# All Questions

29,901 questions
32 views

### Plotting phase diagram of mixed gas (Bubble and Dew points)

I'm developing a software which plots the Phase diagram (PT) for a mixed gas solution. I have the methods for Bubble and Dew points almost working. When I look at phase diagrams of commercial ...
18 views

### Finding the ionic product through conductivity [closed]

The conductivity of saturated barium sulphate solution at $\pu{25 °C}$ is $\pu{3.6e-4 S m^-1}.$ The water from which the solution was made had conductivity of $\pu{0.6e-4 S m^-1}.$ What is solubility ...
47 views

### How does a pH glass electrode work?

Every source I read mentions the potential difference building up at the glass membrane (according to the Nernst equation). But how is this difference actually measured? Sticking an electrode into a ...
17 views

### Aquaregia reaction time [closed]

In what time does aquaregia dissolves metals? If the time differs with different metal, on what factors does the time varies?
16 views

### How do I go about calculating which of several carbonates would most easily decay when exposed to an acid?

For instance, I'd want to compare CaCO3, ZnCO3, MgCO3, etc and find out which one will decay with the least amount of an acid? Which laws / principles are involved that I'd need to find out how to ...
35 views

### Why is ozonolysis of benzene possible?

I was looking at a question which asked to predict the product of reductive ozonolysis of benzene using $\ce{Zn/O3/H2O2}$ and I predicted them correctly using the cleaving of the double bond shortcut ...
11 views

### Heat transferred to a calorimeter [closed]

In a calorimeter, 25 mL of H₂SO₄ of density 1,8 g/mL were diluted to 100 mL with water. A temperature variation from 15 °C to 86 °C was registered. What is the heat transferred to the calorimeter? ...
654 views

### Why are isotopes an issue in reading mass spectra?

It is my understanding that the isotope distribution for carbon and hydrogen, for example, are skewed heavily toward one species, i.e., one isotope accounts for ~99% of the abundance of the element in ...
50 views

### Ethanol is added to chloroform bottle

I was doing MCQ and the question asked was ethanol is added to chloroform bottles. I know chloroform it gets converted to phosgene gas (which is poisonous gas in presence of air and light ). to ...
65 views

### Grignard alkene on a carbonyl

I was given the following mechanism to prove today post-lecture: and my attempt is given below. Now, when the negative charge on the alkene attacks the carbonyl, the electrons are pushed onto the ...
44 views

### Is this balanced redox equation correct? [closed]

I'm trying to balance an equation using oxidation numbers $\ce{MnO4^- + H+ + Cl- -> Mn^2+ + Cl2 + H2O}$ my suggestion: $\ce{MnO4- + 8H+ + 5Cl- → Mn^2+ + 2.5Cl2 + 4H2O}$ the 2.5 $\ce{Cl2}$ is ...
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### What is the mechanism of ring contraction of 6-bromo-7-methoxy-2,3,4,7-tetrahydrooxepine from seven to five?

I have recently come across a paper from here.I have tried to workout the mechanism for the following reaction presented in the paper. I was able to workout mechanism till acetal formation.It is a ...
33 views

### What is the term for passing an eluate back through an adsorption column?

In my experiment I am passing a solution through an adsorption column, collecting the eluate, then passing the eluate back through the same column. Is there a concise term which describes this ...
45 views

### What Chemical Compounds Combust when Burning Coal & What is Coal Made of

My research suggests that when burning Coal to produce energy (or just burning coal in general), Carbon Dioxide is released into the other along with other gaseous chemicals. What other chemicals ...
29 views

### Is the cleavage of ester bond in fats endothermic or exothermic? [closed]

When a triglyceride (castor oil) is broken down into glycerol and corresponding fatty acids is heat liberated or absorbed ? If yes, is there a trend in the the heat of reaction depending on what the ...
20 views

### Any method for testing Nitrate and Nitrite in biological fluids like aqueous humour?

If anyone knows the methods of detection of nitrate and nitrite in biological fluids such as aqueous humor, saliva of animals, please let me know. Any relevant literature for the same is available, ...
1k views

### What does “lit.” mean in boiling point or melting point specification?

For example, this Xanthene 99% specification from Sigma Aldrich states: \begin{array} \\\hline \text{bp} & 310-312 ~^\circ\mathrm{C~ (lit.)} \\\hline \text{mp} & 101-102 ~^\circ\mathrm{C~ (...
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### Understanding lattice matching of graphene on silver (111) crystal surface and meaning of the √3 x √3 lattice?

Figure 1 in Ivor Lončarić and Vito Despoja, Phys. Rev. B 90, 075414 Benchmarking van der Waals functionals with noncontact RPA calculations on graphene-Ag(111) (available in Researchgate) shows a ...
9 views

### Please what is the implication of this spontaneity of a reaction when Q >, Q<, and when it =0 [closed]

Please what is the implication of this spontaneity of a reaction when Q >, Q<, and when it =0
39 views

### Equivalent weight of oxygen molecule [closed]

In the reaction: $$\ce{O2 + 2H2 -> 2H2O}$$ The oxidation state of oxygen changes form 0 to -2, so the equivalent wt of oxygen molecule is 16. And similarly it is 2 for hydrogen. Am I right? If i go ...
29 views

### Is it correct that at >115 °C: 3MgCO3·Mg(OH)2·3H2O(s) + Mg(HCO3)2(aq) ⤑ 4MgCO3·Mg(OH)2·3H2O(s) + CO2? [closed]

Is it correct that $\gt \pu{115 °C}$: $$\ce{3MgCO3·Mg(OH)2·3H2O(s) + Mg(HCO3)2(aq) -> 4MgCO3·Mg(OH)2·3H2O(s) + CO2?}$$
35 views

### Titration of aspirin

I have performed an experiment to test how temperature affects how fast aspirin dissolves by titrating solutions at various time intervals. According to this website, aspirin reacts with water as such:...
21 views

### How do I calculate the proportion of respective conjugates of one base mixed with several acids (and/or conversely) at different temperatures? [closed]

How do I calculate the proportion of respective conjugates of one base mixed with several acids (and/or conversely) at different temperatures, and is there a free software tool that would allow me to ...
41 views

### Silver (111) surface structure, and is bulk structure body-center or face-center cubic?

I'd like to understand the atomic arrangement is on a silver (111) surface. Step 1 would be to find out the bulk crystal structure. Wikipedia lists silver as face-center cubic (fcc) here and here ...
27 views

### “Hairy” corrosion on anodized alu-part in water

I got a water tank with a mechanical assembly in. The assembly consist of parts of anodized aluminium mounted on stainless steel plates (AISI 304). This is submerged down in fresh water. The tank is ...
31 views

### Why does steam distillation work?

I'm aware that there is a similar question here but it didn't really answer my specific questions. I understand that steam distillation is used to separate an insoluble liquid from an aqueous solution,...
36 views

### The effect of nitric acid on the rate of corrosion of copper

I conducted an experiment concerning the rate of corrosion of copper when submerged in three solutions. In the first solution, 5ml concentrated nitric acid and 10 ml distilled water was added. In the ...
49 views

### 4-Bromophenol vs 4-aminophenol pKa in water comparison confusion

Recently the other week, I was asked the following question: Would you expect 4-aminophenol to have a higher or lower pKa than 4- bromophenol when measured in water? And I thought about this on ...
28 views

### Mechanism of Acid Hydrolysis

I wanted to ask a question about acid catalysed hydrolysis. I learnt in an introductory course to Physical Organic Chemistry that there are different ways that an ester can be hydrolysed acidically: ...
24 views

### How do fuel cells work? [closed]

I have been reading an introductory book on fuel cells, and it's indicated that SOFC need to be brought to $\pu{600\! -\! 1000 ^\circ C}$ to be more efficient. So, my understanding is that if I want ...
17 views

### Identification of Acid,Base [closed]

Why $\ce{AlCl3}$ being an acid on dissolving in aqueous solution did not give $\ce{H+}$ ion?
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### How do metals split the oxygen double bond during corrosion?

For a metal like $\ce{Mg}$ to corrode into $\ce{MgO}$, the double bond in $\ce{O2}$ must break. Since the dissociation energy of $\ce{O2}$ is 500 kJ/mol, using estimates from the Boltzmann ...
147 views

### Cause of uniform glow in cathode ray tubes

I got the following extract from a chemistry book (emphasis mine): It is observed that current does not flow through the gas at ordinary pressure even at high voltage of 5000 volts. When the ...
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### Why does hydrogen burn spontaneously in fuel cell at room temperature?

It's well known that if you mix $\ce{H2}$ and $\ce{O2}$ in ambient conditions, the $\ce{H2}$ will be stable indefinitely, and will only react with $\ce{O2}$ to form water when ignited by a flame. The ...
52 views

### DNA-Sequencing (detection of the change of pH-value) after emulsion PCR

I have troubles with understanding the exact order of the steps for DNA-sequencing after the Emulsion PCR (EmPCR). The EmPCR fills each bead with the same DNA strand (copies it $n$ times, till the ...
25 views

### Why the bond angles of crystalline compounds uniform while in the amorphous state the same compound has non uniform bond angles?

For example, let us take amorphous and crystalline quartz. While in crystalline quartz all bond angles are uniform, in amorphous form bond angles vary even though quartz has the same valency. Why is ...
80 views

### Equilibrium constant for a solid-solid equilibrium

Suppose there are two equations: \begin{align} \ce{A(s) &<=> B(g) + C(s)} &\quad &K_1 \tag{R1}\\ \ce{B(g) &<=> D(s) + E(s)} &\quad &K_2 \tag{R2} \end{align} ...