CHEMISTRY COMMUNITY

Maya Serota 3G

It doesn't necessarily mean that the molucule will be more stable, but molecules with more lone pairs will have smaller bond angles due to electron repulsion.

Maya Serota 3G

The formula in the textbook was discussed in the box that was on the syllabus.

Maya Serota 3G

I believe scores will be posted in about two weeks but we pick up our physical exams the second week of winter quarter.

Maya Serota 3G

It is similar to one of the questions that was reviewed in the final review session on Friday night.

Maya Serota 3G

Acids release H+ (hydronium) ions into the solution and bases release OH-(hydroxide) ions.

Maya Serota 3G

It will be written as NO2 when it's nitro and ONO when it's nitrito.

Maya Serota 3G

My TA said that we will need to be able to recognize it, but we will most likely not be given something ambiguous on the border of the diagonal.

Maya Serota 3G

We will need to be able to identify when a reactant is an acid, but my discussion was told it will not be ambiguous.

Maya Serota 3G

Could someone explain exactly what it means when a product is a conjugate acid or base? Thank you!

Maya Serota 3G

Ligands are Lewis bases. They have at least one pair of electrons that they donate to a metal atom/ion.

Maya Serota 3G

Will Dr. Lavelle be going over what he taught in lecture on Wednesday in lecture tomorrow?

Maya Serota 3G

The only instructions on the syllabus are to do the homework on relevante topics so I assume molecular structure and acids and bases. Also Dr. Lavelle said we will be able to turn in both week 9 and week 10 homework during week 10.

Maya Serota 3G

We will only need to be able to make comparisons to the bond angles discussed in class and understand why bond angles might be smaller or larger due to electron repulsion.

Maya Serota 3G

I believe the TAs will hold review sessions for the final in which they go over past exam questions and explain the answers, but we have not been given access to a entire final exam and it’s answer key.

Maya Serota 3G

It has two centers. The carbon is has tetrahedral electron geometry and tetrahedral molecular geometry. The Oxygen has tetrahedral electron geometry and bent molecular geometry.

Maya Serota 3G

What percentage of our grade is the final exam worth?

Maya Serota 3G

No ! They don’t determine or change a molecules shape when drawing the VSEPER models.

Maya Serota 3G

Lone pairs are close to each other than any other combination of pairs. Therefore lone -lone have the greatest repulsion strength.

Maya Serota 3G

A = the central atom, X = an atom bonded to A, E = a lone pair on A.

Maya Serota 3G

We just need to know comparisons, not exact bong angles.

Maya Serota 3G

Since Hydrogen bonds are so strong, a greater amount of energy is needed to separate them. Thus molecules with hydrogen bonds typically have higher boiling / melting points.

Maya Serota 3G

As you go up a group and across a period to the right, electronegativity increases. If you go down a group and to the left on the periodic table, atom size increases.

Maya Serota 3G

If this is the case you can’t conclude what type of bond it is. My TA said that we won’t be given something ambiguous.

Maya Serota 3G

Yes, you draw all of the possible structures. This does not depict the real molecule but gets as accurate as possible with Lewis Structure diagrams.

Maya Serota 3G

Sigma bonds are formed by end-to-end overlapping of atomic orbitals and Pi bonds are when the lobe of one atomic orbital overlaps another

Maya Serota 3G

Hydrogen bonds are the strongest intermolecular bonds which is why water has such a high boiling point.

Maya Serota 3G

You want to construct the bonds based on which structure results in the formal charges of each atom being closest to zero (unless you want a certain charge on the molecule)

Maya Serota 3G

I find the first way more efficient, but as you said either way works.

Maya Serota 3G

The structure represents it that way because it is the best we can do, but in reality there aren’t actually double and single bonds like that.

Maya Serota 3G

You want the most electronegative atom to carry any extra negative charge and the least electronegative atom to carry any extra positive charge.

Maya Serota 3G

You just want to get as close to 0 as possible.

Maya Serota 3G

You can't represent the actual structure -- that is a limitation of lewis structure diagrams. Any of the resonance structures you draw will be considered correct.

Maya Serota 3G

The midterm is 120 minutes long and worth 120 points.

Maya Serota 3G

I am also confused about this question. I looked it up and the answer differs on various websites. Anyone who can clarify would be much appreciated!

Maya Serota 3G

A molecule can have resonance structures when it has a lone pair or a double bond on the atom next to a double bond.

Maya Serota 3G

Could someone explain how the formal charge is assigned to an atom? Thank you!!

Maya Serota 3G

The standard nomenclature for writing the charge of an ion says to follow the number with the sign i.e. 2+

Maya Serota 3G

Yes I am pretty sure the the fundamentals covered in test 1 will also be on the midterm and final.

Maya Serota 3G

To add to that a key concept Dr. Lavelle has pointed out many times is that orbitals are actually mathamatical equations; that will probably be helpful for the midterm.

Maya Serota 3G

There is no way to figure this out on th spot — Dr. Lavelle said we just need to have those two exceptions memorized.

Maya Serota 3G

I believe Dr. Lavelle mentioned we would be going over multi-electron atoms in the next lecture.

Maya Serota 3G

You might be given something like 4s2 and will have to find the four quantum numbers associated with that electron. N would be 4 and you would go off of that.

Maya Serota 3G

The actual value will be given to you in the question. From there the equation for percent yield is (theoretical/actual) x 100.

Maya Serota 3G

That is the case because the amount of energy released is discrete, not continuous. That means that only specific levels of energy can be emitted and no values in between. These specific values were represented by n=1, n=2, n=3, etc on the diagram in lecture.

Maya Serota 3G

With constructive interference, is the resulting amplitude just the lengths of the individual waves added together? Or can it not be measured that way?

Maya Serota 3G

Also if it is helpful, Dr. Lavelle said in lecture that if your answer is smaller than x 10^-15 you can conclude the object does not exhibit wavelike properties.

Maya Serota 3G

Does anyone know when we are expected to get our test 1 scores back? Is it usually the following week in section?

Maya Serota 3G

I understand how and when to use Planck's constant, but why do we use it? How was that specific number derived and what does it represent?

Maya Serota 3G

Will we be marked down on an exam for using the incorrect amount of sig figs in our answer?

Maya Serota 3G

Are we going to be expected to know how to write the formula for something like "magnesium sulfate heptahydrate," for example, for the test in our discussions? Or will we just be given chemical symbols? I would check with your TA to be completely sure, but the information for the test fro...

Maya Serota 3G

After reading these posts I am confused about whether or not a zero is considered a sig fig if there is a number like 13.0
Since the zero is trailing the decimal point would it or would it not be a sig fig when doing arithmetic calculations?

Maya Serota 3G

I understand the theoretical yield will always be greater than the actual yield due to substances sticking the the side of the beaker, etc, but are there ways to minimize or calculate this difference? And is it possible to have a theoretical yield that is exactly equal to the actual yield?

Maya Serota 3G

Thank you so much for sharing. I am also thinking about Medical school -- as someone who has already gone through it, do you recommend doing anything specific as an undergraduate to make a Medical School application especially stand out? I know it is extremely competitive. Thank you again for your t...

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