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Using this equation,
CaCl2(s) --> Ca+2(aq) + 2Cl-(aq) (delta)H = - 325.0 kJ
If you have 15.0 grams of the solid, how much heat is released or gained in kilojoules? |
Using this equation,
$\ce{CaCl2(s) -> Ca^{2+}(aq) + 2Cl^{-}(aq)}$
and $\Delta H = - 325.0 \; kJ $
If you have 15.0 grams of the solid, how much heat is released or gained in kilojoules? |
How much heat is gained/released based off of equation? |
Using this equation,
$\ce{CaCl2(s) -> Ca^{2+}(aq) + 2Cl^{-}(aq)}$
and $\Delta H = - 325.0 \; kJ $
If you have 15.0 grams of the solid, how much heat is released or gained in kilojoules?
![enter image description here][1]
[1]: https://i.stack.imgur.com/Q4mST.jpg |
I am working on a straight-forward NMR graph as part of my test prep. I have a pretty limited understanding of NMR, but I thoroughly read the chapter leading up to this practice question and am having difficulty explaining all of the peaks that I am seeing. Let me show the question and my understanding:
Here is the ... |
Unexplained peak cluster in proton NMR trace? |
When going through one of my chemistry textbooks, I saw that the electrolysis of aqueous lead nitrate led to oxygen being formed at the anode and lead being formed at the cathode.
However, in school, I was taught that only metals less reactive than hydrogen will form at the cathode. This electrolysis contradicts wh... |
How can I make Cu20 from copper?
I am seeing if electrolysis is a good route (in the context of kitchen style chemistry) to cuprous oxide, instead of the traditional heating copper and removing the cupric oxide, etc.
With Epsom salt electrolyte, it is very easy to make copper II hydroxide (cloudy ammonia soluble,... |
Write balanced equations describing the reactions of:
- a) one mole of Al2Me6 with two moles of water
- b) excess of Al2Me6 with Silicon dioxide
- c) excess of Al2Me6 with tin(IV)chloride
my answer so far...
- a) 2H2O + Al2Me6 -----> Al2Me4(H2O)2 ???
- b) SiO2 + Al2Me6 -----> SiMe4 + Al2Me2O2 ???
- c... |
I need to write balanced equations describing the following reactions:
- one mole of $Al_2Me_6$ with two moles of water
- excess of $Al_2Me_6$ with Silicon dioxide
- excess of $Al_2Me_6$ with tin($IV$)chloride
my answer so far...
- $2H_2O + Al_2Me_6 \rightarrow Al_2Me_4(H_2O)_2 ?$
- $SiO_2 + Al_2Me_6 \... |
I need to write balanced equations describing the following reactions:
- one mole of $Al_2Me_6$ with two moles of water
- excess of $Al_2Me_6$ with Silicon dioxide
- excess of $Al_2Me_6$ with tin($IV$)chloride
my answer so far...
- a) $2H_2O + Al_2Me_6 \rightarrow Al_2Me_4(H_2O)_2 ?$
- b) $SiO_2 + Al_2... |
The reaction of (C5H5)Fe(CO)2Cl with an equimolar amount of Li+[C6H5]- gives a product. Draw its structure and apply the 18 electron rule.
In a question I was given the molecular weight and percentages of each element in the compound. I worked out that there is 1 Fe, 13 C, 10 H and 2 O. The product is an Fe atom sur... |
Under Basic conditions a michael addition reaction can be used to convert compound A into Product C. Explain why no Robinson Annelation cyclic product is observed?
Compound A
![reactant A][1]
Product C
![enter image description here][2]
I have worked out that the other compound involved in the... |
Why does no Robinson Annelation Occur? |
Fe(η5-C5H5)2 does not react with hydrogen, but its nickel analogue, Ni(η5-C5H5)2 is readily hydrogenated to give Ni(η5-C5H5)(η3-C5H7). Use the 18 electron rule to explain this behaviour.
My answer so far...
Fe(η5-C5H5)2 18 electron rule = valence electrons from Fe is 8, electrons from C5H5 is 5 therefore 8 + 5 + ... |
Hydrogenation of NiCp2 takes place on the ligand, not the metal, to reduce donor electron count, giving a low-energy closed-shell 18 electron count.
http://en.wikipedia.org/wiki/Nickelocene <BR>
http://en.wikipedia.org/wiki/Ferrocene <BR>
http://en.wikipedia.org/wiki/Hapticity <BR>
http://www.chem.mun.ca/homes/cm... |
All you have to do is to use some of the well known results from Statistical Thermodynamics:
The molar heat capacity at constant volume is
\begin{equation}
\bar{c}_V = \left( \frac{\partial \bar{U}}{ \partial T} \right)_V
\end{equation}
where $\bar{U}$ is the inner energy, $T$ is the temperature, and $V$ is ... |
> The reaction of (C<sub>5</sub>H<sub>5</sub>)Fe(CO)2Cl with an
> equimolar amount of Li+[C<sub>6</sub>H<sub>5</sub>]- gives a product.
> Draw its structure and apply the 18 electron rule.
In a question I was given the molecular weight and percentages of each element in the compound. I worked out that there is 1 F... |
I was drawing out all the isomers of $\ce{C5H8}$ and came upon two structures of cyclopropane attached with double bonds. The group is neither a methylene nor an ethyl... what is it? What are the names of these two molecules? |
I have just been waken up by an alarm and found out that my neighbour did something terrible with his lighter. Luckily, there was no fire, only a plenty of smoke, and our flats were hermetically isolated, so that smoke didn't go to my flat. But, most probably because of my suspiciousness, I noticed some smell of burnt ... |
Surf a civilian aircraft supply. They sell a little absorbant white tab (chemical spot detector) containing $\ce{PdCl2}$. When exposed to CO it goes black.
http://www.aircraftspruce.com/menus/ps/carbonmonoxidedetectors.html
Canary. Goldfish won't work - they can survive on anaerobic respiration,
http://aq... |
2A + 2B ----------> 2C
A + B ----------> C
Why does the equilibrium constant change !!!?
And why the rate of the first reaction square the rate of the second?? I understand it mathematically, but logically and scientifically I can't understand it at all. |
In the news recently is 'Palcohol', powdered alcohol, http://www.palcohol.com/home.html that you add to water or existing liquids to make it alcohol. Presumably this would dissolve and break apart into alcohol and {some other compound}.
What could bond to Ethyl Alcohol in order to:
1) Create a solid, and
2) Not be... |
How could alcohol be made into a powder? |
The [Wikipedia Article Of Fugacity](http://en.wikipedia.org/wiki/Fugacity) contains statement
>The contribution of nonideality to the chemical potential of a real gas is equal to RT ln $\phi$
Here $\phi$ is fugacity coefficient.I think it is wrong it should be fugacity coefficient multiplied by partial pressure ... |
Mistake in Wikipedia Article Of Fugacity? |
[Cyclodextrins][3], which comprise a class of cyclic carbohydrates, use their properties of being hydrophobic within their ring(s), yet hydrophilic outside. Alcohol can be put inside these rings. Then, the entire molecule is still capable of dissolving in water, releasing the encapsulated alcohol molecules. [(src)][4]
... |
The [Wikipedia Article Of Fugacity](http://en.wikipedia.org/wiki/Fugacity) contains statement
>The contribution of nonideality to the chemical potential of a real gas is equal to RT ln $\phi$
Here $\phi$ is fugacity coefficient.I think it is wrong it should be fugacity coefficient multiplied by partial pressure ... |
What is happening [here][1]? Can you explain this technically as well as in layman's terms?
[1]: http://goo.gl/pKYwJ4 |
$$\ce{2A + 2B -> 2C }\\ \ce{A + B -> C}$$
Why does the equilibrium constant change?
And why the rate of the first reaction square the rate of the second? I understand it mathematically, but logically and scientifically I can't understand it at all. |
Combustion of Nitrocellulose-Nitroglycerine(NCNG) solid propellant? |
Unit of the equilibrium constant: contradiction of Bridgman's theorem? |
Reaction involved in Combustion of Nitrocellulose-Nitroglycerine(NCNG) solid propellant? |
CrCl3(Bipy)3 (A) when heated forms (B) which has the formula CrCl3(Bipy)2 and has one free Cl- per mole of (B) (Not given in question but i don't need help with the gravimetric analysis bit, just take my word for it). B can react with ethylene diamine (en) to form (C) which has the formula CrCl3(bipy)2(en) .
(B) ca... |
I have designed a container which is heated up and has to heat up some tube-coils of water inside of it. This container is filled with a fluid that can help store and transfer the heat received from the container to the tube-coils.
My plan was to find some material that I can easily buy and which is not very expensi... |
Rate will not be square most of the time and who said so ? Equilibrium constant scientifically changes because gibb's free energy is extensive quantity and it is related to equilibrium constant through relation that you might know $\Delta G=\Delta G^o +RTln Q $. Where Q is reaction quotient which at equilibrium becomes... |
Rate will not be square in most of the cases and who said so ? Equilibrium constant scientifically changes because gibb's free energy is extensive quantity and it is related to equilibrium constant through relation that you might know $\Delta G=\Delta G^o +RTln Q $. Where Q is reaction quotient which at equilibrium bec... |
I am a bit confused about the correct name of $\mathrm{LaMnO}_3$. Is it lanthanium manganate or lanthanum manganite?
I was assuming that since $\mathrm{SrTiO}_3$ is called strontium titanate, $\mathrm{LaMnO}_3$ would then be called lanthanium manganate, but I got confused when I heard a collegue referring to it as m... |
About the nomenclature: manganate or manganite? |
Mistake in Wikipedia article of fugacity? |
The [Wikipedia Article on Fugacity](http://en.wikipedia.org/wiki/Fugacity) contains statement
>The contribution of nonideality to the chemical potential of a real gas is equal to RT ln $\phi$
Here $\phi$ is fugacity coefficient.I think it is wrong it should be fugacity coefficient multiplied by partial pressure ... |
Mistake in Wikipedia article on fugacity? |
Angle 6 involves an $\ce{sp^2}$ hybridized carbon in the $\ce{C=O}$ double bond. In such cases the $\ce{R-C-O}$ angle is ~ 120 degrees. Just to elaborate a bit more, if you have four objects arranged in space about a central carbon atom (the $\ce{sp^3}$ hybridization case), the four bonds from carbon are going to arr... |
I was reading _[How radioactive poison became the assassin’s weapon of choice](https://medium.com/matter/6cfeae2f4b53)_ and it opens describing how
>The men eventually left, and Andrade cleared the table. As he poured the remaining tea away, he noticed that the consistency of the liquid that tipped into the sink was s... |
We know that chemical potential is defined as ${\mu}_i={\mu}_i^{standard}+RT\ln(a_i)$. Here $a_i$ is the activity of $i^\text{th}$ component of solution. In case of gases instead of $a_i$ it is $f_i$ (fugacity). Activity is the activity coefficient multiplied by concentration or in case of fugacity it is the product ... |
Energetic materials can emit a significant fraction of their carbon as CO. Take advantage of excess local oxygen with more fuel, or push to CO2 with more oxidizer. The lower the average molecular weight of the exhaust, the higher the Isp, all other things being equal. US hydrogen/LOX engines run heavy on hydrogen.
... |
What is happening [here][1]? Can you explain this technically as well as in layman's terms?
I'll summarize it. I see a technician moving fuming mixtures of presumably uranium and organic compounds on and off hot plates. Perchloric acid is mentioned, and a large bottle is present.
[1]: http://goo.gl/pKYwJ4 |
We know that chemical potential is defined as ${\mu}_i={\mu}_i^{standard}+RT\ln(a_i)$. Here $a_i$ is the activity of $i^\text{th}$ component of solution. In case of gases instead of $a_i$ it is $f_i$ (fugacity). Activity is the activity coefficient multiplied by concentration or in case of fugacity it is the product of... |
I know it's the proteins that somehow change their properties at some temparature.
But what kind of change, in terms of molecule-level structure?
|
How does the process of protein denaturatation work? |
First, I'm a high school student and I wonder why every textbook just tells you how to set up those equations and cancel them to get the entropy change but never tells you why you can cancel the same species on both sides. Second, for example, 2B+3H2O=B2H6+3/2(O2) delta H= 762KJ. H2+1/2(O2)=H2O delta H=-286 KJ. So ... |
At constant pressure, change of internal energy equals heat subtract work(PV). So, q= delta E-PV. So is the the change of enthalpy. So we say at constant pressure, the change of enthalpy equals the change of heat. But When the volume is constant, no work is done. delta E= heat, delta enthalpy also equals heat. So why n... |
We know that chemical potential is defined as ${\mu}_i={\mu}_i^{standard}+RT\ln(a_i)$. Here $a_i$ is the activity of $i^\text{th}$ component of solution. In case of gases instead of $a_i$ it is $f_i$ (fugacity). Activity is the activity coefficient multiplied by concentration or in case of fugacity it is the product of... |
We know that chemical potential is defined as ${\mu}_i={\mu}_i^{standard}+RT\ln(a_i)$. Here $a_i$ is the activity of $i^\text{th}$ component of solution. In case of gases instead of $a_i$ it is $f_i$ (fugacity). Activity is the activity coefficient multiplied by concentration or in case of fugacity it is the product of... |
First, I'm a high school student and I wonder why every textbook just tells you how to set up those equations and cancel them to get the entropy change but never tells you why you can cancel the same species on both sides.
Second, for example,
$\ce{2B + 3H2O -> B2H6 + 3/2(O2)}$ $\Delta H= 762~kJ$.
$\ce{H2... |
First, I'm a high school student and I wonder why every textbook just tells you how to set up those equations and cancel them to get the entropy change but never tells you why you can cancel the same species on both sides.
Second, for example,
$\ce{2B + 3H2O -> B2H6 + 3/2O2} \tag{ $\Delta H= 762~kJ$}$.
$\... |
At constant pressure $p=\text{const.}$, change of internal energy equals heat subtract work(PV). So, $q=\Delta E - pV$. So is the the change of enthalpy. So we say at constant pressure, the change of enthalpy equals the change of heat. But when the volume is constant $V = \text{const.}$, no work is done. $\Delta E= q$,... |
We know that chemical potential is defined as ${\mu}_i={\mu}_i^{standard}+RT\ln(a_i)$. Here $a_i$ is the activity of $i^\text{th}$ component of solution. In case of gases instead of $a_i$ it is $f_i$ (fugacity). Activity is the activity coefficient multiplied by concentration or in case of fugacity it is the product of... |
I know that to predict whether combinations of acids and bases will be acidic, basic, or neutral,
WA + SB is basic
SA +WB is acidic
SA +SB is neutral
What is WA + WB? I've been told that it isn't neutral. How do you predict what it is and why is it not neutral? |
<p>
Chemistry Stack Exchange is for scientists, academics, teachers and students of <b>chemistry</b>.
</p>
<p>Questions may be of any level, but should be of the following types:</p>
<ul>
<li>Questions asking for explanation of a chemistry concept</li>
<li>Questions relating to observed chemical phenomena</li>
<... |
What topics can I ask about here? |
What is happening [here][1]? Can you explain this technically as well as in layman's terms?
I'll summarize it. I see a technician moving fuming mixtures of presumably uranium and organic compounds on and off hot plates. Perchloric acid is mentioned, and a large bottle is present.
[1]: https://www.youtube.com/... |
How can i reduce Crystallisation temperature of seed oil to be used in winter as biodiesel?
the glycerol has been removed from the oil, and white spirit is used to reduce its viscosity.
Thanks
(i wasn't able to put tags like biodiesel or diesel) |
How can i reduce Crystallization temperature of seed oil to be used in winter as biodiesel? |
Waxing and pour point are typical specs for fuel. How cold is your winter? If it is very cold, and your tank is above ground, there is little to be done. Insulate the tank (metal-backed rock wool) and heat it. Use a more unsaturated feedstock with no saturated components. That lowers its pour point and removes waxing.... |
How can I carry out a titration to identify mercury in wastewater? |
Which fragmentation is possible at this m/z value for pthalic acid diethyl ester?
I tried mac- Lafferty but it didn't solve my problem.
Any help would be appreciated. |
What does the characteristic peak for pthalic acid diethyl ester at m/z 149 signify? |
Can someone explain to me why doesn't KSO4^- exist, why can't it exist? I couldn't find an answer; I assume if you took one SO4^2- and one K^+ ion, only that one would add and KSO4^- would appear! |
K2SO4 and KSO4-, why can't it exist? |
The salt that you can tipically find in a kitchen is the `NaCl`, isn't this salt supposed to act as an antiseptic ?
I find a lot of recipes that suggest the addition of salt when preparing the mix for the leaven of the bread.
Isn't the salt supposed to act against the formation and the culture of bacteria that ar... |
Why is a good idea to put some salt in the bread dough? |
The salt that you can typically find in a kitchen is the $\ce{NaCl}$, isn't this salt supposed to act as an antiseptic?
I find a lot of recipes that suggest the addition of salt when preparing the mix for the leaven of the bread.
Isn't the salt supposed to act against the formation and the culture of bacteria tha... |
Why is it a good idea to put some salt in the bread dough? |
Can someone explain to me why $\ce{KSO4^-}$ doesn't exist. Why can't it exist? I couldn't find an answer; I assume if you took one $\ce{SO4^{2-}}$ and one $\ce{K^+}$ ion, only that one would add and $\ce{KSO4^-}$ would appear! |
In air, how much $\ce{CO2}$ would be required to prevent a match to light or a butane lighter to work?
I have a basement office that is unusable because of an apparent lack of Oxygen, currently it is my guess that the oxygen is being displaced by $CO_{2}$ .
A bit research suggests that it would take a reductio... |
Common table salt is not necessarily an antiseptic in the conventional "sterilizing" sense. What gives it weakly antiseptic properties in biological context is its ability to absorb water from cells through osmosis, should the concentration of the salt outside the cell be too high, the cell would lose too much water th... |
I know that it is possible to predict whether combinations of acids and bases will be acidic, basic, or neutral:
- weak acid (WA) and strong base (SB) reacts basic
- strong acid (SA) and and weak base (WB) reacts acidic
- SA and SB reacts neutral
How does a WA react with a WB? I've been told that it isn't ... |
Why more attractive metals will be oxidized? Aren't they being reduced, because they attract and receive electrons from negative polyatomic ions? So they will be anodes, where oxidization occurs. Why anodes are negative in voltaic cells and positive in electrolytic cells? Same for cathodes. |
Some ceramicists decorate pottery using soluble salts (usually chlorides and sulfates e.g. copper chloride, cobalt sulfate) which are used individually or mixed to produce different colors.
I have been exploring the use of these chemicals on porcelain. From the MSDS of each chemical I've become aware of the safety ... |
Can someone explain to me why $\ce{KSO4^-}$ doesn't exist (in a solution). Why can't it exist? I couldn't find an answer; I assume if you took one $\ce{SO4^{2-}}$ and one $\ce{K^+}$ ion, only that one would add and $\ce{KSO4^-}$ would appear! |
In air, how much $\ce{CO2}$ would be required to prevent a match to light or a butane lighter to work?
I have a basement office that is unusable because of an apparent lack of Oxygen, currently it is my guess that the oxygen is being displaced by $CO_{2}$ .
A bit research suggests that it would take a reductio... |
I want to redo an experiment. They've used
Nickel chloride: 40 g/L
Nickel chloride can be bought in two forms: anhydrous (NiCl2) and hydrate (NiCl2.6H2O). The paper doesn't say which one they've used. Which one did they mean in the paper? In one liter of water should I dissolve 40 grams of NiCl2 or 40 grams o... |
Some ceramicists decorate pottery using soluble salts (usually chlorides and sulfates e.g. copper chloride, cobalt sulfate) which are used individually or mixed to produce different colors.
I have been exploring the use of these chemicals on porcelain. From the MSDS of each chemical I've become aware of the safety ... |
What is happening [in this video][1]? Can you explain this technically as well as in layman's terms?
I'll summarize it. I see a technician moving fuming mixtures of presumably uranium and organic compounds on and off hot plates. Perchloric acid is mentioned, and a large bottle is present.
[1]: https://www.you... |
I want to redo an experiment. They've used
Nickel chloride: 40 g/L
Nickel chloride can be bought in two forms: anhydrous ($\ce{NiCl2}$) and hydrate ($\ce{NiCl2.6H2O}$). The paper doesn't say which one they've used. Which one did they mean in the paper? In one liter of water should I dissolve 40 grams of $\ce{... |
A question on a past exam for a course I'm studying for asks:
> What's the relation between Van der Waals forces and hydrophobic
> interactions?
From what I understand, Van der Waals forces are just a name to summarize a bunch of little weak forces that only come into play when molecules are placed close to one... |
What is the name of the molecule that has the maximum number of different kinds of atoms?
For example, H2O is water has 2 different kinds of atoms which are H and O.
For example, C6H12O6 is fructose and has 3 different kinds of atoms which are C, H and O.
Which molecule has the record?
|
what is the name of the molecule that has the maximum number of different atoms? |
What is the name of the molecule that has the greatest number of different kinds of atoms?
For example, H2O is water has 2 different kinds of atoms which are H and O.
For example, C6H12O6 is fructose and has 3 different kinds of atoms which are C, H and O.
Which molecule has the record?
|
what is the name of the molecule that has the greatest number of different atoms? |
Overall, wear disposable gloves, goggles, and a dust mask. Add a lab coat, smock, or apron to not contaminate your clothing. Avoid skin contact, don't ingest - including dust.
Manganese heptoxide is a special case with concentrated sulfuric acid. Avoid mixing strong oxidizers (permanganate, chromate/dichromate, p... |
This is a very basic question and I'm surprised it only just struck me. The nature of the bond in coordinate complexes is a coordinate covalent bond. Only the ligand donates electrons for bond formation between the metal and ligand.
Why is it that we never place a positive charge on the ligands? For example, in $\ce... |
This is a very basic question and I'm surprised it only just struck me. The nature of the bond in coordination complexes is a coordinate covalent bond. Only the ligand donates electrons for bond formation between the metal and ligand.
Why is it that we never place a positive charge on the ligands? For example, in $\... |
What is the product of the following hydrolysis reaction? How do you know?
$NH_4NO_3 + H_2O \to$ ?
Thanks so much! |
$NH_4NO_3 + H_2O \to$ ? Determining products of this reaction |
At high enough pressure, atomic material no longer exists, for example under the conditions of a neutron star. Is there a different maximal pressure above which chemical bonds no longer exist? |
We use water to cool down some machines because water has high heat capacity, which means it takes more energy to increase 1 degree. Heat transfer occurs only when temperature is different. We cool down the machine because we don't want it to be too hot, but what does the hot mean? The temp or the heat? When we touch w... |
Which one really determines how people feel. Heat or temperature? |
Why is it that in titration a color change occurs initially but then the solution quickly reverts to its previous color?
Thanks so much! |
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