If your question is part of your high school or college/university homework, please use this tag. Do not use this as the only tag on a question. It signifies that instead of a direct answer, care should be taken to explaining the steps to the solution, preferably sticking to just giving helpful, ...

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1answer
20 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?
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0answers
13 views

Crystallisation [on hold]

A tank holds 10,000 kg of a saturated solution of sodium hydrogen carbonate at 60 degrees Celcius. You want to crystallize 500 kg of sodium hydrogen carbonate without any accompanying water from this ...
0
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0answers
28 views

Determining the name of a compound via IR and H NMR spectroscopy [on hold]

I know that the functional group of this compound is a carboxylic acid, but I can't seem to figure this out. It has a melting point of 105-110. Can someone please help me determine this compound's ...
3
votes
1answer
32 views

Stereoselectivity of hydroboration

The above compound undergoes hydroboration. I originally thought that the $\ce{OH}$ group can attach to any of the 2 carbons plus there are 2 possible enantiomers at each position. So there should ...
2
votes
0answers
19 views

Application of limiting reagents and acid-base stoichiometry

I'm having a bit of trouble with the latter questions of this problem. 15.0mL of 1.4M $\ce{HCl}$ was mixed with 1.00g of $\ce{CaCO_3}$ until all the solid had dissolved. The solution was then ...
0
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0answers
19 views

Estimate specific heat capacity of liquid [on hold]

I am attempting to help a friend with thermodynamics homework, but I am unfamiliar with questions like this. I am given this question: A calorimeter of mass 90 g and specific heat capacity $420\ ...
0
votes
1answer
49 views

How should I construct the orbitals of dilithium using only pen and paper?

For a week I have lessons about quantum chemistry and I have a trouble understanding how to arrive at the good answer for the drawing of the orbital $(\ce{III})$ for $\ce{Li2}$ (see the second ...
0
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0answers
22 views

How do you determine the amount of peaks using percentages? [on hold]

Naturally occuring chlorine comprises 75.53% 35Cl and 24.47% 37Cl, while naturally occuring carbon comprises 98.89% 12C and 1.11% 13C. Mass spectrometry will give how many peaks for CCl4?
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2answers
28 views

Volume of gas given off RHS with volume of gas used in one part of LHS

So I have the following equation: $$\ce{2SO2 + O2 -> 2SO3}$$ and the question: 100cm^3 of sulphur dioxide is used, what volume of sulphur trioxide is given off? Can someone please explain how I ...
1
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2answers
44 views

A problem from thermodynamics

I am trying to do the following problem: Freezing of water at $273~\mathrm K$ and $1~\mathrm{atm}$ Which of the following is true for the above thermodynamics process? p) $q=0$ q) ...
0
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0answers
35 views

Which substituent in the benzene ring activates it most towards electrophilic substitution?

I came across the following question in my textbook: Which of the following gives electrophilic substitution reactions most easily? Phenol Chlorobenzene Benzene Methylbenzene I tried drawing ...
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votes
0answers
13 views

Stoichiometry Question [on hold]

This is a basic stoichiometry question but I still can't figure it out. 50 g of a metal carbonate on heating produces 30 g of its oxide. What is the equivalent mass of the metal? I asked my ...
0
votes
1answer
19 views

Are there any strategies to determine bond order and hybridization rankings without drawing the Lewis Structure?

I'm not Chemist. I'm taking a chemistry class in college, and the test review contains many questions where I'm asked to rank from least to greatest based on bond order, polarity, and bond angles. I ...
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votes
0answers
12 views

net ionic equations help [on hold]

3 questions A,B and C. A is in regards to chromide and the last two are related to hydroxide. I would really appreciate it. Thank you so much A)Consider the reaction when aqueous solutions of ...
3
votes
1answer
48 views

Determination of structure by 13C and 1H NMR spectroscopy

I'm trying to interpret a $\ce{^{13}C}$-NMR and $\ce{^1H}$-NMR spectrum. So far, I've decided that $\ce{CH3-C}$, $\ce{CH2-CH3}$ and $\ce{CH-CH}$ exist in the structure. I'm not sure but I guess there ...
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votes
0answers
27 views

Preparing different concentrations of potassium, each 4 milliliters

I need to prepare different concentrations of $\ce{K+}$ ($\text{10, 20, 30, 40, 50 mM}$) by diluting a solution of $\mathrm{100~mM~} \ce{K+}$ with an isotonic buffer of $\mathrm{5~mM~} \ce{K+}$. I ...
3
votes
2answers
50 views

Can triethylamine/pyridine be used in this reaction?

As part of my homework, I had to plan the synthesis of labetol, a blood pressure drug, from its component parts. One of the steps involved was the following $\mathrm{S_N2}$ reaction: The solutions ...
0
votes
1answer
28 views

Alkyl halide reaction with AgNO2

I want to know that whether both alkyl nitrite and nito alkane are produced or if nitroalkane is the only product. There are many different (contradicting) things written in different books that is ...
1
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0answers
25 views

Finding concentration and moles given final and initial pH

Questions: "How many moles of NaOH is needed to change 500L of solution with pH=2 to pH=11?" "Swimming pool contains 2 million litres of water at pH 7.80 and the pH needs to be changed to pH of ...
0
votes
0answers
16 views

Confusion regarding coexistence of chemical compounds [on hold]

The pair of compounds that can exist together is: (1) FeCl3, SnCl2 (2) HgCl2, SnCl2 (3) FeCl2, SnCl2 (4) FeCl3, KI I didn't know how to decide this!
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0answers
20 views

Which of the following has more replusion? [on hold]

Which of the following has more repulsion? And in what order? A) Lone pair – lone pair B) Bond pair – lone pair C) Bond pair – bond pair D) All have the same repulsion
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0answers
22 views

Ideal Gas Law Question [on hold]

$870\ \mathrm{cc}$ of moist hydrogen is measured at $\mathrm{9\ C^\circ}$ and $659\ \mathrm{mm}$ pressure. Find its volume at normal temperature and pressure. The vapour pressure of water at ...
0
votes
0answers
26 views

Number of moles in the gaseous mixture [on hold]

A vessel contains equal number of moles of methane and helium.Due to a hole in the mixture one fourth of the gaseous mixture effused out.What is the ratio of number of moles of remaining methane and ...
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votes
0answers
22 views

equilibrium problem [closed]

If the reaction below was performed in fixed pressure of 2bar and the initial amounts were of A:70% and B: 30% find the partial pressure of B after equilibrium. A(g)+B(g)《》AB(g) K=85 bar-1
0
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1answer
36 views

A problem on rate of diffusion

At a particular temperature and pressure it takes just 8.256 minutes for a 4.893 liter sample of Neon (Ne) to diffuse through a porous membrane. How long will iodine diffuse in similar conditions? ...
4
votes
1answer
55 views

Effects of Groups on the Nucleophilcity of Nitrogen

The reactivity of nitrogen mustards increases with increasing nucleophilicity of the central nitrogen atom. Select the most and least reactive from each of the following groups of nitrogen ...
-1
votes
0answers
11 views

Energy in Reaction Profile [closed]

What is the difference between the Reaction Profiles when they have 1) Potential Energy 2) Gibbs Free Energy 3) Enthalpy
2
votes
1answer
42 views

How to compare the Heat of Combustion qualitatively? [duplicate]

I have been doing practice problems in General Organic Chemistry. I got some questions that asked me to compare the Heat of Combustion of some molecules. I couldn't get any of those questions and the ...
0
votes
1answer
16 views

Can I get some pointers on what to do in calculating the hardness of water?

Information provided: 1.64 grams of $\ce{Ca(NO3)2}$ and 0.94 grams of $\ce{MgCl2}$ are dissolved in 10 litres of water, calculate the hardness. I have used these two equations: $m = n \cdot M$ and $c ...
2
votes
2answers
39 views

Change in equilibrium when not all product and reactant are increased

$$\ce{2NOCl <=> 2NO + Cl2}$$ What will be the effect on equilibrium concentration of $\ce{NOCl}$ when equal moles of $\ce{NOCl}$ and $\ce{NO}$ are introduced in the mixture at constant ...
1
vote
1answer
44 views

I need advice on how to study chemistry [closed]

I'm a 11th grader and chemistry gives me nightmares. I used to do well in it upto 10th but now I feel like I'm losing it. I feel like I'm gonna fail so bad. Any help or advice anyone pls?
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0answers
8 views
-4
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0answers
28 views

Temperature for certain vapor pressure of diethyl ether [closed]

At what temperature would diethyl ether have a vapor pressure of $250\ \mathrm{mmHg}$, if we are given that at a pressure of $401\ \mathrm{mmHg}$, $T = 18\ \mathrm{^\circ C}$ and $\Delta H = 26\ ...
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0answers
22 views

Advantage of using sodium sulbactam over sulbactam

Part of the question reads: "and explain why it is advantageous to produce the compound as its sodium salt rather than in the carboxylic acid form." My thinking is that the carboxylate can resonance ...
0
votes
0answers
22 views

How to calculate specific heat capacity from molar heat capacity?

I am working on trying to calculate the specific heat of depleted uranium, but I have barely any data on that. Thus far, all I have is the molar specific heat of Uranium in general has a molar heat ...
1
vote
1answer
38 views

Freezing Point Depression Problem

Assuming an ideal solution, which of these 0.10 M solutions would have the least freezing point depression? $\ce{HCl}$ $\ce{NaBr}$ $\ce{KNO_3}$ $\ce{MgSO_4}$ They all produce ...
-3
votes
0answers
30 views

Calculating the electronegativity of phenoxymethylpenicillin [closed]

How do you explain the electronegativity of phenoxymethylpenicillin? I've been told by a teacher that it's polar, but I can't explain why that is. I was hoping that someone could explain how to tell ...
1
vote
0answers
110 views

Does a microwave oven act on the principle of giving vibrational or rotational energy to water molecules? [closed]

Does a microwave oven act on the principle of giving vibrational energy to water molecules or by giving rotational energy to water molecules? I tried to google it but answers are not specific where as ...
0
votes
1answer
16 views

Adding Standard Reduction Potentials

I am working the following USNCO problem (#41 from 2002). Based on this question and answer How to calculate reduction potentials from given standard potentials for cobalt?, it seems that $\Delta G$ ...
-1
votes
0answers
19 views

Can someone explain this reaction of an imine involving a carbonyl shift? [closed]

This looks to me to be a reduction but when I try to work it out mechanistically I get an alcohol with an amine group and I can't see how to convert from there to the product. Thanks!
-3
votes
0answers
68 views

Determination of mass of iron and insoluble filler [closed]

A bottle contained 100 tablets. Most of each tablet was an iron(II) salt. The remainder of the tablet was a filler of calcium sulfate with small amounts of other substances. All the tablets were ...
1
vote
0answers
63 views

Why is this structure impossible

I'm asked the following: Explain why the structure $\ce{H - C = C - H}$ doesn't make sense chemically. Not only am I just looking for a check up of my answer, but am I making any sense in what ...
0
votes
0answers
13 views

How do you find mass percentage composition based on molality?

You take $20.0~\mathrm{g}$ of a sucrose and $\ce{NaCl}$ mixture and dissolve it in $1.0\ \mathrm{L}$ of water. The freezing point of this solution is found to be $0.426~\mathrm{^\circ C}$. Assuming ...
2
votes
0answers
20 views

Microarray SPR imaging vs “regular” SPR?

Background: I am taking a biochemistry course, and we have had some basic introduction to surface plasmon resonance (SPR). I don't have a very strong background in biophysical chemistry. Task: I am ...
0
votes
0answers
22 views

Calculating mass of water removed (vapor pressure)

I cannot figure out how to calculate the mass. "The question is: Suppose the percent relative humidity is 80.0% at 91.4 F (33.0 c) in a house with a volume 245m^3. Then the air conditioner is turned ...
-3
votes
0answers
12 views

Percent Yield-Barium Hydroxide and Phosphoric Acid [closed]

when 162 g of barium hydroxide are added to excess phosphoric acid 521 g of barium phosphate are formed. what is the percent yield? show work.
1
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0answers
26 views

Dimerisation effect on distribution ratio?

The question reads: "Carboxylic acids (RCOOH) form dimers in solvents of low polarity such as benzene and carbon tetrachloride. Using suitable equations, explain the effect of association on the ...
-1
votes
0answers
23 views

How do you find mass percent composition based on molality?

You take $20.0~\mathrm{g}$ of a sucrose and $\ce{NaCl}$ mixture and dissolve it in $1.0\ \mathrm{L}$ of water. The freezing point of this solution is found to be $0.426~\mathrm{^\circ C}$. Assuming ...
0
votes
0answers
20 views

Possibility of isotopic effects in aldol reactions [closed]

Is the rate of aldol reaction same for $\ce{CD3CHO}$ and $\ce{CH3CHO}$?
1
vote
1answer
31 views

How to determine which parts of a formula are ligands in the given amminechloridoplatinum(IV) complexes?

$$\begin{array}{cc}\hline \textit{Formula of Complex} & {\textit{Rewritten Formula (showing the}\\\textit{ coordinating ligands)}}\\ \hline \ce{Pt(NH3)6Cl4} & \ce{[Ph(NH3)6]Cl4}\\ ...