All Questions

3
votes
2answers
62 views

Can an exothermic (endothermic) process increase (decrease) internal energy?

We classify exothermic and endothermic processes based on enthalpy change, $\Delta H < 0$ and $\Delta H > 0$ respectively. I assume this translates to $\Delta U < 0$ and $\Delta U > 0$, ...
-2
votes
0answers
40 views

JEE Main Question - Find the Partial Pressure of Ammonia at equilibrium [closed]

Consider the reaction, N2(g) + 3H2(g) ⇌ 2NH3(g) The equilibrium constant of the above reaction is Kp . If pure ammonia is left to dissociate, the partial pressure of ammonia at equilibrium is given ...
2
votes
1answer
24 views

How does monoethanolamine (MEA) increase pH?

I know pH of a solution increases with increase concentration of $\ce{OH-}$. I'm wondering: when adding MEA, is the $\ce{OH-}$ group from the MEA breaking off, or is it the whole MEA molecule taking ...
-1
votes
0answers
8 views

Why Difference is raised between 16e-and14e-rule (π2Px andπ2Py) in MOED? [closed]

I had listened that there is difference while writing electronic configuration of O2 and N2 why there is a difference between them?
1
vote
1answer
41 views

Complete Oxidation of Methanol

I know that complete oxidation of primary alcohols produces acids: $$\ce{R-CH2(OH) ->[\ce{[O]}] R-CH(OH)(OH) ->[][-\ce{H2O}] R-CHO ->[\ce{[O]}] RCOOH}$$ I wonder if that is the case of ...
0
votes
0answers
24 views

Resistivity of metals [closed]

Well I know the theory which says that the resistivity of a metal is increased with temperature because the vibration of the individual atoms in the lattice become more violent and that resistivity is ...
0
votes
0answers
18 views

Does the mole fraction of a solution change with Vant Hoff factor?

I reason that as mole fraction is a measure of colligative properties, increase in the Vant Hoff factor ( and hence increase in the value of colligative properties) should also leave a mark on the ...
-2
votes
2answers
43 views

Heat capacity and boiling point [on hold]

Two solutions are prepared using equal moles of water, at same temperature: One contains $n$ moles of $\ce{NaCl}$ and the other contains $n$ moles of $\ce{KNO3}$. Is the heat required to raise the ...
0
votes
0answers
10 views

Can factors such as non-chelating ions in solution or the temperature of solution change the d orbital splitting of complexes?

My currently primitive understanding of metal complexes is that the d orbital splitting depends on: Identity of central ion Charge density of ligand Geometry of complex ion oxidation number of ...
1
vote
0answers
23 views

CO2 IR extinction coefficients near the 15 micrometer band

I have searched multiple times for a spectrum or a table of the gaseous carbon dioxide Lambert-Beer extinction coefficients in the IR Earth thermal region. All I found was absorption spectra. Is ...
-2
votes
0answers
83 views
0
votes
0answers
18 views

Composition of gases in water using Henry’s law constants [on hold]

The air is a mixture of a number of gases. The major components are oxygen and nitrogen with approximate proportion of $20\%$ is to $79\%$ by volume at $\pu{298 K}$. The water is in equilibrium with ...
0
votes
0answers
32 views

How do I make alkaline iodide azide solution without azide? [on hold]

I'm trying to do a Winkler titration for my high school depth study. The thing is, I need to source my own chemicals and so far I can buy NaOH and KI, but I can't find sodium azide anywhere. Could ...
0
votes
2answers
32 views

At what position in the distillation apparatus does the temperature match the boiling point of the distilled substance?

A student is separating $\ce{CHCl3}$ (bp = $\pu{61 ^{\circ}C}$) from $\ce{CHCl2CHCl2}$ (bp = $\pu{146 ^{\circ}C}$) by distillation. She has just begun to collect the first distillate in the receiving ...
-2
votes
0answers
28 views

How to make creamy/starchy risotto with brown rice? [migrated]

I've been making risotto with a brown rice blend (Long Grain Brown Rice, Sweet Brown Rice, Wild Rice, Whole Grain Wehani Rice, Whole Grain Black Japonica Rice), and I quite like the texture, and how ...
-3
votes
0answers
31 views

Hydrofluoric acid in the body causing a acidic blood [closed]

Jet fuel splashed on person and hydrofluoric acid seeped in and targeted calcium in pelivis and feet. How would you treat it
1
vote
1answer
29 views

log K vs Internal Energy Question

In a photonionization experiment the neutral molecule absorbed three 266 nm photos. If the kinetic energy of the electron removed during ionization is 1.4 eV, what is the ratio of the simple cleavage ...
1
vote
0answers
17 views

Is the iodide and persulfate reaction bimolecular?

Given the following reaction in an aqueous state: $$ \mathrm{2I^- + S_2O_8^{-2}\rightarrow I_2 + 2SO_4^{2-}}$$ Is it bimolecular o trimolecular? Because two molecules of iodide react with one ...
-5
votes
0answers
19 views

Which of the following has the most number of Atoms [closed]

Which of the following has the most number of Atom? 5 g of lithium, 80 g of Rubidium, 20 g of sodium, or 125 g of the CEsium?
0
votes
0answers
15 views

What is the maximum thickness of electroplating that can be acheived?

I was just wondering if you are electroplating a suitable object what is the maximum thickness that can be achieved? Is there a limit?
-1
votes
0answers
13 views

Balancing equation for Iodoform decomposition reaction? [closed]

Can anyone please help me with balancing the equation for the decomposition of iodoform to produce diatomic iodine, hydrogen iodide gas, and carbon? Heres what I wrote but I am not sure if it is ...
1
vote
1answer
32 views

Is there another name for compound “delta-7 sterine”, does it exist alone?

Is there a more common name for "delta-7 sterine"? Is this spelled correct? I read all over the internet and this compound exists in many articles, but I cannot find any information on it at all, ...
1
vote
1answer
37 views

How to convert soluble colorless [HgI₄]²⁻ back to insoluble red HgI₂? [closed]

When a solution contains $\ce{Hg^2+}$ and $\ce{I-}$, depend on the concentration ratio of $\ce{Hg^2+}$ and $\ce{I-}$, the following reactions can happen: $$\ce{Hg^2+ + 2 I- ⟶ \underset{insoluble red ...
0
votes
0answers
42 views

Is NWChem not respecting Hund's rules when performing a calculation on the oxygen atom? [closed]

I made a calculation with NWChem (Version 6.8) using the SCF method, the aim was to discover the method by doing simple calculations on a oxygen atom $\ce{O}$. Some results are surprising me, one of ...
1
vote
1answer
34 views

Struggling to understand wavevector K for deriving energy levels in reciprocal space [closed]

I don't really understand why, when deriving wavefunctions for arrays of atoms, the wavevector k is introduced and the general idea surrounding momentum space. please help!!
-2
votes
0answers
13 views

Predict the relative energies of following resonating structures [closed]

I am not able to solve this question. Plz help
0
votes
0answers
20 views

Reactivity of formaldehyde and 2-chloroethanal towards nucleophillic addition

Formaldehyde is sterically less hindered than 2-chloroethanal and inductiv effects also support a greater reactivity of formaldehyde over the later. However my textbook states that the reactivity ...
0
votes
0answers
23 views

How does this limit the value of boiling points as criteria for determining the purity of liquids? [closed]

If ideal liquids x and y both have a boiling point of 110 C, what will be the boiling point of a mixture of x and y? How does this limit the value of boiling points as criteria for determining the ...
-3
votes
0answers
21 views

How do I solve this question? [closed]

Analyse the graph and predict the compound
3
votes
1answer
30 views

Is there an inexpensive solvent I can use to dissolve thermal paste without scrubbing?

I'm removing large voltage regulators from circuit boards which are often coated with a generous amount of thermal grease. I've found that 70% isopropyl alcohol works great for softening this and ...
-1
votes
0answers
39 views

How to predict any organic chemistry reaction? [closed]

I was studying organic chemistry and I noticed that at the start after I finished general organic chemistry most basic reactions could be intuitively and logically predicted using a few common ...
-1
votes
0answers
18 views

Transition from energy level [closed]

so when a hydrogen Atom is excited into the n=4 state how many transitions from this energy level are possible by emitting electromagnetic radiation? Is only one transition from this energy level ...
-1
votes
0answers
12 views

Calculation of Photon frequency [closed]

If the binding energy in joules and the energy in joules for an element; chromium is given, how do you calculate the photon frequency needed to eject electrons?
0
votes
1answer
31 views

Reactions between Ca(OH)2 and CO2, and Sr(OH)2 and CO2

So I'm doing an investigation, and it involves using supersaturated solutions of Ca(OH)2 and of Sr(OH)2. I notice that there's always a flaky precipitate formed on top. I need to know about the ...
2
votes
0answers
20 views

Reduction of triphenylmethane dyes in ink

Right now I'm trying to explain why the ink from an ink pen turns colourless in water. I know that the pH is responsible as it breaks apart the conjugated system of double bonds. I'm just not sure on ...
5
votes
1answer
118 views

Energy of photons of given frequency and number

I’m having trouble with calculating the energy of $\pu{5.00e10}$ photons of frequency $\pu{1.00e9 s-1}$. I know that to calculate the energy $E = hf$ is to be used. However, I am unaware as to what ...
5
votes
4answers
176 views

Why does the degree of dissociation change when we dilute a weak acid even though the equilibrium constant $K$ is constant?

$K$ represents the ratio of concentrations of molecules in a solution at equilibrium, which means that $Q_\mathrm{r}$ (that ratio at any given point) looks to be identical to $K$. In other words, the ...
-1
votes
0answers
21 views

Potential Energy of a Molecule [closed]

So im adding the Potential energy of Butane: I have the constant in dyne/A and length in A for Bond length angle constant is in dyne / A and in degrees for Angle energy Electrostatic: k is Coulombs ...
0
votes
0answers
11 views

What are the total amount of resonance structures for these two cations and which is the most stable cation?

Please see the following two cations. I have proposed the following resonance structures. Please let me know if I have missed something. Thank you.
0
votes
1answer
50 views

What is the maximum number of emission lines when the excited electron of a H atom in n = 6 drops to ground state?

When an electron in a higher energy state jumps to a lower energy state in Bohr’s model of hydrogen atom, it emits a photon which has energy equal to the difference in the energy between the final and ...
-1
votes
0answers
19 views

Increasing Solid in equilibrium [closed]

But when we increase the amount of liquid H2O in a closed system, doesn't this increase the pressure? Why this pressure is not increasing the concentration of gas H2O?My question was from this ...
0
votes
0answers
15 views

Predict the aldol condenation product given IR and H-NMR spectra

An aldol condensation product would have a ketone and at least one alkene in the form of R1-C(=O)-C(R2)=C(R3)-R4 H-NMR: 7.09ppm 1H doublet, 7.42ppm 3H triplet, 7.64ppm 2H quartet, 7.75ppm 1H doublet. ...
3
votes
1answer
57 views

Comparison of acidities

My book says To compare the acidities of two compounds, compare the stability of the anions formed by loss of a proton with respect to the original compound. Suppose we have acetic acid and ethyl ...
0
votes
0answers
14 views

Expanding upon an Experiment [closed]

We've been tasked with a Depth Study for my Chemos class, and it has to do with indicators and the pH scale. So far, I've created an indicator using red cabbage and have applied it to different ...
0
votes
1answer
11 views

Calculating the Presence of Anthocyanin in a Solution [on hold]

I've produced a red cabbage solution (boiling red cabbage in water basically), and would like to calculate the concentration of the red cabbage/anthocyanin in the solution. How is this accomplished? ...
1
vote
1answer
19 views

Overall enthalpy balance on a mixing process

Let's say I have a mixing process involving $\ce{A}$ and $\ce{B}$ at temperatures $T_\ce{A}$ and $T_\ce{B}$, respectively. The $\ce{AB}$ mix is at temperature $T_p$. Our $ΔH_\mathrm{mix}$ is defined ...
-2
votes
0answers
31 views

Chemistry Olympiad Question [closed]

Can someone explain how to do this? The answer is C. I know that the direction of electron flow is from the 0.1M to 1.0M end, but I dont know how to calculate the cell potential.
-1
votes
0answers
25 views

Copper voltaic cell potential [closed]

Copper electrodes are placed into two aqueous solutions of copper(II) sulfate at 25 °C. One compartment contains a 1.0 M solution while the other compartment contains a 0.10 M solution. The two ...
-1
votes
0answers
35 views

Definition of conjugation and Dewar resonance energy [closed]

What is a precise definition of conjugation in organic molecules? Why, for instance, do we say a molecule like 1,3-butadiene is conjugated? A valence bond picture might argue the opposite, since ...
0
votes
0answers
18 views

Which is the more effective home insecticide? Boric acid or borax?

I recall my late father introducing me to one of either boric acid or borax... as a relatively low human toxicity very effective insecticide. The thing is, I cannot remember which chemical my father ...

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