# All Questions

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### Corrosion of Aluminum by Baking soda

An aqueous solution of sodium hydrogen carbonate corrodes aluminum foil quite readily. How do you explain this?
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 ...
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?
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 ...
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 ...
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? ...
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 ...
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 ...
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.
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 ...
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?
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?
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 ...
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?
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 ...
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?
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?
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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
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 ...
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?
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.
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? ...
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 ...
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 ...
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 ...
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 ...
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) ...
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 ...
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 ...
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?
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.
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 ...
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 ...
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’...
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 ...
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 ...
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 ...
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+??
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{...