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What is a difference between hyperconjugation and resonance?

The question is quite simple — how to check whether interactions between orbitals (in second-order perturbation theory) corresponds to resonance or hyperconjugation effect? In the paper of Milenković et al. (10.20450/mjcce.2019.1333), for structure below: A following data of NBO-analysis was gathered: The authors claim that: The most important interaction (n-π*) energy, related to resonance in […]

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What is a difference between hyperconjugation and resonance?

The question is quite simple — how to check whether interactions between orbitals (in second-order perturbation theory) corresponds to resonance or hyperconjugation effect? In the paper of Milenković et al. (10.20450/mjcce.2019.1333), for structure below: A following data of NBO-analysis was gathered: The authors claim that: The most important interaction (n-π*) energy, related to resonance in […]

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Thermodynamics and Thermochemistry [closed]

For a diatomic real gas, the molar heat capacity at constant volume is (A) R/2 (B) 3R/2 (C) 5R/2 (D) 3RT/2 Please explain in detail

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Why isn’t just a valence shell ns2 stable?

Why arent elements like Calcium with valence shell ns2 stable, aren’t all the orbitals filled? Why is it necessary to obtain octet? (Ignoring the trivial cases of Hydrogen and Helium)

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Gas laws when both temperature and volume are variable?

Say one has a can full of compressed ideal gas.It is opened.Due to its decrease in pressure , both the volume increases and temperature decreases.How to calculate how much volume increase and temperature decrease is there as both are variable.More constants can be used but volume and temperature must not be measured.

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Pressure Exerted by a Particle in a Fluid

I’m having a really difficult time understanding the concept about fluids and pressures. From my understanding, fluids exert pressure in all directions equally. With that being said, if we look at a single particle of a fluid, for example an H2O molecule, is it also applying pressure in all directions? If this were the case, […]

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What is the order of sn2 reaction

The answer states that d has most reactivity however my opinion is that since steric hindrance does not play a huge role here we should check the stability of intermediate which is sort of carbocation . According to this +M of no2 should make the intermediate unstable wrt others but the reverse is happening Since […]

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Do higher orbitals have more energy or less energy?

I’ve recently learned that as an orbital gets larger, its energy gets closer to 0. Before this, I learned that when an electron moves down an orbital it releases the energy difference between those orbitals. This would suggest that higher orbitals have more energy, but apparently this isn’t the case. Can anyone identify the flaw […]

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Reactivity towards electrophilic aromatic substitution (Nitration)

I should rank these molecules in decreasing order of reactivity towards nitration. 1.) Methylbenzene 2.) 1,3 Dimethylbenzene 3.) 1,4 Dimethylbenzene I think the order should be: 2 > 3 > 1. The reactivity towards an electrophilic aromatic substitution increases with groups which have an +I-effect. In structure 2 there are two methyl-groups next to each […]

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Synthesis cost of Fomepizole

Fomepizole is essential drug for methanol poisoning, I observed it cost too much like in 1000’s of dollar for couple of ml. Is cost due to patents, or due to synthesis cost,structure of molecule looks very small and easy, then why so much difficulty in synthesizing molecule ?