Search found 50 matches

by Luis_Yepez_1F
Sun Mar 17, 2019 9:21 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatlier Principle
Replies: 7
Views: 86

Re: Le Chatlier Principle

Addin a catalyst wouldn't affect the equilibrium, rather it would just speed up the forward and reverse reaction.
by Luis_Yepez_1F
Sun Mar 17, 2019 9:20 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: bomb calorimeter
Replies: 6
Views: 75

Re: bomb calorimeter

Work would be equal to zero, since volume is constant.
by Luis_Yepez_1F
Sun Mar 10, 2019 10:48 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Ideal Gas Constants
Replies: 4
Views: 64

Re: Ideal Gas Constants

Only monoatomic constants need to be known.
by Luis_Yepez_1F
Sun Mar 10, 2019 10:45 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Vol.
Replies: 8
Views: 93

Re: Constant Vol.

Yes since if there is no change in pressure, then zero work would be done.
by Luis_Yepez_1F
Sun Mar 10, 2019 10:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Final Exam
Replies: 23
Views: 155

Re: Final Exam

The final exam is cumulative, so yes chemical equilibrium will be one the exam.
by Luis_Yepez_1F
Sun Mar 03, 2019 10:03 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Final exam
Replies: 8
Views: 77

Re: Final exam

The final exam is on march 17th.
by Luis_Yepez_1F
Sun Mar 03, 2019 10:02 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ignoring x
Replies: 16
Views: 152

Re: ignoring x

You can ignore x when k is less than 1x10^-3
by Luis_Yepez_1F
Sun Mar 03, 2019 10:01 pm
Forum: Ideal Gases
Topic: pV=nRT
Replies: 12
Views: 148

Re: pV=nRT

You can use the equation to find any of the variables, so p,V,n and T. R is a constant.
by Luis_Yepez_1F
Sun Feb 24, 2019 6:48 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible Reactions
Replies: 8
Views: 120

Re: Reversible Reactions

Any reversible reaction is isothermal, but never assume that any isothermal reaction is reversible.
by Luis_Yepez_1F
Sun Feb 24, 2019 6:47 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Internal energy (U) of an isolated system
Replies: 17
Views: 175

Re: Internal energy (U) of an isolated system

There is no change in energy within a closed system. Since energy can neither leave or enter the system.
by Luis_Yepez_1F
Sun Feb 24, 2019 6:44 pm
Forum: Ideal Gases
Topic: Approximations for ICE
Replies: 20
Views: 160

Re: Approximations for ICE

When K is less than 10^-3, you can just approximate. Always remember to prove the approximation using the 5% rule.
by Luis_Yepez_1F
Sun Feb 17, 2019 8:29 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Midterm Grades
Replies: 35
Views: 369

Re: Midterm Grades

I'm guessing week 7 discussion sections.
by Luis_Yepez_1F
Sun Feb 17, 2019 8:27 pm
Forum: Calculating Work of Expansion
Topic: Work
Replies: 8
Views: 91

Re: Work

I would focus on the ones showed on the constants page that is given each test. Also as mentioned, we don't need to know any of the ones that have derivatives or the integrals, these serve mainly as proofs.
by Luis_Yepez_1F
Sun Feb 17, 2019 8:24 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 802176

Re: Post All Chemistry Jokes Here

What do you call an acid with an attitude?

An A-mean-o-acid.
by Luis_Yepez_1F
Sun Feb 10, 2019 6:47 pm
Forum: Phase Changes & Related Calculations
Topic: Work equation
Replies: 4
Views: 56

Re: Work equation

I would look over the equation worksheet, then list out all the constants that aren't listed there and memorize them.
by Luis_Yepez_1F
Sun Feb 10, 2019 6:45 pm
Forum: Ideal Gases
Topic: derivatives and integrals
Replies: 6
Views: 66

Re: derivatives and integrals

When Dr. Lavelle uses derivatives and integrals, it just a way to show how he was able to derive the equations. They are more just used as proofs. Use the equations that are derived.
by Luis_Yepez_1F
Sun Feb 10, 2019 6:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quiz 1 Number 3c
Replies: 6
Views: 74

Re: Quiz 1 Number 3c

It should be in mol/L as it is asking for M or concentration.
by Luis_Yepez_1F
Sun Jan 27, 2019 10:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: First row question
Replies: 3
Views: 66

Re: First row question

Cations from groups 1 and 2 or cations with just a +1 charge are not large enough to have enough of an effect.
by Luis_Yepez_1F
Sun Jan 27, 2019 10:12 pm
Forum: Ideal Gases
Topic: Chemistry Community Posting
Replies: 7
Views: 107

Re: Chemistry Community Posting

You should have your three posts done before 11:59 on the Sunday of that week.
by Luis_Yepez_1F
Sun Jan 27, 2019 10:11 pm
Forum: Ideal Gases
Topic: pH and pOH
Replies: 18
Views: 180

Re: pH and pOH

Usually the question will ask you to solve for one or the other.
by Luis_Yepez_1F
Sun Jan 13, 2019 10:24 pm
Forum: Ideal Gases
Topic: Homework Week 2
Replies: 10
Views: 102

Re: Homework Week 2

From now on, homework will be due whenever your discussion section is.
by Luis_Yepez_1F
Sun Jan 13, 2019 10:22 pm
Forum: Ideal Gases
Topic: Denoting brackets/parentheses
Replies: 9
Views: 82

Re: Denoting brackets/parentheses

Brackets are primarily used to denote that the element is in concentration, parentheses are just used for partial pressures.
by Luis_Yepez_1F
Sun Jan 13, 2019 10:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Tables
Replies: 3
Views: 45

Re: ICE Tables

If I remember correctly, ICE tables can be used for both concentrations and partial pressures.
by Luis_Yepez_1F
Sun Dec 09, 2018 10:11 am
Forum: Trends in The Periodic Table
Topic: 2nd Ionization Energy
Replies: 2
Views: 43

Re: 2nd Ionization Energy

I believe we only need to know the trend of 1st ionization energy for the test, since we haven't really talked too much about the 2nd level.
by Luis_Yepez_1F
Sun Dec 09, 2018 10:09 am
Forum: Dipole Moments
Topic: Forces Present in molecules
Replies: 3
Views: 59

Re: Forces Present in molecules

Vanderwals occur in every molecule, dipole-dipole occurs in polar molecules, and induced-dipole occurs with one polar and non-polar molecule.
by Luis_Yepez_1F
Sun Dec 09, 2018 9:39 am
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 200
Views: 44159

Re: Saying Thank You to Dr. Lavelle

As the quarter comes to a close, I want to thank Dr. Lavelle for providing a fun and interesting learning environment at all times throughout the quarter.
by Luis_Yepez_1F
Sun Dec 02, 2018 10:29 pm
Forum: Hybridization
Topic: S Hybridization?
Replies: 5
Views: 58

Re: S Hybridization?

Yes, but most of the time it is usually for atoms that are not the central atom within the molecule.
by Luis_Yepez_1F
Sun Dec 02, 2018 10:21 pm
Forum: Resonance Structures
Topic: Formal Charge
Replies: 11
Views: 168

Re: Formal Charge

Since it is an ion, the overall FC should not be equal to zero. Ideally, you want the central atom to have an FC=0 and have any charge whether positive or negative on the outer atoms around the central atom.
by Luis_Yepez_1F
Sun Dec 02, 2018 10:17 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 4381

Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]

Thank you so much for providing us with study material :D
by Luis_Yepez_1F
Sun Nov 25, 2018 10:26 pm
Forum: Trends in The Periodic Table
Topic: Bond Lenghts
Replies: 6
Views: 135

Re: Bond Lenghts

You would need the lewis structure before giving an informed answer about the length of the bonds between atoms of certain elements.
by Luis_Yepez_1F
Sun Nov 25, 2018 10:22 pm
Forum: Lewis Structures
Topic: Exceptions to the Octet Rule
Replies: 5
Views: 73

Re: Exceptions to the Octet Rule

Period 3 and above elements can have expanded octets, as well the first four elements, H, He, Li, and Be will try to have 2 e- to finish the first shell rather the 8 e- as it is easier to be stable in this way.
by Luis_Yepez_1F
Sun Nov 25, 2018 10:19 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: labeling hybridization
Replies: 3
Views: 31

Re: labeling hybridization

You would label hybridization by drawing the three possible ways BF3 can look like. As shown in the image provided labeled B. You would show these are resonate by using the double sided arrows. Image
by Luis_Yepez_1F
Sun Nov 18, 2018 8:47 pm
Forum: Bond Lengths & Energies
Topic: Calculating Bond Length
Replies: 3
Views: 69

Re: Calculating Bond Length

We do not need to know the specific length of a bond, we only need to know the trends of bond lengths.
by Luis_Yepez_1F
Sun Nov 18, 2018 8:45 pm
Forum: Bond Lengths & Energies
Topic: Bond Length
Replies: 9
Views: 215

Re: Bond Length

how do we know the bond length? is it something we have to look up? We do not need to know the exact bond length, we just need to know the trend of the size of bonds. There was an example of this on the midterm with how we have a double and single bond in resonance, which showed that the actual bon...
by Luis_Yepez_1F
Sun Nov 18, 2018 8:43 pm
Forum: Dipole Moments
Topic: Test
Replies: 15
Views: 185

Re: Test

The next test is on week 9 I believe.
by Luis_Yepez_1F
Sun Nov 11, 2018 10:57 pm
Forum: Properties of Light
Topic: Test 3
Replies: 24
Views: 381

Re: Test 3

I believe test 3 would be the parts of outline 3 that weren't covered on the midterm and all of outline 4.
by Luis_Yepez_1F
Sun Nov 11, 2018 10:55 pm
Forum: Limiting Reactant Calculations
Topic: Chem Community Points
Replies: 3
Views: 96

Re: Chem Community Points

You need to post at least three times a week, the deadline being midnight of each sunday.
by Luis_Yepez_1F
Sun Nov 11, 2018 10:54 pm
Forum: Empirical & Molecular Formulas
Topic: Midterm
Replies: 1
Views: 103

Re: Midterm

You would take the percentage of molar mass of each element so in CO2 you would divide 12.011/(12.011+2*15.999), then multiply by how many grams of the molecule you have, you would do this again for the hydrogen in H2O, once you have these two weights of the elements you are looking for, you would a...
by Luis_Yepez_1F
Sun Nov 04, 2018 10:52 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge on Central Atom
Replies: 9
Views: 112

Re: Formal Charge on Central Atom

As the central atom's FC becomes zero, the more stable the entirety of the molecule becomes.
by Luis_Yepez_1F
Sun Nov 04, 2018 10:49 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 6
Views: 120

Re: Atomic Radius

The basic reason/logic behind it is that as an atom has more electrons, then the radius increases by the shells.
by Luis_Yepez_1F
Sun Nov 04, 2018 10:13 pm
Forum: Properties of Light
Topic: Photoelectric Effect
Replies: 7
Views: 192

Re: Photoelectric Effect

Yes, because intensity is proportional to electrons ejected.
by Luis_Yepez_1F
Sun Oct 28, 2018 10:21 pm
Forum: Trends in The Periodic Table
Topic: Lewis Structures
Replies: 7
Views: 108

Re: Lewis Structures

If i remember right, the position of the dots do not matter as long as there are no restrictions such as bonds or e- pairs.
by Luis_Yepez_1F
Sun Oct 28, 2018 10:20 pm
Forum: Ionic & Covalent Bonds
Topic: Lewis Dot Structures: Ionization Energy
Replies: 6
Views: 89

Re: Lewis Dot Structures: Ionization Energy

The element with the lowest energy means that it can bond with more elements, which is why it is a great starting point in the center.
by Luis_Yepez_1F
Sun Oct 28, 2018 10:19 pm
Forum: Ionic & Covalent Bonds
Topic: the Octet rule
Replies: 21
Views: 215

Re: the Octet rule

The only exception to the octet rule are the first four elements, as they will try to only finish the first shell which only needs two e-.
by Luis_Yepez_1F
Sun Oct 21, 2018 11:46 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 802176

Re: Post All Chemistry Jokes Here

Q. What do you do with a dead chemist?
A. You Barium.
by Luis_Yepez_1F
Sun Oct 21, 2018 11:44 pm
Forum: Photoelectric Effect
Topic: Test 2
Replies: 16
Views: 290

Re: Test 2

I believe that each concept will be from the quantum world sections, but you still need to know the basics of from the first test that was given to us.
by Luis_Yepez_1F
Sun Oct 21, 2018 11:42 pm
Forum: Properties of Light
Topic: Quantum Equations
Replies: 3
Views: 41

Re: Quantum Equations

Usually you can determine which equations you use based on what the question asks and what information is given to you in the problem.
by Luis_Yepez_1F
Thu Oct 04, 2018 11:17 pm
Forum: SI Units, Unit Conversions
Topic: Hecto as SI Unit [ENDORSED]
Replies: 4
Views: 42

Re: Hecto as SI Unit [ENDORSED]

I believe Dr. Lavelle was showing us formal SI units which are multiples of 3 for brevity's sake, however the hectometer is a SI unit.
by Luis_Yepez_1F
Thu Oct 04, 2018 11:13 pm
Forum: SI Units, Unit Conversions
Topic: Exercise E1 (Question regarding unit conversions) [ENDORSED]
Replies: 3
Views: 51

Re: Exercise E1 (Question regarding unit conversions) [ENDORSED]

If the question does not specify which units to use, then usually you would stick with the unit that is given, so picometers.
by Luis_Yepez_1F
Thu Oct 04, 2018 11:02 pm
Forum: Significant Figures
Topic: Sig Figs
Replies: 3
Views: 90

Re: Sig Figs

If I remember correctly, when it comes to a combination of both multiplication/division and addition/subtraction. You would adhere to the addition rule for sig figs.

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