0
votes
1answer
19 views

If Benzene Is Put In Water [on hold]

How does $\ce{C6H6}$ dissociate in water? I started to read how inorganic acid dissociates in water.And stood against the above question.
-3
votes
0answers
15 views

Which one is dilute:1) 2M of 250cm3 or 2) 5M of 500cm3 [on hold]

Molarity of a solution .titration. Dilution method.of solution .
0
votes
1answer
11 views

Precautions and tips for Qualitative Inorganic Analysis of Coins

I'm a highschool student and as part of an investigatory project, I have decided to analyse which metals are present in our everyday coins. I chose this because in my previous academic year, I had ...
0
votes
0answers
10 views

magnetism in metallic alloys

i am working with a multicomponent alloy system for soft magnetic application,it is iron based and have composition of Fe Mn Si B Mo,how can i calculate the net magnetic moment or saturation ...
0
votes
1answer
20 views

i am trying to calculate a sum in dilutions [on hold]

0.25g of sodium chloride diluted to 100ml i have tried doing it this way but i'm unsure my answer is correct ...
0
votes
0answers
9 views

What is the pressure (in atmospheres) of the gas inside a container connected to an open-end, mercury-filled manometer? [on hold]

What is the pressure (in atmospheres) of the gas inside a container connected to an open-end, mercury-filled manometer? The atmospheric pressure is 0.95 atm. My answer was 0.24 How was 1.19 atm the ...
8
votes
2answers
1k views

I'm disagreeing with my chemistry teacher over this enthalpy of formation problem, so can someone tell me if I am right or why I am wrong?

The enthalpy of formation of gaseous sulfur trioxide is $-396~\mathrm{kJ/mol}$. What is the enthalpy of the reaction represented by the following balanced equation? $$\ce {2 SO_3 (g) -> 2 ...
0
votes
1answer
29 views

Phenol protection

Would an acceptable way to protect a phenolic alcohol be through a Williamson ether synthesis? As in: 1) Deprotonating phenol with sodium hydroxide. 2) Addition of methyl iodide. 3) Deprotection ...
3
votes
3answers
511 views

what does the '-1' superscript mean in units?

For example, the rate of a chemical reaction can be expressed in $\mathrm{mol}/\mathrm{L}^{-1}/\mathrm{sec}^{-1}$. Why is it '-1' and not, say, '-2'? Does it change the meaning if the minus is removed ...
-3
votes
0answers
23 views

Airbags have become a standard safety feature in modern automobiles. [on hold]

Airbags have become a standard safety feature in modern automobiles. Several airbags are placed in the critical locations within automobiles and they inflate almost instantly upon impact to protect ...
-1
votes
0answers
9 views

Mg(OH)2 + 2HCl --> MgCl2 + 2H20 with .933 moles of Mg(OH)2 and 2.34 moles of HCl which is the limiting reagent [on hold]

If you have a balanced equation $$\ce{Mg(OH)2 + 2HCl -> MgCl2 + 2 H2O}$$ and .933 moles $\ce{Mg(OH)2}$ and 2.34 moles $\ce{HCl}$, which is the limiting reagent and how?
2
votes
0answers
35 views

Molecular bond angles

How do Bond angles vary in molecule with a lone pair and central atom of different electronegativity, but in the same period so that ecectronegativity matters more than orbital size? Assuming that the ...
0
votes
1answer
15 views

Confusion with Law of Equivalence

Law of Equivalence states that One equivalent of an element combines with one equivalent of the other. Equivalent of $\ce{Na}$ is $22.99$ & that of $\ce{0}$ is $8$. By the Law of ...
0
votes
0answers
32 views

From an electron configuration, how do we know if it is ionic or covalent? [on hold]

Hi I'm back to contribute some questions! Well let's say 2.8.2 and 2.8.1 ....how are we supposed to know if they are covalent or ionic?
1
vote
1answer
31 views

What do chemical constituent measurement units 'g%g' and 'µg g⁻¹' mean?

I'm trying to understand the following data being presented in this paper measuring the mineral content of the Cannabis sativa plant (leaves and inflorescences): I need to interpret these data ...
0
votes
1answer
20 views

MDLCT (Connection Table) Format specification

Is there a specification for MDL Connection Table format somewhere. At some places it is mentioned that the format writes the line length as a character then the actual line characters. If I save a ...
0
votes
0answers
18 views

How do you calculate average Molecular mass? [on hold]

Molecular mass of air, assuming $80\%$ is $\ce{N2}$ and $20\%$ $\ce{O2}$. Step by step would be great. And gas weight is $M\cdot n$, right? And n is number of molecules/Avogadro's number?
0
votes
1answer
19 views

Why would electrode reaction in galvanic cell stop when there's no neutrality in each cell?

I know that the salt bridge produces ions to balance out the positive and negative ions in each solution, but why won't it work without a salt bride? Would it even work at the start since there's few ...
1
vote
1answer
22 views

Are there some similarities between J-coupling and j,j-coupling?

I'm a bit confused having heard two different terms in different lecture parts: J-coupling There is the J-coupling (= indirect dipole dipole coupling = scalar coupling) which arises from a ...
1
vote
0answers
20 views

Physical meaning of Orbital Polarization

In this paper, the Orbital Polarization (OP) is defined as: $$OP=\frac{n_{x^2-y^2}-n_{z^2}}{n_{x^2-y^2}+n_{z^2}}$$ where $n_i$ is (I suppose) the occupancy of that given orbital. I would like to ...
1
vote
1answer
44 views

Reduction of acetaldehyde from rectus and sinister faces

I am asked to consider the reduction of acetaldehyde from the re and si faces. I am also asked whether the added hydrogen (labeled H* in my picture) is pro-R or pro-S in both cases. In my attached ...
2
votes
1answer
27 views

Bond Dissociation Temperatures for Hydrocarbons

I'd like to know the temperatures that various hydrocarbons such as methane, butane, and propane, etc. will dissociate into hydrogen and carbon. Is there a reference where I can look up these ...
0
votes
1answer
26 views

Rate of Consumption [on hold]

For a practice test I had to do this question: An experiment is done to determine the rate of the following reaction: $$\ce{2Al(s) + 6HCl(aq) → 3H2(g) + 2AlCl3(aq)}$$ ...
2
votes
1answer
37 views

Element letters

Does it change the compound if the element letters are switched? ex. HO or OH. Are those two different compounds or are they one in the same? This may be a simple question or I may have incorrectly ...
2
votes
1answer
25 views

Metal-Ligand-Complex and bond directions: What defines coordinate system of the complex ion? [duplicate]

I have a question concerning metal ligand complexes. In every chemistry text book I have read which treats metal ligand complexes, following situation is discussed: When 6 ligands (in octahedral ...
1
vote
1answer
19 views

pH Indicators for Hoffman apparatus

I've read that bromothymol blue can be mixed in with the electrolyte in the demonstration of electrolysis using a Hoffman apparatus. The indicator clearly shows the local differences in pH for the ...
5
votes
1answer
40 views

Caclulating the Solubility of Fluorite in River Water

I am attempting to work through problems in Chapter 4 of Brunlow's 1979 Geochemistry text. The question is "Calculate the solubility of fluorite in river water with the average composition given in ...
0
votes
1answer
53 views

How to draw glucose using a Fischer projection?

I asked how to draw glucose as a Fischer projection from its given chair conformation but all I got was an unsatisfactory ad hoc explanation involving rotation of my neck muscles to somehow see where ...
0
votes
0answers
18 views

density of potassium bromide

I'd like to know the density and viscosity of aqueous KBr at varying concentrations and at varying temperatures. I was able to find this data at 20 degrees C in the CRC Handbook for Chemistry and ...
13
votes
2answers
2k views

Why are the rare earths erbium (Er), terbium (Tb), yttrium (Y) and ytterbium (Yb) named like that?

I know the history of the discovery of the rare earth elements, that they were discovered near the village Ytterby in Sweden in the 19th century. Four elements are directly named after that village: ...
3
votes
0answers
34 views

Ultraviolet acid base indicator

Is there a chemical(s) that provides good discrimination between absorbance curves for different pHs in the UV light spectrum (100-400nm?)
2
votes
3answers
177 views

Concept of “non-superimposable mirror image” in chirality

I didn't understand the fact that chiral objects are non-superimposable on their mirror images. I mean, if you put your right hand (apparently an achiral object) in front of a mirror, the mirror image ...
1
vote
1answer
99 views

Acidic conditions, high heat, and return to carboxylic acids

Apparently carboxylic acid derivatives such as cyanohydrins can be taken back to "daddy" - a carboxylic acid - under the right conditions. This involves acid, water, and "high heat." What, however, is ...
0
votes
0answers
6 views

question regarding what i can put in category of homework questions [migrated]

I just wanted to know that if I am unable to solve a particular question that is completely unable even to start up with the question and i put it on this site without showing any effort because i ...
0
votes
2answers
28 views

Titration and calculation of the number of moles after a mix

I have the following problem on an assignment that I don't understand. Given the following balanced equation for the titration of HCl with NaOH: $\ce{HCl + NaOH -> NaCl + H2O}$ The initial ...
0
votes
0answers
14 views

How to plot standard curve using D-Galactouronic acid

I wanted to calculate the Pectinase enzyme activity. so how can I plot standard curve using D-galactouronic acid ? also is it possible using glucose ?
1
vote
1answer
43 views

Convert Hexane to 1,6-Dibromohexane

Is it possible by any means or by using some reagents to convert Hexane to 1,6-Dibromohexane Hexane: 1,6-Dibromehexane: The yield should also be good
0
votes
0answers
32 views

How to clean wall painted with water-proof paint tainted with cigarette smoke [on hold]

This article mention The Lingering Effects of Secondhand Smoke Once you put out that last cigarette, the harmful toxins can remain in your home for much longer than you might expect. According to ...
2
votes
1answer
53 views

What is the entropy of mixing of two ideal gases starting out with different pressures?

The entropy of mixing of ideal gas is given by this equation: $\Delta S_{mix} = -nR(x_1\ln x_1 + x_2\ln x_2)$ Does this equation works only when the initial conditions of both compartments are at ...
0
votes
0answers
22 views

Thermochemistry - energy [on hold]

Calculate the change in internal energy for the following reaction at 1.00 atm and 25 C: 2 CO(g) + O2(g) = 2CO2(g) deltaH= -566.0 KJ?
0
votes
0answers
19 views

Relationship between Auto-Ignition Temperature with Pressure and Fuel

Experimentally it appears that increase in pressure, fuel concentration, and chain length causes AIT to decrease until a minimum where even further increase in these parameters increases the AIT. ...
1
vote
1answer
345 views

Interpreting a Formula Tattoo (Bipolar?)

Found This Online. Something to do with bipolar disorder?
0
votes
1answer
27 views

How much oxygen and carbon must be combined to create exactly 100.0 g of CO2 without any leftover? [on hold]

I'm completely stumped on this one. Everything needed for the question is in the title. I know that 20.0 g of carbon and 32.0 g of oxygen make 44.0 g of $\mathrm{CO_2}$ with 8.0 carbon leftover.
2
votes
0answers
23 views

Anti hydrogenation of alkynes-Purpose of NH4Cl

In my orgo textbook, Lithium is used to create a free radical of the alkynes, to then allow the anti addition of hydrogen to get an alkene. "The Dissolving Metal Reduction of Alkynes" is a reaction ...
2
votes
2answers
32 views

Find new energy level of H atom absorbing a photon

The problem I'm on says a ground state H atom absorbs a photon of 97.20nm, what energy level does it jump to. So n would start at 1. I don't have an equation specifically for a change in n though. I ...
0
votes
0answers
19 views

Finding mass equivalence of a photon

The problem has a flame emitting a wavelength of 589nm, and asks for the mass of one photon of that wavelength. I tells me that 1 J = 1 kgm^2/s^2. I converted to J using E=(hc)/wavelength. I'm not ...
5
votes
2answers
92 views

How to assign the signals in the H-NMR of Aspirin?

I need to assign the H-NMR of aspirin, below is aspirin with the H's labelled. The peaks I have are: 2.30ppm (I this is a singlet and would be F) 7.07ppm (I think this is E) 7.29ppm ...
3
votes
1answer
28 views

What's the electronic configuration of Nickel and Oxygen in RNiO3 (R=Rare-Earth)?

Nickel's electronic ground state is $\mathrm{3d^8 4s^2}$ (there's a dispute on this, but let's not worry about it for now). Oxygen's is $\mathrm{2s^2 2p^4}$. In a Rare-Earth based Nickelate with ...
0
votes
1answer
22 views

How are Ca, N, Na, Cl, O, Al and Pb charged, and what salts can they build? [on hold]

How are Ca, N, Na, Cl, O, Al and Pb charged, and what salts can they build? (In a table) I dont understand how to build all possible salts with the given elements. Thanks for help!
0
votes
0answers
19 views

How do we experimentally know the strength of bonds?

How do we experimentally measure the strengths of covalent versus ionic bonds? Also, for a given molecule, how can we know if two pairs of atoms is covalently or ionically bound? Related question: ...

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