instruction stringlengths 15 21.8k |
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Why does the molar conductivity decrease with increasing charge density? |
I have calcium chloride in the form of small (1-2 mm) round white pellets, originally bought at a home-brew shop. The packaging gives no indication what hydrate it is. Since each water molecule adds ~16% of the weight of anhydrous CaCl<sub>2</sub> this introduces a big error when using it to treat water to a specified ... |
Determining which hydrate of calcium chloride I have? |
What is palindromic DNA and why isn't every complementary strand palindromic?
I know AGCT is palindromic, but what is an example of a strand that isn't? |
What is palendromic DNA? |
Which all elements of Group 15 of the periodic table have allotropes?
P,As and Sb have well-known allotropes.
P - White,Red and Black.
As - Yellow,Black and Gray(Grey)
Sb - White,Yellow and Black
([Source][1])
**What about Nitrogen and Bismuth?**
* The same [source][2] sugg... |
Which all elements of Group 15 of the periodic table have allotropes?
P,As and Sb have well-known allotropes.
P - White,Red and Black.
As - Yellow,Black and Gray(Grey)
Sb - White,Yellow and Black
([Source][1])
**What about Nitrogen and Bismuth?**
* The same [source][2] sugg... |
What is palindromic DNA? |
Given the similarity in formula between pentane ($\small\ce{CH3(CH2)3CH3}$, b.p. 36.2 °C) and neopentane ($\small\ce{C(CH3)4}$, b.p. 9.5 °C), why are their boiling points so different? |
> I came across this question where I had to convert
> $\ce{CH3-CH2-Mg-Br}$ to $\ce{CH3-CH2-NH2}$. If I need to do so can I
> just react the given compound with water [...]
Always be cautious about unwanted, side reactions that may occur. Proton exchanges are one huge class of possible side reactions. Protons tran... |
"Water has 2 lone pairs on O, so can it donate both (one as a pi bond) just like those compounds? If not, why?"
As I posted:
"It is possible for pi-donating ligands, like $\ce{NH2^{-}}$ (amide anion), but not really possible for water (neutral, oxygen more electronegative)."
Pi-donation from water would lead ... |
> I came across this question where I had to convert
> $\ce{CH3-CH2-Mg-Br}$ to $\ce{CH3-CH2-NH2}$. If I need to do so can I
> just react the given compound with water [...]
Always be cautious about unwanted, side reactions that may occur. Proton exchanges are one huge class of possible side reactions. Protons tran... |
How is charge density a useful measure of polarising power and polarisability? |
"Water has 2 lone pairs on $O$, so can it donate both (one as a pi bond) just like those compounds? If not, why?"
As I posted:
"It is possible for pi-donating ligands, like $\ce{NH2^{-}}$ (amide anion), but not really possible for water (neutral, oxygen more electronegative)."
Pi-donation from water would lea... |
As cibrail said, DNA is a polymer of nucleotides. They join themselves through phosphodiester bonds (a specific kind of covalent bond) that can grow to as much as millions of nucleotides.
What part in the strand contributes to the overall non neutral charge?
---------------------------------------------------------... |
[According to Wikipedia][1], a single cellulose molecule is:
> a linear chain of several hundred to many thousands of β(1→4) linked
> D-glucose units.
which means a cotton fiber is made of ~1μm cellulose units.
What forces hold the fiber as a whole?
[1]: https://en.wikipedia.org/wiki... |
What forces keep a cotton fiber together? |
Is there a way to efficiently estimate the enthalpy of formation for an organic molecule in computational chemistry? |
What happens to a complexometric titration of calcium carbonate (analyte) and EDTA (titrant) when there is no magnesium (II) chloride crystals added to the EDTA solution? In a water analysis(where water sample is the analyte and EDTA is the titrant)? |
So, after dissolving a good portion of my brain by watching a ton of sci-fi, I started thinking about all of the strange new materials that we will supposedly have in the future. For example, the ever-present "di-lithium" in Star Trek. But, as I started thinking about it, I thought it was a little ridiculous (I know sc... |
Are strange forms of matter possible? |
What mass of fragrance are airborne in scented environments for example in a perfume deparment?
What is the minimum g/m3 of fragrance that a human can detect, and how much is present when it evaporates from an oven, in a cookie shop, from a cut lawn, near a perfumed lady and average levels from a day of walking.
... |
What mass of fragrances does a cubic meter of air contain on average? |
I'm heating up several metal blocks as part of an experiment to determine their specific heat capacities. In a nutshell, I'm heating the blocks of known mass to 100°C, then adding them to an insulated vessel containing water of known temperature and measuring the increase. Pretty basic stuff.
I'm trying to work out ... |
How can I measure the internal temperature of a solid metal? |
I’m heating up several metal blocks as part of an experiment to determine their specific heat capacities. In a nutshell, I’m heating the blocks of known mass to 100 °C, then adding them to an insulated vessel containing water of known temperature and measuring the increase. Pretty basic stuff.
I’m trying to work out... |
I’ve done absolutely no chemistry since high school. Now, 16 years later, I’ve been asked to look at some chemical analyses and I’m having trouble!
Context: I’ve got a series of spectroscopy results giving the concentrations (in mg/l) of chlorine and $\ce{SO4}$ in a sample. I want to find the molar and mass rati... |
What do higher charge density of a cation means?
It means that the positive charge on cation is concentrated in a small volume. Small and concentrated charge can cause greater distortion in the anion and therefore they have greater polarising power, or greater power to cause attract the negative electron cloud of th... |
Do you know the formula:
$$K_\text{a} = \frac{[\ce{H+}][\ce{A-}]}{[\ce{HA}]}$$
?
You will need to find a concentration first, however, on the equation.
$$\ce{HA <=> H+ + A-}$$
And solve for the dissociated hydrogen ion, say $x$.
$$K_\text{a} = \frac{[x][x]}{[\ce{HA}]-x} = \frac{x^2}{[\ce{HA}]-x}$$
... |
Hydrogen and hydroxide both exceed sodium and chlorine in terms of reduction and oxidation potential respectively.
While electrolyzing a concentrated solution of aqueous NaCl, it is known that chlorine is discharged at the anode (contaminated with traces of oxygen). However, at the cathode, hydrogen is charged in p... |
While electrolyzing concentrated aqueous sodium chloride, why is it that chlorine is discharged but not sodium? |
Which orbitals are filled? Is it dimagnetic? According to CFT, CO a strong field ligand so will it pair the elctrons and make it dimagnetic? |
I have a container with 3% hydrogen and the rest is air. How fast the hydrogen will get oxidized by air?
How much the reaction will speed up with increased temperature?
Thanks so much. |
Does hydrogen react with air at room temperature and pressure? |
Just wondering if you fitted a cold water tank overflow pipe into a car park at the height of a car exhaust , if the carbon monoxide fumes went back up the oveflow pipe into the tank would this contaminate the water? |
Contamination would occur if a sufficient quantity of carbon monoxide wouldn't just bubble through but
1. would react with water to form an unhealthy product or
2. is dissolved in water
Both isn't really true:
1. $\ce{CO}$ does not react under these conditions.
2. The solubility of $\ce{CO}$ in w... |
Why is zinc oxide yellow when hot and white when cold?
Is it yellow because of the flame used to make it hot? |
What are the products of partial hydrolysis of $XeF_6$ ?
Is $XeOF_4$ formed or $XeO_2F_2$ ? |
What are the products of partial hydrolysis of $\ce{XeF_6}$? Is $\ce{XeOF_4}$ formed or $\ce{XeO_2F_2}$? |
Which orbitals are filled? Is it diamagnetic? According to CFT, $\ce{CO}$ is a strong field ligand, so will it pair the electrons and be diamagnetic? |
Which species can't appear in the rate expression for this reaction scheme? |
Why does this reaction take place in terms of electronic structure? |
Newbie question,
What is the difference between diatomic molecules and elements?
Also, If oxygen is element of a single atom, then what makes it a diatomic element? But, then I read that a single oxygen atom can bind with another element to form a compound, but it's a diatomic element with two atoms.
Please ... |
What happens to a complexometric titration of calcium carbonate (analyte) with $\ce{EDTA}$ (titrant) when no Magnesium (II) Chloride crystals added to the buffer ($\ce{NH3/NH4^+ + EDTA}$) solution? In a water analysis(where water sample is the analyte and EDTA is the titrant)? |
What happens if don't use $\ce{MgCl2}$ in buffer solution in $\ce{Ca^2+/Mg^2+}$ titration? |
What happens to a complexometric titration of calcium carbonate (analyte) with $\ce{EDTA}$ (titrant) when no magnesium(II) chloride crystals added to the buffer ($\ce{NH3/NH4^+ + EDTA}$) solution? In a water analysis(where water sample is the analyte and EDTA is the titrant)? |
What is the difference between diatomic molecules and elements?
Also, If oxygen is element of a single atom, then what makes it a diatomic element? But, then I read that a single oxygen atom can bind with another element to form a compound, but it's a diatomic element with two atoms.
Please can someone enlighte... |
**Summary** The Magnesium is added because the color change is easier to spot with it, even though calcium also changes the color of the solution in presence of TBT.
**Long explanation and experiment**
Even though your question might looks silly at first, I know it makes sense because I work with Soil Analysis, a... |
What is the effect of rolling a graphene sheet into a carbon nanotube on the lattice constant and the geometry of the graphene? |
How many moles of the substance are in 2.5 g of lead? |
How to synthesize methamphetamine? |
How would you write the Kp expression for the reaction 4 Ag(s) + O2(g) -> 2 Ag2O(s)?
I know normally it would be products over reactants... but there is a solid on the product side and they aren't included, so I don't know how you would write it???? |
Writing Kp expressions? |
In this thought experiment, let’s consider the surrounding to be air that is composed of entirely water vapor (no other species like $\ce{O2}$ and $\ce{N2}$ are present). The surrounding is infinitely large. The system in question is a pan containing a thin layer of liquid water. The liquid water is brought to its boil... |
Is this the right conclusion for a thought experiment? |
I am tying to determine if an acid is a liquid or aqueous solution? Please can some enlighten me.
-LAG |
How would you write the Kp expression for the reaction: $$\ce{4 Ag(s) + O2(g) \rightarrow 2 Ag2O(s)}$$
I know normally it would be products over reactants... but there is a solid on the product side and they aren't included, so I don't know how you would write it? |
I completed a titration experiment in a lab. The aim was to find the concentration of the titrant $\ce{KMnO4}$ solution by titrating it with a sodium oxalate solution of a known concentration.
I first made a standard solution of sodium oxalate solution, using 0.826 g of sodium oxalate powder, then poured 50ml of di... |
How to find the concentration of potassium permanganate in this experiment? |
The benzyloxycarbonyl group (CBZ) is widely used to protect amines, especially in
aminoacid chemistry. A procedure to synthesise the CBZ derivative of glycine from glycine and benzyl chloroformate is given in the description below.
Glycine (0.1 mole) was dissolved in aqueous sodium hydroxide (50 mL of a 2 M solut... |
Why is this procedure containing a mistake? Among other questions |
The most stable conformation of optically inactive butane-2,3-diol is:
(A)![enter image description here][1]
(B)![enter image description here][2]
(C)![enter image description here][3]
(D)![enter image description here][4]
[1]: https://i.stack.imgur.com/ZII1f.jpg
[2]: https://i.stack.imgur.com/9kI... |
Which is most stable conformation of optically inactive butane-2,3-diol? |
What happens to a complexometric titration of calcium carbonate (analyte) with $\ce{EDTA}$ (titrant) when no magnesium(II) chloride crystals are added to the buffer ($\ce{NH3/NH4^+ + EDTA}$) solution? In a water analysis (where water sample is the analyte and $\ce{EDTA}$ is the titrant)? |
What happens if don't use MgCl₂ in buffer solution in Ca²⁺/Mg²⁺ titration? |
Can carbon monoxide contaminate water? |
How to get a protein's dihedral angles ordered by variance? |
According to [Wikipedia][1], a single cellulose molecule is:
> a linear chain of several hundred to many thousands of β(1→4) linked
> D-glucose units.
which means a cellulose molecule is made of ~1μm of glucose units.
According to [Trotman, 1984][2],
> Each cotton fibre is a unicellular ... |
![enter image description here][1]
![enter image description here][2]
[1]: https://i.stack.imgur.com/o7N1N.png
[2]: https://i.stack.imgur.com/L7GBt.png
What is happening in Step 2 and would you please give the reaction mechanism for it as well? |
Is Bromide anion acting as a base in reaction with ethylamine and methylbromide? |
![enter image description here][1]
![enter image description here][2]
[1]: https://i.stack.imgur.com/r0e4i.png
[2]: https://i.stack.imgur.com/tsd4e.png
Are these reaction mechanisms correct for Ammonia and Bromide anions acting as a base respectively? |
Reaction mechanisms of ammonia with water and Ethylammonium ion with Bromide anion? |
Carbonates
-
The quote from your text:
>Carbonates of alkaline earth
metals are insoluble in water and can be
precipitated by addition of a sodium or
ammonium carbonate solution to a solution
of a soluble salt of these metals. The solubility
of carbonates in water decreases as the atomic
number of the metal ... |
For carbonates and bicarbonates, I know that stability increases down the group, and for chlorides and fluorides, stability decreases down the group. Why does this happen? Can someone explain this in detail?
(I am talking about S block alkali metals) |
What is the explanation of the changes in stability going down a group for carbonates, bicarbonates, fluorides, and chlorides? |
Are these reaction mechanisms correct? |
I am tying to determine if an acid is a liquid or aqueous solution? Please can some one enlighten me?
|
Is an acid a liquid or an aqueous solution? |
Carbonates
-
The quote from your text:
>Carbonates of alkaline earth
metals are insoluble in water and can be
precipitated by addition of a sodium or
ammonium carbonate solution to a solution
of a soluble salt of these metals. The solubility
of carbonates in water decreases as the atomic
number of the metal ... |
If I understand you, I can't imagine how to solve the your problem with this approach. Also I don't get the physical meaning of the proposed solution.
If you have to deal with a molecule with more than 100 rotatable bonds, you are just in problems.
You could find the rotatable bonds with some tools (see for example... |
I understand that if you rotate a molecule and it has the same configuration as its enantiomer, then it is indeed the same compound as the enantiomer (meso), and hence is achiral (despite having chirality centers).
What happens however, if you rotate a compound and its fisher projection has exactly the same configur... |
Stereochemistry - What happens if molecular rotation leads to the same compound? |
What is the process or material that can enhance the conductivity of the graphene oxide? |
I was wondering, how do I determine what metal (element) has the highest density by using the periodic table ? Is it possible ? Thank you! |
The question is
". For which exothermic reaction is ?E more negative than
?H?
(A) Br2(l) r Br2(g)
(B) 2C(s) + O2(g) r 2CO(g)
(C) H2(g) + F2(g) r 2HF(g)
(D) 2SO2(g) + O2(g) r 2SO2(g)"
Or, written better, I interpreted ? as delta. There were some syntax errors on the test. r is supposed to be reactio... |
The question is
>For which exothermic reaction is $\Delta\,E$ more negative than
$\Delta\,H$?
>(A) $\ce{Br2(l) <=> Br2(g)}$
>(B) 2C(s) + O2(g) r 2CO(g)
>(C) $\ce{H2(g) + F2(g) -> 2HF(g)}$
>(D) 2SO2(g) + O2(g) r 2SO2(g)"
Or, written better, I interpreted ? as delta. There were some syntax errors on ... |
I understand that if you rotate a molecule and it has the same configuration as its enantiomer, then it is indeed the same compound as the enantiomer (meso), and hence is achiral (despite having chirality centers).
What happens however, if you rotate a compound and its fisher projection has exactly the same configur... |
In principle, **[there are no zeroth-order reaction](http://chemwiki.ucdavis.edu/Physical_Chemistry/Kinetics/Reaction_Rates/Zero-Order_Reactions)**. Experimentally, however, zeroth-order rate law occurs because of the reaction condition. For example, in catalytic reactions such as hydrogenation of an alkene using plati... |
The question is
>For which exothermic reaction is $\Delta\,E$ more negative than
$\Delta\,H$?
>(A) $\ce{Br2(l) <=> Br2(g)}$
>(B) 2C(s) + O2(g) r 2CO(g)
>(C) $\ce{H2(g) + F2(g) -> 2HF(g)}$
>(D) 2SO2(g) + O2(g) r 2SO2(g)"
Or, written better, I interpreted ? as delta. There were some syntax errors on ... |
how phosphorus forms 2 types of bonds with oxygen i.e. 5 in P4O10 and 3 in P4O6.
when only three are needed to complete its octet?
|
why does phosphorus makes 5 bonds with oxygen in P4O10 whereas 3 bonds in P4O6? |
how phosphorus forms 2 types of bonds with oxygen i.e. 5 in $\ce{P4O10}$ and 3 in $\ce{P4O6}$ when only three are needed to complete its octet?
|
Except for the missing equilibrium arrow (these reaction are acid-base equilibria), they are fine. Or do you have any objections :) (what makes you doubt) ? |
In my organic chemistry class there are several reactions that I’ve been told are generally conducted at −78 °C, which is apparently also the temperature of dry ice in acetone. This is all well and good, but I don’t really get what that actually means. Do you put the dry ice in the acetone and then toss in your reacta... |
In my organic chemistry lab (next week, the experiment has not been conducted yet) we are being asked to react anisole with bromine to get 2-bromoanisole (as well as 2,4-dibromoanisole and all the others). In our lab instructions we are told to add anisole, bromine and glacial acetic acid to our mixture. No mention o... |
If one considers boiling points (in °C) of primary alcohols, one finds the following:
- methanol: 65
- ethanol: 79
- 1-propanol: 97
- 1-butanol: 117
- 1-pentanol: 138
This trend is due to Van der Waals forces increasing with molecular weight.
Now if one focuses on melting points, I would expect th... |
No, because for ethene, $\mathrm{p}K_\text{a} = 44$. You won't be able to abstract even one proton.
Maybe, you were thinking in ethyne ($\ce{HC#CH})$? In that case, you are right! The bis-alkylation would work with sodium amide as a base!
But is the simultaneous abstraction of both protons the most plausible rea... |
Are there any simple methods to completely remove nitrate ions from few ml of impure water sample ?
One method I am curious about is the following process :
1. Add one or more reagents to water in test tube, which would crystallize nitrate ions into some solids
2. Then filter out the solids from water such th... |
How to remove nitrate from water sample? |
I am struggling to understand ternary phase diagrams for reactor engineering. The course slides offer little to no help so I'm hoping to find an answer to this question
> How does the slope of the tie-lines affect on which side of the
> equilibrium line the extract/raffinate is?
From what I understand is that i... |
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