CHEMISTRY COMMUNITY

Megan_1F

An amphiprotic molecule will done a proton or accept a proton, thus acting as a Bronsted acid or base. An amphoteric molecule will act as Bronsted base/acid and a Lewis acid/base. Thus, an amphiprotic molecule will be an amphoteric molecule, but an amphoteric molecule may not be an amphiprotic molec...

Megan_1F

The porphyrin ligand is part of the heme complex in myoglobin. It is a tetradentate and a chelating ligand.

Megan_1F

So coordination numbers will be affected by polydentate ligands? (because the polydentate will attach to multiple sites of the transition metal)?

Megan_1F

Cisplatin has the Cl on the same sides, making it stronger when it attaches to the nitrogen base of Guanine in the DNA double helix. This double attachment of chlorine will block DNA replication and thus prevent cell division. Transplatin will only have one chlorine to bind to on one side and will n...

Megan_1F

The ligand to Fe is a tetra dente because it binds to iron at 4 different sites, but is a single ligand. When O2 attaches to the heme complex, it becomes myoglobin. I do not think we need to know the structure of myoglobin, probably just the structure of the heme complex. The heme complex is tetrahe...

Megan_1F

You would probably have to draw it out to distinguish if there is a polydente.

Megan_1F

You would look at the Ka value. If the Ka is a higher number, that implies the numerator is larger than the denominator, and thus more products are dissociated so it is more acidic.

Megan_1F

You can look at the bond length of the acid - longer bond length = more acidic. And you can also look at electronegativity difference in oxoacids = higher difference in electronegativity = more acidic.

Megan_1F

Bronsted definition infers proton transfer and Lewis definition infers electron transfer.

Megan_1F

1. Strong acids lose H+ easily.
2. The resulting anion must be stable.

Megan_1F

What is the order of naming coordination compounds?

Megan_1F

What exactly is oxidation number?

Megan_1F

Cisplatin aims to stop cell division. However, it will affect cancer cells and healthy cells.

Megan_1F

It describes the number of ligands attached to the central atom.

Megan_1F

When the coordination compound has a negative charge.

Megan_1F

Typically, anions are polarized and cations are the polarizing power. Polarizability follow the trend of atomic radius. When you increase the size, you increase the polarizable properties.

Megan_1F

I would recommend writing it small right next to each atom so you can make sure you know which formal charge is assigned to which atom.

Megan_1F

Row 3 and beyond can have an expanded octet because it's in the 3rd energy level - S, P, and D blocks.

Megan_1F

Boiling points depend on the strength of intermolecular forces. Thus, because rod shapes have more surface area, which means more area to have Van DerWaals forces between rod shaped molecules, it will have a higher boiling point.

Megan_1F

The trans version will have the dipoles canceling each other out (opposite ends), thus there is no dipole moment and the molecule is Nonpolar. In the cis version, the dipoles do not cancel each other out, thus creating a dipole moment making the molecule polar.

Megan_1F

Test 2 will be during your discussion on week 8. I believe it should cover the rest of bonding and whatever we learn from then till week 8.

Megan_1F

There may be dipole moments in all types of bonds. Some non polar bonds may have a small dipole, but not a large enough difference in electronegativity that one atom donates all i's electrons to another. Just an unequal sharing of electrons that result in a slightly positive and negative charge.

Megan_1F

Yes, expanded octets start from the 3rd row because the 3rd energy level can have the d block sub shell.

Megan_1F

It is important to note that the sugbshells increase in energy going from s<p<d<f.

Megan_1F

A bond is normally ionic if the two atoms are on the far left and far right of the periodic table. Knowing the trends of the periodic table, one can assume that if two elements are near each other, they must have similar electronegativities, and thus would form a covalent bond.

Megan_1F

the actual structure to a molecule with a resonance structure is a hybrid of its resonance structures.

Megan_1F

What exactly is an operator? In terms of a Hamiltonian?

Megan_1F

Elements in the 3p block can have an expanded octet.

Megan_1F

Does electron affinity have any correlation with potential energy in an atom when it receives electrons - releases energy?

Megan_1F

To draw an ionic lewis structure, you separately draw out each element in their own brackets.

Megan_1F

Yes, you need the brackets to indicate the charge of the ion.

Completely unrelated, but does anyone know what the Midterm covers up to?

Megan_1F

Unless it asks for the spin, I would just write the configuration with [noble gas] sub shells after. However, drawing out the spins and the levels may help to visualize.

Megan_1F

I tend to associate electronegativity with covalent bonding and electron affinity with ionic bonding. Both have the same trends in the periodic table.

Megan_1F

Yes, I think we only need to focus on chromium and copper as the two exceptions. Lavelle continues to say in class that 14A is focussed primarily on the "life science elements." I believe he mentioned in class that we must know the s and p blocks as well as the first row of the d block.

Megan_1F

I agree. It's best to know these principles so you can apply this when needed on the test!

Megan_1F

Cations have a plus to indicate that the atom is positively charged because it lost electrons.

Megan_1F

We most likely will have to calculate momentum to solve for position or wavelength.

Megan_1F

Can someone please explain what Px, Py, Pz are and how they relate to -1,0,1?

Megan_1F

Is Rydberg's constant negative? Or is the equation itself just negative?

Megan_1F

I tried reading the textbook but I find that a lot of the material is more detailed than what we were taught in class. Should we base our material off of lecture or the textbook?

Megan_1F

Thanks for explaining!

Megan_1F

Can someone please tell me which units cancel out when solving the Rydberg equation?

Megan_1F

What is the relationship between amplitude and intensity of light?

Megan_1F

When in doubt, survival by partial credit! Probably best to show your work so your TA is following along with you during the problem.

Megan_1F

The limiting reactant will yield how much product is made.

Megan_1F

I normally balance the metals first, then the nonmetals (except for H and O), then I balance Hydrogen and Oxygen.

Megan_1F

Regarding Sig Figs in our final answer, should we be using the amount of sig figs that is given to us in the problem and work our molar mass around that amount of sig figs?

Megan_1F

I had the same question as well. Do any of you know if we have to complete the 5 problems for the next section by our next discussion? Or will we have time to learn the material first before having to turn in the homework?

Megan_1F

Thanks so much for your advice! I will definitely keep my notes handy as I go through my UCLA journey. Can you tell us a little bit more about your gap year? What types of clubs/ internships/ research opportunities/ etc. you were involved in that helped strengthen your medical school application?

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