CHEMISTRY COMMUNITY

Maria Trujillo 1L

In lecture, it was brought up that enzymes are a zero order reaction. I was wondering why that is true because to be it would make more sense for them to be a first-order reaction since the amount you have would matter? So wouldn't it be dependent on concentration?

Maria Trujillo 1L

Will we need to know how to derive/integrate all of the orders?

Maria Trujillo 1L

What is a good way of memorizing the units for zero, 1 and 2nd order reactions, like in a way that you understand the concepts?

Maria Trujillo 1L

Does anyone have any tips on how to do 14.15 a), b) and C)? Is there a particular way to break the problem down? Does anyone have a preferred first step? Or a chart? I understand how to balance redox reactions, but I am a little thrown off by these problems. Any tip would be nice. Just want to try n...

Maria Trujillo 1L

Why is it that Au+ -----> Au and Au3+ --------> Au?
When the original equation is: Au+-----> Au + Au3+

How can Au3+ and Au be on opposite sides???

Maria Trujillo 1L

In 14.3, why do we split H and Cl and then combine them again? I am really confused on how some balancing problems we can or cannot split elements up such as HCl.

Maria Trujillo 1L

Which molar ratio is to be used when calculating the Gibbs Free energy of a cell reaction? For example in 14.9 it has Ce and I in the equation, but how do I know which molar ratio to use? And on which side of the equation??? Thank you!

Maria Trujillo 1L

I am confused as to why we can use the reverse of the anode equation. When are we allowed to flip the half equations?

Maria Trujillo 1L

When calculating the half-reactions and the final balanced reactions, there are two methodologies to use. The one for the bases requires to use H20 and H to balance the equations, and the acidic one requires using H2O and Oh. How do I know which methodology to use without the question explicitly men...

Maria Trujillo 1L

I understand that potential difference is (-w)/charge and is written in units J/C

Cell potential is E = (-w)/charge

However, I am confused on why wmax=-charge * E

Why is it not -w, but wmax?

Maria Trujillo 1L

I'm not 100% sure, but one line represents the interface between phases in contact with each other which includes a porous disk. Two lines represent the salt bridge.

Maria Trujillo 1L

In problem 14.1, we have to balance the equation in regards to hydrogen and oxygen, but I thought we only needed to balance the elements being oxidized or reduced as well as the electrons. Why do we also need to balance the hydrogens with oxygens? Thank you, the chemical equation is below. H(+) (aq)...

Maria Trujillo 1L

For the Gibbs problems, sometimes we are given the equation which has different molar ratios. Does that mean we just use the information provided of entropies and multiply them by the number of moles per product? Or do we have to set such chemical equation so that the products equal one and convert ...

Maria Trujillo 1L

For problems pertaining to Gibbs Free Energy, will we be given the standard enthalpies and the entropies? I am wondering because we have them in the textbook. Will we be given another sheet for the test with the information or will it be provided in the problem? Thank you!

Maria Trujillo 1L

Hello, I was wondering if the homework from this week can have Gibbs Energy problems or only Electrochemistry? Thank you!

Maria Trujillo 1L

Basically, study chapters 11, 12, 8, and Chapter 9 up to section 9.8 in the 6th edition.

Maria Trujillo 1L

People keep mentioning ideal gasses, and I have no idea what is considered an ideal gas? How do you know the difference?

Maria Trujillo 1L

Hello, what is a good way not to mix up entropy and enthalpy problems, with all these equations, it gets a bit confusing? Thank you.

Maria Trujillo 1L

I understand that we are entering a new unit, but I am confused. What is the difference between thermochemistry and thermodynamics? Does thermodynamics have more to do with calculations? I find it useful to make links and distinguishes between units/topics. Thermochemistry Hess' Law Thermodynamics D...

Maria Trujillo 1L

For clarification. When something goes through a phase change, it does not change temperature but it does take time? If so, won't it eventually change in temperature after the phase change though?

Maria Trujillo 1L

I understand that delta H is equal to the summation of all the changes in enthalpy when a reaction occurs. However, I am unclear how to do this on a problem that involves reactions. I'm unsure which textbook has this problem, but how would you solve the equation below: 3C(s)+S8(s) ----> C3S8(l) I kn...

Maria Trujillo 1L

Phase transitions have a slope of zero in regards to temperature over time. Why does phase transition length, though at a zero slope have such large effects such as causing a greater burn?

Maria Trujillo 1L

Mentioned in class it was said that we should not always expect the same enthalpy for reactions since pressure and because products and reactions can be in different states. For clarification, does this apply to both the forward and reverse reaction?

Maria Trujillo 1L

Will we need to calculate the kJN when working with Hess's law? Or will it always be given?

Maria Trujillo 1L

This is a really good question. I was wondering the same thing as well since a catalyst does add more reactants, guess it would change it. However, I am uncertain. I would assume that it could influence it. I am. however, interested in seeing what others say. Great question.

Maria Trujillo 1L

In class it has been mentioned that Q tells us if a reaction goes forward or not in regards if it is greater or less than K. However, I am unsure if that also relates to determining an endothermic and exothermic reaction. Is it connected or are these separate concepts? Thank you!

Maria Trujillo 1L

Hello, I am confused by what units we are to use when using the Pv=nRT equation, specifically in regards to R. There are various units you can have it in. However, it is unclear to me which ones are the correct ones when regarding to concentration.

Maria Trujillo 1L

In regards to the final will we need to distinguish the difference between the different types of "Bent" and "linear"? For example, can we just write bent or linear or do we need to specify by saying the number of areas of electron density and the number of lone pair densities? F...

Maria Trujillo 1L

In regards to acid rain, I understand that all rain is acidic, but that "acid rain" is more harmful. Is that because it is more concentrated in terms of morality or because it more acidic?

Maria Trujillo 1L

From what I understand from lecture, the more H+ ions the more acidic something is and the more OH- ions the more basic something is or becomes. What I am confused about it, the relationship between Lewis and Bronsted acids and bases. Like what relationship do they hold?

Maria Trujillo 1L

So when you are dealing with oxidation states, you will generally have a + or -, because almost any element can have e- added or taken away in order to get to the nearest noble gas configuration. The goal is to get an octet. An example from chapter 3 HW is 3.23, Cl can have -1 or +7. This is becaus...

Maria Trujillo 1L

105012653 1F wrote:Sorry, I'm kind of confused; what exactly is an oxidation state?

Oxidation state is the same as the charge given to an element when it is by itself.

Maria Trujillo 1L

Will we need to know how to draw the VSEPR geometric shape in the official way or do we just need to know the bond angles?

Maria Trujillo 1L

By following the general rules that we have learned about the geometric shape, is that enough information that you need to know? For example, trigonal planar are all at a 120 degree angle. Is there any exceptions we need to be aware of?

Maria Trujillo 1L

So the other day I was doing a HW problem, specifically 3.39, part C. I noticed that the name of the compound was sodium hypochloride. My first instinct was to write out Na for sodium and then H and Cl for hypochloride. However after checking my answer I discovered that hypochloride is composed of O...

Maria Trujillo 1L

So when you are dealing with oxidation states, you will generally have a + or -, because almost any element can have e- added or taken away in order to get to the nearest noble gas configuration. The goal is to get an octet. An example from chapter 3 HW is 3.23, Cl can have -1 or +7. This is because...

Maria Trujillo 1L

The formal charge equation: Valence electrons (-) Lone pair electrons (-) .5(Bond electrons) I just want to clarify, but if there is no charge in the compound equation, then when you add up the charge it should be zero. With that logic, then when a compound is charged, then you should have that char...

Maria Trujillo 1L

In class we were given the example of NO and the Lewis structure given the formal charge. Although we were not given the formal charge, we end up with N+ and O-, and because of that we know to fill O and leave N with only five e- dots. However, we are given the counterexample where the reverse is do...

Maria Trujillo 1L

The radius is half of the diameter. According to what I recall in lecture, most atoms are about one Ångström in length which is 1x10^-10, smaller than a nanometer (1x10^-9). I'm sure it differs between atoms. However, if you are searching the for the radius of an atom, I assume you add the length(s)...

Maria Trujillo 1L

In regards to using short hand, for example, Ca: [Ar] 4s^2 and Br: 3d^10 4s^2 4p^5, are we allowed to use Neon or Helium, or is it only after Argon that we are allowed to use this shorthand? Like can we do this regarding shorthand, Na: [Ne] 3s^1

Thank you!

Maria Trujillo 1L

So I know that the first three quantum numbers are n,l, and ml, and part of my confusion arises with ml. Is ml like a sub-number of l or is it independent. From where this confusion arises is from whether or not m has the subscript l. Sorry if this is confusing, and thanks for the help!

Maria Trujillo 1L

I know that amplitude is not that often mentioned, nor is there an equation regarding amplitude, that we have encountered. However, I was wondering what the relevance was regarding the photoelectric effect and the first experiment. I know that increasing wavelength and amplitude, will do nothing if ...

Maria Trujillo 1L

For far for quantum, I would say that you be familiar with the following equations: c=wavelength * frequency E= h (constant, *6.63x10^-34) * frequency Ephoton(hv) - Ethreshhold(phi) = Eexcess (1/2me-ve-^2)<---- heads up that is mass and velocity, mass is constant How I am memorizing or just understa...

Maria Trujillo 1L

What I believe Dr. Lavelle meant by discrete is that there are only whole numbers and that is because of how small the particles, such as electrons are. This is evident in the energy levels, like you can't be at level 1.12443262, it has to be 1 or 2, thus you are constrained to those numbers. Which ...

Maria Trujillo 1L

Hello, in class and on some questions I've noticed that when you solve for frequency which is in Hz, that sometimes it is given in either 1/s or s^-1. Is the way you give Hz relevant to the problem or is it just preference?

Maria Trujillo 1L

How do we know what units to give the answer in? If what I am solving for was previously stated in kg, does that mean that my answer must be in kg? Some questions give you initial value in kg and then they give you the value of something else (which you are not solving for, but use in order to get a...

Maria Trujillo 1L

So for this problem we are asked to convert from kilograms to t, but I am unsure what t is. I searched it up, but found nothing convincing. On the test, will we be given units that are not SI?

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