Questions tagged [physical-chemistry]

The study of chemical systems using the laws and concepts of physics. This usually requires the techniques of thermodynamics, statistical mechanics and quantum mechanics.

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Mismatch of coefficients in rate law expression

For example, for the reaction $\ce{A + 2B -> C}$, we have $$\text{rate} = -\frac{1}{2}\frac{\mathrm d[\ce{B}]}{\mathrm dt} \quad \text{and} \quad \text{rate} = k[\ce{A}]^x[\ce{B}]^y.$$ Together, ...
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Oscillator strength of a transition

I am trying to compute the oscillator strength in a molecule. Therefore I've got its Energy level values plus both wave functions $\Psi_i$ and $\Psi_j$ for the transition I want to calculate the ...
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If dG is a state function, why do reversible and irreversible paths differ?

For a reversible process at constant T,P in a closed system with no non-expansion work dG = 0. For an irreversible process under the same conditions, dG < 0. Since dG is a state function I would ...
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Atkins' Physical Chemistry 10th edition Question on steady-state approximation

Please help me with Example 20E.2 of Atkins' Physical Chemistry 10th edition textbook on using the steady-state approximation. I have attached my attempt but am just not sure how to get to the final ...
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Relationship between molecularity and the reaction order

Should the molecularity be equal or less than the reaction order? Consider the reaction: $$\ce{H2(g) + I2(g) → 2 HI(g)}$$ If we consider the mechanism of this multi-step reaction, the molecularity is ...
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Why would T1 relaxation time change ~20 fold between solvents for the same substance?

I have a simple, completely conjugated pyridinium salt with MW of ~300 g/mol. The molecule consists of regular non-labeled atoms (only C, H, N). If the 1H T1 relaxation time for this molecule is ...
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