Search found 65 matches

by Javier Perez M 1H
Sun Jan 24, 2021 9:51 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Tables
Replies: 31
Views: 65

Re: ICE Tables

It depends on what is given. Think of it as an equilibrium reaction where if the products are given instead of reactants you have to decrease products to get your reactants and then use reactants to possibly find the eq concentration of your product.
right everyone? or am I wrong?
by Javier Perez M 1H
Sun Jan 24, 2021 9:47 am
Forum: Phase Changes & Related Calculations
Topic: Endothermic v. Exothermic
Replies: 61
Views: 159

Re: Endothermic v. Exothermic

Definitely, use the delta H to determine whether is endothermic or exothermic.
by Javier Perez M 1H
Sun Jan 24, 2021 9:46 am
Forum: Ideal Gases
Topic: Omitting solid/liquid
Replies: 19
Views: 64

Re: Omitting solid/liquid

Definitely, as stated above do not include nongases nor solvents such as the common H2O except when itls part of the reaction not acting as main solvent that you include the concentration of H20.
by Javier Perez M 1H
Sun Jan 24, 2021 9:43 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Determining pH
Replies: 18
Views: 34

Re: Determining pH

-log(x) function is used to find both the Ph and Poh given the concentrations of OH- or H+. These concentrations are plugged in as x. However, if you are solving and have a Ka value then you cannot directly determine the Poh, you must calculate Ph then -14 and you'll get your Poh.
by Javier Perez M 1H
Sun Jan 24, 2021 9:40 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: X Approximations
Replies: 23
Views: 66

Re: X Approximations

If the Ka or Kb is < 10^-4 then it is fine to ignore the -x from the initial mols.
by Javier Perez M 1H
Sat Jan 16, 2021 10:00 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Temperature
Replies: 12
Views: 57

Re: Temperature

How are we to determine if a chemical equation is endothermic or exothermic? Will it be provided or can we determine this from K values?
by Javier Perez M 1H
Sat Jan 16, 2021 9:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pH of Weak Acids
Replies: 11
Views: 57

Re: pH of Weak Acids

Another factor that might help is whether the pH is higher or lower than 1 or 14.
by Javier Perez M 1H
Sat Jan 16, 2021 9:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE box for partial pressures
Replies: 10
Views: 21

Re: ICE box for partial pressures

Yes the process for solving for partial pressures is quite the same as calculating concentrations. However be aware that you might get cubed equations and there is a different process for solving them.
by Javier Perez M 1H
Sat Jan 16, 2021 9:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Box
Replies: 28
Views: 74

Re: ICE Box

In terms of test taking, I recommend using the ICE box now in order to become more efficient and avoid errors during exams.
by Javier Perez M 1H
Sat Jan 16, 2021 9:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When x is negligible in Equilibrium constant
Replies: 34
Views: 104

Re: When x is negligible in Equilibrium constant

Yeah this is a bit confusing given that he had mentioned that the concentration had to be smaller than 10^-3 but most recently 10^-4. Lavelle please clarify this.
by Javier Perez M 1H
Fri Jan 08, 2021 1:31 pm
Forum: Ideal Gases
Topic: Units of Temperature
Replies: 82
Views: 288

Re: Units of Temperature

So when using PV=NRT temperature is supposed to be inputted in Kelvin? How come though fro most of the questions so far we are being given temperature in Celcius?
by Javier Perez M 1H
Fri Jan 08, 2021 1:22 pm
Forum: Ideal Gases
Topic: PV=nRT question
Replies: 6
Views: 63

Re: PV=nRT question

The question is most likely to ask for one while giving you the units of the other. That is when you rely on PV=NRT to get the units you need based on what you are being asked for.
by Javier Perez M 1H
Fri Jan 08, 2021 1:20 pm
Forum: Ideal Gases
Topic: Bars to atm [ENDORSED]
Replies: 35
Views: 173

Re: Bars to atm [ENDORSED]

Where do we usually encounter the bar unit?
by Javier Perez M 1H
Fri Jan 08, 2021 1:18 pm
Forum: Ideal Gases
Topic: Finding x for K using quadratic equation
Replies: 6
Views: 42

Re: Finding x for K using quadratic equation

Since a quadratic equation has two answers one being negative and the other being positive, you will be going with the positive answer given that there is no such thing as negative matter. However, what if we get two positive answers?
by Javier Perez M 1H
Fri Jan 08, 2021 1:15 pm
Forum: Ideal Gases
Topic: Reviewing PV=NRT
Replies: 7
Views: 55

Reviewing PV=NRT

Where can we find all the answers to the textbook practice problems? I believe it might be on Lavelle's website but I cannot recall under what tab. Given that this concept requires all sorts of equation solving back and forth it might be a good idea to gain a better grasp by literally applying it in...
by Javier Perez M 1H
Tue Dec 15, 2020 7:00 pm
Forum: *Titrations & Titration Calculations
Topic: Acid/Base bonds
Replies: 5
Views: 266

Re: Acid/Base bonds

Good question, it has to do with the components of your acidic molecule. Generally when no O is present just H and some P orbital atom the most electronegative and biggest, towards the bottom makes it more acidic. The more Os are present the more acidic. The higher the overall charge the more acidic...
by Javier Perez M 1H
Tue Dec 15, 2020 6:56 pm
Forum: Naming
Topic: Bis, Tris, Tetrakis
Replies: 4
Views: 49

Re: Bis, Tris, Tetrakis

bis, tris, etc is generally used to name molecules or atoms with more than one bond. It seems the mono-, di- prefixes (which indicates how many atoms or molecules are present) is canceled out when dealing with these complex bonds.
by Javier Perez M 1H
Tue Dec 15, 2020 6:12 pm
Forum: Bond Lengths & Energies
Topic: Bond length
Replies: 7
Views: 52

Re: Bond length

That is true, bond length relies on center to center distance. However, bonds also decrease these lengths theoretically when bonding more than once.
by Javier Perez M 1H
Sun Dec 13, 2020 1:54 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 49
Views: 308

Re: Final Exam

Definitely, this exam had very little time for the amount and type of questions. Many students either didn't finish or rushed through half of it. Both the mathematical questions and the content questions do rely on more thinking than a usual simpler question on the midterms. Being a bad test taker t...
by Javier Perez M 1H
Thu Dec 10, 2020 3:40 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: calculating pH or Poh
Replies: 5
Views: 50

calculating pH or Poh

How do we solve for these and what is the relationship among them?ph, poh, Ka, Pka
Also when is it that we need molarity in these calculations?
by Javier Perez M 1H
Thu Dec 10, 2020 3:38 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength and Stability of Acids and bases
Replies: 3
Views: 31

Strength and Stability of Acids and bases

Hi, how do I know when an acid is strong or weak? Similarly, how do I know the stability such as leaning more to the right or left, etc?
by Javier Perez M 1H
Sun Dec 06, 2020 9:10 am
Forum: Resonance Structures
Topic: Stability
Replies: 13
Views: 108

Re: Stability

Resonance structures tend to be stable when there aren't that many charges around it, the shape is in a way balanced, and the pull of bonding atoms canceling out.
by Javier Perez M 1H
Sun Dec 06, 2020 9:07 am
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: List of Strong Bases and Weak Bases
Replies: 6
Views: 181

Re: List of Strong Bases and Weak Bases

Definitely memorize the list that Dr.Lavelle gave during the lectures it will assist you. Also probably try to see how OH molecules are formed as that will reveal as well which one is stronger and weaker.
by Javier Perez M 1H
Sun Dec 06, 2020 9:02 am
Forum: Sigma & Pi Bonds
Topic: Sigma and Pi Bonds
Replies: 21
Views: 161

Re: Sigma and Pi Bonds

Most definitely, one bond is a sigma everything after in that same bond region would be Pi bonds because those are the ones that stop rotation for the most part.
by Javier Perez M 1H
Sun Dec 06, 2020 8:48 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: strong vs weak
Replies: 10
Views: 75

Re: strong vs weak

Strong acids have weaker bonds meaning the larger the space in between two atoms the stronger it is.
by Javier Perez M 1H
Sun Dec 06, 2020 8:47 am
Forum: Naming
Topic: Oxidation State
Replies: 16
Views: 74

Re: Oxidation State

Why is oxidation state important in acids?
by Javier Perez M 1H
Sun Nov 29, 2020 9:28 pm
Forum: Student Social/Study Group
Topic: Final Format
Replies: 35
Views: 288

Re: Final Format

Will our TA actually go over with us the previous midterms we did if we schedule the appointment? My TA had mentioned something about not being able to view them or something.
by Javier Perez M 1H
Sun Nov 29, 2020 9:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Nonpolar bonds
Replies: 7
Views: 31

Re: Nonpolar bonds

Nonpolar bonds are bonds between atoms of the same element as there is no difference in electronegativity and they share the same number of electrons(not sure if electronegativity is a requirement though). A nonpolar molecule is a molecule that has balance forces all around it. For example, a centra...
by Javier Perez M 1H
Sun Nov 29, 2020 9:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 4
Views: 29

Re: Bond Angles

I would recommend that you see molecules in multiple planes of 360, there fore you just divide the 360 degrees by the number of bonds to get the average bond angle in between atoms in that plane, and if there are lone pairs in that plane it would be safe the assume that the angle would be less.
by Javier Perez M 1H
Sun Nov 29, 2020 9:16 pm
Forum: Dipole Moments
Topic: Tetrahedral Atoms and Dipole Moments
Replies: 7
Views: 46

Re: Tetrahedral Atoms and Dipole Moments

Dipole moments only occur when dipoles cancel out or when the forces are said to be balanced. The best way to determine if the forces are balanced around the central atom is to determine the shape and determine all forces around that central atom in the molecule.
by Javier Perez M 1H
Sun Nov 29, 2020 9:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar
Replies: 10
Views: 67

Re: Polar

Two or more lone pairs means you have a bent structure. Usually, you can tell polarity by looking at the molecule's shape. If it looks uneven it is most likely to be polar.
by Javier Perez M 1H
Sun Nov 22, 2020 7:45 pm
Forum: Electronegativity
Topic: Periodic trend
Replies: 17
Views: 150

Re: Periodic trend

Electronegativity is Electron Affinity (energy released from gain of electrons) plus Ionization energy (Energy needed to release an electron). Thus, all three are basically highest in your top right of your periodic table and decrease as you go left or down.
by Javier Perez M 1H
Sun Nov 22, 2020 7:42 pm
Forum: Student Social/Study Group
Topic: Finals!
Replies: 43
Views: 350

Re: Finals!

Definitely, it will cover all the term's material. However, as long as you been studying well for the last two exams the final should just be a small addition of the new content.
by Javier Perez M 1H
Sun Nov 22, 2020 7:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bonds in depictions of molecular shape
Replies: 3
Views: 15

Re: Bonds in depictions of molecular shape

Yes, your solid bonds or triangle-looking bonds are those facing you, while the dashed triangle ones are those facing away, and while the solid lines or regular bonds are those bonds parallel to you.
by Javier Perez M 1H
Sun Nov 22, 2020 7:36 pm
Forum: Lewis Structures
Topic: Central Atom Question
Replies: 20
Views: 151

Re: Central Atom Question

Hydrogen is just one of the very few elements that will never be your central atom. Every other element can be a central atom for the most part as long as they are the one with the least electronegativity in the molecule.
by Javier Perez M 1H
Sun Nov 22, 2020 7:34 pm
Forum: Lewis Structures
Topic: Polar and non polar elements
Replies: 9
Views: 71

Re: Polar and non polar elements

Whether an element is polar or not might have to do with whether the element is in ion form or not and the overall properties of the element. There are elements that are very reactive.
by Javier Perez M 1H
Sun Nov 15, 2020 8:16 pm
Forum: Ionic & Covalent Bonds
Topic: Polarity of bonds vs molecules
Replies: 6
Views: 19

Re: Polarity of bonds vs molecules

Definitely, if the vectors don't cancel out the atom will be polar. However, are ions always polar since they have a charge?
by Javier Perez M 1H
Sun Nov 15, 2020 8:08 pm
Forum: Ionic & Covalent Bonds
Topic: Resonance Structures
Replies: 5
Views: 42

Re: Resonance Structures

How do molecules form resonance structures? I know that at times it's a molecule that puts in both electrons for a bond to form but what are the main rules?
by Javier Perez M 1H
Sun Nov 15, 2020 8:02 pm
Forum: Ionic & Covalent Bonds
Topic: Difference on how atomic size affects covalent and dipole interactions
Replies: 9
Views: 43

Re: Difference on how atomic size affects covalent and dipole interactions

Why is it that a very electronegative atom with an atom with a bigger atomic radius is harder to dissolve than the same atom but with another atom with a smaller radius?
by Javier Perez M 1H
Sun Nov 15, 2020 7:48 pm
Forum: Lewis Structures
Topic: Lewis structures: central atom/ions
Replies: 1
Views: 38

Lewis structures: central atom/ions

When it comes to drawing Lewis structures, is our central atom such o in H2O always nuetral or when is it that it gains a positive or negative charge? How am I supposed to know?
In ions can outer atoms hold a positive charge or only negative?
by Javier Perez M 1H
Fri Nov 06, 2020 5:30 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 182
Views: 106809

Re: Reading the textbook [ENDORSED]

I think reading the textbook is sometimes more of a supplement when not understanding things, however it better to read it to better grasp the concepts or engrave them into your memory.
by Javier Perez M 1H
Fri Nov 06, 2020 5:26 pm
Forum: Electronegativity
Topic: Electron Affinity
Replies: 6
Views: 27

Re: Electron Affinity

It depends wether its octet is satisfied already. It also depends on its chemical,atomic affinity.
by Javier Perez M 1H
Fri Nov 06, 2020 5:24 pm
Forum: Trends in The Periodic Table
Topic: Bond Length
Replies: 5
Views: 32

Re: Bond Length

electron-negativity does have an impact on bond lenqth. The stronger the smaller the bond length. Simply look at it as a sphere the bigger the sphere or the atom in size due to electron cloud being pulled less by the nucleus due to the amount of electrons and nucleus pull.
by Javier Perez M 1H
Sun Nov 01, 2020 11:55 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: d orbitals
Replies: 17
Views: 97

Re: d orbitals

Each letter shell has a different amount of orbitals and so forth. p=3 d=5 f=7
by Javier Perez M 1H
Sun Nov 01, 2020 11:52 am
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 30
Views: 421

Re: Atomic Radius

More electrons = larger radius
However, there is a bigger increment once they start going into other orbitals or passing N=2.
by Javier Perez M 1H
Sun Nov 01, 2020 11:47 am
Forum: Administrative Questions and Class Announcements
Topic: Participation Points [ENDORSED]
Replies: 62
Views: 1016

Re: Participation Points [ENDORSED]

By what day do we have to post every week?
by Javier Perez M 1H
Sun Nov 01, 2020 11:42 am
Forum: *Shrodinger Equation
Topic: Midterm Scores
Replies: 30
Views: 336

Re: Midterm Scores

He is probably going to post them in a week, I believe they may be curved or something so that might be why he is going to take longer.
by Javier Perez M 1H
Sun Nov 01, 2020 11:30 am
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 182
Views: 106809

Re: Reading the textbook [ENDORSED]

Most definitely, when you don't understand something its good to consult the textbook. If that doesn't work ask TAs and UAs. If you can't reach them then just look it up in the internet there could be articles or videos on the topic.
by Javier Perez M 1H
Sun Nov 01, 2020 10:39 am
Forum: *Shrodinger Equation
Topic: N L ML Atoms, Orbitals, number of electrons
Replies: 3
Views: 48

N L ML Atoms, Orbitals, number of electrons

Hi, can someone explain to me what the significance is of each and how to find the number of electrons when Ml is given? Im having trouble understanding what ml means the most when finding the number of electrons.
by Javier Perez M 1H
Sun Oct 25, 2020 11:48 pm
Forum: Properties of Light
Topic: Midterm Conceptual Questions
Replies: 5
Views: 58

Re: Midterm Conceptual Questions

As for what kind of concept questions there will be, off the top off my head I'd say definitely know the wave model, diffraction, the photoelectric effect, the particle model, Bohr frequency condition, atomic and molecular spectra, conservation of mass, and conservation of energy. The study guide a...
by Javier Perez M 1H
Sun Oct 25, 2020 11:44 pm
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 203
Views: 1296

Re: How are you studying?

Will we be provided with conversion units for the exam? (such as how many nanometers are in a meter and ml in a liter)
Or are we expected to memorize this?
by Javier Perez M 1H
Sat Oct 24, 2020 10:19 am
Forum: *Particle in a Box
Topic: Midterm 1
Replies: 16
Views: 258

Re: Midterm 1

Will how to solve for wave functions be on the exam?
Schrodinger's equation
by Javier Perez M 1H
Fri Oct 23, 2020 7:13 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Homework up to Q19 and Midterm 1 [ENDORSED]
Replies: 7
Views: 137

Re: Homework up to Q19 and Midterm 1 [ENDORSED]

As of now the error has not been fixed in terms of the randomization. It also seems there are no randomizer options from our end.
by Javier Perez M 1H
Fri Oct 23, 2020 5:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Frequency Equation Question
Replies: 5
Views: 60

Re: Rydberg Frequency Equation Question

That is exactly the same question I had because of sapling homework questions 6 and 8 I believe where in the Rydberg equation n1 and n2 are swapped. Can someone please verify that these flip accordingly wether its an emission of absorption.
by Javier Perez M 1H
Thu Oct 22, 2020 5:44 pm
Forum: Photoelectric Effect
Topic: Intensity vs. Frequency
Replies: 22
Views: 140

Intensity vs. Frequency

What is intensity and what is frequency?
As far as I know frequency is just the amount of cycles per an amount of time or waves. However, what exactly is intensity?
by Javier Perez M 1H
Sat Oct 17, 2020 3:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Where can I buy a webcam for a reasonable price?
Replies: 60
Views: 1102

Re: Where can I buy a webcam for a reasonable price?

If you go the route of buying a webcam I would recommend Fry's or Amazon. Possibly B&H as well. Hope this opens your options.
by Javier Perez M 1H
Sat Oct 17, 2020 3:17 pm
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 203
Views: 1296

Re: How are you studying?

Definitely doing a lot of practice problems helps. However, what is the best way to take notes during the recorded lectures? Sometimes I wait for him to go through the whole slide and other times I take the notes as he speaks and thing pop up on the slide.
by Javier Perez M 1H
Fri Oct 16, 2020 5:26 pm
Forum: Significant Figures
Topic: SIG FIGS
Replies: 13
Views: 112

Re: SIG FIGS

Yes, if your question has 4 significant figures then your answer should have 4 significant figures.
by Javier Perez M 1H
Fri Oct 16, 2020 5:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Built-in webcams/Equipment request [ENDORSED]
Replies: 22
Views: 735

Re: Built-in webcams/Equipment request [ENDORSED]

For the exam, my TA said that you will need some sort of camera showing your workspace. If your desktop/laptop doesn't have a camera then you will be forced to take out your phone and login to the zoom session via phone where through that camera they will monitor you during the exam.
by Javier Perez M 1H
Fri Oct 16, 2020 5:10 pm
Forum: Photoelectric Effect
Topic: Sapling HW #4 Part 2 Photoelectric
Replies: 3
Views: 28

Re: Sapling HW #4 Part 2 Photoelectric

Well for this question you will have to keep in mind the following two equations E(photon energy)=hv and c=wavelength*frequency. You are only given K.E and Frequency. You basically plug in frequency into your "C" equation to get the wavelength then plug in your wavelength into your E(photo...
by Javier Perez M 1H
Wed Oct 07, 2020 8:16 pm
Forum: Significant Figures
Topic: Clarification on Significant Figures
Replies: 9
Views: 67

Re: Clarification on Significant Figures

Hope this helps when it comes to significant figures: non-0 numbers are considered significant figures numbers including zeros in between non zero numbers ae considered significant figures as well Zeros in front, or "leading zeroes" are not counted as significant numbers Zeros in back, or ...
by Javier Perez M 1H
Wed Oct 07, 2020 8:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Structure of Exams
Replies: 5
Views: 67

Re: Structure of Exams

Will we be expected to know how to read or draw compound drawings/ structures for our exams? (like question 10 on sapling)
by Javier Perez M 1H
Wed Oct 07, 2020 8:01 pm
Forum: Empirical & Molecular Formulas
Topic: Sapling Hw Week 1 #10
Replies: 20
Views: 286

Re: Sapling Hw Week 1 #10

Also where can we learn to read such symbols or way of displaying a chemical reaction without the lettering we usually use?
by Javier Perez M 1H
Wed Oct 07, 2020 8:00 pm
Forum: Empirical & Molecular Formulas
Topic: Sapling Hw Week 1 #10
Replies: 20
Views: 286

Re: Sapling Hw Week 1 #10

Was this chemical reaction balanced already or did we have to balance it? The one provided in the question
by Javier Perez M 1H
Mon Oct 05, 2020 1:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling Textbook Access Code
Replies: 10
Views: 69

Re: Sapling Textbook Access Code

The trial I believe is a week long (7days to be exact) unless they are providing us with an extended version.

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