CHEMISTRY COMMUNITY

Alexander Chen 3N

yup, you're right

Alexander Chen 3N

I'm confused about your equation for adiabatic processes. I thought $\Delta U = w$ for adiabatic processes.

Thanks for the help Dr. Lavelle!

Alexander Chen 3N

I'm not sure if I am understanding your question, but we do look for the longest chain even if there is a cycloalkane. For example, if there is a decane with a cyclopropane attached to the 2nd carbon, it would be called 2-cyclopropyl-decane. Let me know if you have more questions or if I misundersto...

Alexander Chen 3N

This is because by definition, aldehydes only have 1 R group to connect to, so it must be at the end. On the other hand, ketones, by definition, must connect to 2 R groups, so it cannot be at the end of a carbon chain.

Alexander Chen 3N

Tert describes the structure of the substituent. Here it shows that the butyl group has a tertiary carbon.

Alexander Chen 3N

Alexander Chen 3N

Actually I think I understand it now.

$\frac{d[A]}{dt}$ is just the general term for the instantaneous rate and $k[R]^{n}$ is just the experimentally determined rate at which the reaction occurs.

Alexander Chen 3N

This is page 60.

Thanks for the help!

Alexander Chen 3N

The course reader was very clear on how the integrated rate law is derived. However, I am confused about how the differential rate law is derived and neither the course reader nor the textbook explicitly show this. The course reader states RATE = -\frac{1}{a}\frac{d[R]}{dt} = k[R]^{n} , but I am uns...

Alexander Chen 3N

Did you hear about the man who got cooled to absolute zero?

He's 0K now.

Alexander Chen 3N

I assumed it was hexane because it has more isomers, but I am also unsure.

Alexander Chen 3N

Alexander Chen 3N

If Cl- stays in the cathode, the cathode would be negatively charged, so electrons would be repelled from the cathode. The salt bridge allows these ions to move to the anode and make the 2 solutions neutral in charge. About electronegativty: Chlorine itself is electronegative so it takes an electron...

Alexander Chen 3N

Hope this helps!

Alexander Chen 3N

My TA told me that for the other methods, we should assume that the information given is at the temperature of the reaction enthalpy. For example, if you need to find the reaction enthalpy at 30ºC using Hess's law, the other reactions must also be at 30ºC. I do not believe temperature change can be ...

Alexander Chen 3N

I know number 1.

1. NA ( $N_{A}$ ) is Avogradro's number, but it does represent the number of particles.

Following for the others.

Alexander Chen 3N

Water boils at a lower temperature at lower pressures. This is because the atmospheric pressure is lower, so less vapor pressure (created by increasing temperature) is needed for the gas to escape.

Alexander Chen 3N

Question 12.23 asks to find the pH of neutral water at 37C and gives the Kw=2.1X10^-14. The answer is pH=6.80. What I'm confused about is the hydronium ion concentration is equal to the hydroxide ion concentration, so if we take the -log of [OH-], pOH = 6.8. Does pH+pOH=14 not apply to systems not a...

Alexander Chen 3N

That would be the equilibrium constant. For example, if $K_{c}=\frac{[a]}{[b]}$ and you add more B, then A would increase and B would decrease until you reach the equilibrium constant.

Alexander Chen 3N

A simple indicator is if the question gives you the Ka or Kb, you should assume that it is a weak acid/base. This is because a strong acid/base has a very large Ka/Kb, so we just say that the reaction goes to completion and the acid is fully dissociated (HCl fully becomes H+ and Cl-).

Alexander Chen 3N

I'm sure we need to know them for Quiz 3. I'm pretty sure we need to know them for the final too.

Alexander Chen 3N

You should alphabetize according to the actual ligand name, not the prefixes. Aqua is before oxalato in alphabetic order, so diaqua comes first.

Alexander Chen 3N

I don't think the asterisks mean that it is a polydentate because neither nitrito nor sulfato are polydentates, but they have asterisks.

I don't know what the asterisks mean either, so I'm following this thread.

Alexander Chen 3N

What you can do to figure this out is draw the lewis structures for each of the ligands and find how many areas of high electron density there are to determine the number of binding sites. If the number of binding sites is greater than 1, it is a polydentate. Additionally, you can use the informatio...

Alexander Chen 3N

MO orbitals describe the electrons in an entire molecule while hybrid orbitals describe the electrons around a single atom. They can and often do appear together, but the MO diagram only shows the energies of the electrons while we can determine the shape of the areas of electron density from what w...

Alexander Chen 3N

If H20 is water, what is H204?

Drinking, bathing, washing, swimming, etc.

Alexander Chen 3N

I hate it when I make a chemistry joke, but there's no reaction.

Alexander Chen 3N

Chemistry version of Pen Pineapple Apple Pen. So dumb, yet so funny!

https://www.youtube.com/watch?v=nqL75fASb6U

Alexander Chen 3N

l=0 is the s orbital
l=1 is the p orbital
l=2 is the d orbital
l=3 is the f orbital

If you have any more questions let me know!

Alexander Chen 3N

Sorry for the late reply, but R is Rhydberg's constant and $R = 3.28984\times 10^{15} \textup{ Hz}$

Alexander Chen 3N

3

This can be seen more easily if you convert this to scientific notation. $2.34\times 10^{-4}$

Alexander Chen 3N

I didn't get rid of the negative, the number that is being square rooted is positive. I first used the equation E = h\nu to find the energy. Then I used \Delta E = E_{final} - E_{initial} where E_{n}=\frac{-hr}{n^{2}} . You just equations that have variables you know and variables you need to find, ...

Alexander Chen 3N

Here's my work, but I didn't include every step, so if you have any questions about it, please let me know.

Hope this helps! :)

-Alexander Chen

Alexander Chen 3N

Hey Grace!

I worked out the problem for you in the picture below.

Let me know if you have any questions!

Alexander Chen 3N

Hi Raj!

I just went through this question and got that the principle quantum level is 6.

Attached is a picture of my work.

Let me know if you have any more questions!

Alexander Chen 3N

I believe Dr. Lavelle said we would have a formula sheet during exams that will give us the formulas and constants that we would need. The only thing you would have to know is when to use what, because each question will not tell you the constant or formula you need to solve the question.

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