CHEMISTRY COMMUNITY

Maria Solis Disc 1G

If you really want to study this, if you read the book theres yellow sections called How to do, or somethig like that, and it explains step by step the derivations and connections between topics.

Maria Solis Disc 1G

I was told by my PLF that they are used only for elementary step rate laws

Maria Solis Disc 1G

Considering he didn't mention it, I assume it's fair game to include both.

Maria Solis Disc 1G

Internal Energy should always be q+w

Maria Solis Disc 1G

Chem_Mod Re: Disregard liquid and solid reactants in rate law? "That is correct. As for water, water or any other molecule that is not the solvent, if it is part of a reaction, it can be in the rate law. However if the solvent is water, you do not include water in the rate law since you have ex...

Maria Solis Disc 1G

In the book, it says that bomb calorimeters are usually metals, so they maintain the volume although pressure may increase. To make the bomb calorimeter an isolated system, it can also be submerged in water to make it isothermal.

Maria Solis Disc 1G

No, since they are not part of the actual reaction.

Maria Solis Disc 1G

In the book I read that the equilibrium constant is changed if the reaction is changed by a multiple ( such as NH3 to 2NH3). How would the constant change? Also how would we find the Equilibrium constant if multiple reactions ( and their K values are given) but not the overall reaction.

Maria Solis Disc 1G

I searched this up online, and it said the units for A are the same as the rate constant units. In other words the units of A depend on the rxn order.

Maria Solis Disc 1G

Considering it is moderately simple to derive, I would memorize how to derive the equations just in case.

Maria Solis Disc 1G

Catalysts show up in the beginning of the reaction and at the end. The substances that are consumed are called intermediates.

Maria Solis Disc 1G

Here is a video, not the best quality though.

Maria Solis Disc 1G

When doing calculations and temperature isn't given, can we assume standard condition. What is standard condition, beside being at room temperature?

Maria Solis Disc 1G

When drawing a cell diagram, why is platinum or carbon i belive included in the diagram if it is not involved in the actual reaction.

Maria Solis Disc 1G

Oxidation releases electrons (on right side of equation), reduction uses electrons (on left side of equation) in short terms.

Maria Solis Disc 1G

I honestly do not know what residual entropy is, but Dr. Lavelle mentioned rotational state, translational state, vibrational state, and an electron's state in the actual atom.

Maria Solis Disc 1G

During lecture today it was said that as temperature increases, thermal motion increases, meaning that entropy increases. Using the equation S=q/T it is implied that entropy is inversely proportional to entropy. Can anyone explain this please?

Maria Solis Disc 1G

entropy is q(reversible)/T. q(p=reversible)= delta H (enthalpy) if pressure is constant.

Maria Solis Disc 1G

The methods we've used so far seem to be only on expansion. So for now we should only be required to know those theoretically.

Maria Solis Disc 1G

Can someone explain the different types of calorimeters there are. I am lost on how to recognize what calorimeter to use and how to solve these types of problems.

Maria Solis Disc 1G

While doing a problem how would we recognize what method to use. Like how would we know if we need to use delta u.

Maria Solis Disc 1G

I was also told that you HAVE TO check the 5% rule, you cant just choose if you want to check. It's better to be safe than sorry.

Maria Solis Disc 1G

During class today Dr Lavelle stated that all diatomic molecules bond enthalpies were accurate, and that all other bond enthalpies were averages. I was wondering if someone could explain what a diatomic molecule was. I also vaguely remember Dr. Lavelle stating that C2's bond enthalpy is composed of ...

Maria Solis Disc 1G

I was told by my T.A. that the 7th edition has more errors than the 6th. This has also happened to me, and the 7th edition is the one that tends to be wrong.

Maria Solis Disc 1G

On this weeks test, will we need to know what acids/bases are strong/weak out of memory, or will we be told or be given a Ka/ Kb.

Maria Solis Disc 1G

I know that when you change a rxn's condition the reaction is moved from equilibrium, but I was wondering how an increase or decrease in temperature specifically effected a reaction.

Maria Solis Disc 1G

The ice table is used for finding out how much of a weak acid or base reacted. From the problems I've seen only bars and molarity were used, but I'm not completely positive.

Maria Solis Disc 1G

I don't believe that a reaction goes to completion if you keep adding reactants. On the contrary the reaction will keep shifting. I am not completely sure though.

Maria Solis Disc 1G

In short the reaction shifts to accommodate a change in the reaction. Such as a change in temperature or concentration.

Maria Solis Disc 1G

I'm slightly confused on how to identify a pure solid and liquid when looking a written reaction. Can anyone please explain how to identify these.

Maria Solis Disc 1G

Yeah I know that but like overall letter grade is what I'm asking.

Maria Solis Disc 1G

A ligand is just an ion/ molecule that is bonded to the central atom. You basically figure them out using the lewis structure I believe.

Maria Solis Disc 1G

Dr. lavelle went over it really briefly and said that ph=-log10[h30].

Maria Solis Disc 1G

Hey so does anyone know how the grading in this class is done. Is the class curved or is there a specific rubric. I've been asking around but still can't seem to find out.

Maria Solis Disc 1G

For some of the questions from this chapter, in the textbook, they give the names of molecules rather than formulas in the questions. For test 3 will we be expected to know any basic molecules yet by the name.

Maria Solis Disc 1G

First I used the equation E=hv to find the energy of a photon. Then I used the kinetic energy equation E=(1/2)mv^2 to find the energy of a electron that is released. Then using the concept of conservation of energy I set the initial energy of a photon equal to the sum of the Ionization energy (AKA t...

Maria Solis Disc 1G

In one of Dr. Lavelle's lectures he mentioned how a p orbital was left unhybridized. Can anyone explain this to me, and also would this unhybridized p orbital also contain electrons or not?

Maria Solis Disc 1G

If you look at the atoms normal electron configuration, it may be inaccurate to the number of bonds that the atom has in a certain molecule. The hybridized d must be included if a atom has more than 4 bonds (8 electrons), such as those that exceed the octet rule.

Maria Solis Disc 1G

For the final, and test 3, will we be expected to know how to draw molecules, using electron densities (including the hybridized and non-hybridized models).

Maria Solis Disc 1G

From my understanding, as of so far, there is always one sigma bond between two atoms and the rest are pi bonds between those same atoms.

Maria Solis Disc 1G

I'm honestly quite lost also but what i found online says that electron affinity is an experimentally measured value, while eletronegativity is given in relationship to the values of other atoms in the periodic table

Maria Solis Disc 1G

The overall polarity of a molecule can be considered the vector additions of the all the dipole moments. they can either cancel each other out or add up.

Maria Solis Disc 1G

First draw the direction of the dipole. The dipole should point towards the more electronegative atom in a molecule. therefore the end that the dipole points at is delta negative, and the end where the dipole starts at is delta positive. It may be confusing but try drawing it out, it'll help.

Maria Solis Disc 1G

I am not completely positive but i believe bond order is the average bond length of the resonance hybrid. I am almost positive though that to calculate bond order you divide all the number of bonds between the central and outer atoms (sticks)and divide by the number of outer atoms that you used.

Maria Solis Disc 1G

When you draw the lewis structures other of the answers given also seem to be radicals.

Maria Solis Disc 1G

A radical is basically a molecule that has more than one unpaired electron. In this case the answer is OH since there can only be a single bond in OH, O must have 5 electrons, resulting in one being unpaired.

Maria Solis Disc 1G

From my understanding you fill the 4s before the 3d usually. Only when the 3d is an exception, such as when you are 1 e from completing the 3 d orbital, do you complete the 3d first, since youre ultimate goal is to get a more stable atom. But when you write down the electron configurations first mak...

Maria Solis Disc 1G

At the beginning of the quarter Dr. Lavelle said we didn't have to know them now, but that later we would. My PLF also said that with time, after doing many problems, you would probably end up memorizing them anyways. Don't worry about it too much , but do try to memorize them.

Maria Solis Disc 1G

I would assume that we would need to know the basic groups, just because it was covered in high school chem. It's better to be safe than sorry, so I'd say just memorize the groups. On one slide though, the one where the periodic table is color coated in 3 different colors, where I believe he did men...

Maria Solis Disc 1G

The peer learning that I am aware of is the one that AAP offers. To join that one, you have to be a part of AAP, but i also did a google search and found this https://www.lscore.ucla.edu/ls-core-peer-learning/ . If you aren't a part of AAP you can investigate the one that this page offers.

Maria Solis Disc 1G

On Friday's lecture Dr. Lavelle kept mentiong ml, can someone please explain what that is, as I am majorly lost. Also instead of doing a lowercase l can i use a cursive l, since one of the reasons i got lost was because i kept confusing the l with a 1.

Maria Solis Disc 1G

So I'm having a hard time remembering the electron configurations, such as as the orbital shapes. I was wondering if anyone had a shortcut or method of memorizing these.

Maria Solis Disc 1G

I assume we wouldn't, just because on the last exam we were given known values.

Maria Solis Disc 1G

Alright Thank You!!!! Also I'm almost certain that you cannot make up for a previous week, because what i do remember is Dr. Lavelle saying the max number of points per week was 3.

Maria Solis Disc 1G

In the lecture the professor said that gammas rays were the lowest, for sure, measured wavelength at 10^-12, but that anything below 10^-15 was unlikely, and that anything below 10^-18 was undetectable. He said that on the quizzes and test though, the answers were going to be obviously small, at aro...

Maria Solis Disc 1G

Would posting 3 times in a single day count towards the 3 posts per week that i must submit.

Maria Solis Disc 1G

When I was doing one of these questions myself the number wasn't adding up to 100%. Although significant figures may have caused you to get to 99% you can try truncating all your answers to see if you get 100%, if you rounded all your answers.

Maria Solis Disc 1G

Although Dr. Lavelle said the cutoff was 10 ^-18, he specifically said that we wouldnt have to worry about the cutoff since the answers would be obviously small, like 10^-30

Maria Solis Disc 1G

It all depends on the person. What works best for me is either rewiting notes in different colors, which helps me remember things better, or even making a little song out of the study notes. You can also try flashcards!

Maria Solis Disc 1G

You should definitely ask your TA. My TA for instance told us she didn't mind if we wrote with pencil. But its all up to the TA I guess.

Maria Solis Disc 1G

I remember the professor mentioning that the real value was the one starting with 2.99, but that for convenience he used the one starting with 3.00.

Maria Solis Disc 1G

If you're talking about the homework problem it should give you the molar mass of caffeine, and the percent composition. so you would multiply each percentage by the total molar mass. I don't think we should be expected to know the formula for caffeine, considering it's so early in the year.

Maria Solis Disc 1G

You would multiple all the coefficients by 7, since you can't have 3.5 as a coefficient. You can't use 3 or 4 because that wouldn't uphold the exact proportion of 3.5.

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