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1answer
10k views

Solubility order for alcohols [closed]

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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2answers
636 views

Transition Metal Compounds [closed]

So I have a few dumb questions. I'm still in high school and am doing something on magnetic properties of transition metals. I'm facing a few roadblocks. 1) What're compounds like $\ce{CoBr2, CoCl2, ...
3
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2answers
18k views

How to calculate the percentage of calcium carbonate in sea shells in an experiment [closed]

We have a investigation in my chemistry class in which we must calculate the amount of calcium carbonate in sea shells. We can have as many sea shells as we wish, lab equipment, and hydrochloric acid ...
2
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2answers
966 views

Synthesis of 2-benzylcyclohexan-1-ol from cyclohexanone

There are no conditions given and a mechanism is required. I first thought it could be along the lines of Claisen rearrangement but that needs an aromatic ring. Since the Claisen rearrangement can't ...
2
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3answers
1k views

What are the most important resonance structures of 5-aminocycloheaxa-2,4-dienone?

Here attached is a question from my exam. My TA removed 1 point out of 7 for a reason. Can anyone decipher for what? There's the writing in red but it is illegible to me. I don't understand to what he ...
2
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2answers
2k views

How do i convert benzoic acid to meta-fluorobenzoic acid?

in not more than 3 steps. i did it but the process was a little long. here is my attempt
2
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2answers
4k views

Most acidic compound amongs the following unsaturated ketones?

In the given picture, I know that the most acidic will be (a), because of potential of ring expansion. I tried a few times but wasn't able to get a satisfactory six membered ring. I think (a) is the ...
2
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2answers
313 views

Why is the second reaction being neglected?

If we want to find the concentration of $\ce{H+}$ ions at equilibrium when a weak conjugate base such as $\ce{C2H3O2-}$ added to water, why do we take the conjugate base reaction for calculation i.e $$...
2
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1answer
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What total energy (in kJ) is contained in 1.0 mol of photons, all with a frequency of 2.75 • 10¹⁴ Hz?

There is a question, that says: What total energy (in $\mathrm{kJ}$) is contained in $1.0~\mathrm{mol}$ of photons, all with a frequency of $2.75 \cdot 10^{14}~\mathrm{Hz}$? My answer was: The ...
2
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2answers
817 views

Concentration, how to determine grams of NaCl needed

Disclaimer: It has been a very long time since I have done any chemistry. My friend posted this question on social media, I've copy+pasted it here: Exactly $16.0~\mathrm{ml}$ of a solution A is ...
2
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1answer
2k views

Ring expansion and carbocation formation

If in a reaction the carbocation is formed outside the ring then why does the ring expansion does not happen as follows:
2
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1answer
2k views

What is the mechanism for the double bond migration in 4-methylcyclopent-2-en-1-one?

Please explain using only enolisation and protonation steps: My workings so far: Seems completely wrong... Can someone please correct me? *i just proposed a new mechanism:
2
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2answers
4k views

What does all chromatography have in common?

We're learning about chromatography in class, and I'm confused about all the different types (e.g. those that separate liquid-liquid solutions vs. those that separate liquid-solid solutions vs. those ...
2
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4answers
565 views

Could I get a hint on the structure of this molecule based on HNMR spectra?

Chemical formula is $\ce{C7H6O3}$. IR spectra has a peak at 3238, which I believe could be an alcohol, phenol, or carboxylic acid. There's an additional peak at 3015, which I believe is either an ...
2
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2answers
3k views

When is rotation around double bonds to form cis-trans isomers allowed?

The Rhodopsin molecules in the retain contain a derivative of vitamin A called cis-retinal (Figure 6). On exposure to light, cis-retinal becomes an isomer called trans-retinal (Textbook Question). ...
2
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1answer
246 views

Mathematical form of four hybrid orbitals

The mathematical form of the four $\ce{sp^3}$ hybrid orbitals are given below. \begin{align} \ce{ \tag{a} sp^3 &= 1/2s + 1/2p_x + 1/2p_y + 1/2p_z\\ \tag{b} sp^3 &= 1/2s + 1/2p_x - 1/2p_y - 1/...
2
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2answers
2k views

Using sigfigs when measuring with an instrument with marks other than powers of ten?

If an instrument does have markings that are powers of ten, then finding the precision of the instrument is easy. For example, if a graduated cylinder had markings for every 0.1mL, or every mL, or ...
2
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2answers
3k views

Symmetry representations for CH3CN

Can anybody share the symmetry labels for acetonitrile ($\ce{CH3CN}$), please? I mean I to assign the symmetry labels to orbitals of acetonitrile
2
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1answer
7k views

Calculating the concentration of salt water

$23.4\text{ g}$ of $\ce{NaCl}$ are dissolved in $100\text{ g}$ of water. Calculate concentration of salt in the solution. Here's my work: Number of moles of salt is $0.4\text{ mol}$ Volume of ...
2
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2answers
23k views

How do I figure out the relative polarity of organic compounds?

It's a question on my quiz which I guessed right and couldn't do the reasoning: Based on the intermolecular forces, predict the boiling points of the following substances and list them in the order ...
2
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1answer
291 views

Kinetics of an irreversible bimolecular reaction

Assume the reaction $$\ce{A + B ->} \text{Products}$$ is of second order kinetics and that the rate constant is $k$. The differential equation is given by $$\frac{\mathrm d}{\mathrm dt} [\ce{A}] = -...
2
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2answers
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Why is lead sulfide found in nature, whereas lead oxide is less common?

This question probably applies to other heavier metals as well. The only rationalization I can figure is that lead in the +2 oxidation state (which is most common) is a borderline soft acid and ...
2
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1answer
908 views

Bond length comparison between sulfur tetrafluoride and thionyl tetrafluoride

I'm comparing sulfur tetrafluoride and thionyl tetrafluoride. The lone pair has more s character compared to a double bond. Therefore, sulfur in $\ce{SF4}$ should have a greater s character compared ...
2
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1answer
587 views

What would the phosphorus-NMR of trifluorodiphenylphosphorane look like?

I'm fairly new to NMR especially $\ce{^{19}F}$ and $\ce{^{31}P}$ NMR, we've not been formally taught NMR yet but we're expected to know $\ce{^{19}F}/\ce{^{31}P}$ NMR for our exam for basic molecules. ...
2
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1answer
1k views

Sulfurous acid tautomerisation

In the structure of $\ce{H2SO3}$ there is a lone pair on sulfur. Why can't sulfur make a bond with one of the hydrogen atoms and a double bond with oxygen to avoid lone pair?like given below because ...
2
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1answer
18k views

What is the IUPAC name of [Co(NH3)5H2O]Cl3?

I am not getting if it is Pentaammineaquo cobalt(III) chloride or Aquopentaammine cobalt (III) chloride-should the prefix be ignored while naming the ligands in alphabetical order? Besides how should ...
2
votes
3answers
896 views

What is the enol form of 4-methylcyclohex-2-en-1-one?

What is the enol form of this compound? I have made an attempt, but it doesn't look quite right. Also which hydrogen should be taken off (left or right hand side of the carbonyl)? And I dont think ...
2
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1answer
1k views

Determine the isotope half-life?

A sample of $\ce{^{41}Ar}$, a radioisotope used to measure the flow of gases from smokestacks, decays initially at a rate of 34,500 disintegrations/min, but the decay rate falls to 21,500 ...
2
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1answer
671 views

Can a Cl atom bond with a non-carbon atom?

I am currently doing the questions: Write equations for the reaction of Chlorine with Propene and 2-butene using structural So I know that Propene is $\ce{H3C-CH=CH2}$ and $\ce{Cl}$ is $\ce{...
2
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1answer
296 views

Calculating Ratio of Stability Constants

Solution I contains a mixture of $\ce{FeCl2}$ and $\ce{FeCl3}$, and solution II contains a mixture of $\ce{K4Fe(CN)6}$ and $\ce{K3Fe(CN)6}$. The concentrations of iron-containing species satisfy the ...
2
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1answer
1k views

Find the number of water molecules “embedded” in sucrose

Recently I got a question as follows: How many molecules of water are joined with 12 atoms of carbon in a molecule of sucrose ? (A) 12 (B) 11 (C) 6 (D) 10 I am unable to ...
2
votes
1answer
61 views

Ratio of Tb ions?

Estimate the ratio of $\ce{Tb^3+}$ to $\ce{Tb^4+}$ in $\ce{Tb_6O_11}$ ? For my solution I knew that I had to get a sum of 22 from 6 $\ce{Tb^3+}$ and $\ce{Tb^4+}$ ions so I just added different ...
2
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1answer
2k views

Explain the enolisation process of 5,8-dihydroxynaphthalene-1,4-dione

I have no idea really how to get started... Where does the hydrogen for the first deprotonation come from? My working thus far:
2
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1answer
4k views

Understanding gas stoichiometry for the reaction of xenon and fluorine

A $20.0$-L nickel container was charged with $0.500$ atm of xenon gas and $1.50$ atm of fluorine gas at $400$ $^{\circ}$C. The xenon and fluorine react to form xenon tetrafluoride. What mass of xenon ...
2
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2answers
788 views

Can Ketones next to a Nitrogen hetero atom tautomerise?

I worry that the electronegative N will stabilise keto form so much that equilibrium will be so far towards keto it would be unreasonable to call the enolisiation process a factor
2
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2answers
97 views

how to determine timescale with characterization methods?

There are 4 different timescales on material characterization (as classified in the Atkins textbook ): a)Time during which a quantum of radiation or a particle can interact with a molecule. b)...
2
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1answer
13k views

How do you calculate the total heat capacity of a reaction

I need help with this one homework question: I am combining $100\,\text{mL}$ of $0.5~\text{M}~\ce{HCl}$ and $100~\text{mL}$ of $0.5~\text{M}~\ce{NaOH}$ to obtain $200~\text{mL}$ of $0.25~\text{M}~\...
2
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1answer
3k views

Synthetic roadmap from 3-methyl-2-butanol to 2-methyl-2-butanol

This is for a homework assignment, I'm usually very good with reactions and am really disappointed after getting it wrong four times, where did I go wrong?
2
votes
1answer
151 views

Ionic Radius of Iodine in High Temperature Form

The ionic radius of iodine in the high temperature form can be determined once the unit cell is known, but how can I calculate the radius of $\ce{I}$ given that the cubic lattice parameter is 6.10 Å.
2
votes
1answer
434 views

Understanding the difference between physical and chemical changes

Which of the following is a chemical change? A. Hydrolysis of a dipeptide. B. Stretching of a balloon. C. Freezing of water. D. Breaking a stick. I'm pretty sure that the answer is (A), but I'm not ...
2
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1answer
3k views

Absolute configuration when hydrogen (lowest priority group) is in the plane of the page (and not a wedge or dash)

I have learnt that: Our absolute configuration is R(if clockwise) or S(if anticlockwise) when we rank the priorities, when the hydrogen (or other lowest priority group) is at the rear i.e. into the ...
2
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1answer
1k views

Dalton's law of partial pressure

A mixture of helium and neon gases is collected over water at $28.0 \rm~^\circ C$ and $745\rm~ mmHg$. If the partial pressure of helium is $368\rm~ mmHg$, what is the partial pressure of neon? (Vapor ...
2
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1answer
1k views

How to synthesise 2-aminoethyl benzene

Starting with benzene, describe the synthesis of 2-phenylethan-1-amine providing all the reagents and conditions. I am not really great at organic chemistry and my knowledge is pretty limited. I am ...
2
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3answers
3k views

Solubility of Ag3AsO4 in 0.02 M K3AsO4

Calculate the solubility of $\ce{Ag3AsO4}$ in $0.02~\mathrm{M}~\ce{K3AsO4}$ neglecting the activity coefficients. Find the relative error. $K_\mathrm{sp}(\ce{Ag3AsO4}) = 6.0 \cdot 10^{-23}$ I know ...
2
votes
1answer
1k views

Distinguishing Test for Organic Compounds

Given the following pairs of samples, how do I distinguish between them? benzamide vs ethanamide ethanoyl chloride vs ethanoic anhydride My Approach: We could easily convert the amides to amines by ...
2
votes
2answers
799 views

Calculate the partial pressure of NO2

Calculate the partial pressure of $\ce{NO2}$. $$p_{\ce{N2}}/p_{\ce{O2}}=5$$ $$\ce{N2(g) + O2(g) <=> 2NO(g)}$$ Let’s assume $K=0.1$ $$K= \frac{p_{\ce{NO}}^2}{p_{\ce{O2}}\cdot p_{\ce{N2}}}$$ $...
2
votes
1answer
2k views

Volume of products - stoichiometry

$\rm 20\,cm^3$ of ethyne, $\ce{C2H2}$, is reacted with $\rm 500 \,cm^3$ of oxygen. The equation for the reaction is: $$\ce{2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(l)}$$ What is the total volume ...
2
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1answer
3k views

Is there a certain amount of titrant that is ideal?

For an AP chem lab dealing with determining the amount of citric acid in orange juice by titrating with NaOH, one of the discussion questions goes like this: Choose an amount of beverage to be ...
2
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1answer
2k views

Nitrogen and an unknown gas is leaked into a common vessel… The gaseous mixture contains 0.4 moles of nitrogen. Molecular mass of the other gas is?

For 10 minutes each, from two identical holes, nitrogen and an unknown gas is leaked into a common vessel of 3L capacity at 300K. The resulting pressure is 4.15 bar. If the gaseous mixture contains 0....
2
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1answer
898 views

Find number grams of the solute in a dissolution given its density and Molarity

Have a dissolution of $\ce{HNO_3}$ in water. The density is $1.42\ce{g/mL}$ with a concentration of $\ce{16M}$. What is the concentration in % mass/mass? Alright. So the % mass/mass is expressed ...

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