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777888:
I hope that someone can help me! Thank you!

1)Can a reaction have proton transfer?

Because in my notes, it says chemical reactions fall into 2 major categories:
-proton (H+) transfers
-electron transfers


2)When writing half reactions, do you perserve the subscripts in the compound or write as a coefficient?
eg) 2Al + 3Cl2->2AlCl3
would the half rxn of Cl be 3e+3Cl2->Cl3(-) or 3e+3Cl2->3Cl(-)?


3)Why is the change in oxidation number same as the electron transferred?


4)For oxidation numbers, do we assume that covalent compounds transfer electrons?

5)What is a non-spontaneous reaction?

Mitch:
5.) Does it want an example?

Donaldson Tan:

--- Quote ---1)Can a reaction have proton transfer?

--- End quote ---

proton transfer reactions would refer to acid-base reaction. a bronsted acid is defined as a proton donor and a bronsted base is proton acceptor.


--- Quote ---2)When writing half reactions, do you perserve the subscripts in the compound or write as a coefficient?
eg) 2Al + 3Cl2->2AlCl3
would the half rxn of Cl be 3e+3Cl2->Cl3(-) or 3e+3Cl2->3Cl(-)?

--- End quote ---
Yes, you preserve the subscripts, unless it's more than meets the eye. eg. HCl(aq) isn't hydrogen chloride molecule exist a matrix of water molecules, but actually H+ and Cl- ions. When one writes the half reaction involving HCl(aq), he will quote one of the ions.

BTW the correct half equation for chlorine is:
6e + 3Cl2(g) -> 6Cl-(s)


--- Quote ---3)Why is the change in oxidation number same as the electron transferred?

--- End quote ---
oxidation number essentially refers to number of electron "gain" or "lost" when an atom forms covalent bond. eg. the oxidation number of carbon in O=C=O is +4.  it uses 4 electrons to bond with oxygen. Being more electronegative, the electrons from oxygen tend to be more attracted to the oxygen nucleus than that of carbon, hence carbon "loses" 4 electrons, thus its oxidation number is +4.


--- Quote ---4)For oxidation numbers, do we assume that covalent compounds transfer electrons?

--- End quote ---
NO


--- Quote ---5)What is a non-spontaneous reaction?

--- End quote ---
non-spontaneous reactions are chemical reactions whose product is energetically higher than the reactants. such chemical reactions are also endothermic

777888:
THANK YOU :)

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