All Questions

1
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2answers
53 views

“Asymmetric molecules are necessarily polar”

Is a molecule with no symmetry necessarily polar? Can a polar molecule still have some elements of symmetry (i.e. mirror image is the same as itself)? I think so ... because we can have achiral ...
1
vote
1answer
10 views

Is it possible to normalize $K_c$ between different reactions for comparison?

A follow up question from this answer: Compare: $\ce{A(aq) +B(aq)->AB(aq)}$ $\ce{2A(aq) +B(aq)->A2B(aq)}$ We have two similar reactions but the equilibrium constants can vary by a ...
0
votes
0answers
18 views

What do kf and kb, the forward and reverse rate constants, depend on in a reversible reaction?

What do the forward and the backward reaction constants depend on?
1
vote
0answers
14 views

Help with concentration calculation & partial pressure

I have been charged with answering the following: Please could you calculate the partial pressure of $\ce{H2S}$ at pH7, 105 bar pressure at 30 ppm $\ce{S-2}$ My attempt so far: $\ce{H2S + H2O ...
6
votes
0answers
35 views

CO2 removal from mushroom growing tent

I'm trying to grow oyster mushrooms that like high temperatures. They look great in an indoor terrarium, and can eventually yield several tasty meals :) However oyster mushrooms are hard to grow ...
2
votes
1answer
677 views

Why does my coffee creamer have titanium dioxide in it and is it safe?

From the manufacturers website of a coconut french vanilla coffee creamer: Ingredients: ORGANIC COCONUT MILK (WATER, ORGANIC COCONUT CREAM), DRIED CANE SYRUP, NATURAL FLAVORS, COLORED WITH ...
0
votes
0answers
34 views

Why is active mass of a pure solid or liquid always taken as unity?

Active mass is defined as the molar concentration ie. number of Gram-moles per litre. My book then wrote Active mass of pure solid/liquid is always 1 . The book reasoned that Molar ...
1
vote
1answer
20 views

Why is Electrostatic Potential Energy positive when the charges are like?

We know that in an atom charge of an electron at infinity is zero. As it approaches the nucleus it become more and more negatively charged. We also know that E.P.E is positive when charges are like ...
2
votes
1answer
30 views

Efforts made to reduce the amount of CFC

Till now I have heard $\ce{CO2}$ is the main reason of global warming. I have studied the remedies to control $\ce{CO2}$ many times through books, awarness programs, etc. But today I learned about ...
2
votes
2answers
33 views

How to determine the composition for a sucrose/ zinc nitrate solution from its freezing point?

A $4~\mathrm{g}$ mixture of sucrose ($\ce{C12H22O11}$) and zinc nitrate ($\ce{Zn(NO3)2}$) is dissolved in $150~\mathrm{g}$ of water. If the resulting solution freezes at $-0.768~^\circ\mathrm{C}$, ...
1
vote
1answer
36 views

Melting ice off of trucks fast

When a truck comes into the shop with extreme ice that is rock hard, is there a way to remove it fast?, any tricks of the trade?
7
votes
1answer
750 views

Does bleach turn a substance white or colorless?

From what I understand, bleach works to weaken the ability of a substance to absorb light. Thus this seems to be "whitening" i.e. reflecting all light. In contrast, colorlessness (according to ...
-2
votes
0answers
24 views

How to determine leftover substrates in sulfur and fluorine reaction? [on hold]

If 12 moles of fluorine gas are mixed with 5 moles of sulfur, how many moles of sulfur remain after 9 moles of fluorine react? A bit confusing to solve, given the following: $$\ce{S + 3F2 -> ...
3
votes
0answers
24 views

How does the radial distribution function of Vanadium differ from that of Calcium and how does this affect the ionic electron configurations?

When Vanadium is ionised it loses the 4s electron first, meaning that it's 3+ ion has a different electron configuration to Calcium despite it being isoelectronic. Can it be explained in terms of ...
4
votes
1answer
187 views

Why is an ester more acidic than a ketone?

Every book I've read says: Esters are more acidic than ketones, because the resonance between the two oxygen atoms gives less opportunity for the delocalization of the electron pair on the alpha ...
0
votes
0answers
13 views

Calculating the heat in joules gained by a calorimeter [on hold]

25.0 ml of hot water at temp 37 degrees C was added to 25.0 ml of cold water in a "coffee-cup" calorimeter at temp 22degre C. the final temperature of the calorimeter was 28.0 degrees C. 1. Calculate ...
0
votes
0answers
26 views

Why nitrogen is inactive but oxygen is more active? [on hold]

Why is nitrogen, being the major component of the atmosphere, inactive but oxygen, the minor component, is most reactive? As per Le Chatelier's principle, if the concentration of a reactant is much ...
1
vote
0answers
19 views

Buffer Power of the amphiprotic substance

The mass balance for a generic amphiprotic substance $[AH^-]$ this: $$ [HA^-]=C \cdot \dfrac{K_{a1} [H_3O^+]}{K_{a1}\cdot [H_3O^+] + [H_3O^+]^2 + K_{a1} \cdot K_{a2}} \quad Eq.1 $$ where: C = ...
1
vote
0answers
18 views

Absorbtion of light by a Coordination Compound

A $\ce{[M(H2O)6]^{2+}}$ complex typically absorbs at around $600$ nm. It is allowed to form a new complex $\ce{[M(NH3)6]^{2+}}$ that should have absorbtion at? The absorbtion is beacuse of transition ...
0
votes
1answer
31 views

Why is NaCl insoluble in CCl4?

Now I know it's something related to the fact that $\ce{CCl4}$ does not have a net dipole moment but I can't connect the dots.
1
vote
0answers
15 views

What is the type of dependence of the rate of reaction on the amount of catalyst?

I have performed an experiment where I had some test tubes with the reagents and different amounts of catalyst. I started the reactions and measured the time they took. Then I calculated the rate of ...
0
votes
0answers
12 views

water softner in the hard water for soften the water [on hold]

Hard water converted to soft water by using water after, Whether, that water can used for other house purposes except drinking. How much water softener can be used (Approx) for 500 ltr water. i know ...
1
vote
2answers
24 views

What causes Starch's lump creation when solvent (butter/water/oil) is added and how to prevent them

When liquid(water/butter) is added to starch lumps of starch are formed. Which are completely dry from inside. Adding more solvent doesn't seem to help therefore it is not a case of saturated ...
4
votes
1answer
35 views

why does a glass tube show white bands after being heated with a torch?

When I use a torch to split a glass tube, there's always a hazy white band which appears. Does anyone know what the cause of this is? (FYI, it was a hydrogen-oxygen torch. The glass is fused quartz ...
2
votes
0answers
28 views

Validity of Trouton's Rule

I would like to know under what circumstances is Trouton's rule obeyed by liquids and why certain systems i.e. substances may deviate from Trouton's rule. By the way I know what Trouton's rule is ...
0
votes
1answer
33 views

Smallest whole number coefficient?

What is the smallest whole number coefficent of $\ce {Cr^{2+}}$ when the equation is balanced? $$\ce {Cr^{2+}_{(aq)} + Al_{(s)} -> Cr_{(s)} + Al^{3+}_{(aq)}}$$ I don't understand, how can this be ...
0
votes
0answers
18 views

Using knowledge of radial distribution functions, how is it possible to explain the different electron configurations of V3+ and Calcium [duplicate]

I recognize that the 3d orbital decreases in energy to lower than the 4s once it becomes occupied (even if I don't completely understand why?!). However, how is the difference in electron ...
0
votes
1answer
46 views

Net charge of Peptides at pH1 and pH0

Taking Glycine and aspartic acid. As both the amino acids are fully protonated at pH 0 ad pH 1, how does the peptide bond form? Is it a two step mechanism where the OH from an alpha carboxyl group ...
0
votes
1answer
22 views

Acid-Base Titration: Do Acids and Bases Have the Same Coefficients of Moles if They Neutralize One Another?

The questions states: Ammonia has the formula NH3. Household ammonia is a dilute aqueous solution of NH3. Aqueous ammonia is a base that can neutralize acids. If 18.2mL of 0.800 M HCl solution are ...
2
votes
1answer
18 views

Volume of different gas in a container

I know that technically two or more gases in one container should have different volumes. But when you imagine the gas molecules being mixed together, it look sorta like the two gases have the exact ...
0
votes
0answers
10 views

Devitrification vs glass transition temperature

This graph comes from a so-called "differential thermal analysis". It is studying the effects of temperature on glass. I dont understand what the difference between "glass transition" and ...
0
votes
0answers
17 views

Find atomic radius using density [on hold]

I'm studying crystal structures and I'm supposed to be able to find atomic radius using just the density, but I don't understand how! An example is a metal sample with a weight of 5.722 g and the ...
1
vote
2answers
87 views

Reductive amination of (protected) 3-Oxopropanenitrile: Will azetidin-2-ol be formed via intramolecular ring closure?

What happens during this reductive amination? I got the first product; the lithium aluminium hydride will reduce the nitrile to an amine. But what about the reductive animation step? As far as I can ...
-1
votes
0answers
23 views

What are all isomers of alkenes excluding cyclo? [on hold]

could someone please give me a list of all isomers of alkenes from C1 to C7 excluding stereoisomers and cycloisomers?
0
votes
0answers
47 views

Finding the final temperature problem [on hold]

A 0.6850-kg ice cube at -12.40°C is placed inside a chamber of steam at 365.0°C. Later, you notice that the ice cube has completely melted into a puddle of water. If the chamber initially contained ...
0
votes
0answers
31 views

Application of Grahms Law of diffusion

$\ce{H2}$ (di-hydrogen) and $\ce{He}$ are kept in a container at partial pressure $p_1$ and $p_2$. A thin perforation is made in the wall of the container and it is observed that both gases diffused ...
3
votes
1answer
65 views

Why are all the orbitals that have the same principal number in Hydrogen degenerate?

In hydrogen, all orbitals with the same principal quantum number 'n' (1,2,3...) are degenerate, regardless of the orbital angular momentum quantum number'l' (0,1...n-1 or s,p,d..). However, in atoms ...
-1
votes
0answers
13 views

Apply Hess's Law, Thermochmical equation OR q = m * C * Delta T to this reaction? [on hold]

If 0.5 grams of one element is combined with 200 milliliters of an acid (For example, Sodium(s) being put in Hydrochloric Acid) and the temperature change is recorded, then the same is done for the ...
0
votes
1answer
25 views

Finding the concentration of an ion

What is the concentration (M) of the chloride ion when 18.5 mL of a 0.622 M solution of barium chloride is combined with 15.6 mL of a 0.726 M solution of aluminum chloride? The volumes can be ...
3
votes
1answer
43 views

What does “a metallic oxide has 40% oxygen” mean?

If a metallic oxide has $40\%$ oxygen, find the equivalent weight of the metal. This amounts to finding the atomic weight of the metal and the charge on the cation (in effect identifying the ...
0
votes
2answers
45 views

Doubt on Photoelectric effect

In the experiment to conduct photoelectric effect a clean metal was irradiated by monochromatic light of proper frequency, electrons are emitted. Why was monochromatic light used in the experiment? ...
0
votes
0answers
20 views

what is the # of protons on adjacent atoms? what is consider adjacent? [on hold]

looking at the nmr for aspirin, would i consider CH3 as 3 protons adjacent to the aryl hydrogen a couple of carbons away?
0
votes
0answers
13 views

about stereochemistry/major product [on hold]

Supply the correct major product formed from the following reaction link to the reaction/picture - http://i.imgur.com/9tmrS38.png
2
votes
1answer
30 views

Is there a heat capacity of an object when it is melting?

Is there a heat capacity of an object when it is melting? I'm questioning it since the temperature doesn't change during phase transitions and the units of heat capacity is Joules/Kelvin.
3
votes
3answers
88 views

“There are no chemical cliffs”

Are there any reactions with no activation energies? Prof just told us there are no chemical cliffs. Is this true? I read something about nuclear decay as being a reaction with no activation ...
4
votes
0answers
35 views

Osmium tetroxide and meta-chloroperoxybenzoic acid

Can these be used to induce acetal ring closures? For example, when dealing with a molecule that has both a C=O functional group and an alkene as part of its structure and there is the possibility of ...
0
votes
0answers
20 views

Imine stability in acids and bases

I understand that imines can be hydrolyzed in acidic medium. But what about in basic medium? Can imines still be hydrolyzed? I have a plausible mechanism ... nitrogen's withdrawal of electron ...
2
votes
1answer
32 views

Why hybridization occurs in diatomic molecule

In diatomic nitrogen There are two electron configurations I'd like to compare: 1s2 2s2(lone pair) 2p3(the bonding electrons sigma,pi,pi) 1s2 2sp(lone pair) 2sp(sigma bonding) 2p2(pi,pi bonding) ...
-2
votes
0answers
18 views

Determination of acid contents in sour fruits project? [on hold]

Determination of acid contents in sour fruits project? Any idea about it or any references.
0
votes
1answer
20 views

Potassium permanganate oxidation of sugars

I am told that all three sugars below can be oxidized to their corresponding carboxylic acids using potassium permanganate. This strikes me as bloody wrong because only hemiacetal sugars ...

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