CHEMISTRY COMMUNITY

Haley Fredricks 1B

Any mention of something that has a mass (electrons, protons, neutrons, etc) will use DeBroglie's Equation, while any light/photons will NOT, because they do not have mass.

Haley Fredricks 1B

What pulls the H+ from molecules is a negatively charged species. Once the original molecule is negatively charged, it will repel other molecules or atoms that are negatively charged.

Haley Fredricks 1B

Since both of these are strong acids, these are two you should probably know. I would say the ones you should definitely know the names of are the strong acids and bases.

Haley Fredricks 1B

In class today, Lavelle went over an example where Cl is the central atom with 6 bonds and one lone pair, so I think as long as the formal charge is 0 it is okay.

Haley Fredricks 1B

Bond strength can help determine which atoms are more tightly bound. More bonds between atoms (eg. triple vs double) means that the atoms will be more tightly bonded. In addition, large electronegativity difference can also generate a stronger bond.

Haley Fredricks 1B

Anika Chakrabarti 3K wrote:I'm pretty sure we aren't going to do actual calculations with Ka until 14B. What does Kw represent, though? I don't remember learning that

Kw represents the constant for H20. Kw=[H+][OH-]=1.0x10^-14

Haley Fredricks 1B

When you're given a salt (ex: BaCl) in water, how can you tell if it will act as an acid or base in solution?

Haley Fredricks 1B

This means that there is a complex containing a ligand that forms a ring of atoms including the central metal atom. In other words, more than one bond is formed between the metal ion and the ligand.

Haley Fredricks 1B

An amphoteric compound is one that can react as either an acid or a base. A lot of metals (like copper, zinc, tin, aluminum, etc) can form amphoteric oxides or hydroxides.

Haley Fredricks 1B

Yes single bonds are always sigma bonds

Haley Fredricks 1B

I believe both occur depending on the situation. When H2SO4 dissociates in water, it can form a mixture of HSO4- and SO42- molecules. This happens because after the first hydrogen is taken off, the reaction is slightly different for the second.

Haley Fredricks 1B

The ones I have that he mentioned were Chromium (which assists insulin in control of blood sugar), Iron (myoglobin, hemoglobin, electron transfer in the oxidation of carbohydrates, proteins, fats (respiratory chain), Cobalt (vitamin B12), and Manganese, Nickel, Copper, and Zinc (critical for enzyme ...

Haley Fredricks 1B

I believe you use the Lewis Structure to determine the Hybrid orbitals

Haley Fredricks 1B

Bronsted Acids are said to be able to donate a Hydrogen cation, while Lewis Acids are said to accept an electron pair.

Haley Fredricks 1B

Dipoles point towards the more electronegative atom in the molecule

Haley Fredricks 1B

It says that the three types of intermolecular forces are: London Dispersion, Dipole-Dipole, and Hydrogen bonds. Where does dipole-induced dipole fall within these three categories? Or is it not in any of them?

Haley Fredricks 1B

Intermolecular forces are just talking about between molecules. The bonds within molecules are intramolecular forces.

Haley Fredricks 1B

If you check the formal charges, all are 0 when you use double bonds, so it is much more stable for the molecule to use double bonds instead of single bonds.

Haley Fredricks 1B

Lavelle mentioned in class that single, double, and triple bonds are considered single regions of electron density in VSEPR model, so the double bond wouldn't cause a greater repulsion in this model.

Haley Fredricks 1B

Lone pairs cause molecules to be polar because they have a strong negative presence and are usually not cancelled out by a symmetric pull in the other direction.

Haley Fredricks 1B

Rod shaped molecules have a greater surface area and can get closer to each other than spherical molecules, which means that their attraction can be greater.

Haley Fredricks 1B

yes, if the difference in electronegativity is less than 1.5 then it is covalent, and if the difference is greater then 2 it is ionic.

Haley Fredricks 1B

How can we determine between elements which will have a higher boiling point? Based on the type of intermolecular forces (so london dispersion and or hydrogen bonding) you can tell which will have higher boiling points. The more attracted molecules are to each other, the higher the boiling point wi...

Haley Fredricks 1B

Dipole-dipole attractions arise from differences in electronegativity

Haley Fredricks 1B

There are very few exceptions to the octet rule (in terms of it not being completed). Boron and Aluminum are the two that most often don't complete an octet (having 6 valence electrons instead of 8)

Haley Fredricks 1B

Yes electronegativity have to do with how much an atom wants the electron (more electronegative means they are close to being in a stable configuration)

Haley Fredricks 1B

When you get to the d orbital and l values of 2 and -2, they correspond to multiple planes, not x, y, and z. So for example 3dxy, 3dyz., etc.

Haley Fredricks 1B

3p elements have a 3d orbital technically, but it isn't used because there isn't a need. However, if more electrons need to be accommodated (for formal charge reasons), the 3d orbital can be accessed. The 3d orbital has the ability to hold 10 electrons which is where the expanded octet electrons are...

Haley Fredricks 1B

Technically, yes, but in reality it more has to do with the formal charge. Whatever makes it the lowest is how many the octet should be expanded to.

Haley Fredricks 1B

This would be an expanded valence which is okay if its one of the exceptions (possibility of a 3d orbital). The most common ones are Sulfur, Phosphorus, and Chlorine.

Haley Fredricks 1B

You remove electrons from the 4s before the 3d. Even though you fill 4s before 3d, the energy of the 3d orbital drops once electrons have been added. Whatever is written last in the electron configuration is where you take the electrons off of (for anything but exceptions)

Haley Fredricks 1B

4s has lower energy than 3d, but once an electron is put in 3d then its energy lowers which is why you write 3d before 4s in the electron configuration.

Haley Fredricks 1B

Are electron configurations for ions that are in the same isoelectronic series as Cu and Cr also exceptions to the normal (filling up 3d before 4s)?

Haley Fredricks 1B

For the specific molecule, the bond length between two carbons is different because it is a resonance structure and the electrons are delocalized. This means that the single and double bonds between carbons or other atoms in a resonating molecule will not be two distinct values, but more of an avera...

Haley Fredricks 1B

For both Chromium and Copper, the 3d orbital is the last to be filled up with electrons (even though 4s is written after in the electron configuration). Despite this, it is more stable to have a half full or completely full 3d orbital with only a half full 4s orbital. Because of this, the 4s shell f...

Haley Fredricks 1B

I don't think it really matters, but I think Lavelle said it was best to use lines to represent bonds because it is more obvious/symbolic.

Haley Fredricks 1B

By determining the formal charges on each of the atoms in each variation you can see if one is more stable than others (0 is the most stable).

Haley Fredricks 1B

In class we talked about how the 2nd electron is always harder to remove (ionization energy for the 2nd electron is always higher than for the 1st electron), but I was wondering if this includes atoms like Mg and Ca, in group 2. Since taking off the 2nd electron would give them a full octet of valen...

Haley Fredricks 1B

Yes you would. If you multiply the km/hr by 1000 (or 1000m/1km) and by 3600 (60sec*60min/1 hour) it will come out to m/sec

Haley Fredricks 1B

Celena Kim 3I wrote:Do you know if in future tests, we will also be provided with a formula sheet?

Yes, the formula sheet will be provided for all of the tests I believe.

Haley Fredricks 1B

I believe it would be +/- 5mm

Haley Fredricks 1B

Because the indeterminacy equation states that the product of the indeterminacy of momentum and the indeterminacy in position of an electron is equal to or greater than a constant value, it is impossible to have small values of indeterminacy for both the momentum and the position. Just like in the e...

Haley Fredricks 1B

The norm is that the 4s orbital would fill up before the 3d orbital, so each element would have 4s^2 before 3d. However, in both Cu and Cr, the 4s orbital is not full, while the 3d orbital is partially full or completely full (3d^5 or 3d^10) for the purposes of stability. This is why they are called...

Haley Fredricks 1B

I don't think quanta have units, but rather act like moles which can be used to describe the amount of something (in this case energy).

Haley Fredricks 1B

I am a little confused on all of the equations in the unit so far. What are the classifications of each equation (like when you can use what)?

Haley Fredricks 1B

Is it effective to do the whole homework list? Or should I focus on doing a few problems from each section? I find that it is most efficient for me to read through all the problems and focus on the ones I am not sure how to do or that I want more review on. I skip some that I feel I can in my head ...

Haley Fredricks 1B

In class, when describing the circular standing waves around the nucleus in an atom, the phrase "in phase" was used. What does this mean in regards to energy levels?

Haley Fredricks 1B

The Rydberg Equation is used to predict the wavelength of light from an electron moving between energy levels of an atom.

Haley Fredricks 1B

No, you should be answering each individual question with the number of sig figs in the question (depending on addition or multiplication it could be different). There isn't a general set number of sig figs for the homework.

Haley Fredricks 1B

For this equation I started by putting a 2 in front of NO so there are 4 oxygens on the left and two nitrogens. Then, I put a 2 in front of the NO2 which makes 2 nitrogens and 4 oxygens on the right which should be balanced.

Haley Fredricks 1B

They would not be considered limiting reactants because neither is limiting the other in regards to the production of the product.

Haley Fredricks 1B

M 11 asks " A reaction vessel contains 5.77 g of white phosphorus and 5.77 g of oxygen. The first reaction to take place is the formation of phosphorus(III) oxide. If enough oxygen is present, the oxygen can react further with this oxide to produce phosphorus(V) oxide.(a) What is the limiting r...

Haley Fredricks 1B

I have a hard time discerning these two terms as well, but what I have gathered is that the molar mass is the mass per mole of particles, and it is measured in g/mol. This is found using the atomic weight of the constituent elements. The molecular weight is in atomic mass units (amu) and is found us...

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