All Questions

7
votes
3answers
8k views

Why does the solubility of some salts decrease with temperature?

It is well known to us that the Solubility of solute in a solution increases with the increase in the temperature because, when the temperature increases the molecules of the solvent gain more kinetic ...
-1
votes
1answer
15 views

Determining the equilibrium constant

this is freely translated, I hope it's not too bad. The reaction to dehydrate Methylcyclohexane to Toluene in the gaseous phase: Formulate the reaction equilibriums constant. Now, that's not a ...
-1
votes
0answers
4 views

The factor by which the percent hydrolysis of CH3COO Is greater in CH3COONH4 than in CH3COONa is

Both Conc. Being 1 M ,The factor by which the percent hydrolysis of CH3COO Is greater in CH3COONH4 than in CH3COONa is
38
votes
5answers
36k views

Why does bond angle decrease in the order H2O, H2S, H2Se?

I know that bond angle decreases in the order $\ce{H2O}$, $\ce{H2S}$ and $\ce{H2Se}$. I wish to know the reason for this. I think this is because of the lone pair repulsion but how?
0
votes
0answers
5 views

Conformer generation for radicals

Is there an automatic way to generate conformers for radical like systems (spin multiplicity is doublet)? My system for the study is a substituted fullerene with a missing H atom from the functional ...
0
votes
0answers
10 views

What fluorescent materials absorb visible light and emit UVC light?

What fluorescent materials, if any, exhibit anti-stokes shift such that they absorb visible light and emit ultraviolet light in the range of 250-285 nm? I'm interested in particular in materials that ...
0
votes
0answers
16 views

Calculating the amount of a product at the reaction equilibrium

$\ce{Cr2O3}$ can be reduced to the elements chromium with high temperature and carbon by this two reactions: $$ \begin{align} \ce{Cr2O3(s) + 3C(s) &-> 2Cr(s) + 3 CO(g)} \label{rxn:1}\tag{1}\\ \...
-2
votes
0answers
14 views

How is the Iron electron configuration 1s2 2s2 2p6 3s2 3p6 3d6 4s2? [duplicate]

How come the electron configuration of iron is 1s2 2s2 2p6 3s2 3p6 3d6 4s2 not, 1s2 2s2 2p6 3s2 3p6 4s2 3d6 ?
-1
votes
1answer
22 views

Does diluting the titration flask change the molarity

I was solving the following problem on a test and I thought the answer was A, but the answer is actually D. Below is the problem and my reasoning: Answer choice B is clearly incorrect because the ...
0
votes
1answer
10 views

Determining the concentration after half-life period

I was given the reaction In diluted solution and with neutral pH, the reaction reacts according to a reaction velocity law of pseudo-1. order: $$-\frac{dc_{DNPA}}{dt}=k_{obs},\quad k_{obs}=k\cdot c_{...
-1
votes
1answer
14 views

Can I have a homogeneous 2 molal solution of copper(II) sulfate at 20 °C?

I'm doing a high school chem project where I am making a calibration curve of copper(II) sulfate for spectrophotometry in which I make solutions with five different concentrations. The most ...
-1
votes
0answers
12 views

Bonding Scheme for Structure and Bonding Lab

I want to know how I would do bonding scheme for NH3, H2O and C6H12.This is my first time being introduced to this concept. I know how to identify the electron geometry and hybridization.
13
votes
2answers
545 views

Negative oxidation states of Si

According to List of oxidation states of the elements, silicon has a possible oxidation state of $-4$. Now, I've been looking everywhere for a compound that contains Si(-IV), but I cannot find any ...
0
votes
2answers
2k views

How to rotate a chiral carbon

I know that to correctly assign R,S priorities I have to rotate the above figure until the H is projecting into the page (away from me). However, I don't know how to rotate the H and the rest of the ...
10
votes
1answer
135 views

Possibility of π–π stacking in non-aromatic systems

Is it possible to have π–π stacking for non-conjugated double bond systems? For example, can the carbonyl groups of two urea molecules participate in π–π stacking? Although urea prefers to stay in ...
-1
votes
2answers
23 views

Solubility and pH

I was reading about antacids. It stated that in earlier times $\ce{NaHCO3}$ and a mixture of aluminium and magnesium hydroxide were used as antacids. In excess $\ce{NaHCO3}$ can make the medium ...
-1
votes
0answers
22 views

Cr to Cr2o3 (not in powder form)

how do you obtain Cr2O3 from Cr (large pieces)? Is there any acids who could be used? I only know of heated (NH4)2Cr2O7 to get Cr2O3 but this result in powder. I'll appreciate any suggestions! ...
2
votes
2answers
468 views

If polar non-polar intermolecular forces are stronger, why do polar compounds elute first in GC?

I remembering reading that the interaction between a polar molecule and non-polar molecule is stronger than the interaction between two non-polar molecules. However, in analytical chemistry classes, ...
2
votes
1answer
31 views

Model of an ideal liquid in chemistry

In chemistry there are ideal models/concepts of ideal crystal, ideal gas and even ideal solution, but there is no model/concept of ideal liquid. In physics (fluid dynamics, to be precise) there is a ...
2
votes
1answer
34 views

will the autoionization of water reduce due to common ion effect?

When a weak acid is added to water , will the dissociation of water reduce due to common ion effect caused by increased H+ concentration due to acid , my text book said common ion effect is caused by ...
-1
votes
0answers
12 views
-1
votes
0answers
31 views

Copper sulfate and Postassium iodide Reaction [on hold]

I conducted an experiment with these two aqueous solutions. I understand that the following is not true: CuSO4(aq) + KI(aq) → CuI2 + K2SO4 This means that since CuI2 doesn't exist, so the ...
-1
votes
0answers
8 views
5
votes
0answers
39 views

How to Calculate Lennard-Jones Parameters from TDDFT?

I am trying to develop parameters for AMBER force fields and to calculate Lennard-Jones parameters for the $\ce{Fe^3+}$ ion. I did a deep search and found that the best way to do this with a high ...
2
votes
2answers
63 views

Density of d-block elements

Something that confuses me slightly is the trends in density when comparing periods 4, 5, and 6 in the d-block. Looking at periods 5 and 6, the density peaks at group 8, with ruthenium and osmium, ...
1
vote
2answers
53 views

Which Oxygen atom in HCOOH (formic/methanoic acid) does Carbon donate its electrons to, to obtain a partial positive charge?

I was wondering if the Carbon atom in HCOOH (methanoic/formic acid) forms a positive partial charge by donating its electrons to both the Oxygen atoms, since they both possess a higher ...
6
votes
2answers
1k views

Would sodium explode in salt water?

I’ve seen the video etc of sodium being put into freshwater and the reaction of flames/small explosion but I wonder if the same reaction would occur if conducted in salt water such as the ocean.
3
votes
1answer
1k views

Decomposition of iron(III) acetate?

I recently asked about the synthesis of iron (III) acetate. I want a rather concentrated solution to use as a calligraphy ink (which will be dissolved in alcohol/water). Will it be okay to heat the ...
7
votes
1answer
5k views

Does iron(III) sulfate react with copper?

As my understanding, there should be an oxidation-reduction reaction: $$ \ce{2 Fe^3+ + Cu → 2Fe^2+ + Cu^2+} $$ However, I always see the process using $\ce{FeCl3}$ to etch copper, but I never ...
-1
votes
0answers
16 views

Equations for Iron (III) Nitrate reacting with Sodium Carbonate? [on hold]

I know that Iron (III) Nitrate reacts with Sodium Carbonate to form a precipitate. But I'm not sure how to write these equations. I have to also indicate oxidation states (charges on each ion) & ...
0
votes
0answers
33 views

Probability of the single molecule reaction to happen

I am trying to simulate the single particle second order reactions with known rate constants $k_1$ and $k_{-1}$ in Python. The point of this simulation is to fit the real experimental data to the ...
0
votes
1answer
20 views

Is there any difference between thermal energy at room temperature in fluids(water) vs air?

Context of the question: I was reading on hydrogen bonds, specifically how close they are to the thermal energy of the fluids. So I googled the value of thermal energy at room temperature, which was $\...
1
vote
2answers
37 views

Waste water treatment [on hold]

This is a very simple question: Why are oxidized compounds generally thought to be less toxic/polluting than reduced species? This is used in waste water treatment where oxidizing agents (such as ...
2
votes
1answer
31 views

Is Beer-Lambert law also valid for fluorescence and luminescence?

When I measure optical density in a microplate reader the absorbance is proportional to the concentration and the height of the liquid. Is Beer-Lambert law also valid for fluorescence and luminescence?...
1
vote
0answers
9 views

Natural orbital population analysis in Gaussian

Within (restricted) density functional theory and Hartree-Fock, respectively the Kohn-Sham orbitals and spin orbitals are the natural orbitals, with occupation numbers either 2 or 0. As I understood, ...
-1
votes
1answer
28 views

What does the quantum number l refer to? [on hold]

Pls tell me if I am correct on the following points about quantum number l: 1)l refer to the names of orbitals and their shapes 2)the number of l tells the number of types of orbital in a shell
-1
votes
1answer
22 views

Opening the imidazoline ring in tolazoline

Hello. I was studying about the alkaline ring opening or purines. While doing research, i came across this compound. This got me thinking if we can use the same procedure to open the imidazoline ring ...
-2
votes
0answers
27 views

partial pressure [on hold]

The partial pressure of the $\ce{CO2}$ in a reactor kept at $\pu{2000 K}$ is $\pu{0.700 atm}$. After addition of hydrogen, the equilibrium $\ce{CO2(g) + H2(g)<=>CO(g) + H2O(g)}$ with $K_p=4.40$ ...
-1
votes
0answers
20 views

How does seed crystal provide orientation to silicon melt in Czochralski process?

As i was curious in knowing orientation planes provided by seed crystal to silicon wafers(Ingot). In Czochralski process silicon melt of around 1400 degree a Here process is explained in general In ...
0
votes
0answers
26 views

Should I use MCPBA here?

I came across a question that asked for a method to convert propene to glycerol. I used the method in the pic, but I'm worried about two steps- Step-2, This reaction is just made up by myself! I'm ...
2
votes
1answer
37 views

Reaction energy of oxygen and hydrogen

From the bonding energy of following bonds that I found in a Wikipedia article, I calculated the reaction energy that would be released when oxygen and hydrogen are reacted to produce water. The phase ...
-1
votes
0answers
8 views

How do i calculate the standard enthalpy change by using the substitution method? [on hold]

unless if using the cycle method is easier, please do show the calculation please
4
votes
1answer
26 views

Rule of Thumb for separatory funnel volumes

Is there a general rule of thumb in terms of how one chooses the volume of separatory funnel used for an extraction? It's my understanding that it is the amount of product that determines this as ...
-1
votes
0answers
17 views

Finding unknown compound [on hold]

A compound X (mol. wt. = 86) doesn't shows tautomerism and has double bond equivalence equal to 1. But, Structural Isomers of X can show tautomerism. (Structural isomer of X is a mono substituted ...
-1
votes
2answers
40 views

Finding mole fraction from molality

Calculate the mole fraction of ammonia in a $\pu{2.00 m}$ solution of $\ce{NH3}$ in water. What I know is that the formula for mole fraction is $$X = \frac{\text{no.-of-moles-of-solute}}{\text{(no.-...
0
votes
1answer
52 views

Confused about energy change diagrams

I have been reading about endothermic and exothermic reactions, as well as change in enthalpy. From what I have read, an exothermic reaction is where more energy is given out as bonds are made when ...
-1
votes
0answers
25 views

How were the densities of elements in the periodic table solved? [on hold]

Is there a formula for finding the density of an element? Example: density of Aluminum is 2.70 $\frac{g}{cm^{3}}$ I've tried using the ideal gas law (PV = nRT) with using the constants at STP (1 mol =...
9
votes
4answers
732 views

Largest alkane having a given alkane as its base name

What is the largest (most carbon atoms) alkane having heptane as its base name? For example, 2,2,3,3-tetramethylbutane is the largest (most carbon atoms) alkane retaining butane as its base name.
5
votes
3answers
129 views

Does gas chromatography follow the “like interacts with like” rule of thumb?

The "like interacts with like" rule of thumb works well when there are polar and non-polar molecules that are mobile (liquid-liquid extraction, membrane vs cytosol, questions of solubility). Polar ...
1
vote
1answer
193 views

What classifies as a solvent/base in SN1, SN2, E1, and E2 reactions?

I need to clarify some terminology for an intro to organic chem class. We are studying substitution and elimination reactions and it has not been made clear what exactly these terms describe. For ...

15 30 50 per page