All Questions

Filter by
Sorted by
Tagged with
1
vote
1answer
2k views

Corrosion of Aluminum by Baking soda

An aqueous solution of sodium hydrogen carbonate corrodes aluminum foil quite readily. How do you explain this?
4
votes
1answer
13k views

Making ice from carbonated water

Sorry if this is not the place for asking this question, but I'm going to do a real life project and don't know where else to ask. I'm going to prepare and sell snow cones next summer. For making ...
17
votes
4answers
33k views

Ozonolysis conditions for benzene

What are the precise conditions under which benzene undergoes ozonolysis? All anyone can tell me is that it undergoes ozonolysis under "vigorous" conditions. But, what vigorous conditions?
21
votes
2answers
5k views

What is the edge of a diamond like?

The chemical structure of a diamond is defined as an endless lattice in which each carbon atom is covalently bonded to four other carbon atoms situated at the four ends of a tetrahedron. But of ...
5
votes
1answer
6k views

Selectivity in aldol condensation between pivaldehyde and acetone

In a crossed aldol condensation (condensation between aldehyde and a ketone), the primary products are such, that the carbonyl group of the ketone remains intact, and the $\alpha$-hydrogen of ketone ...
2
votes
1answer
1k views

What is the reason behind the characteristic colours of elements?

I've been trying to find out about this for some time now and when I searched online, I couldn't get any proper reasons. My question is: What is the reason for the characteristic colours of elements? ...
9
votes
2answers
68k views

Isothermal vs. adiabatic compression of gas in terms of required energy

I am working on an instruction manual of sorts to be used with an introductory course in thermodynamics. As an example of problem solving, I attempt to answer the following question: If you have ...
1
vote
1answer
824 views

If I add some KOH, where will the reaction shifts?

I just got a final test and one of the question is: $\ce {Ni^2+}$ + 6$\ce{NH_3}$ $\ce {<=>}$ $\ce{[Ni(NH3)6]^2+}$ If we add some aqueous $\ce{KOH}$ after the reaction reach equilibrium, where ...
4
votes
1answer
2k views

Is there any substance that's a 0-0-0 on the NFPA diamond?

Is there any substance that's a 0-0-0 on the NFPA diamond? Basically a perfectly safe chemical.
2
votes
1answer
122 views

Red glow in the dark pigments

I want to do some spectrometry experiments with glow in the dark paints. The red paints I've read product details for all seem to require a uv light to charge. Are there any red glow in the dark ...
8
votes
2answers
49k views

Calculating charge on amino acid from pKa

I have been given $\mathrm pK_\mathrm a$ values of an amino group, a carboxyl group and a side chain of cysteine. How can I find the ionic charge on it at different $\mathrm{pH}$ values?
5
votes
1answer
719 views

What is the joke that is shown in this picture?

There is supposedly a joke shown in this picture relating to periodic trends. Does anyone know what it is? And could they also explain where the elements on the eye exam came from?
-2
votes
1answer
3k views

What pressure difference is needed across the length of a 15 cm vertical drinking straw in order to drink a liquid of density 1.0 g/cm³?

What pressure difference must be generated across the length of a $15\ \mathrm{cm}$ vertical drinking straw in order to drink a water-like liquid of density $1.0\ \mathrm{g\ cm^{−3}}$? I am really ...
4
votes
6answers
55k views

Why does electronegativity increase across a period?

What explains why electronegativity increases as you move across a period? Does it have something to do with the shielding effect of added electrons?
4
votes
1answer
5k views

What is the group number or name for elements between group 3 and 4 (F-block) on the periodic table?

What is the group number or name for elements between group 3 and 4 (F-block) on the periodic table? I noticed when I look at a periodic table of elements, the elements of the F-block between group 3 ...
2
votes
1answer
453 views

What prompts sodium to give up an electron?

What triggers sodium to convert from elemental Na to Na+? I know that it wants to have a full valence shell and all that, but how does it just eject the electron out?
0
votes
1answer
3k views

How to test oxalic acid in potatoes

How could you test that there's oxalic acid in potatoes.For example, what chemical reacts to oxalic acid and then what will happen if it reacts?
1
vote
0answers
84 views

Can anyone identify this uncaptioned diagram?

It's from the start of part 3 / chapter 19 in Lewin's Genes X (see this page in Google Books)... Looks a bit like a Ramachandran plot(?) but the axes only go to 100 / 70ish, but I don't even know ...
1
vote
0answers
6k views

Finding reaction rate from pressure change [closed]

I conducted a lab in which different concentrations of $\ce{HCl}$ were used and $\ce{Na2CO3}$ was added. The pressure change was measured for a reaction with the different concentrations. Now I am ...
3
votes
1answer
673 views

Phase diagram analysis

The figure is a portion of the titanium copper phase diagram for which only single-phase regions are labeled. Specify all temperature composition points at which eutectics, eutectoids, peritectics and ...
4
votes
1answer
430 views

Toilet spray effect

When we want the bad smell in toilet to go away we use a toilet spray to clean the air. But does it really cleans it, or just the elements in that spray have better effect on our smell sense. And we ...
1
vote
1answer
1k views

Silver electrorefining

Ok, so let's say I have raw silver which is polluted with a bit of gold, copper and lead. So through electrorefining I want to make pure silver out of it. Let's say I have it all in an acidic ...
3
votes
2answers
2k views

Strong acid equilibrium

So a teacher at school told me that strong acids do not create an equilibrium in general, while weak acids do (thats the difference, strong acids namely ionize completely). However, I lately stumbled ...
1
vote
1answer
181 views

How do I find the ratio of the reaction of the residue and HCl?

A mixture weighing $4.08\ \mathrm g$ of $\ce{BaO}$ ($M(\ce{Ba})$ = $138\ \mathrm{g\ mol^{-1}}$) and an unknown carbonate $\ce{XCO3}$ was heated strongly. The residue weighed $3.64\ \mathrm g$. This ...
0
votes
1answer
5k views

What does “Anal. Calcd.” stand for written out?

I'm wondering what the abbreviation "Anal. Calcd. stands for exactly. It is put in front of calculated (expected) values for elemental analyses. "Analytically calculated" makes no sense for me, but ...
1
vote
1answer
8k views

What is the actual reason for geometrical isomerism?

My teacher explained it as restricted rotation between the double bonds. But I think there is more to it. After all, why is it considered to be a type of isomerism itself? Whether an alkene is cis or ...
1
vote
1answer
101 views

New technology that has replaced the old radioisotope

What technology has the radioisotope Cobalt 60 replaced in medicine? E.g.,PET preferred over CT scans
1
vote
1answer
2k views

Why does this shortcut work for calculating pH (proof required)?

My teacher gave me a shortcut regarding calculation of resultant pH if the solutions are mixed and if the difference between the pH of individual solutions is 1. If there are two solutions, the pH is ...
1
vote
1answer
101 views

What are the properties of various solutions at pH <2 that may cause injuries?

For example, why do some solutions not cause any injuries at pH 2 while HCl does?
0
votes
1answer
162 views

Safety concerns for radical halogenations of methane in sunlight?

I wanted to know about the substitution reaction of alkanes particularly interested in the reaction of methane with fluorine and chlorine.
1
vote
2answers
179 views

How will these hydrogen atoms interact?

Assume that we have a space with just two $\ce{H}$ atoms and their distance to each other is $d$. Let's say they don't have initial velocity. What is the force with which they will act on each other? ...
3
votes
3answers
9k views

The entropy change during micellization

I was reviewing the thermodynamics of micelle formation from the Wikipedia page and this book. I understood most of the arguments but micellization is supposed to be an entropy driven process with a ...
15
votes
5answers
24k views

Why is Charcoal such an excellent adsorbent?

Charcoal (also activated charcoal) is known to adsorb a huge variety of substances including a variety of paints, dyes and many different kinds of ions. Moreover, the amount of adsorption at normal ...
10
votes
1answer
348 views

When and how in anaerobic digestion is water dissociated?

Anaerobic digestion and methanisation of organic feedstocks is a complex series of processes that result in biogas. One way to look at this is a very top-down, stochiometric approach as in the Buswell ...
3
votes
2answers
4k views

Why are wave functions orthogonal?

It seems that all wave functions studied in physical chemistry are orthogonal (e.g. particle in a box, hydrogen atomic orbitals). Does this come about because we purposefully make them orthogonal, or ...
1
vote
0answers
1k views

Perfluorobutanesulfonic acid (PFBS) Safety and Toxicity

I was wondering if anyone had any experience with PFBS or PFOS (perflurooctane sulfonic acid)? I am thinking about trying to purchase some of these fluorosurfactants in bulk in order to (hopefully) ...
5
votes
1answer
511 views

Electrolysis Lab

How do I keep hydrogen or oxygen in a test tube when pulling them out of water? I have a Styrofoam cup with two metal thumbtacks pushed though the bottom, and about 100 ml of distilled water mixed ...
0
votes
1answer
38 views

Where to find Atmospheric data for various cities [closed]

Hi im searching for atmospheric data on the following: Air quality, Dust Particle Concentration, Pollution, Average Temperature etc for various cities such as ...
1
vote
1answer
2k views

Pair of analogous periods on the periodic table

On the periodic table, period 2 and 3, 4 and 5, 6 and 7 and so on have similar blocks, identical length and groups. What are such pairs of analogous periods called?
0
votes
1answer
41 views

What conditions to use to crystallise Equine Myoglobin?

What are the crystallisation conditions for Equine Myoglobin? I've tried repeating some from the PDB but no success.
1
vote
2answers
1k views

Can these changes be reversed by changing temperature?

An egg turning hard when boiled. A spoon full of batter cooking on a hot griddle. I said that they both cannot be reversed, because I think if you throw both the egg and batter into the freezer, it ...
2
votes
0answers
702 views

Molding/shaping sodium polyacrylate?

I've been researching sodium polyacrylate, which normally comes as those "aqua gems" for plants, or fake snow. Specifically, I've been hoping to find information on molding, casting, or otherwise ...
4
votes
1answer
5k views

Stability of branched alkenes

I'm having difficulty understand the relative stabilities of the compounds 2,4-dimethyl-3-methylidenepentane < (3⁠Z)-2,5-dimethylhex-3-ene < (3⁠E)-2,5-dimethylhex-3-ene which, for simplicity’...
3
votes
1answer
889 views

How does molecular orbital overlap affect energy?

If there is more overlap of the same sign wave function, this apparently leads to lower energy. I don't understand why. My professor said that there would be fewer nodes, and fewer nodes means lower ...
4
votes
1answer
13k views

How to store chloroform?

I'm going to be aliquoting out ethanol-stabilized chloroform into smaller containers. It's presently in a large bottle sealed with a rubber(y) sheet so I can only draw it out with a needle. My ...
5
votes
3answers
42k views

pH range outside conventional 0-14 [duplicate]

Is a pH value outside 0 - 14 possible? I asked my teacher who said: yes, it is, but very difficult to achieve. Then on the internet, I found multiple answers, one saying it is but because of a fault ...
2
votes
1answer
256 views

electrolysis - selection of what is going to be on anode and cathode

I have a question about electrolysis. How do we know what will be on anode and cathode if we have for example NaCl diluted in water. How do we know if it's gonna be Na+ or H+??
3
votes
1answer
144 views

Isoelectric pH of colloids?

How did we derive the relation between the isoelectric pH and the dissociation constants for the amino and carboxyl groups on zwitterionic amino acids. $$pI=\frac {pK_{a1}+pK_{a2}}{2}$$ where $$\ce{...
3
votes
1answer
117 views

Are there any molecules with the same spectrum?

Are there any two distinct types of atom or molecule that have identical emission or absorption spectra?
1
vote
3answers
570 views

Unified theory of chemical bonds

My question is related to the edge between Subatomic Physics and Chemistry, but I decided that here is the best place to discuss it. As we all know, Theoretical Physics is a well developed field of ...

15 30 50 per page
1
702 703
704
705 706
740