CHEMISTRY COMMUNITY

MichelleTran 1I

A chemistry lab is a lot like a party! Some drop acid, some drop the bass.

MichelleTran 1I

MichelleTran 1I

Chemistry is a lot like cooking, only you really shouldn't lick the spoon.

MichelleTran 1I

Why do chemists learn about ammonia first?

It's pretty basic, really.

MichelleTran 1I

MichelleTran 1I

Are you full of beryllium, gold, and titanium? Because you're Be-Au-Ti-ful!

MichelleTran 1I

If a king farts, is it a noble gas?

MichelleTran 1I

I can't trust atoms anymore, I heard they make up everything.

MichelleTran 1I

An extensive property means that the value you get depends on how much you have of it, for example, volume is an extensive property because how many liters, mL, etc. you have of it determines the volume. On the other hand, intensive properties are constant, no matter how much you have of it. E.g. Wa...

MichelleTran 1I

Thanks again Lyndon for the practice exam! Helped a lot! C:

MichelleTran 1I

Are worksheets from other TA's/LA/UA's available on the chemistry community?

MichelleTran 1I

The midterm covers everything up to last Friday's lecture, so Chemical Equilibrium, Acid and Base Equilibria, Thermochemistry, Thermodynamics to the end of entropy, but not including Gibb's free energy.

MichelleTran 1I

I think knowing them will be helpful, but the BDE would probably be given on the test/in a table maybe? That's how it's been for the examples we worked on in class and such.

MichelleTran 1I

Thanks for posting this again, Lyndon! See you tomorrow at the review session!

MichelleTran 1I

What is Cesium and Iodine's favorite drama?

CSI C:

MichelleTran 1I

An acid with an attitude is jut an a-mean-o-acid

MichelleTran 1I

I told a chemistry joke on here once, but I didn't get a reaction :C

MichelleTran 1I

Pressure and volume have an inverse relationship, therefore if you want to change the pressure within the reaction you have to change the volume of the container. To increase the pressure, volume must decrease, so that particles within the container are more squished together, creating greater press...

MichelleTran 1I

Though the concentrations don't affect Kc, the coefficients in a balanced equation are needed to calculate the equilibrium constant. You need to raise the concentrations to the power of how many mols are in the reaction.

MichelleTran 1I

The formulae themselves have no difference, but K is only used when the chemical reaction is at equilibrium. Using the equation with Q helps you determine whether the reaction goes forward or in reverse to reach equilibrium.

MichelleTran 1I

Having the lowest formal charge is more important because the molecule will be more stable overall. There are some exceptions to the octet rule as well, so generally, following the rule of lowest formal charge would be the better bet.

MichelleTran 1I

Cl is the least electronegative atom in the molecule, but since it has 7 valence electrons, it only has room left for one electron to complete the shell. It's more stable overall to have oxygen in the middle of the molecule.

MichelleTran 1I

The Octet Rule guideline only applies to period 2 elements because they must completely fill the second shell to achieve a stable state. The following elements on increasing period have the option to fill an additional d-orbital, so they are not confined to the Octet Rule.

MichelleTran 1I

For that one, you would have to say no, because depending on the work function of the Hg atom, only certain wavelengths will be emitted when an e- reaches a certain energy level. In other words, atoms have discrete energy values, and if the wavelength emitted is not that value, then the atoms will n...

MichelleTran 1I

Each element on the periodic table has their molar mass listed below the atomic symbol. The units are in g/mol!

MichelleTran 1I

You would need to divide by Avogadro's number to get the weight in grams and then multiply by 10^3 to convert to kg. But I'm assuming that if you're converting the mass, the mass of the element is given?

MichelleTran 1I

Would we use the E= -hr/n^2 along with E=hv to solve for nu and the subsequently c=lambda*nu to find wavelength?

MichelleTran 1I

I think it's the other way around. Through the wave functions and Schrodinger's equations, you are able to get the quantum numbers for each electron in an atom (n, l, m(l)). However, Lavelle has said we won't be doing Schrodinger's for this test.

MichelleTran 1I

I remember in class Lavelle said he wanted us to use kg since it is the SI unit for mass. That way, with all the equations the units will be able to cancel out.

MichelleTran 1I

I've only ever heard that we need to post three questions or comments by Sunday. I think the new week starts each Monday, since Sunday is the last day to post. You can create your own post by going into Chem 14A > [A Topic, e.g. "The Quantum World"]> and then hitting "New Topic" ...

MichelleTran 1I

In symmetrical electron density distribution, the likelihood of finding an electron in any given point within the orbital is relatively the same. In asymmetrical electron density distribution, there are certain areas where it is less likely to find an electron. For example, in the nodal plane, the l...

MichelleTran 1I

In electron configuration, a superscript indicates the number of electrons occupying each orbital. So in your example, it means two electrons are in the 2S orbital.

MichelleTran 1I

I would ask your TA which they would prefer, but technically speaking, as long as you notate it correctly as nm, or x10^-9 m it should be fine, since they both mean the same thing.

MichelleTran 1I

It's best to just stick with what the textbook and Dr. Lavelle has been using in class, "v" (nu).

MichelleTran 1I

Each atom has a minimum amount of energy needed for an electron to be released. That is the threshold amount of energy needed. Any energy more than that is excess and is given to the electron that is released. It is not used in calculating the energy of a photon.

MichelleTran 1I

A chemist and his friend go into a bar. The chemist says "I'll have some h2o, please." His friend says, "I'll have some h2o, too." His friend is now dead.

MichelleTran 1I

If you use 100g, you don't have to worry about having to calculate percentages and using complicated numbers, it speeds up the process without doing too many extra steps!

MichelleTran 1I

I thought I heard someone say they were supposed to be done by week 2? But then again, it also says the modules are done anonymously?

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