All Questions

2
votes
0answers
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 ...
0
votes
0answers
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 ...
2
votes
0answers
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 ...
-1
votes
0answers
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?
-2
votes
0answers
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 ...
2
votes
0answers
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 ...
-1
votes
0answers
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? ...
9
votes
3answers
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 ...
0
votes
1answer
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 ...
3
votes
1answer
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 ...
-1
votes
2answers
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 ...
4
votes
0answers
30 views

What does “at%” mean and how it differs from “mol%”?

Sorry if my question is a bit obvious, but for some reason I'm getting confused with the percentages in this question: Concentration of $\ce{A}$ is $\pu{80 at\%}$ and concentration of $\ce{B}$ is $...
0
votes
1answer
38 views

Posible Pair of Enantiomers

What is the number of possible enantiomers in monochlorination of 2-methybutane? My approach When $\ce{Cl2}$ is added to any alkane it prefers $3^\circ > 2^\circ > 1^\circ$. When it is being ...
0
votes
3answers
77 views

Strontium-89 vs strontium-90

Why is radioactive strontium-89 is considered medically useful for bones (along with other benefits) whereas strontium-90 (also being radioactive) is harmful for human body? How does the addition of ...
-1
votes
0answers
22 views

sigma and pi bonding strengths [duplicate]

sigma bonds has a greater orbital overlap than pi bonds hence making sigma bonds stronger than pi bonds. How does the greater overlap contribute in a stronger bond?
2
votes
2answers
41 views

What reagents or series of reactions would allow for selective hydroxylation of an allylic methyl group outside of a ring?

Sample transformation for selective hydroxylation of an allylic methyl group outside of a ring. Selenium dioxide would not work since hydroxylation would be favored inside the ring.
-1
votes
1answer
26 views

Methyl iodide in water

Iodide being a good leaving group and water being quite a weak $\ce{Nu-}$, does $\ce{CH3I}$ undergo $\mathrm{S_N1}$ reaction? I was taught that whenever a protic solvent which can ionize the halide ...
-2
votes
0answers
18 views

Double coordinate covalent bond [on hold]

Can there be a bond where 4 shared electrons come from 1 atom in the molecule? Please explain why.
3
votes
1answer
53 views

Cahn–Ingold–Prelog Rules, cyclic structures, and breaking ties

(3S,5R)-3-ethyl-5-methylcyclohex-1-ene Does anyone know how one reaches the conclusion that the 5C is R? I tried using the Cahn–Ingold–Prelog priority rules but kept getting confused. From chem....
-1
votes
0answers
16 views

Gauss primitives located on non-atomic positions

I have the .wfn file including Gauss primitives. And I want to move several primitives to other coordinates... but how can I do it? I know there's a way to make a new atom in appropriate place and ...
0
votes
2answers
35 views

What is the physical meaning of fractional oxidation numbers of elements in compound

Many times I encounter oxidation numbers like -1 in the peroxide for oxygen, -1/2 in superoxide, and in some other compounds some elements have 8/3 or such like that...what is the physical meaning of ...
0
votes
1answer
44 views

DCC coupling of N-hydroxysuccinimide and Dimethoxy Acetic acid

I am forming N-hydroxysuccinimide ester: by DCC coupling with N-OH Succinimide and 2,2-Dimethoxy Acetic Acid. (Solvent: distilled THF). What I see on $\mathrm{^{1}H}$-NMR is 3 major singlets: $\...
0
votes
1answer
39 views

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 ...
1
vote
1answer
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 ...
-1
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
1answer
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, ...
8
votes
1answer
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~ (...
2
votes
0answers
43 views

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 ...
-1
votes
0answers
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
0
votes
1answer
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 ...
-2
votes
0answers
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 $\gt \pu{115 °C}$: $$\ce{3MgCO3·Mg(OH)2·3H2O(s) + Mg(HCO3)2(aq) -> 4MgCO3·Mg(OH)2·3H2O(s) + CO2?}$$
0
votes
1answer
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:...
0
votes
1answer
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 ...
1
vote
0answers
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 ...
1
vote
0answers
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 ...
0
votes
1answer
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,...
0
votes
0answers
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 ...
0
votes
3answers
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 ...
4
votes
1answer
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: ...
1
vote
0answers
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 ...
-4
votes
0answers
17 views

Identification of Acid,Base [closed]

Why $\ce{AlCl3}$ being an acid on dissolving in aqueous solution did not give $\ce{H+}$ ion?
3
votes
1answer
60 views
+50

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 ...
11
votes
1answer
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 ...
0
votes
1answer
45 views

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 ...
2
votes
2answers
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 ...
-2
votes
2answers
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 ...
6
votes
1answer
80 views

Equilibrium constant for a solid-solid equilibrium

Suppose there are two equations: $$ \begin{align} \ce{A(s) &<=> B(g) + C(s)} &\quad &K_1 \tag{R1}\\ \ce{B(g) &<=> D(s) + E(s)} &\quad &K_2 \tag{R2} \end{align}$$ ...
0
votes
0answers
21 views

Book Recommendations for Inorganic Chemistry Mechanisms [duplicate]

I am looking for a book which has details or basics to reaction mechanisms for inorganic chemistry for highschool level(preferably) or maybe undergrad level. Basically I am looking for a book which ...
0
votes
1answer
35 views

What happens to copper(II) hydroxide when it's heated? what's inside its decomposition?

So just wondering, copper(II) hydroxide undergoes thermal decomposition when it's heated. But isn't it a solid by itself too? Why does it turn into another solid and water all of a sudden? Can ...

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