perplexity
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Unit of the equilibrium constant: contradiction of Bridgman's theorem?
11 votes

(this is a comment to Phillip answer; upon editing it failed to get saved on due time) Basically $K_c$ is valid as long as the solutions show colligative properties. These "concentration" constants ...

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Equilibrium constant expression for heterogeneous equilibrium
Accepted answer
7 votes

First, as kaliaden commented, the true equilibrium constant $$K(T,p) = a(\textrm{CaO,s}) a(\textrm{CO$_2$,g}) / a(\textrm{CaCO$_3$,s}) \approx p_\textrm{CO$_2$} / p^\circ \equiv K_p(T)$$ where $a$ ...

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Bonding and anti-bonding orbitals in the light of time-dependent Schrödinger equation?
7 votes

As F'x has indicated, the sum of atomic orbitals $\phi_k$ (AO) that form the molecular orbital $\psi_j$ (MO) $$ \psi_j = \sum_k c_{jk} \phi_k $$ is just a solution (an approximate solution) to a self-...

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How does initial rate of reaction imply rate of reaction at any time?
6 votes

A first order reaction is defined as a reaction in which the reaction rate obeys the equation $$r(t) \equiv \mathrm{d}[A(t)] / \mathrm{d}t = k[A(t)] \tag{1}$$ Your first equation $$r(0) \equiv \...

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How can antibonding orbitals be more antibonding than bonding orbitals are bonding?
6 votes

There is no such thing as conservation of orbital energies at different fixed values of $R$, the internuclear distance. Obviously, at $R \rightarrow \infty$ the energies are the same regardless of the ...

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Hund's rule & different H₂ molecules
4 votes

For H$_2$ there are only two electrons and thus you can only have singlet (electrons with opposite spin projection) and triplet states (electrons with equal spin projection). The spin wave function ...

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How do 1s and 2p orbitals overlap?
2 votes

It is important to know that the overlap must be performed with the wave functions $\psi_j(\vec{r})$, not the density, $\rho_j(\vec{r}) = \psi_j(\vec{r})^* \psi_j(\vec{r})$. Wave functions have signs; ...

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Clarification on Photodissociation
2 votes

Photodissociation is a unimolecular reaction triggered by absorption of light. You start with one molecule, a bond (or more) breaks and you end up with two (or more) products. In water you can get $\...

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What reactions will their reaction rates increase with time?
0 votes

There are several, but the rate can only increase in time under certain limits, that is, assuming certain approximations. Obviously at "final time" (for instance, when the equilibrium is reached) the ...

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