# All Questions

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1 vote
22 views

### NMR Inductive effect of Carbon single and double bonds with Oxygen

I am trying to determine and understand the chemical shifts on NMR of the B and C carbons. Although it is quite obvious, I am trying understand why the inductive effect of the oxygen with the double ...
• 497
13 views

### What are examples of protein structure that react positively with Molisch's Test? [closed]

It is known that aside from carbohydrates, glycoproteins and nucleic acid reacts positively with Molisch's Test. What are some specific examples of glycoproteins that yields positive result under ...
33 views

### Which one reacts first with NaOH; Triglycerides or FFA?

I want to saponify Crude Palm Oil (CPO) with NaOH. The CPO itself contains 97,35% of triglycerides and 2,5% of free fatty acids. Which one reacts first with NaOH?
1 vote
56 views

### Can an equilibrium be reached when there is an excess amount of one reactant over the other reactant?

For example, consider a net reaction between ferrous nitrate and potassium thiocyanate: $$\ce{Fe^3+(aq) + SCN-(aq) <=> (SCN)^2+(aq)}$$ Can an equilibrium be reached if there is a much greater ...
• 11
1 vote
19 views

### Rationalisation of stabilising dispersion interactions in HgS via QM

It is well-known that mercury(II) sulfide, HgS, is extremely inert- for example, it has one of the lowest solubilities of nearly all known compounds in water(check Wikipedia). There are two well-known ...
• 628
20 views

### Why does the octet rule apply to atoms with more than two shells? [duplicate]

If the third shell needs 18 electrons to be full, why is it considered to be stable with just 8? That wouldn't be a full shell.
42 views

### Oxidation of Methanol - how to write the half reaction

I am trying to write the half reaction equations for: $$\ce{CH3OH + O2 -> HCOOH + H2O}$$ The primary goal for me here is to find out which reactant is oxidising without using prior knowledge of ...
• 105
20 views

### Where do lactone groups occur in graphene oxides and how are they identified using FTIR measurements?

Usually, the literature (for example, Serodre et al. [1]) shows the occurrence of lactones in graphene oxides through potentiometric titration measurements. In the nanosheets, do these groups occur in ...
15 views

### Why does change in pressure not affect Kp? [duplicate]

Why doesn't change in pressure affect KP when you use partial pressure to work it out?
23 views

### Temperature's change while dissolving common substances [closed]

As a non-chemist nor chemist-related researcher, I got to know how to calculate change of temperature of known amount of water while dissolving known amount of table sugar, table salt, etc. The point ...
• 11
1k views

### Are there any aromatic systems that don't contain any rings?

I'm curious if there are any aromatic systems that don't contain any rings. I just wonder and want to know if there is any exception to the aromatic system. I know the definition of aromaticity is ...
• 119
84 views

### Does carbon dioxide come out of solution on freezing?

Years ago in a lab where I was working someone had the excellent idea of cooling down their can of coke by pouring liquid nitrogen over it. The can exploded and resulted in quite a mess. My question ...
• 1,398
41 views

### Breaking Bad's 99.1% Methamphetamine Purity [closed]

Is there any chance that we can produce 100% Purity of Methamphetamine?
• 1
1 vote
68 views

### How are photons converted into thermal energy?

I know when light strikes an object it excites electrons into higher energy states. I know thermal energy is basically just a lot of atomic and molecular kinetic energy. Does the excitation of the ...
• 11
1 vote
69 views

### Converting structures into Fisher projections

I am really struggling with converting pyrano/furanosides into their Fisher projection counterparts. Especially when they are drawn like in the shown projection. When do you know to connect the ...
• 11
1 vote
76 views

### How many multivalent elements are there?

According to this video there are 20 multivalent elements, and from the periodic table, I see 20, but according to multiple websites, including this, it says there are only 5. What am I not ...
• 37
308 views

### Is it appropriate to call an element an amphoteric substance?

In most of Japanese high-school textbook it is written that Al,Zn,Sn and Pb are amphoteric element(in Japanese 両性元素）because they react both with strong acid and base. For example Al reacts like below. ...
30 views

### Why does the coordination of alkaline earths by graphene oxides increase as a function of the increasing ionic radius of the species?

The literature describes that the affinity of graphene oxides towards alkaline earth metals presents a positive correlation with their ionic radius (for example, Klímová et al. (2016) and Sófer et al. ...
20 views

### How much energy is needed for the result of burning lead paint to be ionized? [closed]

if one oxidizes 2PbCO3-Pb(OH)2 in a high heat environment (~500°C), how many Watts does the electrode need to ionize all of it? whats the effective range of the ionization? I'm asking to verify if ...
31 views

### Is there any calcium carbonate analogue drawing carbon from dry air?

Is there a nonliving (wood does not count) substance or process that accretes a solid material by withdrawing carbon from the air, in a manner analogous to calcium carbonate being accreted from ...
42 views

### Liberation of hydrogen in various acids by copper [closed]

Why doesn't copper liberate hydrogen with $\ce{HCl}$? When surfed it on the internet and asked my friends and teacher, they all said that because it was under hydrogen in electromotive series, but I ...
49 views

### Why can't galavanic cells run without an electrolyte? [duplicate]

If all that needs to happen in a galvanic cell is transfer of electrons from one electrode to another, why can't we just join them directly? What is it that the electrolyte does that keeps the cell ...
35 views

From the article by Kamakura et al. [1]: …powder was prepared by solvothermal reaction of $\ce{Pb(NO3)2}$ and $\ce{H2tadt}$ in a mixture of water and acetone… What does $\ce{H2tadt}$ mean here? ...
• 107
24 views

### What is a "universally activated methyl donor?

From Cerebral Folate Deficiency Syndrome: Early Diagnosis, Intervention and Treatment Strategies The accumulated L-dopa in the CNS will be converted to 3-O-methyl-dopa using the enzyme catecholamine ...
• 3,186
43 views

### Calculating the threshold frequency and kinetic energy of emitted electrons [closed]

I was working on the following problem: The work function of sodium is $\pu{2,5 eV}$. We illuminate it with a radiation that has a wavelength of $\lambda = \pu{2.0E-7 m}$. What is the threshold ...
• 19
39 views

### Photoelectric effect problem: what is maximum wavelength for the photoelectric effect to happen? [closed]

I was working on the following problem, Find the kinetic energy of an electron removed from the surface of a certain metal by a radiation of frequency $\lambda =5\times10^{15}\; Hz$, if the ...
• 19
15 views

### Titration of solutions [closed]

A 10g sample of iron (¡¡) sulphate.FeSO4 was dissolved in water to make 250cm3 of solution.Exactly 25.0 cm3 of the solution was titrated with 0.025 mol/dm3 potassium manganate (vii),KMnO4,until the ...
1 vote
7 views

### Crude palm oil DOBI analysis

I'm performing Crude Palm Oil DOBI spectrum analysis using uv-1900i UV-VIS spectrophotometer at a range of 269nm and 446nm but it's only giving peak absorbance at 446nm but no reading at 269nm,what ...
35 views

### Store Palladium Chloride in Solution

I have one gram of palladium chloride ($\ce{PdCl2}$) and I want to use very small quantities of it, in milligrams somewhere. It is not possible for me to get my hands on a scale that can measure that ...
243 views

### Intense purple colour of litmus paper in contact with calcium oxide

When conducting an experiment to identify some common chemicals, I tested crystal/powder samples of the chemicals with moist litmus paper. When I put a piece of blue paper on some $\ce{CaO}$ powder, ...
36 views

### Are substituents placed alphabetically in the name of a cycloalkane?

I named this molecule 1,5-diethyl-2-methyl-4-propylcyclohexane. Is this correct? Or should we somehow use the size of the substituents?
• 29
164 views

### How do we know the ionic charge of iron or elements such as iron on the periodic table?

How do we find iron's ionic charge? I was taught that we use roman numerals but I don't see any on the basic periodic table of elements (I'm using this one). So how do we find iron's charge of Fe 2+ ...
• 37
1 vote
101 views
+50

### Why Hg doesn’t form hydroxide?

In my textbook it was written that if you put alkali solution into Hg2+ solution you won't get Hg(OH)2 but you get HgO. And this is because Hg has high electronegativity and this makes polarization of ...
75 views

### Equilibrium Bond Length & Diatomic Molecules

Must every diatomic molecule always have an equilibrium bond length? That is, is there always a distance between two nuclei such that the Coulomb attraction between the electron and protons ...
49 views

### What does it mean and what are the implications of individual electrons being identical?

In Jeremy Harvey's Computational Chemistry, I found the following statement: [...] all electrons need to be treated as being very strictly identical to each other, so the wavefunction cannot treat ...
25 views

### Project Title for High School Project Competition [closed]

I'm looking for a chemistry project for an high school project competition. I'm 9th grade. I want to do a project in "Materials and Nano Technology" branch of chemistry but I couldn't be ...
1 vote
63 views

### Why do we say "octadiene" and at the same time name another compound "octanediol"?

Why do we say "octadiene" and at the same time name another compound "octanediol"? We also say for instance "pentanedione", but on the other hand we say "butadiyne&...
• 29
19 views

### Explanation and terminology of a phenomenon [closed]

Please observe the picture given- I want to know what exactly is this phenomenon and what exactly is causing it. Context - an organic solution (WD40) is spilt on a wet surface outside, light bouncing ...
• 19
1 vote
63 views

### What is the point of the up arrow (↑) which shows "gas evolved" or "gas liberated", if you could just write the state symbol (g)?

What is the point of the up arrow (↑) which shows "gas evolved" or "gas liberated", if you could just write the state symbol (g)? And would you write the up arrows (↑) and down ...
• 29
20 views

### What happens to the chemical structure of cellulose after carbonization?

My notion is that carbonization removes the hydrogen and oxygen in cellulose $\ce{(C6H10O5)_n}$, leaving the carbon. Therefore in simpler terms, carbon is left which is in the form of char. Is my ...
• 7
113 views
+50

### Why is Hg2Cl2 less soluble in water than HgCl2?

I learned that $\ce{Hg2Cl2}$ is almost insoluble to hot water and $\ce{NH3}$ water in my textbook, but $\ce{HgCl2}$ dissolves well in water. I wanted to know the reason and searched for it. It's ...
47 views

### Why would a reaction be nonspontaneous at higher temperatures?

Typically we think of a higher temperature speeding up the reaction rate and/or supplying the activation energy of a reaction. So why is it the case that some reactions are only spontaneous at lower ...
• 13
26 views

### Can certain chemicals change the color of a solid? For example, can liquid potassium or liquid sodium change the color of a red construction paper? [closed]

I have seen many videos and posts online about how many liquid chemicals change their color when come into contact with other liquids or fire. However, I have never seen anything about changing the ...
17 views

### Adjusting the Equilibrium of a Solution to change pH by kinetic impact [closed]

I am a physics student with introductory chemistry experience. Im being tasked with using collisions to show the differences in elasticity of collisions (basically how much kinetic energy is lost). I ...
29 views

### What is the degree of dissociation of Et3N [closed]

What should be the degree of unsaturation of Et3N. I'm trying to calculate and it comes out 0, but my text book tells me the answer is 3. I'm taking the number of C atoms to be 6 and H atoms to be 15 ...
21 views

### In cellular respiration, is water the product or the reactant? [closed]

Easy, water's the product! NOPE, my chem professor doesn't think so. Am I actually wrong or is a mistake on the exam?
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34 views

### Back titration of aspirin

We are planning to determine the aspirin content of tablets for a school project and learned that we need to do back titration first with NaOH then HCl. What would be the best indicator to use for ...
54 views

### Does boron have s–p mixing in borane?

I am looking at $\ce{BH3}$ MO diagram. According to the internet, boron has $\mathrm{s\text{–}p}$ mixing between its $2\mathrm p_z$ and $2\mathrm s$ orbital. However, MO theory also states that ...
39 views

### Why is the Gibbs free energy of titanium(IV) chloride reduction to titanium metal positive?

I use the Ellingham diagram to find the Gibbs free energy at the equilibrium state to find the partial pressure of chlorine. I have to use the Van 't Hoff reaction isotherm and the partial pressure of ...
My teacher show a case of backbonding in $\ce{O(SiH3)2}$. In that, we know oxygen is present in sp3 hybridization, with two bond pair and two lone pair. Silanide has empty 3d orbital, so obviously ...