CHEMISTRY COMMUNITY

Sarah Nichols 4C

No, because for strong acids and bases we assume 100% dissociation, so after the reaction there will be no reactants in solution, only products

Sarah Nichols 4C

You only need to add the -ate ending if the coordination compound has an overall negative charge/is an anion. Otherwise you would leave the transition metal name alone

Sarah Nichols 4C

Cl being more electronegative is the reason HCl is the stronger acid, and as far as I know this is the only explanation we have to be aware of!

Sarah Nichols 4C

I would assume we do not have to know how to do this, since the examples for salts as acids and bases in lecture did not cover this

Sarah Nichols 4C

What specific atoms in the novocaine structure, C13H20N2O2, make it a base and why?

Sarah Nichols 4C

How and why would the pH of a solution differ if you use a weak base instead of a strong?

Sarah Nichols 4C

When listing the ligands in alphabetical order, do you go by just the name of the ligand or do you include the prefix? For example, would it be biethylene chloro because b comes before c or chloro biethylene because c comes before e?

Sarah Nichols 4C

I think this is saying that oxoacids with other electronegative atoms are stronger because these atoms delocalize the negative charge and make it less likely for a proton to bind/stay bound. For example, in OCl- (hypochlorite ion), the negative charge is largely localized on the single oxygen atom; ...

Sarah Nichols 4C

The lewis definition of a base is the species that donates an electron pair. The bronsted definition is the species that accepts a proton. A conjugate base is, in a reaction, the species formed by the reactant acid after it donates a proton. So to clarify, a conjugate base is defined very similarly ...

Sarah Nichols 4C

As far as I know, any topic on the syllabus is fair game for the final. So I would say just go back through that and go over the things you're a little shakier on. Hope this helps!

Sarah Nichols 4C

For Lewis acids and bases, the acid and base in a reaction are identified by which donates an e- pair(Lewis base) and which accepts an e- pair (Lewis acid). Lewis structures can be helpful to identify acids and bases because they visually represent the transfer of the e- pair

Sarah Nichols 4C

As far as I know, it is just a matter of memorizing the strong acids and bases to know which will dissociate completely in water

Sarah Nichols 4C

A structure can form chelating complexes only if it is polydentate

Sarah Nichols 4C

Yes, a coordination compound is a transition metal bonded to ligands, specifically by coordinate covalent bonds, in which the ligand donates both e- from a lone pair

Sarah Nichols 4C

If you want to think about it in terms of a formal equation, it would be:

Oxidation state of metal=net charge of compound-(total charge of anions)

it may be easier to just remember the concept though, that the net charge of the compound must be the sum of the charges of all the ions

Sarah Nichols 4C

How would the calculations differ if the ligand was neutral? If the ligand was neutral, you would still do the calculations the same way. If the compound has a net charge but the ligands are all neutral, then that net charge must come from the metal ion and its oxidation state would equal this net ...

Sarah Nichols 4C

Yes, it goes ligand names in alphabetical order(with greek prefixes denoting how many are present), the the transition metal cation name(with Roman numeral denoting the oxidation state), then, if there are anions, the anion name plus -hydrate(with Greek prefix denoting how many water molecules prese...

Sarah Nichols 4C

When there is a lone pair, it has stronger repulsion than an atom, so it will force the atoms in the molecule closer together and slightly decrease the angle
This will also happen if one of the atoms is larger than the others

Sarah Nichols 4C

The orbitals in sigma bonds overlap to a greater extent than in pi bonds, so electron density is more concentrated

Sarah Nichols 4C

Dissociation energy is the energy required to break a bond, so the stronger the bond is the more energy will be required to break it (higher dissociation energy)

Sarah Nichols 4C

Because there are more electrons

Sarah Nichols 4C

B=C<E<A<D

Dipole-dipole interactions are weaker in the gas phase because the molecules are farther apart

Sarah Nichols 4C

Ionic bonds are typically stronger than covalent because of the coulombic attraction between ions of different charge

Sarah Nichols 4C

The most electronegative atom will carry the negative charge

Sarah Nichols 4C

Doctor Lavelle mentioned both ways of drawing resonance structures. I don't know that one is necessarily better, but since in the examples we've been drawing the structures out separately with the double-sided arrows, we should probably stick with that :)

Sarah Nichols 4C

Can someone explain how shielding works? I understand the concept as when there are more expanded shells of electrons the electrons are further away and the ones in the furthest shell are not pulled on as much, but is it the idea that the ones closer to the nucleus are "stealing" more of ...

Sarah Nichols 4C

Ionic bonds are typically stronger than covalent bonds because of the coulombic attractions between ions of different charges

Sarah Nichols 4C

Atoms in period 3 or higher can accommodate more than 8 electrons because they have d-orbitals in their valence shell. The octet guideline comes from the fact that full s- and p-orbitals accommodate 8 e- together (s2 and p6)

Sarah Nichols 4C

For this week's 5 homework problems, can we turn in problems on any topic as midterm review or do they have to be from the chemical bonds section since that is what we were doing last in lecture?

Sarah Nichols 4C

Electronegativity is calculated from the measured ionization energy and electron affinity, which is why they all have similar trends. As ionization energy and electron affinity increase, so will electronegativity because it is a product of these two measurements

Sarah Nichols 4C

Interionic and intermolecular attractive forces are attractions caused by opposite charges (in the case of anion/cation attraction) or opposite partial charges, in the case of polar molecules

Sarah Nichols 4C

The Electric Dipole Moment in molecules is simply the measure of the charge difference between atoms in a polar covalent bond. It occurs because of a difference in electronegativity between the two atoms.

Sarah Nichols 4C

A molecule is most stable when all of the atoms have the lowest possible formal charge. If you think you have found the correct structure, check formal charges and if they are mostly 0 or +/-1 to 2, that is an indication that your structure is correct

Sarah Nichols 4C

The octet (8 e-) comes from the full s- and p- subshells; s2p6 totals 8 electrons. Atoms in period 3 or higher have valence shell d-orbitals, so they can accommodate more electrons than the standard 8 for atoms with lower atomic numbers

Sarah Nichols 4C

It's usually given in kilojoules per mole (kJ/M)

Sarah Nichols 4C

5s will be filled before 4f

Sarah Nichols 4C

These values are experimentally measured bond lengths of an N--O bond in NO3- and a C--C bond in C6H6 specifically. These are important because they show that real-life models of molecules with resonance structures are not any one of these possible structures at a time, but actually an average of al...

Sarah Nichols 4C

The quantum number m sub s denotes the spin of the electron: +1/2 is 'spin up' and -1/2 is 'spin down'

Sarah Nichols 4C

The way I understand it is that the orbitals are just wave functions modeling where the electrons are most probably located. As the number of electrons increases, the patterns of where they could be located (from the s-subshell, to the p, d ,f) are added to model the atom, which is why the orbitals ...

Sarah Nichols 4C

For the p subshell, x,y, and z are arbitrary because they are all symmetrical

Sarah Nichols 4C

The easiest way for me to do conversion problems like this is to be able to visualize them using dimensional analysis, so you would set up the problem
110 pm x (1m/10^-12pm) x (1 angstrom/10^-10m) that way the units cancel and you are left with your answer in angstrom

Sarah Nichols 4C

As Brian said, the subscripts are arbitrary, but it is helpful to separate the p sub shell into its x-,y-, and z- components to remember Hund's Rule. 1s^22s^22p^3 and 1s^22s^22px^12py^12pz^1 are saying the same thing, but the second makes it clearer that each orbital in this sub shell is filled sing...

Sarah Nichols 4C

To calculate the energy of the photon, you can use the equation E=hv (using the frequency that's either been given in the question or that you've calculated using wavelength). Then to match each kind of radiation to the appropriate event, you would look at the electromagnetic radiation spectrum and ...

Sarah Nichols 4C

DeBroglie's equation suggests that any particle with momentum (in motion) actually has wavelike properties, however these properties can only be observed/detected in particles (like electrons!) with a small enough mass. Electrons can be experimentally proven to have wavelike properties because there...

Sarah Nichols 4C

Is it possible for interference to be both constructive and destructive (at different times) with the two waves staying the same? I believe that if two waves were not in phase, but also not perfectly 180 degrees out of phase with each other, there would be some points where their interference would...

Sarah Nichols 4C

Yes, because the energy per photon, E=(h)(frequency), so light with lower wavelength/higher frequency has higher energy per photon. Each photon interacts with one electron and must have enough energy to eject one electron, which is why light with higher frequency ejects more electrons.

Sarah Nichols 4C

For the line with the frequency listed as 300MHz, I converted to Hz and got 3.00x10^8 Hz, but then using wavelength=c/frequency you would get a wavelength of 1m, which doesn't make sense for the "events" context of this question. Not sure what part I'm doing wrong?

Sarah Nichols 4C

Sarah Nichols 4C

For the first example, I think the confusion is that when doing dilutions, you are starting with a stock solution with some concentration of a substance already dissolved. So you would use M1V1=M2V2 with the molarity of the original substance given in the question, along with the desired new volume ...

Sarah Nichols 4C

I'm pretty sure we are allowed to choose some from the review section as well for Homework 2, since we are still covering some of that material for this week and the syllabus just says to turn in 5 hw questions related to class material

Sarah Nichols 4C

This question asks which contains the greater number of moles of atoms, 7.36x10^27 atoms of Ru or 7.36x10^27 atoms of Fe
I was thinking they should contain the same number of atoms, since a mole of atoms of any element contains 6.0221x10^23 atoms, but I'm not sure if I'm thinking about this wrong

Sarah Nichols 4C

Your textbook also should have come with a little slip with a code inside that you will need to access the eBook on Sapling Learning

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