All Questions
41,207
questions
0
votes
0
answers
4
views
Electrolysis with salt water on steel plates creates horrible black liquid [duplicate]
We are doing an electrolysis experiment using distilled water with sea salt on clean stainless steel plates. A horrible black gunk has formed in the water, very quickly. What is this?
I don't believe ...
- 101
-1
votes
0
answers
8
views
How do I determine if a nucleophile attacks the electrophilic atom directly or indirectly?
How do I determine if a nucleophile attacks the electrophilic atom directly or indirectly? For instance a nucleophile could attack the carbon in a molecule with a carbonyl directly, but in another ...
0
votes
0
answers
13
views
How did Dalton explain the law of multiple proportions?
The law of multiple proportion states the ratio of the masses of the elements in two compounds which the element forms with another element are simple whole numbers. How does Dalton's atomic theory ...
0
votes
0
answers
17
views
Peppermint oil and antiseptic mouthwash
Upon mixing peppermint oil and antiseptic mouthwash in a test tube I noticed immediately a white precipitate forms. I attempted to look up why this was except I couldn’t find any information anywhere ...
- 11
-2
votes
0
answers
20
views
Mechanism of reaction between P4(White phosphorous) and NaOH
P4(white phosphorous) + NaOH ---------> PH3(phosphine gas) + NaH2PO2
I came across this reaction in my chemistry course on Inorganic chemistry. My teacher wrote this reaction on board, I became ...
1
vote
2
answers
30
views
What is Dornic Acidity and how to measure it?
Context: I work with dairy product (cheese making) and in order to improve the quality of my process, I have documentation (in French) which refers to Dornic Acidity over time.
This graph represents ...
- 293
-2
votes
0
answers
13
views
Etching copper with Sodium persulfate
I would like to know what kind of UV resist ink I will need if I am using sodium per-sulfate as an etch-ant.
- 1
5
votes
1
answer
59
views
Stereochemistry of nitrosyl chloride addition to an alkene
My book states addition of $\ce{NOCl}$ to propylene results in 2‐chloro‐1‐nitrosopropane:
Would it follow syn or anti addition?
According to Mallya and Nagendrappa [1], the reaction would follow syn ...
- 53
-1
votes
0
answers
23
views
Do these nucleophiles favor SN1 or SN2 for a second degree carbon?
I would like to know whether the following species are strong or weak nucleophiles(with the solvent indicated):-
Cl- and Br- in polar protic and aprotic solvent
RSH/H2S in a polar aprotic solvent
...
- 25
-2
votes
0
answers
25
views
What model comes after the Molecular Orbital Theory? [closed]
I'm simply curious about it. Please explain briefly about the model, or give references to where I can read about them in an easy to understand language.
0
votes
0
answers
46
views
Would a 0.3 micron filter be effective in blocking formaldehyde fumes produced by curing cyanoacrylate?
I’m looking into purchasing a mask that blocks particles larger than or equal to 0.3 μm in size. I’m hoping it blocks the formaldehyde fumes produced by curing cyanoacrylate.
How effective such mask ...
-3
votes
0
answers
26
views
Explaining this data and trend? [closed]
This is a graph that's very similar to that of one experiment I'm doing. I was doing a reaction with Aluminum and Copper (II) Chloride, and I got an exponential graph and a logarithmic graph for two ...
- 1
-1
votes
0
answers
34
views
Can shop-bought caustic soda be used to measure titratable acidity of wines?
When making wines, it's occasionally necessary to measure the wine's 'titratable acidity' (TA). To do this, a 0.1N solution of NaOH is titrated with a wine sample. 0.1N NaOH solution can be purchased, ...
- 119
4
votes
0
answers
48
views
What is local and global aromaticity?
I was browsing through some research papers, I came across the terms locally and globally aromatic. What does it mean? I was thinking locally aromatic meant it was conjugated in a specific space not ...
-4
votes
0
answers
35
views
What is the name of this chemical C15H35COOC3H7? [closed]
My friend needs help with his homework and I don't know what is the name of this C15H35COOC3H7. Does it even exist?
- 1
-4
votes
0
answers
21
views
How to convert between mmol/L and mg/L? [duplicate]
(This is not a "homework" question, I am a post doctoral biologist trying to convert data from an old MS to a form that I can use)
What is the formula for converting mmol/L to mg/L?
- 85
0
votes
0
answers
33
views
Chemistry: The Central Science 14th edition, chapter 3, Design an experiment problem
I am new to chemistry as well as StackExchange network, so any advice is appreciated.
I tried to answer it myself, but I am sure it is not completely correct and there are certainly alternative ...
-4
votes
1
answer
51
views
Can I increase the melting point of paraffin wax over 100 degrees celsius [closed]
Can I increase the melting point of paraffin wax over 100 degrees celsius at room temperature and pressure.
- 101
1
vote
0
answers
25
views
Understanding Cahn-Hilliard Equation in terms of Units
The Cahn-Hilliard equation may be formulated as
$$
\frac{\partial c}{\partial t} = M \nabla^2 \left(\frac{\partial \hat f}{\partial c}\right),
$$
where $c : \Omega \to [0,1]$ describes the ...
- 43
-4
votes
0
answers
23
views
Gold or platinum— which one is more reactive? [closed]
Different sources present the reactivity series of metals differently. In some cases, I've seen that they placed gold before platinum. But in some other cases, platinum was placed before gold. So, ...
- 9
-4
votes
0
answers
24
views
Converting mmol/L to mg/L [closed]
Very simple question here, but I am a biologist trying to do some light chemistry... (This is not a "homework" question, I am a post doctoral biologist trying to convert data from an old MS ...
- 85
2
votes
0
answers
20
views
Gouy-Chapman model
Recently I have been investigating the problem of a neutral solutions (with equal number of anions and cations) interacting with an infinite surface $z=0$ with electrostatic potential $\phi(z=0)=\...
- 121
1
vote
0
answers
34
views
Monochlorination of (R)-2-chlorohexane: Number of possible chiral dichloro products
How many possible chiral dichloro products can be formed when (R)-2-chlorohexane reacted with one equivelent of $\ce{Cl2}$ in the presence of UV radiation (monochlorination only)?
$$\ce{C6H11Cl + Cl2 -...
user124377
-5
votes
0
answers
9
views
Why is the difference in electrons between the sub-shells 4. And the difference in orbitals between subshells 2 [closed]
I know the difference in electrons between the s-orbitals and the p-orbitals is 4. Since s=1-orbital=2e- and p=3-orbitals=6e-.
Difference is 4e-
P=3orbitals=6e and d=5orbitals=10e
And a difference of ...
-4
votes
0
answers
23
views
Conversion of Allene to alkyne [closed]
Is there a reaction that converts an Allene into its respective Alkyne ? If yes, then what are the reagents and necessary conditions ? How is the yield of the conversion and the rate ?
- 5
-4
votes
0
answers
27
views
What is the best book to get a grasp of the mathematical methods in p-chem? [closed]
I would love to know a list of books whose main aim is to illustrate the mathematical methods behind p-chem and theoretical chemistry.
I'm studying to be a modeller in biophysics/chemical physics so, ...
-1
votes
0
answers
40
views
is H2S a strong nucleophile?
The nucleophilic strength of:-
H2S>H2O in polar protic solvent
H2S<H2O in polar aprotic solvent
Now, H2O is widely considered to be a weak nucleophile. Based on some research, H2S is ...
- 25
-4
votes
0
answers
10
views
Reaction Yield Question for a quiz [closed]
a) What mass of pentene (C5H10) is required to completely react with 74.8 g of oxygen gas to form carbon dioxide and water?
b)If the percentage yield of the reaction is 75.0%, what mass of carbon ...
-4
votes
0
answers
12
views
Why is I- selectively discharged before Cl- [closed]
I- is more stable than Cl- as it has a lower charge density. This can also be seen in HI being a stronger acid than HCl as I- is more stable than Cl-. However I- is selectively discharged before Cl- ...
-4
votes
0
answers
14
views
What is the increase in intracellular concentration? [closed]
bearing in mind intracellular conc of Na⁺ is 15mM and extracellular is 140mM, I can’t seem to be able to work out the answer without finding out the volume (which we don’t have)
3
votes
0
answers
45
views
Can a spontaneous reaction have zero or negative activation energy?
Is it possible for a certain spontaneous reaction to have zero or negative activation energy?
My high school teacher explains that it shouldn't be possible since it breaks the Arrhenius equation, ...
- 49
1
vote
1
answer
34
views
Does sodium percarbonate break down into 'safe' compounds in water?
I'm writing this question as a wine brewer (not a chemist), so apologies if I use inaccurate terminology.
I'm interested in using sodium percarbonate as a cleaning/sanitising solution for brewing ...
- 119
2
votes
0
answers
27
views
Transforming hydroxyl group to carboxylic acid in an aqueous environment
I am looking for a way of converting a hydroxyl group into a carboxyl group in an aqueous environment for eventual coupling to an amine. There seem to be plenty of ways of achieving this in various ...
- 29
1
vote
2
answers
150
views
What is the number of acidic hydrogens and the n-factor of hypophosphorous acid?
My teacher said that the hydrogen which is directly linked with oxygen or more electronegative atom is an acidic hydrogen, and that the $n$-factor for an acid is the number of acidic hydrogens.
Then ...
2
votes
0
answers
33
views
How do other elements fit into a diamond's carbon lattice (e.g. nitrogen in yellow diamonds)
Traditional pure-carbon diamonds have a simple structure (tetrahedral, if I'm not mistaken). But common types of diamonds have other elements within them. For example, yellow diamond has nitrogen in ...
- 121
1
vote
0
answers
9
views
Charge Transfer and Multireference Methods
I have read in literature that systems that exhibit "high charge-transfer character" are best treated using multireference/multiconfigurational methods. Why is that? What makes such a system ...
- 19
0
votes
1
answer
35
views
Do azaindoles primarily exist in anionic form at physiological pH and act as bases?
I am reading an article where they describe azaindoles (bicyclic pyridine/pyrrole rings) as being basic with $\mathrm{p}K_\mathrm{a} \approx 4.6.$
I suppose at physiological $\mathrm{pH}$ and after ...
- 111
3
votes
1
answer
39
views
Amino Acid Derivative Naming Conventions
Is there a trivial name for compounds based on glutamic acid, or other amino acids, where it is not the α-amino acid group that is functionalised? (I.e. that shown on the right)
Glutamylsulfonic acid, ...
-1
votes
0
answers
27
views
Is there a reaction between elemental sulfur and acetic anhydride
If I mix acetic anhydride with elemental sulfur and reflux it will a chemical reaction occur?
- 7
-1
votes
0
answers
15
views
Stability of cyclopropyl methyl carbocation
I know CPM C+ is exceptionally stable but my teacher today told us that "tri benzylic" is also less stable than mono cyclopropyl methyl . Is this true?
0
votes
0
answers
33
views
Why is effervescence endothermic?
The reaction of sodium bicarbonate and sulfuric acid is quite endothermic... it seems.
Of course, the chemical change is actually exothermic, but from what I've read, the production of carbon dioxide ...
- 175
0
votes
0
answers
33
views
Why does ethylene glycol give a positive Fehling's test? [closed]
I am studying the Fehling's test and am curious why ethylene glycol does give a positive test result. I recreated the observations in my experiments and I have no clue whatsoever why an alcohol should ...
- 11
-1
votes
0
answers
37
views
Searching for rate constants for O2-*/OOH* reactions with organic and inorganic systems [closed]
I need to find some books/papers that collect experimentally measured rate constants of the reactions of inorganic cations, anions, as well as organic aromatic and conjugated bond systems with O2- and ...
- 99
0
votes
0
answers
16
views
Is there a need to change sign for enthalpy value for a reaction that appears in reverse when using Hess's law?
Problem
Given the enthalpies of the following reactions
\begin{align}
\ce{2H(g) &-> H2(g)} &\quad \Delta_\mathrm{r}H^\circ &= \pu{-437.6 kJ mol^-1} \tag{R1}\\
\ce{C(s) + 2 H2(g) &-&...
1
vote
2
answers
56
views
In qualitative analysis for basic radicals, why are group 2 cations not precipitated along with group 4?
To ensure that group 4 cations are not precipitated with group 2, we add dil. $\ce{HCl}$ to ensure only group 2 sulfides of lower $K_\mathrm{sp}$ are precipitated.
For group 4, we add $\ce{NH4OH}$ ...
- 19
1
vote
1
answer
61
views
Can we compare absorbance of two peptides when the read concentration from Qubit Protein Assay are different?
I have two peptide A and B. And I would like to know the solubility level of these peptide in certain solute. For that purpose I use Qubit Protein Assay.
The Qubit readout I get is this:
Note that ...
- 159
-1
votes
0
answers
23
views
Shape of Diphenyl Ether
The understanding I have of delocalisation in a molecule like phenol is that instead of the oxygen being sp3 hybridised, it becomes sp2 hybridised and the unhybridised d orbital becomes conjugated ...
- 1
0
votes
1
answer
52
views
How to compare bond angles of boron and phosphorus trifluorides? [closed]
My books and many websites claim the bond angle of $\ce{BF3}$ is greater than the bond angle of $\ce{PF3}$:
$$∠\ce{F-B-F}\quad >\quad ∠\ce{F-P-F}$$
When I tried to figure it out I came to the ...
- 17
1
vote
1
answer
38
views
Internal Electrophilic Aromatic Reaction in 3-chlorobutylbenzene
I recently came across the reaction scheme: Aluminum chloride to 3-chlorobutylbenzene.
In Jerry March, reaction scheme is provided for 4-chlorobutylbenzene with $\ce{AlCl3}$ where ring closure occurs ...
-3
votes
0
answers
23
views
Whether compound is optically active or optically inactive [duplicate]
Just wanted to ask whether a compound having chiral center but also symmetry(POS or AOS) is optically active or optically inactive. If there is no definite answer than what is most expected
