CHEMISTRY COMMUNITY

Tatyana Bonnet 2H

n is the number of electrons involved in the reaction. After balancing your equations, the number of electrons on the product of the oxidation and in the reactants of the reduction should cancel out. That number of electrons = n

Tatyana Bonnet 2H

I remember from a previous post Lavelle saying that it does not matter the order as long as the phases are separated (the cathode and anode placement stays the same though). Some textbook problems didn't show them in the "correct" order so just be sure to understand what substance is being...

Tatyana Bonnet 2H

Chemical Equilibrium was a fun one to do as well as doing lewis structures because it was fun to draw out although a little time consuming.

Tatyana Bonnet 2H

Catalysts are needed for the reaction to proceed so they would be seen first on the reactant side and then reappear as a product.
Intermediates are part of the elementary steps but not part of the overall final reaction so they would be produced first (product) and then used up as a reactant.

Tatyana Bonnet 2H

Yup, if there is no volume change, no work is being done on the surroundings or system so w=0

Tatyana Bonnet 2H

I think we are finishing content on Wednesday. Based off the last final it is important to review old material but I think the bulk of the questions and harder conceptual ones will be based off of the new material as we haven't been tested on it.

Tatyana Bonnet 2H

I like to handwrite my notes. I write down the notes during lecture and as for the textbook I noticed it was too time consuming to write notes on everything since a lot was covered during lecture, so I like to create little study guides/ cheat sheets of important equations and key concepts.

Tatyana Bonnet 2H

The anode is where the oxidation occurs and is usually located on the left of the galvanic cell, and the the cathode is where reduction happens and is on the right of the cell. The anode is on the far left in the cell diagram and cathode on far right.

Tatyana Bonnet 2H

Before each exam I like to lay down and listen to some music or classical music that I like to calm myself down before the test and review the key concepts over one more time. Try to focus on what you struggled with and new material because for the last final I spent too much time reviewing old cont...

Tatyana Bonnet 2H

The anode should be on the far left of the short-hand and the cathode on the far right, and the cl- ions should be in the middle closest to the salt bridge.

Tatyana Bonnet 2H

Took lots of naps and took a break from chemistry, I had too much of an overload midterm week.

Tatyana Bonnet 2H

The charge of the compound determines the oxidation numbers of the atoms. For example, ClO- has an overall negative charge. However the individual atoms don't have an oxidation of negative one, but a sum that equals -1. O has an oxidation number of -2 so Cl has an oxidation number of +1 in this comp...

Tatyana Bonnet 2H

I studied more of textbook problems and trying to understand the mathematical aspect for the content of midterm 2 and was surprised at how many conceptual questions there were that it threw me off more than midterm 1. Definitely gonna pay attention to that more.

Tatyana Bonnet 2H

I recommend going over sections you felt you had trouble with from the previous midterms and focus on understanding this units content as that will be the only new content showing up on the final and will be probably have a little more questions than the others. Textbook problems and looking over pr...

Tatyana Bonnet 2H

As others have stated, covert kPa to atm so that you can use R=8.206x10^-2 L Atm/K Mol. For other problems that give values other than the ones in the R gas constants try to find a way to convert them to fit the units in the constant.

Tatyana Bonnet 2H

What I like to do first is assess the questions and see, if I am confident in doing the problem do it first instead of spending time stressing about it if I don't understand it at first. This allows me more time to digest those other problems. I also like to not look at the time until after doing a ...

Tatyana Bonnet 2H

A molecule is thermodynamically stable if G<0, meaning it is spontaneous and products are favored.
A molecule is thermodynamically unstable if G>0, meaning it is non-spontaneous and reactants are favored.

Tatyana Bonnet 2H

Since I Carly has been put on Netflix I have been watching that, really brings back childhood memories. And I'm rewatching New Girl for the hundredth time :')

Tatyana Bonnet 2H

Delta H = q at constant pressure. Since Delta H = Delta U + Delta PV. Delta U = q +w and since w=-P(external)Delta V at constant pressure, -PdeltaV and delta PV will cancel out, making Delta H =q.

Tatyana Bonnet 2H

I like to think about the reward which in this case is just getting the test over with. I like to put on some music and watch study with me videos on YouTube to motivate me to study and push me to be productive. If you're feeling stressed or down do something to distract you that makes you happy so ...

Tatyana Bonnet 2H

I think the integrals are more conceptual and showing the process of how the equation was derived. We just use the derived equations that have ln to solve problems.

Tatyana Bonnet 2H

Residual entropy increases as more ways to arrange the molecules increase. Since N2O is not symmetrical and can have different orientations as opposed to CO2 and Cl2 where it is symmetrical, so it has residual entropy. For these problems its best to draw out the lewis structure to see the placement ...

Tatyana Bonnet 2H

The sign of work is in relation to the system and energy flow. It is positive if work is done on the system because it is gaining energy from surroundings. It is negative when work is done by the system because it is losing energy to the sorroundings.

Tatyana Bonnet 2H

The deadline is Sunday at midnight and its the same with sapling. Every new week in essence starts on Monday for this class.

Tatyana Bonnet 2H

Work in relation to the system is based on whether work is done on it or by it. When work is done by the system the value is negative cause energy is leaving the system. When work is done to the system the value is positive because the system is gaining energy from its surroundings.

Tatyana Bonnet 2H

Vapor and gas are interchangeable. It's like saying water vapor, it is water in the gas phase.

Tatyana Bonnet 2H

External pressure is the pressure pushing down on the piston and when the system does work it is "pushing against" the external pressure to expand.

Tatyana Bonnet 2H

I feel this too! What I like to do to kind of compartmentalize the topics is after watching the lecture on a topic, I do the associated sapling homework problems on it right after as its fresh in my mind. After that I find time to review and read/skim through the reading sections for the topic to se...

Tatyana Bonnet 2H

The ones that do work on the surrounding would have w = a negative value since its transferring energy to surroundings. So looking at the equations you want to look for the change in moles of gas. If the change is negative (less moles of gas in products) w will be positive. ( w=-nRT where R and T ar...

Tatyana Bonnet 2H

In closed systems matter does not change, but energy as heat or work can be exchanged with the surroundings. I am assuming if it is compressed that the pressure can change as energy can be exchanged as work, but mainly for closed systems the main focus is on its ability to exchange energy and not ma...

Tatyana Bonnet 2H

According to the list provided from sapling, HClO3 and HClO4 are considered strong acids

Tatyana Bonnet 2H

No we will not have to memorize them seeing as the textbook problems provide us charts and values for the problems.

Tatyana Bonnet 2H

I have been recovering the sleep lost from studying for this test by taking naps :) Definitely taking a break from schoolwork and just relaxing by watching my fav tv shows.

Tatyana Bonnet 2H

Based off of last quarter it took around a week/week and a half and is usually released around 1-2 pm.

Tatyana Bonnet 2H

Endothermic require energy, so if temp is raised more energy is being input through heat thus favoring the products and raising K. Exothermic reactions release heat, so if temp is raised it would be favoring the reverse reaction which requires heat, favoring the reactants and lowering K. The vice ve...

Tatyana Bonnet 2H

I would assume it would be used to convert from pressure to molarity and vice versa. Problems I have encountered were used in this context. I would say that however it is used in the textbook problems is most likely how it will be applied on the midterm since it is heavily based off of them.

Tatyana Bonnet 2H

The -log of the H+ concentration will give you the pH and the -log of OH- gives you the pOH. If you wanted to get the concentration from the pH or pOH you would do 10 to the power of negative pH or the pOH. Just remember the pH is from the concentration of H+ and and pOH from OH-, the same letters c...

Tatyana Bonnet 2H

The reaction is changed and is affected by the adding/removing of products or reactants, but the K stays the same. That is why the statement is false, because increasing the concentrations affects the reaction by making it produce more of the reactants in order to reach equilibrium again.

Tatyana Bonnet 2H

When you reverse a reaction you take the inverse of K, 1/K, because you are essentially just flipping the products and reactants of the reaction. So in the reverse reaction the products are the reactants from the original reaction and the reactants are the products.

Tatyana Bonnet 2H

A larger Ka means more acidic because the larger number comes from a greater amount of products than reactants indicating that it is dissociating more completely and the forward reaction is favored. Likewise the smaller the pKa the more acidic it is because you are taking the -log of the Ka.

Tatyana Bonnet 2H

The twilight series is a comfort for me, the soundtrack is amazing too. A comfort show I have is New Girl its funny and I rewatch it all the time.

Tatyana Bonnet 2H

It is on Friday the 29th and I believe it will be during your lecture time.

Tatyana Bonnet 2H

Kc is used in terms of molarity and concentrations whereas Kp is in terms of partial pressure. In some problems it can ask for Kc of gases and it will give the molarities to solve for etc. To be safe just stick to the units it gives you, for example if it gives you gases with pressures of atm it is ...

Tatyana Bonnet 2H

Yes you can use the ICE table for both partial pressure and concentration. Just make sure your units are the same throughout the table to reduce the risk of error.

Tatyana Bonnet 2H

Hi! You use the inverse of K when you are looking for the K value of the reverse reaction. For example: If you have A--> C+B, and lets say the K value is 3 (this will be the "original" reaction you are looking at) The reverse reaction C+B--->A will have a K value that is the inverse of the...

Tatyana Bonnet 2H

Hi! To start this you would want to get the concentration of of SO3 in the beginning of the reaction (Initial). Dividing .780 mol/1.50 gets you .52 mol/L. This will be the initial concentration of SO3. The problem tells us that at equilibrium there is .160 mol of O2, converting that into concentrati...

Tatyana Bonnet 2H

Water is only included when it is a gas/ not a solvent. If it is a solid then it does not go in the ICE chart, and if it is a liquid it does not also because it would be acting as a solvent, and the change in concentration of the water in the reaction would be too small to be significant in the valu...

Tatyana Bonnet 2H

Yes Q is used at any time to see where the reaction is at in relation to equilibrium and K is the constant value at equilibrium. If Q=K then it is at equilibrium.

Tatyana Bonnet 2H

Physically speaking, temperature is the only way to change the K value because it causes favoring of either the products or reactants to be formed due the change. Doubling k and/or taking its inverse is more mathematical and is used when comparing reverse equations or equations that have been "...

Tatyana Bonnet 2H

hey, this is unrelated to your question since it's already been answered, but your screen name is currently your UCLA id number. your login username should be your id number, but your screen name can just be your name + discussion session instead of your id (for security reasons hahaha) Hi thank yo...

Tatyana Bonnet 2H

Looking at the electronegativities helps as lower the difference the more covalent. However you can also look at the size, since S is the bigger than O it would create more covalent character as its distorted easier, and between the MgS and CaS options, Mg is closer to S incorporating the lower EN d...

Tatyana Bonnet 2H

London dispersion forces are also greater as the size of the atoms/molecules get bigger. The bigger atoms have higher polarizability, will become distorted more easily and create stronger London dispersion forces. This explains the difference in boiling points as well.

Tatyana Bonnet 2H

Yes you are correct. If there is one lone pair (and 2 atoms) the electron geometry will be trigonal planar, however the molecular geometry is bent. Since it has 3 regions of e- density, the bond angles would be a little less than that of a trigonal planar with no lone pairs, so <120* If there are 2 ...

Tatyana Bonnet 2H

The electron diffraction of the crystal show the wave properties of electrons. The diffraction was shown in the slit experiment when the waves interfered with each other resulting in the light emission not hitting the other side exactly where the slits were, as expected if it were in the particle mo...

Tatyana Bonnet 2H

Agreeing with what everyone else has said, molecular shape is referring to the shape that is occupied by the atoms (bonds) while electron geometry refers to the shape created by all bonds and electrons. A central atom with 3 electron density regions would in essence have a trigonal planar electron g...

Tatyana Bonnet 2H

They don't rotate because they are connected side by side, if one atom were to rotate they would no longer be side to side breaking the pi bond. Therefore, pi bonds keep a structure in its plane unless broken.

Tatyana Bonnet 2H

Th lone pairs will be located in places where they have less interaction with other atoms since they repel them. In the see-saw shape for example, the lone pair would be located on one of the equatorial atoms since it would be repelling only 2 atoms (the axial atoms). If the lone pairs were on an ax...

Tatyana Bonnet 2H

I would think so because the final includes all the outlines and stuff we have learned although I don't think there will that many problems as compared to the other sections.

Tatyana Bonnet 2H

Whenever there are lone pairs, there is extra repulsion that repulses other bonds more greatly. This would cause the original bond angles to be less as they get closer together as a result of the lone pairs pushing them away.

Tatyana Bonnet 2H

Hybridization is essentially the orbitals that represent the electron density regions. If there are 2 regions then the hybridization of the center atom will be sp, since there are two regions, 2 orbitals are accounted for. Just add up the s, p, and d until you get the number of regions. 3 regions is...

Tatyana Bonnet 2H

Yes a lone pair is a region of electron density as well as a bonded pair. Single, double and triple bonds are all one region of electron density, but have diff numbers of pi and sigma bonds.

Tatyana Bonnet 2H

okay, that makes sense. could someone give me an example of when sp3d hybridization would take place. It would happen when an atom has 5 electron density regions and is in period 3 or later, such as PCl5. P is in period 3 meaning it can have an expanded octet which includes the d-orbital. With its ...

Tatyana Bonnet 2H

As others have said drawing out the lewis structure and determining if it has resonance will help to determine if it has delocalized pi bonds. HCN for example when drawn out shows C and N having a triple bond indicating it has 2 pi bonds. However HCN does not have resonance so the pi bonds are not d...

Tatyana Bonnet 2H

I think we do have to memorize the shape and the angles, although Lavelle said we won't necessarily be drawing them, we will still have to recognize them and apply them to problems.

Tatyana Bonnet 2H

I watch out for conceptual details from lecture, and read through the textbook to solidify them and find the textbook problems to be really helpful since they are worded similarly to the exams.

Tatyana Bonnet 2H

Covalent character for covalent bonds is how low the difference in electronegativity is, the lower it is the more covalent. In terms of ionic bonds, the more polarizable the anion, the more easily distorted it is so its pulled closer to the cation. The larger the anion (polarizable), and smaller the...

Tatyana Bonnet 2H

The atomic size would effect bond strength in covalent bonds as the bigger the atom the larger the distance between the two the weaker the bond. This is talking about the bond between individual atoms. The boiling point is referring to intermolecular forces between molecules, so CH4 interacting with...

Tatyana Bonnet 2H

The lewis structure with the lowest amount of energy will always be favored as it is the stablest. The structure with formal charges all equal to zero, or if that isn't an option, the structure with the most amount of atoms with a 0 charge and the central atom having its lowest possible formal charg...

Tatyana Bonnet 2H

Something that has helped me is creating a list of all the topics we have covered, and redoing the textbook problems/modules that go with it. For topics you feel you have a better grasp of, do a few questions, but focus on the more challenging topics so that you can feel confident on all of topics a...

Tatyana Bonnet 2H

The 3+ means that the atoms are more positive, meaning they lost electrons (which are negative). Since As lost 3 e- that leaves the 4s and 3d orbital still filled as the three electrons in the p orbital were removed. The same goes for Ge with its 2 electrons removed. When removing electrons they are...

Tatyana Bonnet 2H

Ionic bonds tend to be between s and p block elements. This is because of the bigger difference in electronegativity. The larger the difference in electronegativity, the more likely it is ionic. The smaller the difference, and the closer together the elements are on the periodic table, the more they...

Tatyana Bonnet 2H

3d would come before 4s because once 3d starts getting filled, it has lower energy than 4s. Other exceptions taught during lecture were Chromium being written as [Ar] 3d5 4s1 instead of [Ar] 3d4 4s2 because it is more stable having its orbitals "half full" as opposed to having one orbital ...

Tatyana Bonnet 2H

can anyone give a general definition of what ionic character is? And how exactly do you rank them? Ionic character essentially( in the context of covalent bonds ) is the covalent bonds characteristic of not having electrons equally shared/being polar. Covalent character means (in the context of ion...

Tatyana Bonnet 2H

The magnetic quantum numbers (ml) are the orbitals in a subshell. Essentially ml is equal to the positive and negative values of l and the numbers in between. [ l, l-1..., -l] l=subshell shape( l=0 is s),( l=1 is p),(l=2 is d),( l=3 is f) s subshell (l=0) ml= 0 p subshell (l=1) ml= -1,0,1 d subshell...

Tatyana Bonnet 2H

To help classify them you would have to draw out the lewis structure. The molecule/compound that does not have a complete octet will readily accept electrons making it the acid. The molecule with lone pairs able to give away will be the base. Like the example during one of the lectures, BF3 drawn ou...

Tatyana Bonnet 2H

Yes all molecules have London dispersion forces, and it is one of the weakest intermolecular forces. When two molecules come in close proximity they "induce" a partial negative/positive on each other instantaneously making it temporary.

Tatyana Bonnet 2H

The formal charge of the same element can differ based on the amount of bonds it has and the number of valence electrons as those numbers would result in varying charges when plugged into the formal charge formula. To be safe try to find the formal charge of all atoms of the element, even if they ar...

Tatyana Bonnet 2H

Each post you make counts for 1 point, you can make up to five points per week which equates to 50 points for 10 weeks. Your 5 posts must be made within the given week before midnight Sunday to get the credit as they don't carry over and you can only get a maximum of 5 points per week.

Tatyana Bonnet 2H

We don't need to memorize it but having a general idea of the trend and its relation to ionization energy is helpful. If we need the numbers, the chart will be provided on problems that need it.

Tatyana Bonnet 2H

Some new shows on Netflix called The Queens Gambit and Grand Army are really good I recommend watching them! Some of my favs are new girl, criminal minds and Pose.

Tatyana Bonnet 2H

Electron affinity is measurable and shows the amount of energy released or absorbed when adding an e- to an atom, whereas, according to my TA, electronegativity is more of a scale without a set measure that describes the ability of the atom to attract/pull electrons.

Tatyana Bonnet 2H

Wavelength can not be negative as it is a measurement, having a negative value in this context would not be applicable.

Tatyana Bonnet 2H

E=hv and[ C=lamba x v ]is relating to energy and wave properties of light, so v in the different font would be frequency. In de Brogiles equation and kinetic energy equation they deal with speed/motion of particles in some way so v would symbolize velocity.

Tatyana Bonnet 2H

A good tip is to reward yourself with something after doing any amount of work you feel you can accomplish and are actually motivated to do in a certain time period. After you are done you can watch an episode of your favorite show, or what I like to do is play among us to de-stress :)

Tatyana Bonnet 2H

I think all homeworks are due Sunday night at midnight of the corresponding week they are due.

Tatyana Bonnet 2H

Yes c will always be the speed of light as its a constant. C=wavelengthxfrequency

Tatyana Bonnet 2H

Constance Newell wrote:do yall know how long we have?

We have the whole discussion time which is around 50 minutes, my TA said if a little extra time is needed it will be provided.

Tatyana Bonnet 2H

Since the exam will be multiple choice I would look at the units offered through the answers, if its in nm then just convert the answer found in m to nm if necessary.

Tatyana Bonnet 2H

I don't think there are any restrictions, my TA said the use of graphing calculators is ok.

Tatyana Bonnet 2H

To match each type of radiation to the event you have to look at the wavelengths you get for each row in the chart. You would then match the event to the wavelength they correspond with. For example, since reading is looking at visible light which is within the range of 400-720nm that event would go...

Tatyana Bonnet 2H

It would be good to know the order in regards to questions regarding wavelength. For example, knowing that Radio waves have the longest wavelength and then below that comes infrared(nm are in the 1000s), then visible light (720-400nm) and UV has shorter wavelengths with 400nm and below. I have seen ...

Tatyana Bonnet 2H

Closed book means that we don't get to use our notes during the test, however we do get access to the periodic table and a sheet of constants and equations I believe. Since we will be taking it with our TAs, they will be monitoring our workspace as well to see if we are testing fairly.

Tatyana Bonnet 2H

If the empirical and molecular formula are the same, that means that the empirical formula found is actually the molecular formula. This would be the case if the molar mass of the empirical formula found is the same as the molar mass of the molecule/compound given to you. If you were to divide the M...

Tatyana Bonnet 2H

Electrons are excited when energy from the photon is present but does not exceed the threshold/work function resulting in the electrons to jump energy levels (excited). The electron is ejected when the amount of energy exceeds the threshold/work function.

Tatyana Bonnet 2H

Yes I think we will be provided an equation sheet and some constants etc. will be provided in questions too. If you go to the class website he has a document with constants and equations that you can access.

Tatyana Bonnet 2H

To find out if the formula is the molecular one, you would need to find the mass of the current empirical formula you found and compare it to the given Molar mass of the compound/molecule in question. If it is not equal, then that means the formula you created is empirical. To find the molecular for...

Tatyana Bonnet 2H

After finding the molarity, you use it to find the molarity of the compound or element you are trying to find the volume for. For A )that would be Na+. Looking at the compound in the solution which is sodium carbonate Na2(CO3) you see that Na has a subscript of 2 so the amount of mols of the compoun...

Tatyana Bonnet 2H

Yes that is correct. The decimal makes the zeros significant. If you were to have 0.05000, it would have 4 sigs figs as the decimal makes all the zeros to the right of the 5 significant, while the zero to the left is not. With decimals less than one the only 0s that are significant figures are ones ...

Tatyana Bonnet 2H

Since molarity has units mol/L, the v would have to be in Liters to be able to cancel out units of volume (L) in the problem and/or end up with a molarity that is mol/L. If the problem gives mL you have to convert to L to solve and, if needed, convert back to mL once finished.

Tatyana Bonnet 2H

To put it into simpler terms, the problem is asking what the length of the fibers would be. We are given that 1.00 mol of Ag atoms make up that length so we just need to figure out the diameters of the atoms and multiply that by the total amount of atoms in orders to get the length. First we would g...

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