CHEMISTRY COMMUNITY

Adrianh72

A ligand is anything that is attached to the metal atom to form the complex.

Adrianh72

Lewis acids and bases deal with what electrons do while Bronsted acids and bases deal with the protons.

Adrianh72

Is the first review session still happening today? How long should we stay before we can assume the TA isn't going to show up?

Adrianh72

I think they would give us the charge because transition metals can have several, but I think our TAs would be able to give us a definitive answer.

Adrianh72

Shorter bonds are stronger, and so they are less likely to dissociate in water whereas longer bonds are weaker and so more likely to dissociate in water.

Adrianh72

I'll use videos too, but I have a very short attention span so I have to be actively doing something too. So what I'll do is have my lecture notes open while watching Khan Academy videos and add anything I need to or just annotate my notes for clarity.

Adrianh72

A polydentate ligand has mutiple bonds around the central atom, so I suppose the best way to determine if a ligand is one is through drawing the structure.

Adrianh72

The way I go about this (specifically on Test #2) is I label one bond as a sigma bond in each bond and then go back and fill the rest in with pi bonds.

Adrianh72

Dipoles always point from the positive towards the negative.

Adrianh72

Go past the Privacy waver and there is another box titled "Options". next to this tab is an "Attachments" tab. Click it and then click add file.

Adrianh72

I'm sure the TA's will accept that. I would just label what's week 9 and week 10.

Adrianh72

It's because they have several electrons with similar energies so many of them can be removed.

Adrianh72

I believe in class he mentioned that even though they have come out with new names, labs still use the old ones. So I would probably focus on the "Name" column.

Adrianh72

Yes we do because, for instance, what distinguishes linear from bent shape are the lone pairs so we must look at them when determining molecular shape.

Adrianh72

Maria Poblete 1D wrote:Test 2 should cover everything from after the midterm (around Focus 2D) up to the VSEPR model and bonding angles. Hope this helped!

Will we need to memorize all the molecular shapes by test 2?

Adrianh72

It's anything covered in class from the midterm until now. So mostly dipole moments and VSEPR I'd say.

Adrianh72

Today in lecture, Dr. Lavelle pointed out that we'll be going over hybridization on Monday. I know it doesn't help you now, but just wanted to make sure you know that he will be going over it.

Adrianh72

Arianna Perea 3H wrote:The more lone pairs there are, the smaller the angles get?

Not always because sometimes the lone pairs are on opposite sides so the repulsions can cancel each other out.

Adrianh72

The elements in the second period, F,O, and N have the electronegativity needed to form these bonds.

Adrianh72

LDF is a type of Van Der Waals.

Adrianh72

I think we can do some chemical bonds but some of it should be from the new stuff. Just because chemical bonds are still "recently covered".

Adrianh72

By using the DeBroglie and Kinetic Energy Equations, wavelength comes out equaling λ = h/√(2mE)

Adrianh72

The value of l increases because the l value for an s-orbital is 0 and the l value for a p-orbital is 1.

Adrianh72

Does anyone know why the arrow always points to the negative one? I tried searching up an explanation for my answer above, but couldn't find one.

Adrianh72

Yes, the arrows that represent the dipole moment always point towards the partially negative atom.

Adrianh72

By almost shared is it like the electrons are transferred back and forth between atoms or what? I'm confused about this concept too.

Adrianh72

Katherine Brenner 3H wrote:Will you have lone pairs during an ionic bond?

In covalent Lewis Dot Structures, we usually look at shared electrons vs. lone pairs, but in ionic bonds, we don't have those shared electrons, so technically all the electrons are lone pairs.

Adrianh72

Main group elements in period 3 and downward, radicals, and elements in a molecule with an odd number of electrons can all break the octet rule.

Adrianh72

Noble gas notation is mainly used out of pure convenience. You can use it whenever, but it makes more sense to use it for the elements with larger atomic numbers. I, personally, would use it for the elements after Neon.

Adrianh72

Right now, we are just expected to put the atom with lowest ionization energy in the center and make it symmetrical if possible. Our next section is called "Molecular Shape and Structure", so I think we'll learn this in detail here.

Adrianh72

Here, they indicate that the shorthand electron configuration is being used. Meaning that it starts with the previous noble gas and then continues from there rather than starting at 1s.

Adrianh72

An expanded valence shell is one that has more than 8 electrons. Only some elements can have them and so if a lewis structure shows more than 8 electrons, it has an expanded shell.

Adrianh72

A resonance structure is just made up of the several lewis structure variations that can occur.

Adrianh72

Since Dr. Lavelle said we only needed to know the first row of the d-block, Chromium (Cr) and Copper (Cu) are the only exceptions we need to know. And this is because they are d5 and d10, respectively.

Adrianh72

Yes. Noise cancelling headphones are an example of this. The way they work is that they try to replicate the noise of your surrounding, but out of phase. So when the sound waves produced by the headphones interact with the sound waves from the ambient noise, wave destruction occurs and the sound is ...

Adrianh72

I believe so because we are still learning about the quantum world in lecture.

Adrianh72

Principal means n, orbital means l, and magnetic is ml.

Adrianh72

It usually makes more real-life sense to use grams, but since the SI unit is kg, it's often asked for in chemistry problems.

Adrianh72

Are intensity and amplitude related to each other in any way? Like does high amplitude equal high intensity or vise versa?

Adrianh72

Yes. In Dr. Lavelle's email, he said week 3 homework will only be quantum topics.

Adrianh72

Atomic spectra is the unique light pattern given off by each element when the atoms are excited. In high school, we did an experiment where we'd burn an element and then look at it through a spectroscope. In the spectroscope, you would see lines of different colors like the ones below. What we were ...

Adrianh72

With constructive interference, the waves are in phase with each other, so you can think of it as being aligned. I like to think of it in terms of "positive" and "negative". Since they are aligned, the positive (parts above the axis) interact with the positive of the other wave a...

Adrianh72

Spectroscopy can be used to identify other atoms as well because each atom has a unique spectra.

Adrianh72

I don't know what kind of answer you are looking for (specific or general), but doing experiments in a vacuum decreases the possibilities for error and interference. Photons always move at the speed of light in a vacuum, so doing an experiment outside a vacuum would change that.

Adrianh72

To add on to the previous reply, one needs to know an element's general electronegativity to tell whether a molecule is polar or not. The electronegativity trend is shown on the periodic table as increasing from bottom-left to top-right (with some exceptions). So if a molecule is made of atoms on op...

Adrianh72

I'm under the impression that the purpose of this question is to give us practice with explaining/creating lab procedures. The answer given in the book is "Measure 482.2 g of H2O on a balance and pour it into a beaker. Then weigh 27.8 g of KNO3 and mix it with the water until it totally dissolv...

Adrianh72

I'm a little confused. Let's say there are three reactants present. If two of the reactants are used up completely while the other is in excess, are there two limiting reactants? Is this possible?

Adrianh72

How do we know that (OH)2 is replaced by a sulfur ion? Is it solely based on the fact that sulfide is mentioned in the question?

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