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4
votes
2answers
284 views

Addition of NaCl and CaCl2 to snow

In cold countries, it is a common phenomena to add salt to melt or clear snow. However, only specific salts are being commercially. So my question is that why only sodium chloride and $\ce{CaCl2}$ are ...
2
votes
2answers
2k views

Chirality of buta-1,2-diene

My teacher says buta-1,2-diene is symmetric and hence optically inactive but I think it's the opposite, because allenes with an even number of double bonds are optically active because they have no ...
0
votes
2answers
202 views

Confused with oxidation numbers

If -2 is a oxidation number and 2- is the charge, then what is - by itself, is it a oxidation number or charge? As in $\ce{Ag+}$. Also do you see $\ce{Cu + 2Ag+ -> Cu^{2+} + 2Ag}$ as a redox ...
5
votes
3answers
2k views

Easy method of analysing iodine content in supplements?

Most health-food stores carry supplements supposedly containing iodine for people with iodine deficiency. I recently bought some kelp tablets that are supposed to have iodine but as a consumer how can ...
0
votes
2answers
1k views

Calculus and physical chemistry [duplicate]

Is calculus and differential equations really that useful in physical chemistry? How does knowing that helps me in physical chemistry? And how much of calculus must I know in order to do physical ...
1
vote
1answer
63 views

Searching for a solvate that changes its solvation property

I'm looking for a solvate that changes its solvation property when being dried. One example of such a material is gypsum: at temperatures up to 250°C it becomes γ-anhydrite which will slowly hydrate ...
1
vote
1answer
165 views

Dissociation of ligand

If a ligand K[Ag(CN)2] is dissociated.. Which one is correct dissociation equation? $$\ce{K[Ag(CN)2] -> K+ + Ag+ + 2CN^-}$$ or $$\ce{K[Ag(CN)2] -> K+ + [Ag(CN)2]^-}$$
3
votes
2answers
3k views

Boron trihalides acidity

Boron trihalides ($\ce {BX3}$) is a Lewis acid, because it can accept an electron pair, as Gilbert N. Lewis definition. Now my question is, please arrange ($\ce {BF3}$), ($\ce {BCl3}$), ($\ce {BBr3}$),...
6
votes
2answers
179 views

How to find trace methanol content in fermented fruit/distillate?

Suppose we have some fermented (optionally also distilled) fruit/fruit juice. The sample therefore contains water, sugars, ethanol etc. Which analysis method is the simplest to find out whether the ...
2
votes
1answer
870 views

What is the difference between the reactivity of Lead subacetate and Lead II acetate undergoing a hydrothermal process?

I am attempting to adapt a hydrothermal method for synthesizing $\ce{PbS}$ nanocrystals to my school that contains a mixture of cationic and anionic surfactants sodium dodecyl sulfate (.05 mmol, SDS) ...
0
votes
0answers
52 views

Modelling planar ring molecules and their evolutions [duplicate]

This is the next step of my previous question. I am trying to simulate a circular chain (ring) of molecules which are planar (two dimensional). What I do is take a planar unknot and embed it into a ...
8
votes
1answer
9k views

Hardness and softness are terms used to describe which aspect of acidic behaviour?

What do hardness and softness mean? Is it something to do with the polarisability.
9
votes
3answers
1k views

Oxalic acid structure

What is the reason why oxalic acid has its second $\ce{-COOH}$ group flipped? I'm guessing it's something to do with steric repulsions between the $\ce{-COOH}$ groups but I'm not sure.
0
votes
1answer
776 views

Heat of combustion per mole and per kilogram

I need to calculate the heat of combustion per mole and per kilogram of complete combustion of, say, X. I write reaction : $\ce{X + O2 -> ... + Q}$ Find Q using Hess law Now, what do I do after ...
3
votes
2answers
6k views

Stability of transition metals in aqueous solution

Which is more stable in aqueous solution: $\ce{Cr^3+}$ or $\ce{Mn^3+}$? Why? My approach: $\ce{Cr^{3+}}$ should be more stable as the $\ce{3d}$ electrons will enter the $\mathrm{t_{2g}}$ orbitals. ...
0
votes
1answer
66 views

Modelling planar molecules and their evolutions

I am trying to simulate a chain of molecules which are planar. Can anyone please give me an example of the molecular chain which can stay as planar with it's minimum energy state is planar. A ...
0
votes
1answer
2k views

Does Nitrogen dioxide change colour if we put it in a constant temperature of e.g. 100 kelvin?

The changing of the colour of $\ce{NO2}$ is because of a change in temperature, resp. heating and cooling?
2
votes
2answers
149 views

How do i detect the compounds a plant is made of, automatically?

Let's say I want to take a random plant , and get the chemical formulas of the compounds he's made of. Is there an automated method for doing so and how costly is it(roughly) ?
7
votes
3answers
22k views

How to determine the pH of a mixture of two weak acids?

We’ve two solutions: Solution 1 $\ce{HCOOH}$ its concentration is $c_1=10^{-2}\ \mathrm{mol/l}$ and its volume is $V_1 = 50\ \mathrm{ml}$ and its $\mathrm{pH}_1 = 2.9$. Solution 2 $\ce{CH_3COOH}$ ...
2
votes
1answer
99 views

How do I lookup a polymer by its structure?

This is more of a meta-chemistry question, but, here goes... Given the structure of a polymer, how can I search online for which polymer it is? Specifically, I have an image like this: I'd also ...
7
votes
5answers
42k views

Why is weight of 1 mole of substance equal to atomic/molecular mass in grams?

Why is weight of 1 mole of substance equal to atomic/molecular mass in grams? According to me, it happens because mole has been defined in such a way. It is defined as the numbers of particles in $\...
-8
votes
1answer
908 views

Find the molecular formulas of these alkanas and alkenes [closed]

Can Somebody please solve this chemistry question It came as a part of a previous test and i wasn't able to find a way to use ny/nx since all my answers would be negative. It wasn't a homework problem....
0
votes
1answer
587 views

What is the compression work? [closed]

A cylinder contains 2 kg of steam at 200 kPa and 200 $^\circ$C. Now steam is compressed at constant pressure until its temperature rises to 250 $^\circ$C. What is the work done during this compression ...
0
votes
1answer
127 views

Boilng vodka for A/C cleaning

I hope this doesn't sound too strange. I have plenty of cheap vodka and want to clean the A/C on my car. So I thought about boiling 1/2 litre of vodka in my car while I ran the A/C with ...
6
votes
1answer
2k views

Why is Cyclodextrin cavity hydrophobic?

Actually this is going to be a list of interconnected questions. Please bear with me. Wikipedia article on cyclodextrin (CD) says that it is hydrophobic from inside. (1) How is it hydrophobic when ...
0
votes
1answer
302 views

Octahedral Voids

The total number of octahedral void(s) per atom present in a cubic closed pack structure is (a) 1 (b) 2 (c) 3 (d) 4 PS- I answered it (d) 4 but a key on internet says it is (a) 1. Please clarify ...
4
votes
2answers
9k views

Cathode + Anode + Rechargeable battery

I'm confused by the following from this webpage: The cathode is a metal oxide and the anode consists of porous carbon. During discharge, the ions flow from the anode to the cathode through the ...
11
votes
2answers
24k views

Why NH4OH? Why not NH3(aq)?

The title says it all. I had this question when helping someone with their high-school chemistry homework. What are the reasons that someone would use an (from my point of view) obfuscated notation?
0
votes
1answer
1k views

Titration color change duration [closed]

Why is it that in titration a color change occurs initially but then the solution quickly reverts to its previous color? Thanks so much!
2
votes
2answers
1k views

Which one really determines how people feel. Heat or temperature? [closed]

We use water to cool down some machines because water has high heat capacity, which means it takes more energy to increase 1 degree. Heat transfer occurs only when temperature is different. We cool ...
5
votes
2answers
123 views

Maximum Pressure of Covalently Bonded Material

At high enough pressure, atomic material no longer exists, for example under the conditions of a neutron star. Is there a different maximal pressure above which covalent bonds no longer exist?
0
votes
2answers
1k views

Determine products of NH4NO3 hydrolysis [closed]

What are the products of the following hydrolysis reaction? How do you know? $$\ce{NH4NO3 + H2O <=> ?}$$
14
votes
1answer
3k views

The bond in coordination complexes

This is a very basic question and I'm surprised it only just struck me. The nature of the bond in coordination complexes is a coordinate covalent bond. Only the ligand donates electrons for bond ...
2
votes
1answer
2k views

what is the name of the molecule that has the greatest number of different atoms? [closed]

What is the name of the molecule that has the greatest number of different kinds of atoms? For example, H2O is water has 2 different kinds of atoms which are H and O. For example, C6H12O6 is ...
10
votes
2answers
18k views

What's the relationship between Van der Waals forces and hydrophobic interactions?

A question on a past exam for a course I'm studying for asks: What's the relation between Van der Waals forces and hydrophobic interactions? From what I understand, Van der Waals forces are ...
3
votes
1answer
154 views

metal salt solutions g/l means hydrate or anhydrous

I want to redo an experiment. They've used Nickel chloride: 40 g/L Nickel chloride can be bought in two forms: anhydrous ($\ce{NiCl2}$) and hydrate ($\ce{NiCl2....
2
votes
2answers
1k views

Are there any safety guidelines for mixing sulfate with chloride?

Some ceramicists decorate pottery using soluble salts (usually chlorides and sulfates e.g. copper chloride, cobalt sulfate) which are used individually or mixed to produce different colors. I have ...
2
votes
1answer
323 views

Voltaic and electrolytic cells

Why more attractive metals will be oxidized? Aren't they being reduced, because they attract and receive electrons from negative polyatomic ions? So they will be anodes, where oxidization occurs. Why ...
1
vote
1answer
112 views

Why is it a good idea to put some salt in the bread dough?

The salt that you can typically find in a kitchen is the $\ce{NaCl}$, isn't this salt supposed to act as an antiseptic? I find a lot of recipes that suggest the addition of salt when preparing the ...
-2
votes
3answers
7k views

Why can't a potassium sulfate anion KSO4(-) exist in solution?

Please explain to me why $\ce{KSO4^-}$ doesn't exist as a molecular ion in (aqueous) solution. I couldn't find a reason why. I assumed if you took one $\ce{SO4^{2-}}$ and one $\ce{K^+}$ ion, then ...
3
votes
4answers
3k views

Where does the characteristic peak for phtalic acid diethyl ester at m/z 149 originate?

Which fragmentation is possible at this m/z value for phthalic acid diethyl ester? I tried McLafferty but it didn't solve my problem.
6
votes
1answer
136 views

How can I reduce Crystallization temperature of seed oil to be used in winter as biodiesel?

How can I reduce Crystallisation temperature of seed oil to be used in winter as biodiesel? The glycerol has been removed from the oil, and white spirit is used to reduce its viscosity.
2
votes
1answer
26k views

Predicting the pH of a weak acid and weak base solution

I know that it is possible to predict whether combinations of acids and bases will be acidic, basic, or neutral: weak acid (WA) and strong base (SB) reacts basic strong acid (SA) and and weak base (...
3
votes
1answer
23k views

at constant volume why the change of enthalpy doesn't equal the change of heat

At constant pressure $p=\text{const.}$, change of internal energy equals heat subtract work(PV). So, $q=\Delta E - pV$. So is the the change of enthalpy. So we say at constant pressure, the change of ...
6
votes
1answer
308 views

Calculation of the enthalpy change of reactions

First, I’m a high school student and I wonder why every textbook just tells you how to set up those equations and cancel them to get the entropy change but never tells you why you can cancel the same ...
1
vote
1answer
814 views

About the nomenclature: manganate or manganite?

I am a bit confused about the correct name of $\mathrm{LaMnO}_3$. Is it lanthanium manganate or lanthanum manganite? I was assuming that since $\mathrm{SrTiO}_3$ is called strontium titanate, $\...
2
votes
2answers
773 views

Concentration, how to determine grams of NaCl needed

Disclaimer: It has been a very long time since I have done any chemistry. My friend posted this question on social media, I've copy+pasted it here: Exactly $16.0~\mathrm{ml}$ of a solution A is ...
0
votes
2answers
188 views

Generally available fluid with good heat transport properties

I have designed a container which is heated up and has to heat up some tube-coils of water inside of it. This container is filled with a fluid that can help store and transfer the heat received from ...
2
votes
3answers
336 views

Heating CrCl3(bpy)3 — isomerism and ligand exchange

$\ce{CrCl3(bpy)3}$ (A) when heated forms (B) which has the formula $\ce{CrCl3(bpy)2}$ and has one free $\ce{Cl-}$ per mole of (B). B can react with ethylene diamine ($\ce{en}$) to form (C) which has ...
1
vote
2answers
6k views

Reaction involved in Combustion of Nitrocellulose-Nitroglycerine(NCNG) solid propellant?

I'm working on solid propellant based microthrusters and I am using NCNG as the solid propellant. I want to know the reaction taking place and the mass fraction of the products obtained on combustion ...

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