CHEMISTRY COMMUNITY

Desiree1G

Also when can we pick up the exams next quarter?

Desiree1G

Has the worksheet been posted?

Desiree1G

one more

Desiree1G

Here are some more pictures:)

Desiree1G

Adding on to their question ^ does it, in that case, mean the coefficient in the rate law is not 1/x but just 1?

Desiree1G

No it depends on your Big K = to small k 1 over small k -1.

Desiree1G

Remember Specific Heat Capacity is m*delta T*C and it is, in fact, an intensive property because no matter how much of something there is, its ability to absorb heat at the particular temperature is the same.

Desiree1G

I'm really confused by this one too because of the KOH and Ni in the cell diagram :/

Desiree1G

Solutions of the same phase are separated by a comma and arranged in the oxidized, reduced order

Desiree1G

I am confused on this too but essentially I think it is because the oxidation number for Bromine do not change.

Desiree1G

In addition to what some classmates said, we should also know enthalpy and entropy because they are part of a Gibbs equation.

Desiree1G

If Gibbs is at 0 it is at equilibrium, if it is negative then it is exergonic meaning it is also spontaneous. If it is positive it is endergonic which means it is non-spontaneous. The lower the delta G is the more stable it is.

Desiree1G

OIL RIGS helps me remember that when Oxidation happens it Loses Electrons. When Reduction happens it Gains electrons. It is oxidation because it lost two electrons therefore increasing it's positive charge.

Desiree1G

Gibbs free energy for sure and some electrochemistry is possible. I'm not sure how much:/

Desiree1G

Delta G^0 is for standard conditions such as standard temperature (25 degrees celcius/298K). Delta G is for nonstandard conditions and depends on those, this means temperature, for instance, is not standard.

Desiree1G

It is usually based on your givens and if you have enthalpy then most likely the first one will be used. It helps to check off what you have and see what you can plug in.

Desiree1G

When Gibbs free energy is equal to 0 that means that the reaction is at equilibrium meaning that no more work can be done.

Desiree1G

That is also another way of saying it is isometric which means volume is constant

Desiree1G

Standard temperature is 25 degrees celcius, however for Gibbs free energy we always use Kelvin so it is 273+25 which is 298 K

Desiree1G

Gibbs is the amount of useable free energy. So this is the total change in the energy minus the temperature times the total change in disorder of the system.

Desiree1G

Yes and I remember because Lyndon said once he was "Feeling a little Pressured and Dense. He wished he could just watch TV and get HUGS.
(PV TV HUGS).

Desiree1G

Open you can think of it as if something can fall out of it, hence it can exchange heat and matter. Like a plant, it is exposed. Closed well nothing can fall out, but heat can still be exchanged. Isolated nothing is exchanged because it is isolated away from everything.

Desiree1G

Some people say to use H+, and I'm not sure if it's the same as with acids and bases because during that time using either one was fine.

Desiree1G

When the reactions says it is isothermal that means that the temperature is constant (iso=same). If this is the case then there is no change in the internal energy therefore U is 0.

Desiree1G

Yes remember K does not have a unit because it is a ration and I believe those units cancel out.

Desiree1G

Most likely Gibbs and maybe some electrochemistry, but mostly Gibbs.

Desiree1G

Enthalpy is the delta H and Entropy is the delta S. Basically Enthalpy is the total energy in the system and entropy is the measure of disorder. Also, note that the second law of thermodynamics shows that disorder is increasing.

Desiree1G

I'm new to uploading videos apparently, so hopefully, this video of the acapella performance uploaded below in the attachments...

Desiree1G

Thank you, I had such a hard time finding it haha!

Desiree1G

It's from 7-10 on Monday Franz 1178. I cannot find the worksheet either :(

Desiree1G

Typically the problems provide initial molarity or ask for you to calculate the molarity or initial values. I is for initial molarity, C is for change, and E is for equilibrium concentration

Desiree1G

I believe it is best to memorize some for strong acids and bases. I do not remember which ones, but I think the ones common in homework are good to know.

Desiree1G

I would know them, better safe than sorry. Maybe more the ones that we saw in the homework probs too.

Desiree1G

Electronegativity is the tendency of an atom to attract a bonding pair of electrons and Cl is more electronegative than I. The weaker the bond the more likely it will lose an H+. Also HOCL is more stable.

Desiree1G

Cisplatin is one that comes to mind because it stops cell division

Desiree1G

Typically we compare A-H bonds with other bonds like that and the oxoacids (AO-H) bonds with others like it.

Desiree1G

Hi, if you are referring to the 2 after C then that is the level it is on and it is not a power. If it is the 2 after the P then that is a power. Yes you should write this when writing the sigma bonds.

Desiree1G

The longer the A-H bond the easier it is to remove the H+. With AO-H bond the more electronegative the central atom the more acidic the molecule will become.

Desiree1G

Radicals have at least one unpaired electron and they have an odd number of valence electrons. Note they're also very reactive

Desiree1G

I'm not sure if this is 100% for certain but I think there is a few we just sort of have to remember are polydentate, for instance, en, ethylenediamine or dien, diethylenetriamine. But I doubt he will give us some that we have not reviewed

Desiree1G

Okay so the 3/III, as I learned, is the oxidation number, so basically for b) if you calculate the oxidation number NH3 and OH2 are neutral meaning they are 0 and add that to cobalt which was "unknown" it will equal 3 because your oxidation number is 3. Essentially, I would write it like t...

Desiree1G

Transition metals are capable of adopting ions with different charges because in mind they are in the d-block so they one or more unpaired electrons in one of their ions.

Desiree1G

I'll do an example so hopefully, it makes more sense. Take for instance, [Fe(CN)6]^(4-) --hexacyanoferrate (II) ion (note 6 is a subscript). Note that transition metals charge vary. I usually start by putting an X to represent "unknown" for my metal which is Fe. So, I have: X+(-1)6= -4. Th...

Desiree1G

I recall it was supposed to be in alphabetical order, so in that case your first one would be correct.

Desiree1G

I do believe so because the coordination sphere consists of the central ion or atom along with all the ligands.

Desiree1G

Coordination number I know as simply the number of bonds used to attach to all ligands.

Desiree1G

Hi, so I had had the same question, but I learned that electron arrangement basically means all the electron densities around the atom. In other words, all the stuff around it so that could be the other element(s) and any lone pair of electrons, (this is the steric number.) Once you have this, you l...

Desiree1G

A sigma bond is the strongest type of covalent chemical bond. A pi bond contains p-p orbitals and it is a covalent bond formed by the side to side overlap of orbitals, which can be easily broken. Also, a single bond consists of a sigma bond, and let's say you have a double bond, this consists of a s...

Desiree1G

I have a feeling it will cover things we have been over since after the midterm and probably a bit from before, such as VSEPR models, knowing molecular shape and structure names, and polarity. There may be some stuff from this week that could potentially be there.

Desiree1G

I can't say I'm positive, but I don't think we will worry about that for VSPER in Chem 14 a. However, I think it is important for when you draw your Lewis structure though :)

Desiree1G

So what helps best is to draw the Lewis structure of the compound. So you have your central atom and typically the other surrounding atoms. If there are no lone pairs and it has 4 surrounding atoms it is tetrahedral (tetra=4). However, if it is trigonal planar (tri=3) then it only has 3 surrounding ...

Desiree1G

Yes, there is a difference. So trigonal pyramidal has a pyramid shape and if you can try to imagine it with a base in a triangular shape. (it may be helpful to look for a 3D image). Also, t's bond angles are slightly less than 109 degrees and this is because it has one lone pair of electrons that ca...

Desiree1G

I believe the shape/angle change has to do with electron repulsion. (This is important because it determines if something is polar or nonpolar.) I also read online that lone pairs occupy more space compared to bonding pairs of electrons, hence this results in greater repulsion between lone pairs of ...

Desiree1G

Can someone explain bond lengths, I understand the whole single bond is weaker...but what are the most important things for us to know about them?

Desiree1G

I believe you already know, but keep in mind a single bond the weakest bond, and a triple bond is strongest. I think HI is a stronger acid because the bond is weak which means it can be broken easily. Also, acids want to take in more electrons and considering the single bond is a weaker bond it will...

Desiree1G

Between bonds, do you mean ionic and covalent? If you do, I usually look at the elements. If it has a metal in it, it is ionic because ionic bonds typically transfer one electron from a metal to a nonmetal. And if it has a positive charge it is a cation. This means it lost an electron hence making i...

Desiree1G

The most stable configuration is one in which its formal charge would be 0. This can be determined with the formula V-(L+S/2), where v is the valence electrons, L is the lone pair of electrons and S is the shared electrons over 2.

Desiree1G

V is for valence electrons, L is for lone pair of electrons, and then S is for shared electrons. Don't forget also the formula V-(L+S/2)

Desiree1G

I believe the difference is that de Broglie's equation includes matter. Matter according to the de Broglie has wave-like behavior and this equation, therefore, is meant to include how to calculate the wavelength of an object of mass. The wave equation we worked with initally (c=wavelength*v) did not...

Desiree1G

I think it is possible they may provide numbers we do not know for the test, however once we do practice problems I think you will memorize them. Currently the speed of light and plank's constant are ones we will gradually remember.

Desiree1G

The definition that makes the most sense to me is, the ejection of electrons from the surface of a metal when exposed to UV radiation of frequency above the threshold frequency of the metal.

Desiree1G

I don't believe sig figs matter too much in this case, but I usually go with three in those cases. Verify with the TA

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