# All Questions

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### Thermal stability of barium peroxide and barium oxide

why is barium peroxide more thermally unstable than barium monoxide Do I answer it based on the bonding and structure?
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### Properties of semi metal

My textbook writes a lot about metal and non-metal but only two sentences about semi-metal. This is what textbook: Semi-metal are also called metalloid, have the properties of metal and non-metal. ...
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### Why do double bonds break

So today we performed an experiment, where we mixed cyclohexene with Bromine water. The equation was which seems to make sense. The Bromine water we were using was decoloured as evidence that this ...
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### How do zeolites work in a cat cracker?

Been learning about catalytic cracking of long chain hydrocarbons into shorter chain hydrocarbons, in which the catalyst zeolite is used so that the temperatures needed for the cracking are much lower ...
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### Phase Diagram of Polymorphs vs. Binding Energy. [on hold]

Phase diagrams show how various polymorphs are favored at specific temperatures and pressures. I am interested in a 3-axis diagram showing the binding energy on the third axis. Ideally there would ...
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### Fire resistance of PVC

In a paper that I'm reading, it states that The presence of Chlorine atoms in polyvinyl chloride make it flame resistant and I'm just wondering why the presence of Cl will make it flame ...
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### A way to calculate orbital energy of an electron

Maybe this is just not included in my course, but I still wonder how to calculate the binding energy of an electron at a certain electron orbital. Intuitively,The ionization energy of an element ...
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### Exothermic reactions at high temperature and the chemical equilibrium

Why are many exothermic reactions, like Haber process, conducted at high temperature, thus their unfavourable equilibrium position?
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### If $ds>=dq/T$ for a spontaneous change is $ds<=dq/T$ for a non-spontaneous change and is that even possible?

I am struggling with the concept of entropy but might be on the verge of understanding it. The Clausius inequality - $ds>=dq/T$ - is true for all spontaneous changes with the equality for ...
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### How is ethanenitrile protonated?

I know that the proton will attack the HOMO, but I'm having difficulty imagining how this will happen. Thank you.
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### Find the final temperature and the amount of ice left in the system [on hold]

10 g of ice at -10°C is added to 10 g of water at 85°C. What is the final temperature and amount of ice left in the system? (System is kept inside an ideal insulator). a) 0°C, 0 g b) 0°C, 2 g c) ...
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### Q-value for fission [on hold]

if the Q-value for fission of Bi-209 is approximately 160 Mev,estimate the critical energy for fission of this nucleus?
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### Is Benzene Carbaldehyde a correct name?

.. For Benzaldehyde? I'm (always) getting confused between common and IUPAC names. If the above name is correct then is it common one or IUPAC, and why don't we use it more often? Any help would be ...
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### stone which turns to black on exposing to atmosphere?

My mom is using a stone like substance as a dye for hair recommended by a herbalist. That stone becomes black when exposed to air. Do you know which compound is this?
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### How is the octane percentage defined?

Normally octane percentage is mentioned on petrol (95% octane). How is this defined? Is it percentage of chemical or some other parameters?
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### Why do many pharmaceuticals contain fluorine?

What exactly does fluorination of some compound do in a biological sense? I read the following things about what fluorine does for drugs: Fluorine withdraws electron density and can make an acid ...
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### Electrolysis on aqeuous solution

I know when electrolysis on a concentration aqeuous solution which contains halide ions($Cl^-$ , $Br^-$ , $I^-$). The halide ions is discharged although $OH^-$ is more easily to discharged. For ...
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### Why are square planar coordination compounds with four different ligands optically inactive?

Why square planar co- ordination compounds of type Mabcd do not show optical activity, although they contain 4 different ligands ( i.e. chiral central metal atom)
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### How can we measure electronic excitation in some “nm”(nanometres)?

I have no idea to which concept this belongs: The widest range over which electronic excitations in organic compounds occur, is A) 200 nm – 780 nm B) 220 nm– 500nm C) 250 nm– 700 ...
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### Which vibrational modes of CO2 and CSO do not lead to IR absorption bands?

I recently came across this question, I have no idea about IR: Which of the following vibrational modes show no IR absorption bands? A) Symmetric CO2 stretch B) Antisymmetric CO2 ...
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### Chemical composition of petrol

What is the chemical composition of petrol? What are the molecular available in petrol? Some time which is marked with 95% octane. So what is the remain element occupied 5%?
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### Fermentation in the presence of UV light

Does the presence of UV light, or any radiation for that matter, affect the process of fermentation? I'm not sure, but I seem to recall somebody telling me before that yeast will not function ...
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### Trouble to predict the effect of pressure and temperature for a reaction in equilibrium

I have trouble to predict the effect of decreasing pressure and increasing temperature on the reaction $N_2 +O_2 = NO_2$. Increasing temperature caused this reaction to shift in the forward direction ...
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### Why can't the conjugate base of benzoic acid be stabilized by conjugation with the aromatic ring?

All the carbon and oxygen atoms are sp2 hybridised and can have a p orbital in the correct plane yet only conjugation of the COO- group occurs. I can't think why. I can't draw resonance structures for ...
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### Compressible Factor

I 've a soft question on the terminology of compressibility factor. It is termed compressible factor because, its value determines how any reals gas is compressible with respect to an ideal gas ...
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### Electrochemical Equilibrium with molar mass [on hold]

The electrochemical cell described by the cell notation has an $\mathrm{E^o\ of\ 0.10 V}$. Calculate the maximum electrical work (kJ) the cell has done if $\mathrm{157.41 g}$ of $\ce{H+(aq)}$ (Molar ...
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### How can double compounds like XeO4 form tetrahedral structures despite having double bonds?

Xenon tetroxide is tetrahedral despite having double bonds. Is it something to do with d orbitals? Also things like sulfur trioxide (trigonal planar with three double bonds but the sulfur is ...
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### Why are only ozonides of heavier elements stable?

Most ozonides which are stable are of Cs, Rb, K but not of Na, Li. Why? Why they have no mention often?
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### Cation exchange capacity via IR spectroscopy? Is it as good as barium exchange? What is the intutition on how it works?

Cation exchange capacity is often regarded as the single best summary statistic for soil fertility. Years ago, I learned how to measure it myself, in a soil lab. I used compulsive barium exchange, ...
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### Plotting p/T against T

This is about the ideal gas equation $$pV=nRT$$ to plot ${p}\over{T}$ against $T$, where ${nR}\over{V}$ is constant. How would this graph look like?
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### Doubt in Cannizzaro reaction

My doubt is, how do we predict the products of a cross Cannizzaro disproportionation in presence of a concentrated base? Ie, How to judge which of the aldehydes (both don't have any alpha hydrogen) is ...
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### Analytical chemistry - solid phase extraction [on hold]

how to use solid - phase extraction of Zn(II) , Cu(II) , Pb(II), Co(II) employing L2 chemically attached to sol-gel ( L2 : N',N'2-bis[ (1E)-1-(2-pyridy1)ethylidene] ethanedihydrozide
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### use solid-phase extraction of Zn(II) ,Cu(II) , Pb(II),Co(II) employing N',N'2-bis[ (1E)-1-(2-pyridy1)ethylidene] ethanedihydrozide to sol-gel [on hold]

use solid-phase extraction of Zn(II) ,Cu(II) , Pb(II),Co(II) employing N',N'2-bis[ (1E)-1-(2-pyridy1)ethylidene] ethanedihydrozide to sol-gel
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### Flakes rather than cubes [on hold]

In the supermarket, I walked to the seafood section. Then, I discover the ice surround is not in cubes, it's in flakes form, meaning thin piece of water. So,my question how do these water flakes ...
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### What is the difference between carboxylate ions and groups?

I would like to know the difference between carboxylate ions carboxyl groups? An example is is $\ce{COOH}$ and $\ce{COO}$.
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### Oxygen dissolve in water

I know that $CO_2$ and $O_2$ are slightly soluble in water ($H_2O$) In my understanding, when carbon dioxide dissolve in water, they will react to form carbonic acid just like the equation below. ...
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### The pH of a neutralized solution

If pH is defined as the concentration of Hydrogen ions in solution, then how can a 'neutralized' solution (defined as having an equal amount of Hydrogen and Hydroxide ions) have a pH other than 7? ...
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### Reactivity series of metal

I have learned about metal and their reactivity series. However, why metals have different reactivity? What are the factors of different reactivity rate for metal? All I can think of is the number of ...
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### determine temperature increased? [on hold]

On heating a gas it pressure and volume both increases.By lowering temperature one fourth of initial number of moles of air are taken in to maintain the double pressure and volume. By what fraction ...
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### Strong and weak acid

I know sulphuric acid is a strong acid and acetic acid is a weak acid. However when I write them in their chemical symbol. Sulphuric acid: $\ce{H2SO4}$ Acetic acid: $\ce{CH3COOH}$ And I realise ...
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### How ‘lively’ would this ‘health’ potion be?

I’ve stumbled across a rather peculiar recipe for a allegedly ‘health’ potion in a computer game, composed of an unspecified amount of each of the following: rust (iron oxide) saltpetre (potassium ...
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### I need help with finding out how to get 2g of Lead (II) Iodide? [on hold]

I need to get 2 grams of lead (II) iodide precipitate but I don't know how much lead (II) nitrate and potassium iodide I need to get that result. The balanced chemical equation is: \ce{Pb(NO3)2 + ...
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### Find the amount of moles [on hold]

How can I calculate the amount of moles of water that is formed given a theoretical value of -55.90 kJ/mol $\ce{H2O}$ that is formed and from using the amount of joules of heat that is liberated.
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### What are the specific disadvantages of using a bio-catalyst (called Lipolase) in the synthesis of the drug pregabalin?

I am studying the synthesis of a drug pregabalin, for which both chemical and bio-catalysts are used. Using a biocatalyst is way better than chemical route, as explained here. In fact, The invention ...
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### Drabkin Method for Hemoglobin Determination

Good evening, I have done several measurements of whole blood diluting it in Drabkin's solution. I need to plot calibration curve but I don't know how to. The concentration calculation is done by this ...
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### Lowest CAS Registry Number on Record

I've been looking for a while and I still can't get a straight answer. I just need to know the lowest CAS Registry Number on record and the corresponding chemical.
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### What is 'equality' of chemical bonds?

I was trying to solve a test series and I saw this question: "Why all $\ce{C-O}$ bonds in $\ce{CO_3^2-}$- are equal but not in $\ce{H2CO3}$?" I am completely confused by this question.
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### Does dissociation require energy to occur?

I assume spontaneous separation to ions of salt solution (or acid) requires energy to occur, right? Where does that energy come from? Is it from the heat of the solution? Now, if someone devised a ...