CHEMISTRY COMMUNITY

Ke Huang 2G

Yes, the exams should occur during lectures.

Ke Huang 2G

You should be able to choose to pay with credits for this quarter.

Ke Huang 2G

We only include it when they are gases, not solids or liquids

Ke Huang 2G

The pressure and volume are inversely related.

Ke Huang 2G

I think going over the homework problems and problems in the book is very helpful.

Ke Huang 2G

Does anyone have any advice for study?

Ke Huang 2G

It can be both base or acid.

Ke Huang 2G

I was having this question too. Thanks for asking!

Ke Huang 2G

Chlorine is more electronegative.

Ke Huang 2G

I was thinking about it too.

Ke Huang 2G

As pH increase, Ka increase, pKa decreases.

Ke Huang 2G

I did have to guess on the last seven questions too. Hope that there would be some curve.

Ke Huang 2G

I am planning on going over all my notes.

Ke Huang 2G

I think it may be live-format only like usual since Dr. Lavalle did not mention anything about it.

Ke Huang 2G

CHI3 has a higher melting point because I has more electrons, which creates more polarizability.

Ke Huang 2G

I am kind of stressed by the finals. I can not believe that my first quarter of college will end like this.

Ke Huang 2G

How many questions will we have for the final? Will we have partial credits for some questions?

Ke Huang 2G

I felt the same. I am stressed by the final since I have already missed some questions in the midterms.

Ke Huang 2G

Can we use the ligand names chart on the website during the test?

Ke Huang 2G

If the electrons can move, which results in renosounce structure, it is considered delocalized.

Ke Huang 2G

This is because the structures are different for each drawn.

Ke Huang 2G

After getting the number of electron density regions, write them in a way like sp, sp2 etc.

Ke Huang 2G

It would be bent because it has two lone pairs and two bonds.

Ke Huang 2G

Yes, to see if the molecules are polar/ nonpolar, you need to know about the shape.

Ke Huang 2G

Does the trigonal bipyramidal arrangement have a bond angle of 180 degrees?

Ke Huang 2G

It means that every bond has two characters, covalent characters, and ionic characters.

Ke Huang 2G

Yes, London forces happen in all types of molecules.

Ke Huang 2G

Depending on the situation, expanded octets can expand more than 10 valence electrons.

Ke Huang 2G

I think 93+ is A, 90+ is A-, and 87+ is B+.

Ke Huang 2G

The smaller the difference is between the electronegativity of two elements, the greater the covalent character is.

Ke Huang 2G

I love taking a walk outside and just relaxing.

Ke Huang 2G

I think this one is tougher than the last one. And the fact that no partial credits will be given for 6/7 points questions is scary.

Ke Huang 2G

I think the final is cumulative.

Ke Huang 2G

Does anyone know when we will know midterm 2 grades?

Ke Huang 2G

Ionic bonds refer to the interaction within one molecule. Ion-ion interactions refer to the interactions between two ions or two molecules.

Ke Huang 2G

if we use only single bonds sometimes, the numbers of electrons represented in the lewis structure will be less than the total numbers of the valence electrons that molecules have. If we use too many double bonds, we may find out we have more electrons in the structure than what we need. So it is im...

Ke Huang 2G

You can tell the partial charges by comparing the electronegativity between the two atoms in a molecule. If one atom is much electronegativity than the other, that atom would be having a partial negative. You can also calculate the charges of each part by the formal charge equation.

Ke Huang 2G

I think both hydrogen bonding and dipole-dipole forces are involved. The -2kj/mole might only represent the dipole-dipole force.

Ke Huang 2G

The trend of the electronegativity and electron affinity is very similar. They both increase going towards the right top of the periodic table. This is because the elements want more electrons to fill their orbitals.

Ke Huang 2G

Going across the period, the atomic radius becomes smaller as the positive charges in the nucleus attract electrons outside much tighter. This means that it is harder for the electrons to move and lose. So the ionization energy, which is the energy needed to take an electron away, increases.

Ke Huang 2G

Why increasing the size of the molecules will increase the Dispersion? I thought that increasing the size of the molecule will reduce dispersion because it will increase the distance between molecules/atoms(r^6).

Ke Huang 2G

There are subshells past f, but we don't usually use those in this class.

Ke Huang 2G

It will be easier to memorize the trends of the periodic table if we understand the reasoning behind it. You can probably try to practice explain how you compare the elements when you do the practice.

Ke Huang 2G

I like the videos from Khan Academy too. Their videos are short and organized. So it is easy to find what you are looking for in the series.

Ke Huang 2G

I get anxious when I have big exams too. Remember you are not the only one. I always try to take a jog to just relax and then go back to study when I feel too anxious. This really helps a lot.

Ke Huang 2G

As you move to the right of the periodic table, the radius decreases because electrons are attracted to the nucleus as the nucleus has more positive charges.

Ke Huang 2G

You can solve v by rewriting it as v= energy/ h.

Ke Huang 2G

I would recommend it. It has been really helpful that they went over all the concepts from the class.

Ke Huang 2G

I put in the wrong units many times and now I can finally remember it. The unit for mass is different from when we calculate the molar mass stuff. It is kilograms. And velocity should be in m/s.

Ke Huang 2G

It does not matter whether energy is absorbed or released, we can just remember that n initial is the original energy level the particle is in and n final is where the particle is going. If the energy number we get is negative, we know that the energy is released.

Ke Huang 2G

We need to use this constant when we need to know the mass for one atom by dividing the molar mass from periodic table by this constant.

Ke Huang 2G

I failed many times on this one too. If you got everything to put in the equation, make sure that you have the right units for mass and velocity, which should be kg and m/s.

Ke Huang 2G

Happy Halloween! It has been a very special one because of this pandemic.

Ke Huang 2G

I think the scores may come out probably in a few weeks

Ke Huang 2G

I was not able to attend Dr.Lavelle's discussion sections. Could someone tell me what parts of the outline will be covered? Do we need to know stuffs about orbitals and Schrodinger's equation?

Ke Huang 2G

Did Dr. Lavelle send an email with the new Constants and Equation sheet? I did not get one. Are those the same as the ones on the website? Can I use the ones on the website?

Ke Huang 2G

You can get energy per photon by using E=hv. And then you can calculate the numbers of photons by diving Energy emitted total(60 joules in a second) by energy per photon as calculated in the beginning.

Ke Huang 2G

I was doing the problems with calculating the wavelength with the equation wavelength= h/p where p=mv. I noticed that I made mistakes changing units of mass from kg to g. We should be careful about that. Thanks for reminding me!

Ke Huang 2G

I think question b is asking the energy of the radiation given, which has a frequency of 2.50×10^16 Hz. This energy is the required energy that an electron needs to be ejected. We can use E=hv to calculate the energy of the radiation.

Ke Huang 2G

Do we need to memorize how to converse units, such as from ounces to kilograms and from miles to kilometers? Will we be given these numbers on the tests?

Ke Huang 2G

I think going over the book questions are very helpful for me. They help me find many topics that I did not fully understand.

Ke Huang 2G

Some parts of molecules may have the same charges that make them repel each other. There might have some van der Wal forces, but they might be too weak.

Ke Huang 2G

For the first question, you can calculate frequency using c= frequency times wavelength. Then you can calculate energy per photon by using E= hv.

Ke Huang 2G

I think they are multiple choices, so there is a high possibility that no partial credits may be given.

Ke Huang 2G

I think when it is changed to positive, it refers to the energy that light should have in order to excite or eject an electron.

Ke Huang 2G

Yes. I think the sig figs of the answers depend on the least number of sig figs that a number has in the question.

Ke Huang 2G

My TA said we can try using our phones during next week's discussion section.

Ke Huang 2G

I think it depends on what the questions asks. If it needs us to balance the equation, we can write the states. If it only needs us to calculate something, we can save time without including it.

Ke Huang 2G

You would need to multiply by 10^3 when you try to convert kilograms to grams.

Ke Huang 2G

Do we need to memorize both the name and the symbol of elements for the Periodic Table? Will the Periodic Table on the tests provide us the names?

Ke Huang 2G

I think we need to convert the unit to match what the question asks. If the questions asks in unit of ml, we can convert the unit of L to ml by multiplying 10^3.

Ke Huang 2G

I think as long as we use same units for V1 and V2 using the equation, it is okay to use ml or units other than L.

Ke Huang 2G

I think we have only covered molar mass in the class so far. The unit of molar mass is g/mol and the unit of molecular mass is amu. To calculate the molar mass of molecules, we can add up the molar mass(the number on the bottom of each element symbol) in the periodic table.

Ke Huang 2G

I think we should probably go with four sig figs since the periodic table on the resources part of the website has four.

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