For questions relating to energy required for or produced by reactions, including questions of endothermicity/exothermicity, bond enthalpy, etc.
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Software Bond Dissociation Energies, Bond Energy and Hybridization with Polarity
I want to calculate BDE to measure the cost of hybridization of two molecules. There are many examples of protein ligand docking on the internet but there are no examples of hybridization of ligand to ...
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1answer
74 views
Calculating bond disassociation energy and bond energy for ATP [closed]
I'd like to calculate Bond Dissociation Energy and Bond Energy for ATP to a similar molecule. What free (at least for academic use) computer programs which natively support and document BDE?
If you ...
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1answer
36 views
What does reaction exothermicity say about the stability of molecules
If a reaction is exothermic it means that the energy state of the products is lower than that of the reactants so this will be the state that 'nature' will naturally strive for. Often you see that ...
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2answers
66 views
Lewis model and modern physics
Electron affinity of chlorine = -349 kJ per mole. And, first ionization energy of sodium = 496 kJ per mole while energy required for combining= 147 kJ per mole.
Isn't it a contradiction against ...
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1answer
43 views
Hot and cold air interaction in a sealed environment
What would happen if air heated to 1200 degree's Fahrenheit in a sealed environment was injected with colder air?
No specific pressure defined yet just a general idea of potential interaction between ...
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1answer
48 views
Energies of atomic orbitals on molecular orbital diagrams
When we plot molecular orbital diagrams we use a linear combination of atomic orbitals.
Where can I find the energies of particular atomic orbitals?
In the picture below, the energies of 2s and 2p ...
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1answer
45 views
How to calculate weight of $\ce{CO_2}$ in one kg of fuel
I'm trying to do homework and I have the answers to the problems but I can't read the explanation because it's illegible and I can't find how it's done in my notes.
Here's the simplest example:
...
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1answer
53 views
Software for chemical reaction simulation in ICE
I want to study what happens in a internal combustion engine in which fossil fuels are mixed along with other chemical additives.
Example:
Acetone drastically reduces surface tension.
Most fuel ...
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1answer
79 views
What is the nature of chemical energy?
Is chemical energy basically stored energy?
I'm not sure how to define "chemical energy" while I know many physical formulas for energy e.g. potential, movement and other.
Is chemical energy an ...
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2answers
233 views
Why are there quantised energy levels in the vibrational energy of a molecule?
Why are the energy levels for vibrational energy in a molecule discrete as opposed to continuous?
I don't understand how a vibration can't have continuous amounts of energy that depend on the ...
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1answer
50 views
Can we create a galvanic cell with only half a cell connected to the ground?
I have a question about electrical potential in galvanic cells ,suppose that we have only half a cell wich means that we have only one Ox/Red couple (one metal and the other as ionic solution ...
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1answer
238 views
What's the energy density of liquid nitrogen?
Liquid nitrogen seems to be attracting a bit of attention at the moment as a medium of energy storage, both for electricity grid applications and for transport.
For example, Highview are doing ...
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2answers
74 views
Van der Waals question
Imagine two atoms, and only consider the Van der Waals force. The electron cloud will jitter due to its quantum mechanical nature- some of these jitters forming dipoles, some not. However, on average ...
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1answer
138 views
Why are noble gases stable?
Generally, noble gases are very unreactive. Why?
I understand that it has to do with electron shielding prospective electrons that could join the atom or leave and the energies associated with both ...
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0answers
59 views
Calculating laser wavelength/power to cause emission of light in a gas?
It's been a long, long time since I've had to worry about electron excitation levels and band gaps. Please forgive (and correct!) my terminology and misconceptions.
I've become interested in ...
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0answers
27 views
Should the anode potential be increased or decreased to generate current?
I am taking a course on fuel cells and we were talking about the activation energy needed to start a chemical reaction.
I would think that the answer to this question is that the anode potential ...
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2answers
238 views
How do I balance this combustion reaction?
I have butene being burned in a fuel rich engine and I can't seem to balance this reaction
$C_{4}H_{8}+a(O_{2}+3.76N_{2})->bCO_{2}+cH_{2}O+dC_{4}H_{8}+e(3.76N_{2})$
When I try write equations for ...
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2answers
253 views
How do I find change in Gibbs free energy of this reaction?
How do I find the change in Gibbs free energy of the reaction $\ce{H_2 + \frac{1}{2}O_2 -> H_2O}$ when it is at $\ce{75}$°$\ce{C}$ and $\ce{1 atm}$. Do I calculate the Gibbs free energy of each ...
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1answer
3k views
Calculate the heat capacity of the calorimeter?
I've been struggling with this problem that I can't seem to figure out. I think I know how to solve it but I think there's missing information.
The combustion of 1 mole of glucose ...
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2answers
72 views
What is the energy package released to the outside world?
Consider a chemical reaction where two different particles form another one
$$O+O_2\rightarrow O_3.$$
I find it confusing how this can be an exothermic process. How to picture the release of ...
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1answer
141 views
Algebra of conserved quantities for chemical reactions
So there is the standard formation enthalpy $\Delta H^0_f$ and there is also formation entropy.
Are there more (independent) quantities? What about the heat capacity? Is there a general theoretical ...
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0answers
73 views
Calculating the heat capacity of ice [closed]
I tried calculating the heat capacity of ice with $C = \frac{Q}{\Delta T}$, where $Q$ is the energy required to heat 1 kg of ice from $T_1$ to $T_2$, and where $\Delta T = T_2 - T_1$.
I end up with ...
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1answer
95 views
Rotation energy barrier for carboxypyrazolate
In this molecule, which is 3,5-dimethyl-4-carboxypyrazolate (unless I got it wrong):
I do not think there is free rotation around the bond indicated in red, because one can write a resonnance ...
