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If we consider Uranium-235 , the mass of protons and neutrons combined together is more than the calculated atomic mass of the nucleus . Why is it so?

If we consider U-235 (Uranium-235) , the mass of protons and neutrons in the nucleus combined together is more than the calculated atomic mass of the nucleus . Why is it so ? (Whereas For C-12 (...
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0answers
4 views

Spurious term in Thomas-Fermi-Hartree energy functional

I am quite a beginner in DFT and I am studying the theory behind the computational tools. I have some doubts about the Columb approximate functional term: $U[n] = \frac{1}{2} \int d^3 r \int d^3 r^\...
0
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1answer
8 views

Enthalpy, heat of solution test: Calcium chloride vs magnesium chloride in water

I did a school experiment to measure the heat of solution (enthalpy) of various salts dissolved in water. My results are completely different to the teacher's answer. Specifically my test showed ...
0
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1answer
7 views

Formula for rate constant

Please if anyone can help me, I was in a class with my lecturer when he mentioned that the formula for rate constant in first order reaction is this In which what I know recently is that the rate ...
-1
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0answers
3 views

can I measure free chlorine content in treated water using ORP sensor? if yes guide me how?

In my project, I need to measure ph, turbidity, and free chlorine content in treated water from wastewater, I found sensors for ph and turbidity but when I search for chlorine sensor, I found it but ...
2
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0answers
10 views

Are there any ADME predictions tools available for Python/RDKit?

Is there any Pythonic way (a.k.a: a module, an rdkit package, etc) or an API I can use for ADME predictions? I need to prioritize some compounds for purchase/synthesis and some sort of ADME scoring ...
-1
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1answer
17 views

Why is Cu(II) more stable than Cu(I)? [duplicate]

Seeing Copper has an exceptional electron filling in its valence shell(4s1 3d10), the way I see it is that on +1, a d10 configuration should be more stable and hence easier to attain than a d9 which ...
3
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0answers
9 views

Can someone help me understand the motivation behind and visualize the dihedral potential and the Urey-Bradley potential?

I am studying statistical mechanics and force-fields, and I see a lot of this formula being thrown around with no explanation: $$U_{\mathrm{dihedral}} = \begin{cases} k(1+\cos (n\psi + \phi)),&...
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0answers
18 views

Why aren't all the fluorescence transitions the same wavelength?

If all the excited molecules at higher S1 vibrational states rapidly relax to the lowest S1 vibrational state, why do the fluorescence transitions from v' = 1, v' = 2, v' = 3, and other states to v&...
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0answers
12 views

What Math and chem fields should I study for working with materials science [closed]

I'm coming into my first year at a 4-year university after finishing my associates at a two year school. I think that I am interested in focusing on materials science, I feel like there is still so ...
-2
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1answer
26 views

Why do we only take into account the first product while calculating a limiting reactant?

High school chemistry student here. Currently, we are learning stoichiometry and I noticed that when we calculate the limiting reactant of a reaction with multiple products, we almost always just take ...
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0answers
15 views

Why is there a mirror image effect in the absorbance and fluorescence spectra?

I've read some answers online but I still can't seem to understand the mirror image effect. Why is the highest energy absorption (v" = 0 to v' = 4) the lowest energy fluorescence (v' = 4 to v&...
-1
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0answers
8 views

Finding rate constant from a change in pressure experiment

I measured the change in pressure for the decomposition of hydrogen peroxide in the presence of a manganese(IV) oxide catalyst at 5 different temperatures: $$\ce{2 H2O2 (l) ->[MnO2 (s)] O2 (g) + 2 ...
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0answers
9 views

Effect of electrolyte on electrolysis of water

Why would concentration of the electrolyte and not the type of electrolyte used affect current density in an electrolytic cell because I believe the mobility of the ion does have an effect on current ...
3
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0answers
16 views

Is it feasible to calculate the rate law of the oxidation of ethanol using colorimetry?

My IB Chemistry class needs to have our Internal Assessment ideas finalized by next week, and I'm torn between a few experiments. I'm considering performing an oxidation of ethanol and potentially ...
-2
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0answers
16 views

How can someone in the lab synthesize n-allyl-4methyl-benzenesulfonamide from 4-toluenesulfonyl and allylamine

I am trying to figoure out the conditions and choice of solvents and catalysts in order to run this synthesis.
2
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1answer
30 views

TEMPO Radical Analogue

After investigating what makes the persistent radical TEMPO stable, I was wondering if another compound which is more feasible for my needs would be comparable to it. Would oxidizing 2,2’-dimethyl-...
-1
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0answers
19 views

Dissipating Cl2

Is there a way to keep Cl2 gas very low in a 55 gallon drum? HOCl is stored in it and there is some Cl2 off gassing in top headspace. Was wondering if there was anything I could use in one of the bung ...
-2
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0answers
20 views

Does pressure x volume = kinetic energy?

Sorry don't know if this is more for physics or here, essentially I had a question on the root mean square velocity of gas particles equation and didn't know what it was so tried to work something ...
-1
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0answers
17 views

Is there a term for a gel-like substance with a higher concentration of salinity than EO water?

I am writing a story about a planet that is covered in water but the water is closer to a gel-like substance with a higher concentration of salinity than EO water. I just wanted to know if that was a ...
0
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1answer
38 views

Finding Kp using log Kp

I am working through some MIT lecture notes trying to understand adiabatic flame temperature. There is a section in these notes where $K_p$ is calculated for the following reaction at $\pu{1600K}$. $$\...
1
vote
1answer
30 views

Decline in current during electrolysis

I observed a sharp decrease in the current when I carried out the electrolysis of water. Just to set the context, I used a voltage of $\pu{12V}$ and the concentration of my electrolytes were $\pu{0.15 ...
-4
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0answers
14 views

I could find the rate of reaction. But am really not able to find the molar mass of the polymer [closed]

Methyl methacrylate was polymerized at a mass concentration of 200 g dm−3 in toluene using azobisisobutyronitrile as initiator at a mass concentration of 1.64×10−2 g dm−3 and a reaction temperature of ...
1
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0answers
23 views

Hydroboration, steroselectivity and anti-markovnikov product [duplicate]

My first question has to do with the fact that Hydroboration produces an anti-markovnikov product, why?. I don't see how that happens. A wikipedia artical says that B has a partial positive charge ...
-1
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0answers
18 views

Effect of electrolytes on the rate of evolution of hydrogen [closed]

What role do ions like $\ce{Ca^{2+}}$ and $\ce{Sr^{2+}}$ as electrolytes play in the electrolysis of water (how do they contribute to current when they don't take part in electrode reactions) and how ...
3
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0answers
17 views

Calculating temperature of partial condenser, flash calculations

The iterative method I have learned to make flash calculations for a binary system where I know the inlet feed (F [mol/s]), total composition of the two components ($z_1$ and $z_2$), the amount of the ...
0
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0answers
11 views

How to calculate the unknown concentration with delta H and delta S? [closed]

3-ethyl-4-methylhexa-1,3-diene undergoes a combustion reaction. For this reaction, the following concentrations were used: [O2] = 0.06 M, [CO2] = 0.09 M and [H2O] = 0.10 M. Determine the concentration ...
-1
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0answers
22 views

Dilution confusion

I have run into what I imagined would be simple mathematics, but it turns out I need some help. My problem is I have a bottle of Geobacillus stearothermophilus and the concentration of the spores is $\...
0
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0answers
19 views

Removing denatured Crystalbond?

I have some water-soluble crystalbond that is attached to silicon and, because of some overheating (to about 150 Celcius) during a final processing step, the crystalbond seems to have charred (white/...
-1
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1answer
26 views

Is acac- a weak field ligand?

From the chemical structure of acac- compared to NH3 and en, is acac- a stronger or weaker ligand strength? How and why do we know this?
-1
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0answers
16 views

Precipitating matals from aqua regia solution [closed]

good day , I have a problem precipitating metals from aqua regia solution that I have made from an ore , it does changes the color when I dip some stannus chloride in to the beaker . But does not give ...
-1
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0answers
20 views

Plastic-eating microbes at home

I wanted to know if I can nurture a bacteria which is not difficult to find and with time I can train them on harsh chemicals and soon introduce plastic into it with the hope that it will eat it up ...
-2
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0answers
8 views

How to compare experimental results with gas or solvent phase quantum mechanical calculations

I have a question how can we compare gas or solvent phase DFT calculations properties with experimental solid/crystalline phase properties? How can we validate our theoretical methods? Thanks, Shen
0
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2answers
50 views

Concept of Equivalent Weight [duplicate]

I'm having a hard time understanding what equivalent weight means physically. I've looked at many articles on Google but the definition always seems nebulous to me. For example, if the equivalent of $...
-1
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0answers
9 views

Estimating enthalpy change of vaporization using bond strengths

If we were to consider the vaporization of liquid water to gaseous water, my instructor stated that it would be "possible to estimate the enthalpy of vaporization based on differences in bond ...
5
votes
2answers
280 views

Why is the base-centered orthorhombic crystal lattice a unique crystal system?

I'm having difficulty understanding why the base-centered orthorhombic crystal system is a unique crystal system. When I draw two base-centered orthorhombic unit cells next to each other there appears ...
-2
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0answers
23 views

Why K2CrO4 Potassium chromate is a good oxidizing agent but K2MoO4 Potassium molybdate is not? [duplicate]

although they are in the same group? Why $\ce{K2CrO4}$ Potassium chromate is a good oxidizing agent but $\ce{K2MoO4}$ Potassium molybdate is not?
0
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0answers
40 views

Does 3‐ethyl‐1,1‐dimethylcyclohexane have a stereocenter?

I knew that we have a stereocenter if the carbon is bonded to four different groups. According to the stereocenter rules, I should have $\ce{CH2}$ bonded to the carbon of the stereocenter (marked with ...
0
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0answers
17 views

Removing wood stain from a ceramic surface

I have a bathtub that I accidentally poured wood stain into. Now the stain is all over the white ceramic surface of the tub. I tried using bleach but it didn't do anything. I'm curious if there is a ...
-1
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0answers
15 views

How are potential energy curves obtained for diatomic molecules using Hartree-Fock? [closed]

I am looking for a brief explaination on this, or a source that explains this more.
-1
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0answers
41 views

Confusion in solution for this Question regarding mole concept

$\pu{48g}$ of graphite and $\pu{16g}$ of $\ce{O2}$ is given. The question is to count the no of molecules of $\ce{CO2}$ produced? Now, the solution in book is this No of $\ce{C}$ atoms = $\frac{\pu{...
-2
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0answers
24 views

Why ice gets stuck on our hands but cold wood doesn't? [closed]

Is that caused by sweat? Kinda confused.
1
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0answers
36 views

phenolsulphonic acid

Phenolsulfonic Acid( PSA) is produced after sulphonation of Phenol at around 100 degrees. They use this product in tinplating. Once a stable PSA is formed after sufficient reaction , unreacted ...
2
votes
0answers
95 views

Why does titanium have lower affinity than scandium?

Electron affinity of atoms in the same row usually increases with the atomic number until the shell or half-shell gets full, and then it drops down. Some transition metals are exceptions from the rule,...
-1
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0answers
24 views

What is the structure of potassium tetraperoxochromate(V)? [closed]

Though some structures are available on the net, different sources are showing different structure, so please share the actual structure of $\ce{K3CrO8}.$
1
vote
1answer
59 views

Comparing O−O bond length in hydrogen peroxide and dioxide(2−) ion

Problem How can we qualitatively compare the bond lengths between $\ce{H2O2}$ and $\ce{O2^2-}?$ Answer Attempt I tried using molecular orbital theory, but since both have peroxide $\ce{O2^2-},$ the ...
3
votes
2answers
31 views

Isobaric entropy relation from isothermal Gibbs free energy relation

I have been given a problem to derive a relation for change in entropy from change in Gibbs free energy: Starting with the isothermal equation $$G(p_2) = G(p_1) + nRT\ln\frac{p_2}{p_1}\label{eqn:1}\...
-1
votes
0answers
25 views

How do I solve this protolysis-reaction question? [closed]

I have measured $\mathrm{pH}$-values to these solutions and filled in a table: $\ce{NaCl}:9.5-10$, $\ce{CH3COONa}:8$, $\ce{Na2CO3}:11.5$, $\ce{NaHCO3}:2$, $\ce{KNO3}:3$, $\ce{NH4Cl}:7-8$ The question ...
-4
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0answers
16 views

inverted reverse osmosis reaction products [closed]

Is an inverted reverse osmosis leading to hydride in h2o ?
-1
votes
1answer
23 views

Addition reaction of alkenes

During an addition reaction of an alkene, how does a double bond break to form two bonds with the two atoms of the reactant plus a bond between the carbon atoms? Not sure if this is a silly question ...

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