (~12 M) or H₂SO₂ (~18 M, and diprotic) very slowly (with a buret or dropping funnel, you could set it up to go drop by drop).

18

Chemistry / Re: How can I precipitate silicon from an acidic solution at room temperature?

« on: 21/06/2019 17:43:26 »

It's hard to troubleshoot chemistry from afar, so please bear with me as I ask some questions:

How do you prepare the sodium metasilicate solution, and how do you know the concentration of Si in it? (did you make it yourself, or buy it, and then did you titrate it, or use spectroscopy etc.?)

For the dirt extract--do you have a way of confirming that the Si is extracted?

After acidification, is the pH stable, or does it change slowly (sometimes, especially when dealing with solids, endpoints can be very hard to reach--you add acid, and the pH falls quickly, then creeps back up...)?

Are you working from a previously published proceedure to do the extraction? I am somewhat surprised that a 0.2 M solution of NaOH would be sufficient to dissolve silica at a reasonable rate (even at 85°C)?

What temperature is the solution cooled to?

Do you have access to a laser pointer? (This can be used to determine whether a sample is a homogeneous solution or a colloidal suspension--no beam will be visible in the homogeneous solution, but you will be able to clearly see scattered light if there are suspended particles).

19

New Theories / Re: How will buckyballs fired at a double slit behave?

« on: 20/06/2019 14:58:43 »

..maybe "Dark Energy" is a better description than "Ghost"

Holy Sh!t, is that what QM waves are? Dark Energy?

A compelling argument as always.
Dark Energy = QM Energy Waves
Dark Matter = QM Matter Waves

I showed you why I came to this conclusion. You people are impossible.

"I don't understand X.
Scientists don't understand Y.
OMG X must be the same as Y!"

Not compelling in the least. Especially since scientists understand X, and can prove (in many different ways) that X and Y are not the same.

20

New Theories / Re: How will buckyballs fired at a double slit behave?

« on: 19/06/2019 16:47:16 »

If you admit to them not being physical, it opens up my bigger theory of spacetime being separate from QM.

But QM isn't entirely separate from spacetime, whether viewed as particles or waves. MOST of it is inextricably linked.
Hints:
wavelength
distance between slits
decay time
etc.

As I have said previously, there ARE some aspects of QM that are not tied to spacetime, like spin, which instead should be thought of in "spin space"
https://en.wikipedia.org/wiki/Spin_(physics)
http://farside.ph.utexas.edu/teaching/qmech/Quantum/node88.html

all variables you list can propagate within matter waves

Precisely! You claimed that spacetime somehow doesn't apply to matter waves. I pointed out that these waves have properties that are inextricably linked to both space and time. Therefore.... these waves must exist in spacetime!