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Usually the range of a $pH$ scale is $0-14$. A higher number on the $pH$ scale means that the substance is **Basic**, a lower number means it is **Acidic**.
Another thought to keep in mind is that there can be a $pH$ less than $0$ and greater than $14$. But let's not get into that right now. The pH scale was made fo... |
Usually the range of a $pH$ scale is $0-14$. A higher number on the $pH$ scale means that the substance is **Basic**, a lower number means it is **Acidic**.
Another thought to keep in mind is that there can be a $pH$ less than $0$ and greater than $14$. But let's not get into that right now. The pH scale was made fo... |
Perhaps you have heard of the following terminology: "rock salt", "cesium chloride", "zinc blende" structures? If so, you may recall that in this case, the main factor dictating structure is "size" or atomic radius ratio, rather than group. For example, in the case of the rock salt structure, it is most likely that the... |
This is a topic that I cannot find much information about. I would like to know what compounds are in the products formed from pyrolysis of canola oil. I found out by accident that when trying to ignite some used canola oil in an aluminum can without a cover, the oil had become a mix of black solids and black liquid. I... |
My book doesn't seem to properly explain the importance of derivating the Gaus spectral line, neither the meaning of it, so my questions are :
**1**.What do the spectral lines of 1st, 2nd, 3rd and 4th derivates of the basic Gaus specter tell us exactly ?
**2**.Why are the second and the fourth derivated spectral li... |
My book doesn't seem to properly explain the importance of derivating the Gaus spectral line, neither the meaning of it, so my questions are :
**1**.What do the spectral lines of 1st, 2nd, 3rd and 4th derivates of the basic Gaus specter tell us exactly ?
**2**.Why are the second and the fourth derivated spectra... |
I saw a test question today that basically boiled down to comparing the ionization energies of $C$ and $Cl$. I know that in the periodic table, ionization energy generally decreases as we move right across a row (because nuclear charge increases), and increases as we move down a column (because atomic radius increases,... |
Compare the ionization energies of $C$ and $Cl$? |
I saw a test question today that basically boiled down to comparing the ionization energies of $\ce{C}$ and $\ce{Cl}$. I know that in the periodic table, ionization energy generally decreases as we move right across a row (because nuclear charge increases), and increases as we move down a column (because atomic radius ... |
Compare the ionization energies of C and Cl? |
If a molecule contains four chlorine atoms. How many molecular ion peaks will this compound show in its mass spectrum? |
If a molecule contains four chlorine atoms, how many molecular ion peaks will this compound show in its mass spectrum? |
I saw a test question today that basically boiled down to comparing the ionization energies of $\ce{C}$ and $\ce{Cl}$. I know that in the periodic table, ionization energy generally increases as we move right across a row (because nuclear charge increases), and decreases as we move down a column (because atomic radius ... |
Little open information can be found on the requirements of the *manufacture, development and testing* of **gel and printing inks**.
It seems that most ink manufacturers have their own specific lab configuration.
Would you know of a recource, or could you list me a possible lab setup for such an endeveavor? While ... |
I'm doing an electrochemistry lab that requires me to construct various galvanic cells in an attempt to solve for $\Delta$H, $\Delta$G, and $\Delta$S values of an unknown. During one part of the experiment, I had to heat a cell to a temperature of 70C and record its voltage in 15 degree increments until the temperature... |
I'm doing an electrochemistry lab that requires me to construct various galvanic cells in an attempt to solve for $\Delta$H, $\Delta$G, and $\Delta$S values of an unknown. During one part of the experiment, I had to heat a cell to a temperature of 70C and record its voltage in 15 degree increments until the temperature... |
>For the process, $\ce{CH3OH(l) -> CH3OH(g)}$
$\Delta G^\circ = 4.30\ \mathrm{kJ/mol}$ at 25 °C. What is the vapor pressure
of $\ce{CH3OH(l)}$ at 25 °C in mmHg?
(A) 0.176 mmHg
(B) 14.0 mmHg
(C) 134 mmHg
(D) 759 mmHg
This question is from the 2012 National Chemistry Olympiad (US).
Attempt at solution... |
I’m doing an electrochemistry lab that requires me to construct various galvanic cells in an attempt to solve for $\Delta H$, $\Delta G$, and $\Delta S$ values of an unknown. During one part of the experiment, I had to heat a cell to a temperature of 70 °C and record its voltage in 15 degree increments until the temper... |
> If a molecule contains four chlorine atoms, how many molecular ion peaks will this compound show in its mass spectrum?
## Limitations of existing answers
Ron's answer is good for molecules that consist solely of chlorine, i.e., a hypothetical $\ce{Cl4}$ molecule. But if there are other atoms as well, then ther... |
> If a molecule contains four chlorine atoms, how many molecular ion peaks will this compound show in its mass spectrum?
## Limitations of existing answers
Ron's answer is good for molecules that consist solely of chlorine, i.e., a hypothetical $\ce{Cl4}$ molecule. But if there are other atoms as well, then ther... |
> My question is, theoretically, what should happen to the voltage as I heat the cell, assuming that the concentrations of the solutions were off?
This question is tough to answer because I don't know what you mean by "off". So let me ask (and answer) a few related questions that I think will help you.
## What s... |
I'm a freshman recently learned how to do TLC and column chromatography. I also know a little about other ways to separate things by chromatography, such as affinity chromatography, gel chromatography, ion exchange chromatography, and gas chromatography, but without many details.
Here I meet problems to solve a questi... |
> If a molecule contains four chlorine atoms, how many molecular ion peaks will this compound show in its mass spectrum?
## Limitations of existing answers
Ron's answer is good for molecules that consist solely of chlorine, i.e., a hypothetical $\ce{Cl4}$ molecule. But if there are other atoms [*of elements that... |
> Is the peroxide effect observed only with addition of hydrogen bromide
> and chloroform?
No, the "peroxide effect" or "Markovnikov" addition of a free radical to an unsaturated bond is observed with other compounds too, $\ce{CCl4}$ is another example.
Also, just to be clear, these reactions involve the additi... |
> Is the peroxide effect observed only with addition of hydrogen bromide
> and chloroform?
No, the "peroxide effect" or "Markovnikov" addition of a free radical to an unsaturated bond is observed with other compounds too, $\ce{CCl4}$ is another example.
Also, just to be clear, these reactions involve the additi... |
Calculate the pH of a 100 mL solution containing 0.0375 moles of the weak base, sodium benzoate, C6H5COONa.
C6H5COO + H2O -> C6H6COO- + OH-
0.0375 mol/.100 L = 0.375M
pOH = 0.43
pH = 13.57
Is this right? Thank you. |
What is the pH of a solution of 3.4*10^-10 moles of HCl in a volume of 150.7L?
This is dilute so I expect pH to be high.
3.4*10^-10/150.7L = 2.26*10^-12 M
Then pH is 11.65. is this correct? thank you |
One kg of each substance below is dissolved in a bathtub full of water. Will it be acidic, basic, or neutral?
KNO2
HF
(CH3)3NHBr
HO-CH2-CH2-O-CH2-Cl
KNO2, K+ NO2- K+ is inert and NO2- is the base of strong acid, so it should be basic overall.
HF, H+ F- H+ is strong acid and F- is strong base so it should be n... |
What is the pH of a solution of $3.4 \times 10^{-10}$ moles of HCl in a volume of $150.7L$?
This is dilute so I expect pH to be high.
$\frac{3.4 \times 10^{-10} mol}{150.7L} = 2.26 \times 10^{-12} \frac{mol}{L} $
Then pH is 11.65. Is this correct? |
Calculate the $pH$ of a $100$ $mL$ solution containing $0$$.0375$ moles of the weak base, Sodium Benzoate, $\ce{C6H5COONa}$.
> $$\ce{C6H5COO + H2O -> C6H6COO- + OH-}$$
$$\frac{0.0375 ~mol}{.100~ L} = 0.375~M$$
$$pOH = 0.43$$
$$pH = 13.57$$
Is this right? Thank you. |
I read this today:
If you mix equal amounts of $1 M$ $H_3PO_4$ and $1 M$ $NaH_2PO_4$ you get a buffer at $pH<6$. The reason given is that a weak acid plus a salt containing the conjugate base forms a acidic buffer.
If you mix equal amounts of $1 M$ $NH_3$ and $1 M$ $NH_4Cl$, you get a buffer at $pH>8$. The reason... |
Weak acid and salt containing conjugate base forms acidic buffer? |
Here is what seems to be a straightforward question: you dissolve some ammonia chloride in water at $25$ $C$, lowering the temperature of the solution. Is the change in enthalpy for the dissolving process positive or negative?
My reasoning: if the temperature of the solution decreases, it means heat was released int... |
If the temperature of a solution decreases, what is the sign of the enthalpy change? |
Here is what seems to be a straightforward question: you dissolve some ammonium chloride in water at $25$ $C$, lowering the temperature of the solution. Is the change in enthalpy for the dissolving process positive or negative?
My reasoning: if the temperature of the solution decreases, it means heat was released in... |
1. I know atoms are held together by Ionic and Covalent bonds and i understand the ionically bonded atoms are held together by electrostatic forces. What about covalent bonds?
2. How are molecules of bonded atoms held together?Are ionic compounds just aggregates of oppositely charged ions and hence don't have any de... |
This topic came up the other day but in regards to the evaporation of water. You might find [my answer](http://chemistry.stackexchange.com/a/28432/13184) to that question helpful.
Here's how I would solve the problem.
1. **Explicitly note standard state used and assumptions.** I will assume:
- Methanol vapor ... |
One kg of each substance below is dissolved in a bathtub full of water. Will it be acidic, basic, or neutral?
$\ce{KNO2}$
$\ce{HF}$
$\ce{(CH3)3NHBr}$
$\ce{HO-CH2-CH2-O-CH2-Cl}$
$\ce{KNO2}$, $\ce{K+}$ $\ce{NO2-}$ $\ce{K+}$ is inert and $\ce{NO2-}$ is the base of strong acid, so it should be basic overall.... |
>One kg of each substance below is dissolved in a bathtub full of water. Will it be acidic, basic, or neutral?
$\ce{KNO2}$
$\ce{HF}$
$\ce{(CH3)3NHBr}$
$\ce{HO-CH2-CH2-O-CH2-Cl}$
$\ce{KNO2}$, $\ce{K+}$ $\ce{NO2-}$ $\ce{K+}$ is inert and $\ce{NO2-}$ is the base of strong acid, so it should be basic overall... |
How to determine the acidity or basicity of dissolved salts? |
I read this today:
If you mix equal amounts of $1 M$ $\ce{H_3PO_4}$ and $1 M$ $\ce{NaH_2PO_4}$ you get a buffer at $pH<6$. The reason given is that a weak acid plus a salt containing the conjugate base forms a acidic buffer.
If you mix equal amounts of $1 M$ $\ce{NH_3}$ and $1 M$ $\ce{NH_4Cl}$, you get a buffer a... |
I read this today:
>If you mix equal amounts of $1 M$ $\ce{H_3PO_4}$ and $1 M$ $\ce{NaH_2PO_4}$ you get a buffer at $pH<6$.
The reason given is that a weak acid plus a salt containing the conjugate base forms a acidic buffer.
>If you mix equal amounts of $1 M$ $\ce{NH_3}$ and $1 M$ $\ce{NH_4Cl}$, you get a bu... |
Why does a weak acid and a salt containing its conjugate base form an acidic buffer? |
I bought an electronic meter which measures the concentration of oxygen in air. But I think the sensor has failed because it is too old, as it had a crusty substance coming from it.but I can no longer find spare sensors for it.
How might this sensor have worked? I presume the property of some substance was measured;... |
In our chemistry books( like Concise Chemistry),it is given that concentrated sulphuric acid is used to dry HCL gas.
But,Concentrated sulphuric acid is an strong oxidising agent so,why isn't HCl gas gets oxidised to H2O and chlorine gas??
Why dry CaCl2(Calcium Chloride) isn't used as drying agent??
[Note: ... |
In our chemistry books (like Concise Chemistry), it is given that concentrated sulphuric acid is used to dry $\ce{HCl}$ gas.
But, concentrated sulphuric acid is a strong oxidising agent so, why isn't $\ce{HCl}$ gas oxidised to $\ce{H2O}$ and chlorine gas?
Why dry $\ce{CaCl2}$ (Calcium Chloride) isn't used as dryi... |
Why isn't dry CaCl₂ used to dry HCl gas instead of concentrated sulfuric acid? |
why is cobalt hexacyano complex uncommon? |
Which of the following is more acidic?
![enter image description here][1]
[1]: https://i.stack.imgur.com/lFACi.png
The most acidic proton is positioned on the carbon that is at the top of the above drawings on each of the two species as deprotonation allows resonance. I am aware of Huckel's rule which stat... |
> Is the peroxide effect observed only with addition of hydrogen bromide
> and chloroform?
No, the "peroxide effect" or "anti-Markovnikov" addition of a free radical to an unsaturated bond is observed with other compounds too, $\ce{CCl4}$ is another example.
Also, just to be clear, these reactions involve the a... |
Recently, I am playing with redox reaction and I come over a compound acidified potassium manganate (VII) ($\ce{KMnO4/H^+}$). I get confused that why they put $\ce{H^+}$ beside $\ce{KMnO4}$. Doesn't the hydrogen ions flow freely in the solution or something else.
And so, when we are writing a chemical reaction with... |
At 25 °C, 10.24 mg of Cr(OH)2 are dissolved in enough water to make 125 mL of solution. When equilibrium is established, the solution has a pH of 8.49. Estimate Ksp for Cr(OH)2 (Ans : 1.47*10^-17)
I have calculate it but not have the same answer as this.
I tried it this way:
1. pH is 8.49 then pOH is 5.51, I us... |
Which of the following is more acidic?
![enter image description here][1]
[1]: https://i.stack.imgur.com/lFACi.png
The most acidic proton is positioned on the carbon that is at the top of the above drawings (the methylene hydrogens) on each of the two species as deprotonation allows resonance. I am aware o... |
I am looking for a complete reference of UV/Vis spectroscopic data for organic materials ( mostly interested in λmax ) .
I have the CRC handbook but it only has data about some organic solvents in water and very limited data on dyes.
Can anyone suggest a comprehensive reference that includes the λmax of a wide ... |
If you leave something outside, its colors seem to inevitably fade or bleach due to exposure. Is this due to UV absorption? What sort of mechanism causes this - is it that man-made dyes deform on a molecular level? Are there notable materials that are exceptions?
I have a full undergraduate background in physics but... |
Why does sunlight cause colors to fade? |
At 25 °C, 10.24 mg of $\ce{Cr(OH)2}$ are dissolved in enough water to make 125 mL of solution. When equilibrium is established, the solution has a pH of 8.49. Estimate $\ce{K_{sp}}$ for $\ce{Cr(OH)2}$ (Ans : $1.47*10^{-17}$)
I have calculated it but not have the same answer as this.
I tried it this way:
1. $\ce... |
Please, I really need this. What methods are there to produce this compound? What are its properties as a component of automobile petroleum? How does it impact on detonation resistance of automobile petroleum? |
> What methods are there to produce this compound? What are its properties as a component of automobile petroleum? How does it impact on detonation resistance of automobile petroleum?
I think it might be produced from catalytic craking of petrolium. But I don't have a clue of what methodes are there to produce exact... |
How to make hydrogen peroxide into a gel or just simply really thick and it has to be able to be in your mouth?
The only thing i have came up with is (Gelatins).
What should i use? |
Functional groups like OH, NH2, attached to nonsaturated compounds ( chromophores) are called auxochromes. These groups tend to shift the wavelength to the infra-red area which is called bathochromic shift. My question is :
Why do these groups shift the wavelength and why exactly to the infra red direction ? Does anyon... |
Will sodium metal, if mixed well with iron oxide, displace the iron in a chemical reaction? I know thermite involves the mixture of aluminium powder and iron oxide, and the single displacement reaction results in molten iron and aluminium trichloride. The other day I melted some sodium metal to the point of melting but... |
Here is what seems to be a straightforward question: you dissolve some ammonium chloride in water at $25\ \mathrm{^\circ C}$, lowering the temperature of the solution. Is the change in enthalpy for the dissolving process positive or negative?
My reasoning: if the temperature of the solution decreases, it means heat ... |
How can I turn mercury metal into mercury oxide? I know that many metals will react with oxygen if enough heat is supplied in the presence of oxygen. If I heated up mercury enough and also supplied oxygen from my oxygen tank, would that result in mercury oxide? Also how about lead? Thank you |
In my Physical Science class, we are learning about chemical formulas and how to balance them. I balanced this equation: Fe2O3 + Al -> Fe + Al2O3
One of the other students asked me if this chemical formula releases or absorbs heat.
could anyone help me give a great explanation for this question? If... |
I've recently encountered a problem when using an analytical (0.1 mg accuracy) scale to determine the mass of a sample of ferrocene powder. The reading in the balance seems to drift either upwards or downwards when I drop some of the powder in an erlenmeyer flask. The reading stabilizes when I add water to form a solut... |
How is drift due to static electricity eliminated from an analytical balance? |
Functional groups like $\ce{OH}$, $\ce{NH2}$, attached to nonsaturated compounds (chromophores) are called auxochromes. These groups tend to shift the wavelength to the infra-red area which is called bathochromic shift.
My question is :
Why do these groups shift the wavelength and why exactly to the infra red dire... |
Functional groups like $\ce{OH}$, $\ce{NH2}$, attached to nonsaturated compounds (chromophores) are called auxochromes. These groups tend to shift the wavelength to the infra-red area which is called bathochromic shift.
My question is:<br/>
Why do these groups shift the wavelength and why exactly to the infra red ... |
In my Physical Science class, we are learning about chemical formulas and how to balance them. I balanced this equation: $\ce{Fe2O3 + Al -> Fe + Al2O3}$
One of the other students asked me if this chemical formula releases or absorbs heat.
could anyone help me give a great explanation for this quest... |
Out there in the real world, university students and school pupils alike favour strict rules that are true as often as possible (or at least have clear, easily remembered exceptions), while their professors and teachers on the other hand try to tell them that these rules are merely to be considered ‘guidelines’ rather ... |
How many moles of C4H10 contain 2.87 x 10^24 atoms?
and also,
How many hydrogen atoms are contained in 8.66 moles of NH3? |
How do I calculate these problems regarding moles and atoms? |
I want to know what is an aqueous solution. For an example let's take 1M aqueous solution of MgCl2. Does it contain MgOH2 also?. I'm confused by the way. This may be silly for some of you. But still i'm a beginner in chemistry. So I hope this doubt would be explained . |
Whats's an aqueous solution? |
I want to know what is an aqueous solution. For an example let's take 1M aqueous solution of MgCl2. Does it contain MgOH2 also?. I'm confused .By the way this may be silly for some of you But still i'm a beginner in chemistry. So I hope this doubt would be explained . |
How many hydrogen atoms are contained in 8.66 moles of NH3?
The answer is given after the log has been taken, so the final answer is 25.19.
What I have been doing is multiplying 8.66 by 6.02x10^23= 5.21332x10^24 and when I take the log of that I get 24.71. I'm not sure what to do to get the correct answer. |
How do I calculate this problem regarding moles and atoms? |
I am looking for an electrolyte to use in water to perform electrolysis. It can't be salt, as salt (NaCl) would cause the chemical reaction of `H2O + NaCl = Cl2 + H2 + NaOH` or `H2O + NaCl = HCl + NaOH` Which both make products with poisonous chemicals (ex: NaOH = Sodium Hydroxide (aka lye) which is poisonous). I am lo... |
What can be used as an electrolyte in water to perform electrolysis other than salt? |
I am looking for an electrolyte to use in water to perform electrolysis. It can't be salt, as salt ($\ce{NaCl}$) would cause the chemical reaction of
$$\ce{H2O + NaCl -> Cl2 + H2 + NaOH}$$
or
$$\ce{H2O + NaCl -> HCl + NaOH}$$
Which both make products with poisonous chemicals (ex: $\ce{NaOH}$ = Sodium Hydrox... |
The $\ce{KNO2}$ is basic, the HF is acid, the $\ce{(CH3)3NHBr}$ being an ammonium salt is acid too, the last one is an alcohol, I would consider it neutral for your purpose. But you are missing one step to get your answer quite right.
Last part, in the pH world, everything turn around two ions H+ (or H3O+) and OH- and... |
What is dust made of? |
I want to know what an aqueous solution is. For example, let's consider a $1~\mathrm{M}$ solution of $\ce{MgCl2}$. Does it also contain $\ce{MgOH2}$? Though it is a simple question, I feel it is important to understand something as vital to chemistry as this. |
What is an aqueous solution? |
I want to know what an aqueous solution is. For example, let's consider a $1~\mathrm{M}$ aqueous solution of $\ce{MgCl2}$. Does it also contain $\ce{MgOH2}$? Though it is a simple question, I feel it is important to understand something as vital to chemistry as this. |
From Googlebooks First Outlines of a Dictionary of Solubilities of Chemical Substances By Frank Humphreys Storer I find that lead tartrate is dissolved by tartrate of ammonia. My question is what is the final product? Thank you. Leyland. |
ammonium tartrate + lead tartrate=? |
silver nitrate is not suppose to cause a precipitation when mixed with iron (ii) sulphate, but the solution turns slightly cloudy but no ppt is seen.
is this suppose to happen? solution are all prepared fresh so that rules out contamination. any reason as to why? this also happens when silver nitrate is added to ma... |
$\ce{AgNO3}$ is not suppose to cause a precipitation when mixed with $\ce{FeSO4}$, but the solution turns slightly cloudy but no ppt is seen.
Is this suppose to happen? solution are all prepared fresh so that rules out contamination. any reason as to why? this also happens when silver nitrate is added to magnesium ... |
$\ce{AgNO3}$ is not suppose to cause a precipitation when mixed with $\ce{FeSO4}$, but the solution turns slightly cloudy.
Is this suppose to happen? solution are all prepared fresh so that rules out contamination. any reason as to why? this also happens when silver nitrate is added to magnesium sulphate . |
Mix equal volumes of $0.1$ $M$ $H_3PO_4$ and $0.2$ $M$ $KOH$. What ion remains in the largest concentration at equilibrium?
My approach: suppose we mix $1 L$ of each solution. For $H_3PO_4$, $K_{a_1}=7.5*10^{-3}$ and K_{a_2}=6.2*10^{-8}, so in terms of the dissociation of $H_3PO_4$, the only ions produced in non-neg... |
I'm having trouble understanding why an ester is a meta directing/deactivating group.
I'm not talking about an ester with its oxygen bound to the ring, like an acylated phenol. I mean the R group is bound to the ring and the alkoxy group is bound only to the carbonyl carbon.
It seems to me like the pi electrons i... |
Why are esters meta directors? Can't the carbonyl donate electrons into the ring? |
Which of these compounds does not liberate heat when water is added to it? |
Mix equal volumes of $0.1$ $M$ $\ce{H_3PO_4}$ and $0.2$ $M$ $\ce{KOH}$. What ion remains in the largest concentration at equilibrium?
My approach: suppose we mix $1 L$ of each solution. For $\ce{H_3PO_4}$, $K_{a_1}=7.5*10^{-3}$ and K_{a_2}=6.2*10^{-8}, so in terms of the dissociation of $\ce{H_3PO_4}$, the only ions... |
Mix equal volumes of $0.1~\mathrm{M}$ $\ce{H3PO4}$ and $0.2~\mathrm{M}$ $\ce{KOH}$. What ion remains in the largest concentration at equilibrium?
My approach: suppose we mix $1~\mathrm{L}$ of each solution. For $\ce{H3PO4}$, $K_{a_1}=7.5\cdot10^{-3}$ and $K_{a_2}=6.2\cdot10^{-8}$, so in terms of the dissociation of ... |
What ion remains in the largest concentration at equilibrium: 0.1 M H₃PO₄ and 0.2 M KOH? |
AgNO3 is not suppose to cause a precipitation when mixed with FeSO4, but the acidified solution turns slightly cloudy when AgNO3 is added.
Is this suppose to happen? solutions are all prepared fresh. any reason as to why? this also happens when silver nitrate is added to magnesium sulphate .
picture is as attac... |
$\ce{AgNO3}$ is not suppose to cause a precipitation when mixed with $\ce{FeSO4}$, but the acidified solution turns slightly cloudy when $\ce{AgNO3}$ is added.
Is this suppose to happen? solutions are all prepared fresh. Any reason as to why? This also happens when silver nitrate is added to magnesium sulphate.
... |
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