# All Questions

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### Software for generating a lattice from a unit cell for molecular crystals?

I am looking for a software package which can take a unit cell (and lattice parameters, etc.) and from that generate a crystal lattice. Ideally it will have functionality for orthorhombic, hexagonal, ...
71 views

### How to calculate the number of protons in a sphere given the volume and the pH?

The spherical radius of a nano-droplet of a solution ($\mathrm{pH}$ of which is $6$) is given as $\pu{20nm}$. I can find the molar concentration of $\ce{H+}$ and subsequently the number of $\ce{H+}$ ...
26 views

### Different Lewis Structures for Sulfate [duplicate]

I was trying to draw the Lewis structure of Sulfate $\mathrm{SO_4^{2-}}$ that I realized that both of these structures are possible: The first one has two double bonds and two dative bonds while the ...
18 views

### Chemical equilibrium [duplicate]

When calculating equilibrium constant with partial pressures if there is a solid involved should we consider it in the total number of moles in mole fraction?
79 views

### How is antioxidant activity of carotenoids determined?

I am doing some research regarding carotenoids and beta-carotene. After extracting the sample, I have not been able to find a way to measure antioxidant activity of beta-carotene. I have $\pu{0.1mM}$ ...
162 views

### Show the acid nature of hydrogen sulfide

We are studying the chalcogens at school. I should prove (show) the acid nature of $\ce{H2S}$ by writing two chemical interactions. I am really sorry if the terms I am using aren't the right ones. It'...
57 views

### Confused on how to draw cis-[Ni(H2O)4(NH3)2]Cl2 [closed]

I got a question on my practice exam telling me to draw cis-diamminetetraaquanickel(II) chloride, but I'm not sure on how to place the two $\ce{Cl}$ atoms.
79 views

### How can one determine an atomic mass with high accuracy using gravimetric analysis?

In the Wikipedia article on gravimetric analysis it is said that gravimetric analysis was used to determine the atomic masses of many elements in the periodic table to six figure accuracy. There are, ...
38 views

### Calculating the Ionic strength of sodium acetylsalicylate

With the addition of aqueous NaOH to an aspirin solutions in water the reaction will yield products of sodium acetylsalicylate and water. I would like to measure the amount of sodium apsirin formed ...
20 views

### Why methaemoglobin is green? [closed]

Haemoglobin (Hb) in air will oxidize to MetHb with darker color (by O2). But in alpha-hemolysis (which result in formation of MetHb by hydrogen peroxide) in agar test will appear with green color ! I ...
12 views

### Acidic strength of phenol derivatives

While comparing the strengths of o-nitrophenol and p-nitrophenol, p-nitrophenol is found to be more acidic. The reason I studied for this is $\ce{H}$-bonding in o-nitrophenol which makes the acid more ...
37 views

### Reduction of amides with lithium aluminium hydride [closed]

Since $\mathrm{p}K_\mathrm{a}$ of primary amides are close to alcohols, will there be an acid-base reaction between amides and $\ce{LiAlH4}$ besides reduction?
34 views

### Characteristics of Isotopes [closed]

I'm currently applying information theory to physics, and have begun considering the nature of isotopes, and in particular, how much information is contributed to the properties of an element by its ...
25 views

### Displacement by more electropositive metal in non aqueous environment

The more electropositive element should displace metal from it's salts' solution. This can be seen in reaction of copper salts with iron. But, if you try using for example potassium metal as the more ...
47 views

### Determining structure from C-NMR spectrum, is my answer correct?

Determine the structure of the compound whose spectral data is given below and explain your reasoning (5 marks for structure, 15 marks for reasoning). The peak at 7.27 ppm does not belong to the ...
20 views

### Calculate pH of borax-boric acid buffer solution? [closed]

In a recent experiment I made a borax-boric acid buffer solution by dissolving 9.535 g of borax in water and adding 92 ml of 0.1 M HCl. The pH of this solution was given as 9.00. I then took 20 ml of ...
28 views

75 views

### R/S chirality question

Consider [(1⁠S,2⁠S,4⁠S)-bicyclo[2.2.1]hept-5-en-2-yl]acetic acid: (Source: http://www.chemspider.com/Chemical-Structure.22823922.html) According to the chemspider nomenclature, this has three S ...
44 views

### Why is 1,2-diiodoethane unstable? [duplicate]

Diiodoethane is a product of the reaction between glycol and $\ce{PI3}$. Why is 1,2-diiodoethane unstable?
36 views

### Reference request on formate potash process

Wikipedia article on Potassium Formate mentions a so-called "formate potash process" for production of potassium, presumably referring to elemental metal. Concise encyclopedia chemistry by Mary ...
37 views

### Hydronium ion concentration to compare pH values

I'm having a bit of trouble with this question: Which has a higher $\mathrm{pH}$ value, $\pu{0.001 M}$ $\ce{HCl}$ or $\pu{0.1 M}$ $\ce{CH3COOH}$ $(K_\mathrm{a} = \pu{1.8E-5})?$ I have calculated ...
28 views

### Question about the setting of DFT (Density Function Theory)-NEB (Nudged Elastic Band) calculation

I'm attempting to calculate Mg ion vacancy migration inside Pyrope unit cell. System has total 159 atoms, beginning and end geometry is optimized. For intermediate image, I'm using one coordinate that ...
43 views

### Validity of Maxwell-Boltzmann distribution for solids [duplicate]

Suppose there is a solid made of avogadro number of, say, aluminium atoms. This solid is kept at 273 K. According to Maxwell-Boltzmann distribution, all the particles or atoms will not have the same ...
329 views