# All Questions

6 views

What are some white compounds that look like powder (like flour) and immediately black after being heated? It turns immediately black and creates a odorous gas. Thanks!
6 views

### Does dehydration synthesis break peptide bonds

What exactly does dehydration synthesis do. I know it forms water but how. Does it have to break up polysaccharides to do this?
6 views

### Dyes that can stain oil and water

Is there such a thing as a dye that can stain both oil and water? In other words, does anyone know of an amphiphilic dye? Maybe a surfactant that is also a pretty shade of blue? Or maybe turn one ...
13 views

### Is there any reason why halogenation of substituted alkanes doesn't occur through free radical substitution?

Say for example, you have isopropyl alcohol. Is there any reason why if you react it with bromine that it won't form a radical, as one of the bromines removes one of the protons adjacent to the ...
16 views

### Bond enthalpy vs. enthalpy of atomization confusion

H-H bond enthalpy is 436 kJ/mol. To break apart a mole of H2 into H atoms, I apparently need to heat it by 436 kJ. Does this only apply at the standard temperature of 298 kelvin? What about H2 gas ...
14 views

### How does phenol react with monoiodomethane in presence of dilute alkali?

What are the products formed when phenol reacts with monoiodomethane in presence of dilute alkali? Also, a reaction with a mechanism would be helpful. Thanks for any help.
8 views

### Why is current non-zero when applied potential is still below E$^0$ in cyclic voltammetry?

In this diagram (Evans et al., J. Chem. Edu.) the current is non-zero, but the potential is still below the normal potential. How can the compound become oxidized at the working electrode, when the ...
32 views

### Chemistry behind Gale's Coffee Maker in Breaking Bad

Is there a scientific basis for the coffee making equipment which Gale describes in Breaking Bad? He talks about maintaining the right conditions for bringing out the coffee flavor without degrading ...
9 views

### What chemical properties make some grassses usable for producing textile fabrics?

Textile Fabrics are made out of cellulose fibres that can be derived from cotton or bamboo. As far as I know all grasses contain cellulose, so why are only a few grasses used? What makes them so ...
13 views

### What is the approximate lifetime of an $S_N2$ transition state complex?

Imagine some $S_N2$ reaction involving an aliphatic $sp^3$ carbon with a halide leaving group (e.g. Iodide or Bromide). Given the rise of femtosecond (e.g. using a mode-locked Ti:sapphire laser) and ...
14 views

### Chromium from electrode not oxidizing in electrolysis

I performed an electrolysis of an aqueous sodium carbonate solution with a platinum electrode and a chromium-vanadium-steel-alloy electrode. The solution turned yellow at the chromium-vanadium-alloy ...
49 views

### Why is cyclopentyne unstable?

Why has no one ever been able to synthesise cyclopentyne as a stable molecule? I've been thinking about this for quite some time and I can't seem to figure it out. Something to do with angular strain ...
38 views

81 views

### Does a grain of salt have exactly equal amount of sodium and chlorine?

Does a grain of salt have exactly equal amount of sodium and chlorine? I know that the formula unit of salt is 1:1, but for example if there is 10000000 atoms of sodium is it possible that that there ...
17 views

### Caffeine boiling and melting points

According to both caffeine's pubchem page and chemspider page its boiling point lies at 173°C and its melting point at ~235°C. How can it melt at that temperature if it already sublimated at 173°C? Or ...
35 views

### Pointless comparison in Clayden et al., Organic Chemistry

In Clayden et al., Organic Chemistry, p. 332, the authors compare the reaction energy profile for ester formation from a) acyl chloride and b) anhydride: They then write The energy levels of ...
29 views

### Need Help Calculating Standard Gibbs Energy of Dissolution

I'm trying to understand how to solve this question for my physical chemistry class, but after many attempts, I am still not getting the same solution as the solution manual. If anyone can help me I'd ...
27 views

### why does Nitrogen fluctuates to much a lower degree with change in temperature

this is my first question in this site.I am referring to this question.The linked question what is the advantage of filling nitrogen in bike tubes over air and I got some answers as *The biggest ...
33 views

### How does one calculate the pH of an aqueous solution of a weak acid and a weak base?

In order to create a simple program which calculates titration curves (also to provide some closure in the comments here) I am trying to come up with all the equations so I can calculate the ...
34 views

### Order of reactivity of carbonyl compounds to Nucleophilic addition reaction

One of the questions in my textbook was to arrange the following in order of their reactivity for nucleophilic addition reaction. $\ce{(p-NO2Ph)_2CO}$ $\ce{(CH3)_2CO}$ $\ce{(p-NO2Ph)COH}$ ...
26 views

### Crossed Cannizzaro products

I have understood the basic mechanism of cannizzaro reaction. But I am unable to understand the products formed in case of a crossed Cannizzaro reaction. Suppose Benzaldehyde and Formaldehyde are ...
26 views

### Doubt in Thomson's atomic model

Why did Thomson assume that electrons are embedded in a positively charged sphere? Why did he not assume that they are positively charged particles embedded in a negatively charged sphere?
23 views

### Why not protons and electrons neutralize in discharge tube experiment?

Here is a question in my science book, I am very curious. Cathode and Anode rays are negatively and positevely charged particles respectively. They travel in a direction opposite to each other. ...
16 views

### Probability of Finding an atom in x axis after a long time [on hold]

An atom diffuses in one dimension on x-axis. At t=0, its position is x = x0. After a sufficiently long time, the probability of finding the atom is maximum at: a) x = plus infinity or minus infinity ...
21 views

### Why is lanthanum a lanthanide and actinium a actinide?

I do know that the lanthanides start with the element lanthanum, but why? Lanthanum doesn't even have an f orbital, so why isn't it considered a transition metal? It's the same way with actinium, ...
14 views

### Coupled and Coupling Reactions

Is Coupling Reactions, Heck Reaction for example, different from Coupled Reactions like the production of Glucose 6-phosphate in living organism?
15 views

### Do superhydrophobic/hydrophobic materials generally have a lot of friction or only a little friction

Also, are there any exceptions that you know of?
46 views

### How to identify ionic compounds

I have a Chemistry lab in which I must design and carry out an experiment to determine the compound in each of eight numbered vials. Each vial contains one of these ionic compounds: BaCl2 CaCO3 ...
28 views

### What is 'coprecipitated (Ni,Fe)S'?

I am writing an essay on the origin of life and I was reading an article on hydrothermal vents. (Peptides by Activation of Amino Acids with CO on (Ni,Fe)S Surfaces: Implications for the Origin of ...
26 views

### rate law for a reaction [on hold]

The rate law for a hypothetical reaction is rate = k [A][B]. If the concentrations of A and B are both 0.020 moles per liter and k = 1.3 × 10È¹ MÈ¹sÈ¹, what is the reaction rate?
14 views

### How to calculate the amount of corrosion? [on hold]

How can I calculate how much of an 50 gram aluminium plate turns into Al2Cl3 in an HCl solution, at a given temperature and pressure after let's say, 3 hours? How to calculate the amount of corrosion? ...
39 views

### What are the known atomic oxygen species?

I'm interested in chemical reaction mechanism with more exotic particles. The Wikipedia page seems to imply that the normal atomic oxygen is $O(^3P)$, is that right? I also came across ...
29 views

### Why do ionic compounds dissociate whereas coordinate complex's won't?

An ionic bond is the bonding between a non-metal and a metal, that occurs when charged atoms (ions) attract after one loses one or more of its electrons,and gives it to the other molecule, for ...
42 views

### How to convert glucose to fructose

How to convert glucose to fructose? Moreover, can there be direct conversion(not necessarily in a single step), or we have to use indirect means, such as from sucrose, or other higher carbohydrates, ...
28 views

### how is the relation between Gibbs free energy and cell potential?

First of all what is exactly Gibbs free energy in regards to an electrochemical process? How can we visualise it? How does Gibbs free energy change in an electrochemical reaction? How is it related to ...
45 views

### Increasing which of the following will decrease the buffer capacity of a buffer made using acetic acid and sodium acetate?

Increasing which of the following will decrease the buffer capacity of a buffer made using acetic acid and sodium acetate? a. the amount of water present c. the [HC2H3O2] b. the [C2H3O2–] ...
24 views

### Styrofoam cup calorimeter? [on hold]

50.14 g of HCl react with 0.50 g of MgO. The formula of the reaction is: 2HCl + MgO -> MgCl2 + H2O Ti of HCl = 20.6 degrees C. It's in a styrofoam cup. Then MgO is added. Tf = 27.3 (after the ...
46 views

### why does znso4 aqueous solution when boiled with solid zinc and solid copper cause zinc metal to be deposited on copper?

I did an experiment where I dissolved 30 grams of zinc sulfate in water and boiled it with strips of solid zinc metal and strips of copper metal and a layer of zinc was deposited on the copper. I ...
16 views

### How does the ambient temperature affect the rate of redox reactions in a salt lake?

Many years ago, I used to work as a gold exploration geologist. One of the main locations was a salt lake in Western Australia detailed in the document WMC Resources Exploration Successes inN Lake ...
16 views

### Bond Lengths in FCC, BCC and HCP Structures

I was wondering what the crystal structures of FCC, BCC and HCP actually look like, and where atoms are placed in their configuration? Specifically I'm looking at elemental nickel, iron and cobalt ...
30 views

### Acid base titration curve

Why we don't get sharp point at equivalence points in case of acid base titration other than the case of strong acid and strong base titration?
17 views

### Do eta-4 benzene ligands participate in Diels Alder or other cycloadditions?

While refreshing myself on denticity to answer another question, I started to read about hapticity, which is the coordination of a ligand through multiple continuous atoms. A famous case is ferrocene ...
47 views

### Why Cl- can't act as bidentate ligand?

Cl- is a monodentate ligand. It has four lone pairs then why it can't donate two lone pairs to central atom and act as a bidentate ligand?
21 views

### Nomenclature of Dihydroxyacetone Phosphate

Why the dihydroxyacetone phosphate is called that way when it has only one OH ?
16 views

### Calculating photolysis time of AgF

How can I theoretically predict the time needed to photolyze n moles of AgF? (with UV) (this is not a homework question) The photolysis of AgF requires UV light - but I don't know which wavelength ...
55 views

### Order of positive mesomeric effect

I learned that the order of +M effect (mesomeric effect) for halogens is as follow : F > Cl > Br > I I wonder why it is so?
22 views

### Reducing temperature on dissolved Pb(NO3)2

I have pretty much zero experience in chemistry whatsoever but I wonder about how much crystal will I get from fully dissolved element when I reduce water temperature. Variables at 40°C 171g of ...
43 views

### What is the correct form for the acid-base equilibrium constant potential: pK_a or pK_A?

In science, the acid-base equilibrium constant potential is denoted or depending of the source (lowercase or uppercase A). Since it is the potential of the acide-base equilibrium constant defined as ...