CHEMISTRY COMMUNITY

Lopez_Melissa-Dis4E

On Lavelle's Chemistry page there is the list of constants and equations that are provided on the exam.

Lopez_Melissa-Dis4E

For a bomb calorimeter, the volume is constant.

Lopez_Melissa-Dis4E

I believe that the slow step (rate determining step) will always be given.

Lopez_Melissa-Dis4E

I believe the final is commutative and will cover all we have learned throughout the quarter.

Lopez_Melissa-Dis4E

Platinum is only used when you have an aqueous solution/gaseous solution as your anode/cathode. Therefore, you will only use Pt(s) in you cell diagram if you have a nonconducting solid.

Lopez_Melissa-Dis4E

You can only go as fast as your slowest reaction, therefore it is determines your overall rate law.

Lopez_Melissa-Dis4E

The equation deltaG=-nFE dives way the relationship between deltaG and E.

Lopez_Melissa-Dis4E

You use Platinum(s) when there is no conducting metal on either the anode/cathode side of the reaction.

Lopez_Melissa-Dis4E

Mercury is an electron conductor itself, therefore it does not need a solid like Pt(s) written in the cell diagram.

Lopez_Melissa-Dis4E

The test will cover up to todays lecture in electrochemistry and Gibbs Free Energy.

Lopez_Melissa-Dis4E

I believe either one gave approximately the same answer.

Lopez_Melissa-Dis4E

Test 2 will cover almost all of chapter 14, not including the Nernst equation.

Lopez_Melissa-Dis4E

The units will either be in J or kJ depending on what it is asking. Sometimes it will be J/mol or kJ/mol.

Lopez_Melissa-Dis4E

It should cover Gibbs Free Energy and topics that we learn during week 7.

Lopez_Melissa-Dis4E

Test 2 should begin next week, I think it should cover Gibbs Free Energy and other topics we cover this week.

Lopez_Melissa-Dis4E

I believe it takes them about 1 week to grade them after the midterm, however since Monday was a holiday then maybe it will take longer.

Lopez_Melissa-Dis4E

When work is (+), then work is being done ON the system.
When work is (-), then work is being done BY the system.

Lopez_Melissa-Dis4E

It takes them about a week to grade all the midterms, so hopefully by Wednesday or Thursday of week seven.

Lopez_Melissa-Dis4E

Cv means constant volume and Cp means constant pressure.

Lopez_Melissa-Dis4E

Delta U stands for the change in internal energy of a system that is solved by adding work and heat.

Lopez_Melissa-Dis4E

You would have to divide by moles so that the unit can cancel out and you are only left with Joules.

Lopez_Melissa-Dis4E

He has not, but I'm sure it will be up this weekend since his review session is on Monday.

Lopez_Melissa-Dis4E

The midterm is during week 6, on February 13 @ 6-8pm. He will later announce each location for the midterm.

Lopez_Melissa-Dis4E

Endothermic requires heat, therefore delta H is positive.
Exothermic releases heat, therefore delta H is negative.
Whether you are forming bonds (endothermic), or breaking bonds (exothermic) you would refer to your positive/negative value of delta H.

Lopez_Melissa-Dis4E

The equation that relates U to work is delta U= q+w, U represents the change in internal energy.

Lopez_Melissa-Dis4E

Because the equilibrium constant is a ratio, the units would cancel each other out. Therefore no units are required.

Lopez_Melissa-Dis4E

You should assume that most equations will be given on the constant/equation sheet.

Lopez_Melissa-Dis4E

According to Le Chatelier's Principle, if you increase the pressure the reaction will go towards the side with less moles.

Lopez_Melissa-Dis4E

Yes they are equal when in pure water.

Lopez_Melissa-Dis4E

Yes, all homework is due during your specific discussion section. The only exception was week 1.

Lopez_Melissa-Dis4E

I work through all the homework problems and reread the chapters along with the lecture notes! It’s really helpful to attend the step up sessions or form a study group so you can teach each other what you don’t know. Hope this helped!

Lopez_Melissa-Dis4E

ICE stands for Initial Molarity, Change in Molarity, and Equilibrium Molarity.

Lopez_Melissa-Dis4E

I believe it's a matter of what the question is asking. I would assume that they are equally important.

Lopez_Melissa-Dis4E

Kelvin should be used when calculating these type of problems due to the fact that 0 Kelvin is absolute 0.

Lopez_Melissa-Dis4E

It all has to do with the overall charge of the compound, if it has a negative charge you will add -ate to your transition metal.

Lopez_Melissa-Dis4E

Personally, I would just use the constant given on the formula sheet to be safe. However you should be aware of significant figures to ensure the correct answer.

Lopez_Melissa-Dis4E

I believe we will be tested on coordination compounds. We are expected to name them, derive the formula from the name, and draw their structures. It would also be beneficial to know how they are significant in a biological point of view. I hope this helps!

Lopez_Melissa-Dis4E

Because momentum and wavelength are inverses of one another, if you know the precise value for one then you don't know the value of the other. (vice versa) That is why it is named the Heisenburg Uncertainty Principle.

Lopez_Melissa-Dis4E

Lone pairs repel the other bonding pairs, therefore the bonding pairs push away from the lone pairs causing a change in the VSPER formula, molecular geometry, hybridization, polarity, and bond angles.

Lopez_Melissa-Dis4E

The oxidation number is basically how many electrons have been lost or gained in a coordination compound.

Lopez_Melissa-Dis4E

It is such a weak acid because the bonds associated with it are strong and F is highly electronegative.

Lopez_Melissa-Dis4E

Riley Dean 1D wrote:All of these are 180 degrees right? regardless of the number of lone pairs of elections?

Yes! If it is linear it will be 180 degrees.

Lopez_Melissa-Dis4E

I believe you need to find the Lewis structure to determine whether it is a radical or not. If the total valence electrons are negative, you most likely have a radical.

Lopez_Melissa-Dis4E

Can someone please explain the concepts behind pi and sigma bonds?

Lopez_Melissa-Dis4E

When you add up the total valence electrons of BeCl2 you will see you only have 16 valence electrons and they fulfill Cl octet rule along with getting their formal charge to 0. Be's formal charge is also 0, thus making it a stable molecule with no extra electrons to add as lone pairs.

Lopez_Melissa-Dis4E

Lavelle has covered only 11 shapes and their corresponding angels so I am assuming those will be the only we will need to know for the upcoming test and final.

Lopez_Melissa-Dis4E

He uses the class average score in order to determine final grades. I hope this helped.

Lopez_Melissa-Dis4E

Will we be going over molecular shapes in lecture today? I just wanted to get a head start on the topic if we will be covering it today.

Lopez_Melissa-Dis4E

The Lewis Structure would be critical in the process of finding out the bond lengths.

Lopez_Melissa-Dis4E

I believe that it is because the stronger the bond, the harder it is to break resulting in a higher boiling and melting point.

Lopez_Melissa-Dis4E

There will be no calculations on the Schrodinger equation because it contains multivariable calculus that is beyond the scope of this course. Overall, we would have to understand its role in wavelength along with psi and psi^2. As mentioned above.

Lopez_Melissa-Dis4E

De Broglie is used when the mass of some particle is involved. (mass of an electron, proton, neutron...etc) The speed of light formula refers to a photon.

Lopez_Melissa-Dis4E

I believe we will not be calculating this any time soon since the Schrodinger Equation is very complex and involves multi-variable calculus. It is beyond the scope of this course.

Lopez_Melissa-Dis4E

When it comes to formal charge your goal is for it to be zero (or closest to zero) because it represents the stability of the specific atom. That is why you take the formal charge of each atom present in your compound, to see if they are all formally charged to 0.

Lopez_Melissa-Dis4E

I believe Dr. Lavelle said that we needed to know up to Lewis Acids and Bases for the midterm. What we will be learning today corresponds to the next test and the final.

Lopez_Melissa-Dis4E

Moris 1H wrote:Why us calculating formal charge important for every Lewis Structure?

Calculating the formal charge is important because when FC=0 that is when your structure is the most stable. That way you can verify that your structure is correct in terms of your placement of electrons.

Lopez_Melissa-Dis4E

Yes, Dr. Lavelle stated that we would need to know Lewis Acids and Bases for the midterm. Basically, a Lewis Acid accepts pairs of electrons and a Lewis Base will donate. You would have to figure out the Lewis Dot structure in order to choose between a Lewis Acid or Base.

Lopez_Melissa-Dis4E

I think the best way to study would be to help out your peers because it will reinforce your own learning. Also going over the modules and homework problems can be super helpful.

Lopez_Melissa-Dis4E

How are H, He, Li, Be exceptions to the octet rule? What does this mean? If we went over it in class, I totally missed it.

Lopez_Melissa-Dis4E

Are periodic trends directly related to bonding? If so, can someone please elaborate on the concept.

Lopez_Melissa-Dis4E

An element's goal is to complete a full outer shell meaning they want to have 8 valence electrons. This means all have to complete the orbital in order to be able to move on to the next.

Lopez_Melissa-Dis4E

Today we reviewed on the high school level of chemical bonding. We spoke about chemical bonds, ionic and covalent. We also began Lewis Dot Structures. We will be continuing this concept more in-depth throughout week 5.

Lopez_Melissa-Dis4E

For part c I also keep getting 12nm, it might be a typo in the book.

Lopez_Melissa-Dis4E

The Rydberg Equation is R[1/n1^2-1/n2^2]= 1/lambda. We are encouraged to use En= -hR/n^2 and then Delta E= E(final)-E(initial).

Lopez_Melissa-Dis4E

We won't be directly tested on the material from outline 1, but we are required to apply it if necessary. I hope this helped!

Lopez_Melissa-Dis4E

Hello, can someone please explain how to solve HW Problem 1A.15 in the 7th edition of the textbook?

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