CHEMISTRY COMMUNITY

kimberlyrose1G

I think it depends on your answer, for example, if the answer is a very large value of J, you should convert it to kJ. Or if the problem gives you what units to have your answer in, that's always what you should go with.

kimberlyrose1G

Will the Peer Learning Sessions continue with the week's content, content for Week 5, or will they be backtracking in order to help with Midterm review?

kimberlyrose1G

When reading Chapter 8 of the Sixth edition I became confused to what work actually is... is it the energy required to perform an action or is it the total energy of the reaction?

kimberlyrose1G

Why is the entropy of a gas in an aqueous solution less than the entropy of a solid in an aqueous solution? To answer your question piggybacking off of the previous reply, entropy should increase as you go from solid to liquid to gas. Therefore the entropy of gas should be more than the entropy of ...

kimberlyrose1G

K describes a reaction when it is at equilibrium, while the reactant quotient (value Q), can describe a reaction that is not at equilibrium, helping deduce whether the reaction is moving forward or in reverse depending on if it is sitting/shifting to the right or to the left, respectively.

kimberlyrose1G

Depending on whether you are talking about an acid or base, yes, similar to the difference between pH and pOH

kimberlyrose1G

During the lecture on January 8th, Dr. Lavelle referenced other terms for shifting or lying, stating that the preferred term is sitting when analyzing the size of the value K.

kimberlyrose1G

The reaction is considered neutral because both the pH and pOH are equal to 7, canceling each other out and making it a neutral reaction.

kimberlyrose1G

Even though K and Q are calculating the same way, K occurs at equilibrium and we calculate Q in order to know if the reaction is at equilibrium or if it working as a forward or reverse reaction, shifting right or left, respectively.

kimberlyrose1G

Why is it that you can sometimes cancel the x on the reactants portion before using the quadratic formula to solve for x in ICE tables?

kimberlyrose1G

You focus on the givens, not the constant for significant figures

kimberlyrose1G

A bronsted base is a proton acceptor, and lewis acid is an electron pair acceptor, so unless B(OH)2 had an additional H added, it is not a bronsted base. There would have to be a reaction where H3O forms to have a clear picture of what is the bronsted base and bronsted acid.

kimberlyrose1G

Is it possible for something to act as both a bronsted base and a lewis acid? As B(OH)2 accepts electron pairs (OH) from water, it also accepts the OH atoms. Or does bronsted base exclusively refer to unattached H protons? A bronsted base is a proton acceptor, and lewis acid is an electron pair acc...

kimberlyrose1G

resonance structures are all of the possible structures, while the hybrid resonance is the average of the resonance structures (the actual structure of the molecule)

kimberlyrose1G

you have to draw all of the resonance structures to show that you know it can be any of them, but will be an average of them all to have the most stable structure

kimberlyrose1G

you should draw all of the resonance structures as the true structure will be an average of them all (so by drawing all of them, you show that you know that it can be any of the structures, but is an average in reality)

kimberlyrose1G

the formal charge that is not equal to zero should not be on the central atom (as it makes the molecule very unstable), and should ideally be on the outer atom that is most/more electronegative

kimberlyrose1G

You calculate the formal charge of each possibility and focus on the one that has an f.c. closest to zero

kimberlyrose1G

Last week we left off on hybridization, which we will go over this week and will be on Test 3. I will NOT be holding workshops over Thanksgiving break, which means that I will not see you all until after Test 3. However, I should have covered everything that will be on Test 3 by tomorrow. Almost th...

kimberlyrose1G

There's no curve for grades higher than a 70% I believe, then they just stay with the regular grade guidelines (70%~C, 80%~B, 90%~A), so I think 50-79% will range within C- to C+

kimberlyrose1G

When we draw the Lewis structure for ClO2, we usually pick the atom with the lowest ionization energy. However, between the two atoms, there is a conflicting trend where Cl gets more rightward and gets more downward in comparison to O. This is counterintuitive because ionization energy increased ri...

kimberlyrose1G

also a single bond is a sigma bond, while any bond larger is one sigma bond plus the remaining # being pi bonds

kimberlyrose1G

Why does the number order change going from S to D? 4s to 3d instead of 4d? In electron configurations, the order goes by principle quantum number (n) so for the most part 3d will go before 4s, except for the elements Chromium ([Ar]4s^1 3d^5) and Copper ([Ar] 4s^1 3d^10) in order for these atoms to...

kimberlyrose1G

Soyoung Park 1H wrote:Do you always check for formal charges even for single bonds?

Yes to make sure that your Lewis structure is the most stable form or if additional bonds need to be made (with respect to the octet rule) in order to increase stability

kimberlyrose1G

kimberlyrose4D wrote:
505095793 wrote:How do we know which atom to put in the center of a Lewis structure?

It's the atom with the lowest ionization energy, and if there's multiple of the other atoms in the compound, it'll be the atom that there is one of.

Also: Hydrogen can never be the center atom

kimberlyrose1G

505095793 wrote:How do we know which atom to put in the center of a Lewis structure?

It's the atom with the lowest ionization energy, and if there's multiple of the other atoms in the compound, it'll be the atom that there is one of.

kimberlyrose1G

Soyoung Park 1H wrote:When do you use brackets around the lewis structures?

Once you have completed the Lewis structure and know the charge is when you put brackets and the charge in the top right corner on the outside of the brackets

kimberlyrose1G

Although the s-orbital fills before the d-orbital when writing the electron configuration, we go by numerical order, that is why 3d will go before 4s

kimberlyrose1G

There is no order, although you should have one electron on each of the four sides before having two on the same side. You should also take a look at/aim for symmetry (having two on the right side, as well as the left side if the element has six valence electrons).

kimberlyrose1G

There is no order, although you should have one electron on each of the four sides before having two on the same side. You should also take a look at/aim for symmetry (having two on the right side, as well as the left side if the element has six valence electrons).

kimberlyrose1G

Each dot represented a valence electron (the number of electrons in the outermost orbital), for single atoms/elements, this is the atomic number, but for bonds, we use the sum of the atomic numbers of the elements presented in the problem.

kimberlyrose1G

It might have been correct in your high school course, but Prof. Lavelle suggested using it only for shared bonds, so mixing the two might make it difficult for completing problems, and according to Lavelle, is incorrect for his course.

kimberlyrose1G

There is no order, although you should have one electron on each of the four sides before having two on the same side. You should also take a look at/aim for symmetry (having two on the right side, as well as the left side if the element has six valence electrons).

kimberlyrose1G

It should be either (h bar)/2 or h/4pi because h bar is equal to h/2pi

kimberlyrose1G

As you become more certain in momentum, the uncertainty of position increases; and vice versa. That's why it's Heisenberg's Uncertainty Principle, because you can only be certain in one or the other, never both at the same time.

kimberlyrose1G

Yes! Although larger objects display particle-like properties, they also emit wave-like properties. So most objects can have wave properties, they're just easier to see in smaller objects like electrons.

kimberlyrose1G

you can determine the electron spin by drawing the electron configuration, the details of the electron spin itself aren't essential but do provide a little background. Basically, if you draw the configuration, you'll have an arrow pointing up or down in the end, so this will tell you whether it is +...

kimberlyrose1G

kg since that is what our SI units tell us (convert grams to 10^-3 kg)

kimberlyrose1G

Intensity is the amount of photons, while energy is per photon (smaller scale as it is describing individual photons)

kimberlyrose1G

For remembering the order of the visible light spectrum (ROYGBV), do we have to know the wavelengths between each color, or is knowing that visible light is between 400-700 nanometers adequate enough?

kimberlyrose1G

First you multiply the number of grams by the atomic mass of the element (if a compound, then you would add together all of the individual atomic masses together) and that will give you the number of moles present in the sample. You would then multiply this value by Avogadro's Number (6.022 x 10^23)...

kimberlyrose1G

It's miscellaneous information at the moment, added in order to further describe the reaction. But you don't need to pay attention to it in order to balance the equation.

kimberlyrose1G

For most periodic tables, the mass of hydrogen is given as 1.0079, with five significant figures so the final answer would be given in a value of five significant figures, following the sig figs rules.

kimberlyrose1G

Based on Professor Lavelle's lectures, he uses four significant figures (6.022 x 10^23) so I'd recommend doing the same to avoid any large errors upon completion of a problem and the answer key he's made

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