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Questions tagged [homework]

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Name of foll. Alkane [closed]

!Please help me. I Need answer of this question of orgamic chemistry. Ques found in 39 years jee mains question book
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344 views

Calculate product quantity from a given formula

I need help to calculate the quantity of product needed from a formula Let met explain, i have the following equation : $\ce{KOH(aq) + HCl(aq) → KCl(s) + H2O(l)}$ In this equation we combine : - 1 ...
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1answer
2k views

What are potential sources of low recovery in this acid-base extraction experiment?

I did an acid-base extraction experiment. First extracted a solid mixture containing benzoic acid, p-nitroaniline, and naphthalene into three separate solutions: NaOH extract, HCl extract, and organic ...
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1answer
539 views

Conditions for free radical bromination using NBS and peroxides?

In the free radical bromination of 1-methylcyclohexene using NBS and peroxides a very important consideration to get the appropriate product is: A. The wavelength of light used for initiation ...
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1answer
218 views

Lab test to compare the reactivity of liquid 1-heptene and liquid heptane

Describe how you would carry out a lab test to compare the reactivity of liquid 1-heptene and liquid heptane. State clearly what the possible results of the test are and what they would indicate. ...
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2answers
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How does the polarity of the eluent and sample affect the Rf value in thin layer chromatography?

A three-component mixture (X, Y, Z) was separated using normal phase TLC. Three eluents of varying polarity were used. Select the TLC plate that was developed using the least polar eluent (click on ...
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61 views

Isotopic Dioxygen Raman Spectroscopy

Comment on the fact that $\ce{^{16}O-^{18}O}$ dioxygen leads to only one v($\ce{O-O}$) Raman active stretching frequency at $\mathrm{728~cm^{-1}}$. Isotopic substitution will make the molecule ...
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1answer
497 views

Mg and Cu Reaction in HCl

When a solid piece of Mg is attached to a solid piece of Cu and is placed into HCl(aq), why does it appear that the Cu slowly starts to bubble?
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1answer
228 views

Osmotic pressure of a solution of a protein?

A small protein molecule, code-named "sloth", has a MM of $\mathrm{1.50 x 10^4}$ g/mol. What is the osmotic pressure exerted at $\mathrm{24.0^oC}$ by 25.0 mL of an aqueous solution that contains $\...
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2answers
646 views

Understanding how electrons are counted for lone pairs vs. bonds especially when understanding resonance?

This is taken from the book Organic Chemistry as a Second Language from page 35. In the following image: It is seen that when the electrons from the double bond are pushed into the lone pair ...
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1answer
4k views

Relationship between a temperature increase of an exothermic reaction, Keq, and kf (forward rate constant)

I'm currently stuck on #30 for Chemistry Olympiad 2015 local exam which reads as: For a reversible exothermic reaction, what is the effect of increasing temperature on the equilibrium constant (Keq) ...
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1answer
135 views

I am not able to understand whether the following reaction will undergo SN1 or SN2

$\ce{CH3-CH2-CH2-CH2-Br + KCN->[EtOH-H2O] CH3-CH2-CH2-CH2-CN + KBr}$ In my text book it's mentioned that the reaction undergoes $\mathrm{S_N2}$ mechanism. I understand that the C-atom attached to ...
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1answer
2k views

Calculating the pH of the endpoint in a titration of weak acid and strong base

Show that the pH at the endpoint in the titration of $\mathrm{0.100\ mol\ dm^{-3}}$ ethanoic acid with $\mathrm{0.100\ mol\ dm^{-3}}$ sodium hydroxide is 8.72. The dissociation constant Ka of ethanoic ...
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2answers
363 views

How to properly rearrange the first law of thermodynamics?

For class we have been asked to show how the First Law of thermodynamics. $$\mathrm dU = \mathrm dQ + \mathrm dW$$ can be shown to be $$\mathrm dQ = \frac{C_V}{R}V\,\mathrm dP + \frac{C_p}{R}P\,\...
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1answer
330 views

Simple Distillation of Unknowns

Can an identification experiment (using acetonitrile, isopropyl, and cyclohexane) using simple distillation and boiling point be improved by using a digital thermometer? Can simple distillation be ...
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1answer
703 views

Reaction of p-methoxybenzyl alcohol and HBr

I had a question in a recent test which asked me to pick the compound that would react fastest with $\ce{HBr}$ with the options being: p-nitrobenzyl alcohol p-chlorobenzyl alcohol benzyl alcohol p-...
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1answer
2k views

Reaction of ethylene glycol with PI3(P +I2)

We know that $\ce{2P + 3I2 -> 2PI3}$ Ethylene glycol reacts with $\ce{PCl3}$ to give ethylene dichloride, but why does it gives ethylene when it reacts with $\ce{P + I2}$? I don't really know ...
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1answer
4k views

back bonding in molecules like BF3

Can anyone please explain me concept of back bonding briefly along with neccesary conditions for back bonding,with some example. As i understand back bonding is donation of electron from electron rich ...
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1answer
249 views

Do cycloalkanes have open chain Alkene isomers?

I've been trying the get the number of isomers of bromocyclohexane and 1,2-dibromocyclohexane.I was taught that every cycloalkane should have an isomer that's an open chained alkene. I searched ...
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2answers
2k views

How to determine the potential of a cadmium zinc cell under standard conditions?

I write the half-equations: \begin{align} \ce{Zn &<=> Zn^2+ + 2e^-}& E^\circ &= +0.763~\pu{V}\\ \ce{Cd^2+ + 2e- &<=> Cd}& E^\circ &= +0.403~\pu{V} \end{align} In ...
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1answer
62 views

Nucleophilicity of alcoxy groups

I found a nucleophilicity order as $\ce{HO-} > \ce{CH3-O-} > \ce{(CH3)2CH-O-} > \ce{(CH3)3C-O-}$ The reason was given that bulky groups reduce nucleophilicity. But why? The order of the $+...
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1answer
156 views

What is the keto form of a hexahydroxybenzene?

The answer has been given as (C). I cannot seem to understand why is it not possible for the keto form to only have one OH convert into keto form shown below:
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2answers
199 views

Why do substances ionise in water to turn into charged species? Wouldn't they prefer to stay as uncharged molecules?

Wouldn't this be more stable if they stayed as neutral molecules? I've learnt that they will seek to reach the ratio of $[A]^a[B]^b/[C]^c$ that matches the $\ce{Ka}$ or $\ce{Kb}$ value. But I do ...
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1answer
1k views

Unit conversion of Molar Conductivity

I know this might be a silly question but I am confused with different answers of internet. My question is: Molar conductivity is given as: Molar conductivity = $k÷M$. SI unit of : k is S/m & ...
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1answer
4k views

Solubility order for alcohols

Order for solubility of isomeric alcohols in a book was given as: Primary alcohol >Secondary alcohol >Tertiary alcohol After this I found a question as : 1) Which is more soluble in water? (a) 3-...
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3answers
1k views

What is CuCl.CO.2H2O?

What is the chemical $\ce{CuCl.CO.2H2O}$, formed via the reaction of copper chloride and carbon monoxide? Does this compound have any use or appear in any noteworthy reaction?
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1answer
81 views

Is Nuclear Spin Isomer a kind of allotrope?

In my book there's a question: Does $\ce{H2}$ shows allotropy ? Enlist its allotropes and their application? I pondered over different way Hydrogen can be arranged(I don't know but I have weak ...
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2answers
3k views

How to calculate what temperature change in entropy for the reaction equal to the change in entropy for the surroundings given Enthalpy and entropy

A reaction has $\Delta H_{rxn} = -107$ kJ and $\Delta S_{rxn} = 285$ J/K. At what temperature is the change in entropy for the reaction equal to the change in entropy for the surroundings? My ...
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2answers
650 views

When pH increases, does the effect of increased [OH-] or reduced [H+] control precipitation of CaC2O4

The image below shows how oxalic acid dissociates and forms calcium oxalate ($\ce{CaC2O4}$ or $\ce{Ca(OOC-COO) as written below}$). When the pH increases, does this result in more or less $\ce{Ca(OOC-...
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1answer
1k views

Stability by using charge/radius rule

I found a question Which is more stable among the following? (a) $\ce{CaCO3}$ (b) $\ce{MgCO3}$ Answer : (a) Explanation was given as: "$\ce{Mg^2+}$ has smaller radius than $\ce{Ca^2+}$ and thus $...
2
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0answers
56 views

Structure of diferric hexaphenate?

I was studying about the ferric chloride identification of phenol. And in the process a product is diferric hexaphenate. But I am having trouble drawing out the structure of it. With ferric ion having ...
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1answer
287 views

Acidity of primary and secondary amines

I was reading a book on organic chemistry by David Klein and I came across this question, but I wasn't able to understand why one amine is more acidic than the other.
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2answers
3k views

How to Prepare a Buffer Solution?

Problem I am given the task of preparing three buffer solutions at pH 10, 9.5, and 9.0. I have available concentrated ammonia and 3M hydrochloric acid. Attempt at Solving By adding HCl to a ...
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3answers
231 views

Is the amount of cubic inches in a cubic foot exact?

I know we are supposed to use SI units and I know they are defined very well. But does that mean that Imperial units of length/volume aren't exact? Don't they have infinite significant figures in ...
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2answers
418 views

Which is the base and acid in the reaction between thiosulfate and hydronium?

Is the following reaction an acid-base reaction: $$\ce{2 H3O+(aq) + S2O3^2-(aq) -> 3H2O(l) + SO2(g) + 1/8 S8(s)}$$ And if so, which is the acid and which is the base?
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2answers
1k views

What happens to acids/bases left out overnight?

I conducted a titration experiment a few days back and was unable to neutralize the solution in time, so I had to leave the solutions of HCl and NaOH out overnight in order to use them the next day. ...
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2answers
5k views

Reduction of oximes with lithium aluminium hydride

I know that $\ce{LiAlH4}$ is good a reducing agent and it donates hydride ions but then I am not able to understand the mechanism of this reaction. I attempted this way I am not understanding what ...
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1answer
96 views

Why is brine solution more effective than granular salt in melting ice on a surface?

Why is brine solution consisting of a small fraction of salt plus water more effective in melting ice than just pure salt on an ice surface?
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1answer
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Reactivity of aldehydes towards nucleophilic attack

Would you expect benzaldehyde to be more reactive or less reactive in nucleophilic addition reactions than propanal? Please explain the reason behind the answer. What i think is that the carbon ...
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0answers
32 views

What constitutes something being designated as big, bulky in terms of SN2 vs E2

When deciding between $\mathrm{S_N2}$ and $\mathrm{E2}$ for primary and secondary alkyl halides, is there a particular method or molecular size or any other threshold, which allows us to designate ...
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1answer
3k views

How to calculate the van der Waals radius of ethane?

Calculate the van der Waals radius for ethane if $b = 0.0493\ \mathrm{dm^3\ mol^{-1}}$. $$b = 4 \times {4 \over 3}\pi \times r^3 \times N_\mathrm A$$ $$\implies r = \sqrt[3]{3b\over 16\pi N_\mathrm A}...
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1answer
1k views

Stoichiometry Chemistry Lab: Copper (II) Sulphate Pentahydrate and Iron Single Displacement Reaction?

In my grade 11 chemistry class, we performed a lab in which we added 1.00g of iron to 6.00g of copper (II) sulphate which was dissolved in water. Using stoichiometry, we predicted that if the iron was ...
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0answers
117 views

What is the product of ethene reacting with dicobalt octacarbonyl, hydrogen and carbon monoxide?

What would be the product? I do know the structure of dicobalt octacarbonyl, but will that help? And after researching a little I found out that this reaction is something like the Pauson–Khand ...
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1answer
155 views

Predicting the product in a series of reactions

I am stuck in finding the final product $\ce{C}$ formed in the following series of reactions: $$\ce{Bu-C#CH ->[NaNH2] A ->[Ph-CHO][H2O] B ->[MnO2] C}$$ where $\ce{Bu}$ denotes the butyl ...
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2answers
1k views

Help with determining the rate constant of a reaction

The question asked was, The initial concentration of $\ce{N2O5}$ in the first order reaction $$\ce{N2O5 -> 2NO2 + 1/2O2}$$ is $1.24\cdot 10^{-2}~\mathrm{mol\,L^{-1}}$ at 318K. The ...
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1answer
573 views

When can I use concentration instead of activity?

To calculate a equilibrium constant you should actually use activity instead of concentration. It is said that in a certain range you can use concentrations instead. This is also what is usually done ...
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2answers
4k views

Why and how carboxylate ion has greater stability than carboxylic acid?

I found it written in my textbook. I think it's a misprint, I can't think of any logic behind this statement. I've only learned that ion is less stable specie so carboxylate ion cannot be more stable ...
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1answer
768 views

How can I calculate the percentage of dissociated dinitrogen tetroxide?

When 36.8g $\ce{N2O4 (g)}$ is introduced into a 1.0-litre flask at 27 °C. The following equilibrium reaction occurs: $\ce{N2O4(g) <=> 2NO2(g)}$; $K_p = 0.1642~\mathrm{atm}$. We have to find the ...
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1answer
222 views

Stability order of octahydrobiphenylenes

I am facing trouble in the following question What is the stability order of the following compounds? In my view cis is less stable than trans. So if prior groups are on the same side of the ...
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2answers
172 views

A metal, M, forms two fluorides containing 40.43% F and 50.44% F by mass. Identify the metal

A metal, $\ce{M}$, forms two fluorides containing 40.43 % $\ce{F}$ and 50.44 % $\ce{F}$ by mass. Identify the metal. I get that you can find out how much of the metal reacts with 1 mole of fluorine ...