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480 views

Comparing IR stretching bands in molybdenum complexes

Why would the infrared stretching frequency of $\ce{CO}$ (which is about $2140~\mathrm{cm^{-1}}$ in gaseous form) be $1982~\mathrm{cm^{-1}}$ in $\ce{[Mo(CO)_6]}$ and even lower in $\ce{[Mo(CO)3(η^6$\...
3
votes
1answer
952 views

What kind of bonds can form between benzene and transition metals in π-complexes?

I'm trying to draw the six π-orbitals (3 bonding, which are filled, and 3 anti-bonding) of a benzene ring when it complexes with metal d-orbitals and which metal orbitals have the correct symmetry ($\...
2
votes
1answer
4k views

Deriving an expression for dU as a function of V and T

I'm currently preparing for a physical chemistry exam tomorrow, and was given the following question for practice: Derive an expression for $\mathrm{d}U$ as a function of $\mathrm{d}V$ and $\mathrm{...
2
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3answers
4k views

why are halogens considered deactivating groups while methoxyl groups are activating?

Something's wrong with how I think of this: methoxyl has the partial negative charge on oxygen which means it's activating. However, halogens are more electronegative yet they're considered ...
1
vote
2answers
3k views

Difference between microcanonical and canonical ensemble

I feel a little unclarity about this. Canonical ensemble is pictured as many systems in heat reservoir of infinite capacity having $N$ (number of particles), $V$ (volume) and $T$ (temperature) ...
6
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2answers
5k views

Amine Nomenclature – When to use “N”

I'm currenty wondering what the correct naming scheme for the following molecule would be: Is this called "2,N,N-trimethylpropan-1-amine" or "2-methyl-N,N-dimethylpropan-1-amine". In other words, do ...
2
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1answer
3k views

What are the specific dangers associated with Grignard reagents?

I would like to know if anyone has had any specific safety-related problems with Grignard reagents. I have taught the year-long introductory Organic Chemistry sequence for about 15 years and have ...
28
votes
3answers
74k views

Is alcohol really a solution?

A friend recently sent me the following chemistry joke: As a lover of puns, I'd like to enjoy it, but I think that it is actually false the way it is phrased. A solution is defined as: "a ...
0
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1answer
207 views

How to name the compound with the formula Br3C-CHCl2?

Name the compound: How should I name $\ce{Br3C-CHCl2}$? Is it 1,1,1-tribromo-2,2-dichloroethane or 2,2,2-tribromo-1,1-dichloroethane?
2
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0answers
489 views

The proper formula of sucrose: why both forms are correct and how one is transformed into another? [duplicate]

During preparations for my exam I've stumbled upon a tormenting question how it happens that the formula of sucrose is written in two different forms: the vertical and the horizontal ones: The ...
7
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1answer
6k views

Why does phosphoric acid mask the colour of iron(III) complex in water?

In the redox titration of iron(III) with permanganate or dichromate, we use phosphoric(V) acid to "mask" the color of iron(III) because it interferes with the end point color change. What's the ...
17
votes
4answers
18k views

Is activation energy temperature-independent?

I know that activation energy for a reaction is the extra energy given to the reactants to reach the threshold energy so that they can collide and react. But then, why is it said that the activation ...
2
votes
1answer
576 views

How to predict precipitate upon evaporation from calcium ions and either chloride, carbonate, or nitrate counterions?

An aqueous solution containing $\ce{Ca^2+}$, $\ce{Cl^-}$, $\ce{CO3^2-}$, and $\ce{NO3^-}$ is allowed to evaporate. Which compound will precipitate first? The correct answer is $\ce{CaCO3}$. I had ...
3
votes
1answer
2k views

Importance of Overall Reaction Order

All my texts make it a point that in a differential rate law, the sum of the exponents on the reactant concentrations add up to the overall reaction order. However, I have yet to see any use in this. ...
4
votes
1answer
180 views

Is there a chemical treatment for pipes to reduce or eliminate leaching of lead into tap water?

Given events in Flint, Michigan, where a switch to acidic river water in the city water supply resulted in leaching of lead into tap water from the insides of pipes, I wonder -- has anyone has heard ...
1
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0answers
157 views

Energy required to break salt bridges in peptides and proteins

Is there a way to calculate the energy required to break a salt bridge in a peptide or on the exposed surface of a protein in aqueous solution? Is there any useful literature on this topic? I'm ...
6
votes
1answer
1k views

What is an entropic trap?

Can someone explain the concept of entropic traps, or provide good sources to look up? The term is not present in any chemistry books I own, and I cannot find online sources explaining it.
0
votes
1answer
51 views

Looking for information about possible ingredients of a fertilizer

I have found it in a local store, "20.20.0 - Kompoze" is written on the pack. In the pack, there are yellowish greenish irregular formed little balls. What is this, do you know ? Please help and ...
5
votes
1answer
183 views

de-yellowing lego

I have a huge lot of yellowed Lego's, I want to try to de-yellow them. I have searched around the internet and this method seems the most promising: http://www.retr0bright.com/ I have a few ...
3
votes
2answers
1k views

Resultant temperature of mixture

**Question: ** There are 2 flasks of equal volume, connected by a narrow tube of negligible volume, filled with nitrogen gas. When both are immersed in boiling water, the gas pressure inside the ...
-8
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1answer
131 views

What chemicals used everyday will cause an explosive reaction if exposed into outer space? [closed]

What chemicals used everyday will cause an explosive reaction if exposed into outer space?
3
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2answers
285 views

How to name the tautomers of hexane-2,4-dione correctly according to IUPAC rules?

Today I was considering to answer the question "Which tautomer of hexane-2,4-dione is more stable?" I wanted to run a few calculations and while preparing a directory structure I wanted to make sure ...
2
votes
2answers
236 views

Fluorine Preparation:How can this be explained on basis of Lewis Acid-Base Reaction?

How can this be explained on basis of Lewis Acid-Base Reaction ? $\ce{2 K2MnF6 + 4 SbF5 → 4 KSbF6 + 2 MnF3 + F2↑}$ References: https://en.wikipedia.org/wiki/Fluorine#Industrial Google Books ...
2
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0answers
516 views

Using electron affinity to calculate lattice energy

I am trying to calculate the lattice energy of $\ce{CaBr2}$, I am uncertain of how to incorporate the electron affinity value provided for $\ce{Br2}$ into my calculation. Since electron affinity is ...
1
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0answers
56 views

Redox Reactions with buckyballs

I have read that buckyballs are excellent electron acceptors, C60 in particular can accept up to 6 electrons. However I do not understand why they have this ability and how they can accept a large ...
2
votes
1answer
391 views

Why does microwaving napalm make it nonflammable?

In this video, microwaving napalm made it nonflammable. What caused this to happen? I assume it was some sort of chemical reaction. Could someone explain? I understand some chemistry, but a not-too-...
1
vote
1answer
347 views

Calculating the molar mass of a gas given state function values

Question: A gas has a volume $255\ \mathrm{mL}$, a pressure $733\ \mathrm{mmHg}$, a temperature $548\ \mathrm{^\circ C}$, and a mass $1.22~\mathrm{g}$. What is the molar mass? My attempt: $$pV = ...
3
votes
1answer
1k views

How does complex ion differ from ligand complex?

As I understand, in terms of "colouring", ligand complex cause a transition metal cation centre's d-shell to split, allowing the electrons in that region to absorb specific frequencies of light, and ...
-1
votes
1answer
9k views

What is the Lewis Structure for CH3CONHCH3?

Chemical formula: $\ce{CH3CONHCH3}$ How could I draw the Lewis structure so that oxygen and nitrogen have a full octet? Currently, I have $\ce{CH3-C=O-NH-CH3}$.
8
votes
2answers
1k views

Diagonalization of Hessian H= PkP$^{-1}$: what do the elements of P matrix physically mean?

This is quoted from Computational Chemistry by Errol J. Lewars' chapter 2's Stationary Points & Normal-Mode Vibrations: ZPE: \begin{align}\mathbf H &=\begin{bmatrix} \dfrac{\partial ^2 ...
3
votes
0answers
144 views

Could any constituent of normal human urine produce a false positive in a Kastle-Meyer test for presence of blood?

From my understanding, one forensic test for the presence of traces of blood at a crime scene is (or was) the Kastle-Meyer test. Doing some research, I understand that in the test, hemoglobin reacts ...
1
vote
1answer
13k views

Does turning propane or butane gas tank upside down help to use the remaining gas?

Some think that when gas (propane-butane mixture for cooking) in a gas tank is almost used (only remainings are left inside and the flame is hardly noticeable) and you turn it upside down it will ...
21
votes
2answers
145k views

What is the difference between D and L configuration, and + and −?

What is the difference between D and L configuration, and + and −? My textbook says they are two different things. It also says that the correct way to name glucose is D(+)-glucose. Could someone ...
4
votes
2answers
949 views

Method to synthesize KAu(CN)2 (or KCN)?

Every reasonably effective method of electroplating $\ce{Au}$ onto another metal's surface (e.g. $\ce{Cu}$,$\ce{Ni}$,$\ce{Ag}$, etc.) involves use of $\ce{KAu(CN)2}$ or in some cases $\ce{KAu(CN)4}$ ...
-1
votes
2answers
5k views

How to calculate the mass of a single atom?

If we know the molar mass of a certain element and Avogadro's constant, how can we calculate the mass of a single atom? Do we need to multiply the molar mass with Avogadro's constant?
-1
votes
1answer
366 views

why does this reaction place the nitro group specifically there? [closed]

the amide up top is activating and the sulfonic acid below is deactivating. I'm just wondering how we know that the nitro group is placed ortho to the amide or meta to the sulfonic acid.
1
vote
0answers
321 views

Why do Pop Rocks fizz longer in milk than in Sprite?

After doing an experiment with Pop rocks in various liquids, it was noted that they fizzed the longest in milk. My daughter compared Sprite, apple juice, water and milk, and milk fizzed the longest. ...
1
vote
1answer
151 views

Minimum resolution to acquire exact mass on a spectra from m/z peak

I'm having a little difficulty with finding what the minimum resolution required to obtain the exact mass of a 400 $m/z$ peak in a mass spectrum. I would appreciate any help.
2
votes
1answer
107 views

Hair Gel Derivative

I need a water-soluble, extremely fast drying adhesive gel. My first thought is hair gel. pros: Water Soluble (easily removed)*** most important High viscosity in liquid form ~60 cps Easily ...
3
votes
1answer
1k views

Tungsten 4+ ion magnetism?

I just had a quiz and struggled on a particular question: Tungsten forms a $+4$ ion. It is observed to be diamagnetic. The electron configuration for this ion may not be what you would expect. ...
0
votes
1answer
2k views

What chemicals react with alcohol?

I am curious if there is any chemicals that react with alcohol to either produce a visible colour change or an odour someone could smell.
1
vote
2answers
7k views

Is styrofoam soluble in gasoline or paint thinner?

Why doesn't gasoline or paint thinner melt through Styrofoam when I try it yet there are videos of others melting Styrofoam in gasoline and paint thinner? Is there something I am doing wrong? This is ...
1
vote
1answer
1k views

Baking Powder instead of soda error

Bit of a random one but I had an oven fire yesterday due to grease. I decided to clean my over as a result but stupidly used baking POWDER rather than soda and wiped it off with vinegar. Now I am ...
2
votes
1answer
2k views

Nitrogen molecule vs carbon-carbon triple bond stability [duplicate]

Why does the triple bond in the nitrogen molecule convey stability, whereas a triple bond between carbon atoms conveys instability?
1
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0answers
1k views

Difference in the change in oxidation states of transition elements and p-block elements

In transition elements the oxidation states differ by one (+2 to +7 in Mn). However, in the p-block elements, the oxidation states differ by two (-1,+1,+3,+5 in the halogen group). Why is this so?
5
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3answers
1k views

Which tautomer of hexane-2,4-dione is more stable?

Which tautomer will be more stable? Both 1 and 2 show intramolecular hydrogen bonding and form 6 membered cyclic ring, thus increasing the stability. I think I need to compare the effect of the two ...
6
votes
2answers
1k views

The naming of benzene

Why is benzene not called as a cyclo triene? Wikipedia says benzene is a IUPAC name, but isn't it a common name?
6
votes
1answer
370 views

How can collission theory of chemical reaction and Law of mass action be connected?

From Wikipedia, Collision theory is a theory ... that qualitatively explains how chemical reactions occur and why reaction rates differ for different reactions. The collision theory states that ...
0
votes
1answer
414 views

Naming amitriptyline by IUPAC [closed]

Can someone guide me through step by step how amitriptyline is named by IUPAC? I know the name per se, but it is very confusing to me, and I'd like someone to explain it to me. The systematic name is ...
2
votes
0answers
45 views

pH, conc vs activity

After studying a somewhat overview of "gamma" activity coefficient (it is not actually in our course but may come in exam as a part of unknown paragraph in ionic equilibrium) I can understand most ...

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