CHEMISTRY COMMUNITY

Henry_Phan_4L

You can add H2O to the side that needs more oxygens, then add double OH- along with it and add double the H2O to the other side.

Henry_Phan_4L

The intermediate can't exist in the rate law because something was used to form it. So since it came from something, you gotta trace it back to the original components.

Henry_Phan_4L

Voltage usually isn't negative.

Henry_Phan_4L

Think of it as the rate that the chemical reaction is going, in terms of time.

Henry_Phan_4L

It's either 80%, which is 96 points, or 80 points, which is 73%.

Henry_Phan_4L

It's pretty simple. The propagation phase describes the 'chain' part of chain reactions. Once a reactive free radical is generated, it can react with stable molecules to form new free radicals. ... Propagation steps often involve hydrogen abstraction or addition of the radical to double bonds.

Henry_Phan_4L

I think a galvanic cell has a potential of any voltage, while the concentration cell has a voltage of 0 at stp.

Henry_Phan_4L

Could the reaction happen faster at a higher temperature?

Henry_Phan_4L

So the one with better oxidizing power is the most positive one?

Henry_Phan_4L

Does reaction order matter in a galvanic cell?

Henry_Phan_4L

You're welcome!

Henry_Phan_4L

I am confused as to whether the change in Gibbs free energy for a reaction at equilibrium is 0 or -RTln(K). And if it is the latter, how can a reaction at equilibrium have a change in energy?

Henry_Phan_4L

What is the difference between the delta G with the degree sign and the total G?

Henry_Phan_4L

Delta nRT is like a less accurate version of PV so it's not ideal to use it every time.

Henry_Phan_4L

Use it when they give you a change in pressure that isn't from a volume change. For example they would say that a cylinder is filled with an ideal gas which increases its pressure from 1 to 10 atm.

Henry_Phan_4L

I think the main point of Gibbs free energy is to determine whether a reaction is spontaneous or not.

Henry_Phan_4L

https://www.youtube.com/watch?v=TnDCxw0y6YM The first 10 minutes gives a good explanation of the equations you need.

Henry_Phan_4L

Can positive and negative work be done on an adiabatic system?

Henry_Phan_4L

Can negative work be done on a system? Does increasing the volume count as negative work?

Henry_Phan_4L

How do you know how steep to make the slopes in a heating curve and how long/short to make the lines??

Henry_Phan_4L

The energy of the reaction should be contained inside the bomb calorimeter.

Henry_Phan_4L

Concentration at equilibrium, so you basically add I and C to get the expected concentration at eq

Henry_Phan_4L

Why doesn't a catalyst affect the equilibrium constant?

Henry_Phan_4L

Henry_Phan_4L

So the first step is to take off a Cl from the compound, because it's an ionic compound and ionic compounds fully dissociate. So for NH 4 Cl, it would turn into NH 4 + . Then do the chemical equation if you added H 2 O to the ion. The products should be NH 3 and H 3 O + . From there you can do an IC...

Henry_Phan_4L

All of them should be short answer. They want to see you do the calculations.

Henry_Phan_4L

Can water be in the form (aq) or does it only usually occur as a liquid or gas?

Henry_Phan_4L

What if there are two products from one reactant? Wouldn't the products then be doubled if you added .100 mol of substance of each?

Henry_Phan_4L

you wouldn't need to convert, but make sure to keep all the units the same because Kp is a ratio.

Henry_Phan_4L

Basically when temperature is manipulated, you can add or remove heat from the system. Usually a reaction takes energy to occur, so increasing the energy makes it easier for the forward reaction to happen.

Henry_Phan_4L

Kw is like [H3O+] and [-OH] combined, which equals 1.0 x 10^-14

Henry_Phan_4L

Could the pH be higher at a different temperature?

Henry_Phan_4L

Can Q fluctuate around K so that it could be higher at one point and lower at another point?

Henry_Phan_4L

Ksp is the degree at which a solid will dissolve in solution. We haven't talked about it in class yet.

Henry_Phan_4L

Finally it makes sense thank you!

Henry_Phan_4L

If it's a coordination compound that overall is neutral, but the complex is negative you add -ate to the end. More specifically, you replace the ending of the metal name with -ate.

Henry_Phan_4L

Based on my understanding it's roughly the same as what the problem gives. So if the concentration was 4.20 x 10^-6 mol then the pH would be 5.38.

Henry_Phan_4L

Are Bronsted and Lewis acids the same thing just with different names? Would H₂SO₄ be considered a Bronsted acid and a Lewis acid?

Henry_Phan_4L

Yeah I think you should use the sig figs for whatever you get as the concentration before you log it.

Henry_Phan_4L

pH and pOH are inversely related. The molal ratio of H30+ and -OH in solution is equal to 10^-14.

Henry_Phan_4L

Is it three iodine atoms or an iodine ion with -3 charge?
I think the molecule would be bent because there are lone pairs on the middle iodine atom.

Henry_Phan_4L

I think it depends on valence electrons and bonding, but if you're talking about molecular structures then it is because electron clouds carry a negative charge, so they want to be as far away from each other as possible, like two magnets repelling each other.

Henry_Phan_4L

Basically one lone pair takes the place of the atom in the middle trigonal planar arrangement. The name is determined by the atoms, so the electrons do the same thing but aren't considered when naming the molecule.

Henry_Phan_4L

The molecule can't be nonpolar because the one lone pair exhibits a different pull on the structure, so the three other atoms in the trigonal pyramidal structure pull away in the other direction.

Henry_Phan_4L

Isomers are polar when the vectors of charge are stronger on one side. The molecules with the largest dipole moment are the ones that have the greatest difference in electronegativity.

Henry_Phan_4L

Isomers are polar when the vectors of charge are stronger on one side. The molecules with the largest dipole moment are the ones that have the greatest difference in electronegativity.

Henry_Phan_4L

Do we need to know electron promotion for the test?

Henry_Phan_4L

I think the energy is relative to the molecule. It doesn't have a sign in the book because it takes 250 kJ/mol of outside energy to break a bond.

Henry_Phan_4L

Is there any way to access it without the textbook?

Henry_Phan_4L

I think the bond angles just depend on the covalent bonds and lone pairs.

Henry_Phan_4L

You have to compare the electromagnetivity between the two atoms. The difference tells you what kind of bond it is, and a higher difference means a stronger bond. Ionic bonds would have the strongest bonds, and hydrogen bonds would be the weakest.

Henry_Phan_4L

I think you should draw the possible resonance structures and put the double sided arrow in between them.

Henry_Phan_4L

Can the oxygen atoms in O₃ bind to each other in a triangle? Is this possible?

Henry_Phan_4L

Schrodinger's equation doesn't have anything to do with the photoelectric effect. Therefore, threshold energy would not be used.

Henry_Phan_4L

Would the degeneracy be the same as the quantum number l then?

Henry_Phan_4L

They're not the same. Electronegativity is how strongly an atom will pull electrons. Electron affinity is the energy released when an atom gains an electron.

Henry_Phan_4L

The jump in energy is negative, so the negative sign cancels it out.

Henry_Phan_4L

Chem_Mod wrote:Yes, E = hv or E = hc/ $\lambda$ .

How did you get that second equation?

Henry_Phan_4L

Yes, but generally you should know that the visible light spectrum is 300 to 700 nm.

Henry_Phan_4L

In the Photoelectric Effect Module, the work function is given as kJ/mol. Can I use that or is that the wrong units?

Henry_Phan_4L

You might be talking about the equation that combines E=hv with c=λv. Substitute v to get E=hc/λ.

Henry_Phan_4L

Energy is higher when the wavelength is smaller or the frequency is higher.

Henry_Phan_4L

Do we get our homework back too? I'd like it back so I can review.

Henry_Phan_4L

It takes more energy to move remove an electron from a lower energy level, since physically the electrons are closer to the nucleus.

Henry_Phan_4L

How many sig figs do we need to use from a periodic table? Is the tenths place ok?

Henry_Phan_4L

Molarity is moles of solute in liters of solution. The unit for molarity is mol/L.

Henry_Phan_4L

Find the percent composition and then convert to moles.

Henry_Phan_4L

The problem with the whole thing is that scientists used 12.000 grams of carbon (diamond) to figure out how many atoms were in a mole. Grams are the best standard that we have, so scientists used that as a baseline measurement. Professor Caram said that scientists are currently trying to use a spher...

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