# All Questions

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37 views

### How to account for dilution in the sample solution when reading calibration standards?

I have been provided the following table of calibration standards from an ICP-MS experiment. (Some text is in German, I am operating in a location where DIN standardization is ubiquitous) I ...
25 views

### Which is more efficient way to generate energy using hydrogen: direct hydrogen combustion or through fuel cell? [closed]

Which is more efficient way to generate energy using hydrogen: direct hydrogen combustion or through fuel cell? Please explain so that even a primary school student can understand.
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### Average hydrogen bond per molecule

Is there a uniform hydrogen bonding between molecules in the compound that experiences hydrogen bonding? Let's say for water molecules, the average hydrogen bond per molecule is 2.So does this mean ...
157 views

### Is it possible to increase the internal energy of an ideal gas in an isothermal process?

Ideal gas is the one in which there are no attractive or repulsive forces acting and hence its internal energy is due to kinetic energy of its molecules. We may then say, for an ideal gas internal ...
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### How to model a molecule of benzene surrounded by 100 molecules of water with molecular dynamics?

I have experience calculating molecular properties (mostly DFT). However, I would like to spend some time on molecular dynamics methods. I would like to ask your advice to direct me towards a program ...
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### Photobromination of cyclohexene

During bromination of cyclohexene in the presence of hv via free radical mechanism, there are two allylic carbons. Why does the major product have only one Br an not a Br on either side of double bond....
2k views

### Is “Sulfuric acid… makes a poor electrolyte… very little of it will dissociate into ions” really true? What does that actually mean?

While researching chromate conversion coating for edits to this answer in Space Exploration SE, I came upon the following passage in Corrosion Resistance of Stainless Steel to Sulfuric Acid Sulfuric ...
52 views

### Why isn't canned food good forever? [closed]

So everything inside the can has been killed and nothing can get in. So why doesn't it last forever then?
59 views

### what does it mean to say oxygen in a given context?

My textbook "chemistry by Julia" says the following When it comes to expressing the molar mass of elements such as oxygen and hydrogen, we have to be careful to specify what form of the ...
45 views

### What is 'absorbance power' in electrochemistry?

I have been asked $\ce{250 mL}$ solution of unknown molarity of $\ce{CuSO4}$ in water was electrolysed using platinum electrodes. After the passage of a current $2 \times 10^{-3}$ ampere for $19.3$ ...
21 views

### Why do we need salt bridge in a cell during potentiometric measurement as there is no or minimum redox activity at electrodes?

In electrochemical cell, we need salt bridge to maintain electrical neutrility in both halves cells during redox reaction?. But in during potentiometric measurement, no or minimum current is drawn and ...
76 views

### How many bonds does oxygen really make in minerals?

I'm studying some metallurgy things and interested in iron oxides. The simple 2-D representation of a mineral like hematite shows $\ce{O=Fe-O-Fe=O}$. But the crystal structure seems to show each ...
37 views

### I’m looking for a reusable adhesive that sticks to skin and is safe to use. It needs to be a thin strip that is sticky on both sides

The key here is that it is reusable. I keep thinking of the silicone chest pad that I use, wish can be washed and reused again. It has lasted me over a year and a half, and continues to stick. But ...
29 views

### What is the rate constant k for the reaction between potassium manganate and oxalic acid?

For my school's chemistry classes, I am investigating the kinetics of the redox reaction between $\ce{K2MnO4}$ and $\ce{C2H2O4}$. I analyzed the data using a colorimeter set to $\pu{565nm}$. ...
39 views

### What are the products when KCl and H2SO4 reacts? [closed]

I have been trying to find the right answer by googling and I just ended up finding multiple answers. Ans #1: $\ce{2KCl + H2SO4 -> K2SO4 + 2HCl}$ Ans #2: $\ce{KCl + H2SO4 -> KHSO4 + HCl}$ Can ...
59 views

### Isomers of a Cycloalkane [closed]

What I know: All alkanes are saturated hydrocarbons with the general formula, $C_nH_{2n+2}$ All alkenes are unsaturated hydrocarbons with the general formula, $C_nH_{2n}$ What's Confusing Me: This ...
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### Magnetic behaviour of potassium permanganate

I was going through the properties of potassium permanganate and found this- It has two physical properties of considerable interest: its intense color and its diamagnetism along with ...
25 views

### Determining the leaving group for substituted benzene in Aromatic nucleophilic substitution

I could figure out that After the substitution of one of the halogens, with the $\ce{-OCH3}$ group(Electron donating group), the ring would be deactivated towards nucleophilic substitution hence the ...
37 views

### what does Area(A) in Randles-sevcik equation refer to? geometrical area of electrode or electrochemical active surface area/

In the Randles-Sevcik equation, $$i_p = 0.4463 \ nFAC \left(\frac{nFvD}{RT}\right)^{\frac{1}{2}}$$ we have an area $A$ in the formula. is this the electrochemically active area or geometrical area? ...
31 views

### How many equivalents of Grignard reagent does a nitrile group consume?

I was looking at reactions of grignard reagent with certain kinds of compounds and came across it's reaction with nitrile group: What I was wondering is what if we don't react the Imine formed after (...
28 views

### Why is Cu2o[Copper(I) oxide] a (p-type)semiconductor?

Statement: Cu2O[Copper(I) oxide or cuprous oxide] is an extrinsic (p-type) semiconductor. Main Question: But why is Cu2O an extrinsic (p-type) semiconductor? My confusion: I understand how Silicone ...
42 views

### Can dehalogenation reaction occur through E2 mechanism? [closed]

I have seen examples of dehydrohalogenation reaction that occur through E2 mechanism but never came across dehalogenation reaction that occur through E2 mechanism (for example, dehalogenation of 1,2-...
9 views

### What unit and dimension for membrane permeability / permeation expression?

Context When studying the diffusion of gases through thin membrane, one may use the diffusion coefficient $D$ used in Fick's laws as (one dimension form): J = - D \cdot\frac{d\varphi}{...
191 views

### What does the state of a substance at a specific T and P mean?

From the phase diagram of water, we see that water is a liquid at 20°C, 1 atm. The state of the water at 20°C, 1 atm is liquid. But there is actually also a water vapor in equilibrium with liquid ...
41 views

### Why is surface tension of water decreasing as sodium chloride concentration increases? [duplicate]

For my IB chemistry IA, I am measuring the impact of salinity concentration on the surface tension of water (i am using distilled water). My hypothesis is: As the concentration of salt increases, ...
58 views

### Linear equations for constructing molecules with covalent bonds

(By training I am a math-guy and my knowledge of chemistry is restricted to school level) I have read a little bit about the electron spheres and sub-spheres, the Aufbau principle and covalent bonds ...
113 views

### Out of tropolone and tropone, which is more soluble in water?

According to me tropolone has intramolecular H-bonding, so extent of H-bonding with water will decrease and thus, will be less soluble. Tropone (Cyclohepta-2,4,6-trien-1-one): Tropolone (2-...
31 views

### Phosphate buffer not electroneutral? [closed]

According to the equations below, the phosphate buffer is not electroneutral, except at pH = 7. But it should be electroneutral, right? What did I miss here? In order to prepare $X\,\pu{ M}$ buffer ...
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I conducted TLC to confirm Rf value of toluene. Eluent was hexane+ethyl acetate(10:1 vol). Then I used UV lamp (254 nm) to identify the spot. But there was no any spot. I had understood that toluene ...
13 views

### What is an effective preservative for guar gum slime?

I am attempting to find an effective preservative for guar gum slime. I am using typical recipes: A borax solution of 4%, a guar gum solution of 5% using distilled water, and a mix ratio of 20:1 (guar ...
12 views

### Common ion effect on Solubility [closed]

The common-ion effect refers to the decrease in solubility of an ionic precipitate by the addition to the solution of a soluble compound with an ion in common with the precipitate.[1] This behaviour ...
401 views

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### VD of a container containing A [closed]

V.D. of a container containing A was found to be 20. Now the container is heated due to which A changes according to the reaction nA=An. After the end of the reaction the vapour density was found to ...