CHEMISTRY COMMUNITY

Vivianvelazquez_1J

Since it will be in CCLE I think is based on the final answer, meaning you get the points or not. I don’t think there will be any partial credit seeing that we will only be submitting answers.

Vivianvelazquez_1J

Prof. Lavelle sent out an email that the test will be through CCLE from 11:15am to 2:45pm. It also state that your work is saved every two minutes, so say you didn’t finish Im sure what was saved last would be what you could submit.

Vivianvelazquez_1J

Yes, except he gave us an extra 30 minutes to sign in, it’s from 11:15am to 2:45pm.

Vivianvelazquez_1J

No, you do not need to print anything for the final. Everything with be through CCLE.

Vivianvelazquez_1J

The final will be through CCLE Prof. Lavelle sent out an email explaining everything step by step.

Vivianvelazquez_1J

For the reaction to be fully balanced the amount of e- on both sides should be balanced. If they are not balanced after balancing O and H then you would multiply one or both half reactions to get equal electrons on each side.

Vivianvelazquez_1J

Lavelle makes the final and TA's make the tests.

Vivianvelazquez_1J

Yes, this will be the last five points out of the total 50 points.

Vivianvelazquez_1J

It should be Anode over Cathode.

Vivianvelazquez_1J

K is determined by [products] over [reactants] so when [products] are greater than [reactants] k is greater than 1. When [products] are less than [reactants] k is less than 1.

Vivianvelazquez_1J

I believe cathode is assumed to be on the right side and anode is assumed to be on the left side.

Vivianvelazquez_1J

An anode is the electrode where oxidation occurs and the Cathode is the electrode where reduction occurs. In other words the anode is the electrode where electricity flows into. In contrast, the cathode is the electrode where the electricity flows out of.

Vivianvelazquez_1J

Galvanic cells and voltaic cells are the same things, they both convert chemical energy into electrical energy.

Vivianvelazquez_1J

Test two covers the second page of Outline 4: Thermodynamics and all of Outline 5: Electrochemistry and its Applications.

Vivianvelazquez_1J

The difference between reactions in basic and acidic conditions is that balancing reactions in a base, you would first balance it like how you would in an acid, but since you're in a basic solution now, you would add enough OH- to both sides of the equation to neutralize the H+

Vivianvelazquez_1J

Q is used when the reaction is not at equilibrium, while K is used when the reaction is at equilibrium.

Vivianvelazquez_1J

When you put a degree/knot symbol with delta G or any other variable, it means the reaction is under standard conditions. When the degree/knot symbol is not present after delta G or any other variable, the reaction is under the conditions given.

Vivianvelazquez_1J

One week of Chemistry Community post starts on Monday and ends on Sunday. You should have a total of 5 posts per week for ten weeks making you a total of 50 points for discussion.

Vivianvelazquez_1J

The posts are usually counted at the end of the quarter. You should do 5/week to stay on track, but as long as you have 50 by the end of the quarter and you didn't do a bunch of them at the same time, you'll be good. is this true? I assumed they were checked every week by the end of sunday It depen...

Vivianvelazquez_1J

Standard Conditions at 273.15K when dealing with concentrations is 1M, and when dealing with pressure is 1 atm.

Vivianvelazquez_1J

Hello, Could you explain the purpose of a galvanic cell and what it is? Thank you! Galvanic cells harness the electrical energy available from the electron transfer in a redox reaction to perform useful electrical work such as powering radios, watches, ect. The key to gathering the current, or elec...

Vivianvelazquez_1J

Voltaic and galvanic cells are the same thing, they are both electrochemical cells.

Vivianvelazquez_1J

A salt bridge, in electrochemistry, is a laboratory device used to connect the oxidation and reduction half-cells of a galvanic cell (voltaic cell), a type of electrochemical cell.

Vivianvelazquez_1J

The Faraday constant represents the amount of electric charge carried by one mole, or Avogadro's number, of electrons.

Vivianvelazquez_1J

Oxidation is a loss of an electron and reduction is the gain of an electron.

Vivianvelazquez_1J

Ions are charged particles because they have a different number of electrons and protons. Depending on the difference of protons and electrons they will have a positive or negative charge.

Vivianvelazquez_1J

The method used to balance redox reactions is called the Half Equation Method. In this method, the equation is separated into two half-equations; one for oxidation and one for reduction.

Vivianvelazquez_1J

Oxidation is a process of losing electrons. An oxidizing agent is a reactant that removes electrons from other reactants during a redox reaction

Vivianvelazquez_1J

When it comes to memorizing charges I think it would be safe to memorize the most common elements that he commonly uses for in class example or homework questions.

Vivianvelazquez_1J

It's easier to memorize the strong bases that are usually used by Lavelle. If you memorize strong acids and bases anything else you see, you immediately know is weak.

Vivianvelazquez_1J

In Friday's lecture, Prof. Lavelle said the midterm will cover everything from outline 1 to outline 4. Except in outline four, there are two sheets of learning objectives and the midterm will have everything on the first sheet, the second sheet however is not on the midterm.

Vivianvelazquez_1J

All equations and constants are given on the first page of our test. However, you will need to know what each symbol or letter means, and you'll need to know the units for each symbol or letter.

Vivianvelazquez_1J

Hess's law is able to be used because enthalpy is a state function. Since enthalpy is a state function, we're able to add the enthalpies together.

Vivianvelazquez_1J

Review session power points are not posted. its usually if you go, you go, and if don't, then you don't. There are some worksheets that are posted with keywords from review sessions, I believe one of them is "pizza rolls."

Vivianvelazquez_1J

You only count gas molecules and their coefficients, not subscripts.

Vivianvelazquez_1J

K in the Boltzmann formula is simply the Boltzmann constant which is 1.380649×10^−23 J/K.

Vivianvelazquez_1J

The First Law of Thermodynamics states that heat is a form of energy, and therefore is subject to the principle of conservation of energy. Meaning that heat energy, just like energy cannot be created or destroyed.

Vivianvelazquez_1J

Midterms and of course finals are cumulative. The only tests that cover what we have learned after the previous tests are test 1 and test 2.

Vivianvelazquez_1J

Lavelle does not make practice midterms he just makes a lot of review sessions for us to attend. however, Lyndon's review sessions have worksheets that are practically practice midterms. The worksheet does not cover everything, but, they are very helpful.

Vivianvelazquez_1J

Ghadir Seder 1G wrote:is the cutoff 10^-3? or 10^3?

10^-3 is the cutoff.

Vivianvelazquez_1J

Solids and liquids are not included, only gases and aq solutions are included in the equilibrium constant. Solids and liquids are pure substances, the molar concentration of a pure substance does not change in a reaction, thus being excluded from the equilibrium constant.

Vivianvelazquez_1J

Yes, the conjugate seesaw applies both ways, meaning if a base is strong its conjugate acid will be very weak, and if an acid is very strong its conjugate base is very weak.

Vivianvelazquez_1J

No, you do not have to memorize any Ka or Kb values because they are not constants. you should know that Ka x Kb = Kw. You should also know how to find Ka when you have Kb or vice versa. You should be able to find the pH and pOH when given the values for Ka or Kb.

Vivianvelazquez_1J

I doubt that he will post the Final solutions anywhere. The best we can get is picking up our test, and seeing what we got points for and where we lost points.

Vivianvelazquez_1J

Since it is a holiday I'm not sure that there will be any peer learning sessions.

Vivianvelazquez_1J

The Peer learning sessions that I have been to don't usually use worksheets, they put questions on the board and we work on them together. The worksheets usually start being made during the middle of the quarter.

Vivianvelazquez_1J

No, Lavelle does not make study guides or practice tests. He makes outlines that tell you what you should be able to do and understand. test one will be on outline 1 on Chemical Equilibrium & outline 2 on Acid and Base Equilibria.

Vivianvelazquez_1J

The only time you don't have to use the quadratic formula with doing calculations for the Ice table is when K is less than 10^-3. Once you plug in your calculations from your Ice table into K the new concentration represented in your denominator, is so insignificant you can cross the x which represe...

Vivianvelazquez_1J

When calculating K water is not accounted for because the molar concentration of pure substances (solids or liquids) does not change in the reaction. Therefore solid and liquids are not included in the K expression.

Vivianvelazquez_1J

solids and liquids aren't included in the equilibrium equation because the molar concentration of a pure substance (liquid or solid) does not change in a reaction.

Vivianvelazquez_1J

Yes, the required amount of Chem Community responses is still 5 per week, adding up to a total of 50 responses by the end of the quarter

Vivianvelazquez_1J

If all the reactants and products are in the gas phase you would use Kp. Kp is for partial pressure when your reactants and products are in the gas phase. While Kc is for when concentrations are being used.

Vivianvelazquez_1J

Test one will cover all topics from outline one on Chemical Equilibrium.

Vivianvelazquez_1J

Hi, I was wondering if I had access to the solutions manual for my textbook. I bought the sapling learning pack that included the textbook, but I cannot seem to find the solutions manual. Please help. If you bought the bundle that is offered on the chemistry textbook site, you should have received ...

Vivianvelazquez_1J

We will not have to know how to find KA values. As Lavelle said in the lecture when he was going over these slides, we will learn how to find KA values in Chem14B.

Vivianvelazquez_1J

8 atoms in thymine could form a Hydrogen bond. A lone pair on N (happens two times), Two lone pairs on O (happens twice), and because N is bonded with H, H can bond with something else (happens twice) adding up to 8 possible Hydrogen bonding sites.

Vivianvelazquez_1J

Light has wave-like properties at all times. And according to the photoelectric effect, light acts as a particle. When light undergoes reflection, refraction, and diffraction light behaves as a wave.

Vivianvelazquez_1J

I don't think we will actually have to use this equation. But on the midterm, he did ask a couple of conceptual questions so maybe just know what the equation is used for.

Vivianvelazquez_1J

I don't know exactly how much naming he's going to give us but I would just memorize the chart to be safe.

Vivianvelazquez_1J

As far as I know you should be doing 5 a week to accumulate 50 post by the end of the quarter completing your online discussion 50 points. Many people say the TA’s add them up at the end of the quarter, or they may just check the dates they were posted.

Vivianvelazquez_1J

I don’t remember him saying we needed to know bond order. Maybe ask your TA or the professor after lecture. As far as I know, we do not need to know the bond orders.

Vivianvelazquez_1J

Watching YouTube videos can help a lot, along with going to as many review sessions as possible. If you can I’d suggest going to workshops in Covel. The step-ups are also very helpful and they help you apply the concepts to actual problems.

Vivianvelazquez_1J

Yes, Hydrogen can obviously bond with other atoms but, hydrogen bonding only occurs when an H atom is bonded with an F, N, or O.

Vivianvelazquez_1J

Vivianvelazquez_1J

In outline 6 Acid and Base Structures and Properties, he states that you must be able to: - Identify common drinks, foods, and household items as acidic or basic. - Recognize acids and bases from their formulas and/or structures. - Identify compounds as Bronsted acids or bases or Lewis acids or base...

Vivianvelazquez_1J

Yes the final can include anything from the first day of lecture up until the last day of lecture. If you don’t know what exact concepts you need to know from each section the outlines always have the concepts that he expects you to know.

Vivianvelazquez_1J

Im sure we could turn in homework on hybridization since me just recently covered it and it was not on the test. If you’re not sure you can always just do homework from outline 5 Coordination Compounds and their Biological Importance. These problems are just from section 9C.

Vivianvelazquez_1J

Hydrogen bonding is when an H atom bonds with an N,O, or F. In the G-C pair there are three hydrogen bonding sites, 2 H-O and one H-N.

Vivianvelazquez_1J

A polydentate ligand is a ligand that coordinates to a metal center by two or more atoms, forming two or more bonds. Polydentate ligands range in the number of atoms used to bond to a central metal atom or ion.

Vivianvelazquez_1J

A ligand is an ion or molecule that binds to a central metal atom to form a coordination complex by coordinate bonding. Ligands are usually thought of as electron donors attracted to the metal at the center of the complex.

Vivianvelazquez_1J

For week 9 we should be completing outline 5 Coordination Compounds and their Biological Importance, which is section 9C in the book. If you have a discussion section on Thursday or Friday most likely your TA will send you an email on when and where to turn it.

Vivianvelazquez_1J

DarrenKim_3G wrote:The Lecture we had the Friday before the midterm up until the lecture we had last friday.

This Monday in lecture the first slide he shows us will also be on test 2.

Vivianvelazquez_1J

Yes, all we need to know is the name of the models. you will, however, need to know how to draw the correct lewis structure and VSEPR notation to figure out what shape the model will be.

Vivianvelazquez_1J

The range mentioned in class was less than 109.5, due to the lone pairs forcing bonding e- closer together.

Vivianvelazquez_1J

You will not need to know the exact angles of the models, you will only need to know the shape of the model. the VSEPR model has a specific notation that can help you figure the shape of the model. If you look up a VSEPR chart you can easily distinguish the shapes from the different models using the...

Vivianvelazquez_1J

VLi_1L wrote:This has probably already been said, but can someone list all the topics that will be covered on this upcoming test

Everything that he has covered after the Midterm up until the first slide he will show us in this Monday's lecture will be on the test.

Vivianvelazquez_1J

Test 2 will most likely be everything we have learned after the midterm up until the end of outline 4 on molecular shape and structure as we all will have it on different days and I think he will have it well balanced.

Vivianvelazquez_1J

I'm sure we can still turn in homework from chemical bonds because we have just taken the midterm and we have not really learned much of molecular shape and structure.

Vivianvelazquez_1J

A resonance structure is when there are different forms of a molecule where all formal charges and bonds are the same but they are distributed around the structure differently. Meaning the different possible structures for the same molecule with the lowest formal charges distributed differently.

Vivianvelazquez_1J

For homework im sure you can turn in homework for chemical bonds as we barley started molecular shape and structure so we don't really know too much and chemical bonds are still relevant. As for the test, it's starting Tuesday November 19 in your discussion section.

Vivianvelazquez_1J

When we were in discussion and we were practicing doing lewis structures, we usually just found the formal charge in our head instead of doing the formal charge equation for every one of them. It was much faster and took less time from all the other problems. Also in the review session during class ...

Vivianvelazquez_1J

Everything from Outline 1: Review of Chemical & Physical Principles and Outline 2: The Quantum World will be on the midterm. Almost everything from Outline 3: Chemical Bonds will be on the midterm cutting off at Focus 2D. everything you need to know about the outlines is on Dr. Lavelle's website...

Vivianvelazquez_1J

The midterm covers everything from the beginning of fundamentals all the way to the end of Focus 2D on chemical bonds. So yes for Chapter 2 (sections A-D) are fair game for the midterm.

Vivianvelazquez_1J

I asked in my discussion on Friday if we would be given an electronegativity table on our midterm because the periodic table he uses in our discussion has the atoms electronegativity on it and he said no. We will just have to remember the trends on the periodic table and apply it to the test.

Vivianvelazquez_1J

I am pretty sure that the midterm will definitely be all free-response and no multiple-choice questions, the first test we took on fundamentals was all free-response. If there are any true or false im sure it will be tied into another question as there will only be 8 questions for the time period of...

Vivianvelazquez_1J

I use to have this calculator and I noticed that it has a lot of problems dividing multiple numbers that you are multiplying together. I had to get a new calculator because it wasn’t working for me but maybe you can just make sure to put all of your multiplying factors in parentheses. Hope this help...

Vivianvelazquez_1J

When we are asked to draw a Lewis structure of a molecule the best thing to do is usually draw the structure with the lowest formal change. Always drawing the structure that is the most stable. In the Dino Nuggets review session they said the most stable is always the best.

Vivianvelazquez_1J

It is more accurate to draw the structure with two double bonds for Sulfate because the formal charge = 0 at that point which is the most stable.

Vivianvelazquez_1J

Patricia Cardenas wrote:The midterm will be Wednesday, November 6th from 6-8 pm. As for the format, I'd recommend looking at past exams.

Is there a location set for the day of the test or will we be most likely taking it with our TA in a different room?

Vivianvelazquez_1J

Single bonds are longer than both triple bonds and double bonds. While double bonds are longer than triple bonds. The stronger the bond the shorter the bonds are, drawing elements closer to each other in the process. Double bonds are stronger than single bonds and triple bonds are stronger than both...

Vivianvelazquez_1J

I don't think we have to know how to find bond lengths If we do I'm sure he will bring it up in the lecture as we have not gone over how to find bond lengths yet. We were only told about one that was observed from C-C.

Vivianvelazquez_1J

Outside of the review sessions, I don't think he gives study guides out. He sent out an Email that he created multiple additional assignments and learning objectives for those who need additional assistance on Sapling Learning.

Vivianvelazquez_1J

Going to step-up sessions or peer learning sessions are really helpful. Memorizing the constants and equations and what they are used for. You can also do all of the homework problems instead of just the 5 you are assigned to do. Looking at the video modules he put up can also help because you can p...

Vivianvelazquez_1J

Natalia Shahwan 4H wrote:is it better to use 2.998 or 3?

I think it's better to use 3 x 10^8 instead of 2.998 x 10^8 simply because it's a whole and easier to remember. Most of the times the solutions usually use 3 x 10^8.

Vivianvelazquez_1J

The equations for photons/particles: E = hv, where E is the energy of the light in Joules (J), h is a constant which is 6.626 X 10-34 J·s, and v is the frequency of the light in s-1 or waves/s (also called Hertz (Hz). The equations used for light are c = λv, when λ is wavelength, v is frequency, and...

Vivianvelazquez_1J

I usually do all of the homework problems that I can so I can actually grasp the concepts. There are a lot of peer learning opportunities that he posts on the chem 14A website that can help a lot. I usually need a quiet place to study so that I can look over my notes and try to memorize the constant...

Vivianvelazquez_1J

One thing that I find really helpful is going to step-up sessions, they usually have worksheets ready and they go into detail with all of the concepts.

Vivianvelazquez_1J

I'm not sure if I completely understand the question but what I know about Hund's rule is that every orbital in a sublevel is singly occupied before any orbital is doubly occupied. All of the electrons in singly occupied orbitals have the same spin (to maximize total spin).

Vivianvelazquez_1J

When you log in you can go to quick links and there should be a tab for your most. It has all of the posts you have created since you joined. A quicker way is when you post a reply or a new subject under your name to the right of the page it tells you how many posts you have.

Vivianvelazquez_1J

When I'm balancing chemical equations I usually start with the element that has the most on the product and reactants side. This usually makes it a lot easier to balance all of the other elements because they all come into place.

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