First, we need to identify the half-reaction for magnesium. It can be represented as:
Mg2+ + 2e- = Mg
Next, we will determine the overall charge generated during the electrolysis using the information derived from the half-reaction. The calculation follows:
4.50 kg Mg (1000 g / 1 kg) (1 mol / 24.305 g) (2 mol e- / 1 mol Mg) (96500 C / 1 mol e-) = 35733388.2 C
The provided EMF is given in voltage. Since 1 V equals J/C, 5 V translates to 5 J/C.
Therefore, 35733388.2 C (5 J/C) = 178666941 J
Finally, 178666941 J (1 kW-h / 3.6x10^6 J) = 49.63 kW-h
For instance, what is the difference in electronegativity for Acetone(CH2O)? Are there two distinct values, namely 0.4 for C versus H and 1.0 for C versus O? How do you decide which one to adopt?
6 Comments
AlwaysReady1
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Apr 3, 2016, 10:14 PM
I may not fully grasp the question, but if you’re seeking to determine a compound's electronegativity to assess its electron-attracting capability, there are various other influencing factors.
It varies depending on the compound. For example, CH2O, known as formaldehyde, has oxygen with two pairs of electrons that can be donated. Neither hydrogen nor carbon can bond further as they are already fulfilling their valence shell requirements.
Robo94
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You're attempting to apply a concept from a binary system to a more complex one. I assume you're aiming to figure out a molecule's dipole moment. In the case of a diatomic molecule (where A is bonded to B), the potential difference can simply be determined as A minus B. For larger molecules, the calculations become much more involved.
If this inquiry is related to homework assistance, it’s a distinctly different method from what you might be accustomed to. I recommend starting with water and then expanding out from there.
Check this out: https://www.khanacademy.org/science/organic-chemistry/gen-chem-review/electronegativity-polarity/v/dipole-moment
Philosoaxolotl
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Electronegativity pertains to single elements (or rather individual atoms) and lacks straightforward applicability to broader molecules.
What precisely are you aiming to do with this data? If you're delving into how electrons transition between molecules, the situation is more intricate—within a molecule, the more electronegative elements pull electrons from other atoms (which frequently happens in organic compounds, such as when oxygen bonds with carbon and pulls in some of its electrons). Nevertheless, this effect diminishes in lengthened molecules. The system is more complicated as molecules do not possess a single, constant electronegativity (which is more accurate for atoms); instead, they exhibit varied localized charge regions that will respond differently.
From what I gather, your question pertains to the electronegativity difference among the atoms within an acetone molecule. This indeed relies on which two atoms you are examining and won't remain constant throughout; however, the difference won't simply match the values listed in an electronegativity table due to the factors discussed earlier.
This explanation might seem a bit hazy, and I’m just an undergraduate, so please take my interpretation lightly, but I am open to clarifying further if needed.
cheeseborito
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That statement is inaccurate.
Electronegativity represents the attraction an atom holds for the electrons in a covalent bond with another atom. Essentially, an element does not have a singular electronegativity; it fluctuates based on its bonding partners. We cannot discuss the electronegativity of an atom in isolation.
While average values are useful for practical discussions (though they may not capture the nuance), the effective electronegativity of an oxygen atom bonded to carbon will remain fairly consistent.
As far as my understanding goes, even though my definition of electronegativity may lack precision, the influence an oxygen atom has on the electrons of a carbon atom is affected by what the carbon is bonded to. For instance, the local charge around the oxygen in acetic acid will be more pronounced than that in decanoic acid.
I may have phrased the electronegativity issue poorly—what I meant was the interaction between pairs of atoms as related to one another. An oxygen will exert a consistent pull regarding a carbon atom, but the changes in local charge can differ due to the influence of surrounding atoms, making the topics we typically utilize electronegativity to clarify substantially more intricate.
Answer: The change in enthalpy will be -13.
Explanation:-
Endothermic reactions absorb heat, while exothermic reactions release heat. In the case of an endothermic reaction, the change in enthalpy is represented as positive, whereas for an exothermic reaction, it is negative.
When one mole of A combines with one mole of B to form three moles of C
So the stoichiometric ratio being halved also results in the enthalpy for the reaction being halved.
Thus, for this reaction:
The resulting change in enthalpy is -13.
