Search found 100 matches

by Alfred Barrion 2H
Sat Mar 14, 2020 10:10 pm
Forum: Ideal Gases
Topic: T variable in pv=nrt
Replies: 10
Views: 103

Re: T variable in pv=nrt

For simplicity, it would be easier to use Kelvin, especially since Kelvin is used in the constants.
by Alfred Barrion 2H
Sat Mar 14, 2020 10:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Printing for Final
Replies: 9
Views: 234

Re: Printing for Final

No need to print out anything for the final! If you feel more comfortable with the constants and equations sheet printed out, maybe that will be helpful.
by Alfred Barrion 2H
Sat Mar 14, 2020 10:02 pm
Forum: General Rate Laws
Topic: Factors Affecting k
Replies: 16
Views: 158

Re: Factors Affecting k

k can only change when there is a temperature change.
by Alfred Barrion 2H
Sat Mar 14, 2020 10:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Time
Replies: 13
Views: 259

Re: Final Exam Time

The final will be 3 hours and 30 mins! From 11:15AM-2:45PM
by Alfred Barrion 2H
Sat Mar 14, 2020 8:03 pm
Forum: General Science Questions
Topic: Final Content
Replies: 5
Views: 141

Re: Final Content

I feel like some questions on the final would be structured similarly to hw questions.
by Alfred Barrion 2H
Sat Mar 14, 2020 7:03 pm
Forum: General Rate Laws
Topic: integrals and derivatives
Replies: 7
Views: 110

Re: integrals and derivatives

I believe it was used to show how the equations work but would not necessarily be applied on a test.
by Alfred Barrion 2H
Sat Mar 14, 2020 5:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Submission
Replies: 8
Views: 202

Re: Final Submission

In Lavelle's email he said it would be a quiz posted on CCLE.
by Alfred Barrion 2H
Sat Mar 14, 2020 5:29 pm
Forum: General Science Questions
Topic: Final Overview
Replies: 5
Views: 128

Re: Final Overview

I would make sure you have a broad understanding of Lavelle's course outlines, but to also be mindful of kinetics since it is our most recent material!
by Alfred Barrion 2H
Sat Mar 14, 2020 5:28 pm
Forum: General Science Questions
Topic: Summer 14BL
Replies: 1
Views: 76

Re: Summer 14BL

I'll be taking 14BL this summer as well, does anyone have any experience?
by Alfred Barrion 2H
Sat Mar 14, 2020 5:28 pm
Forum: Administrative Questions and Class Announcements
Topic: Grading Scale
Replies: 14
Views: 287

Re: Grading Scale

I think its really similar to Chem 14A, 50% is a C-, and he will scale depending on class performance, but it will not hurt you.
by Alfred Barrion 2H
Sat Mar 14, 2020 5:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Online Final
Replies: 3
Views: 67

Re: Online Final

Per his last email, Lavelle said that he didnt want us to go through the trouble of scanning or using different apps. I think it will just be some multiple choice and fill in the blank questions.
by Alfred Barrion 2H
Sat Mar 14, 2020 12:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constants
Replies: 8
Views: 102

Re: Equilibrium Constants

Yes, the coefficients in a chemical equation affect the K constant.
by Alfred Barrion 2H
Fri Mar 13, 2020 10:04 pm
Forum: First Order Reactions
Topic: Units for t
Replies: 13
Views: 127

Re: Units for t

It honestly depends on the context of the question, but I use seconds because it is the SI unit. It also depends on your k.
by Alfred Barrion 2H
Fri Mar 13, 2020 9:11 pm
Forum: General Rate Laws
Topic: Temperature and kinetics
Replies: 5
Views: 69

Re: Temperature and kinetics

Yes, because at a higher temperature molecules move faster and have more collisions.
by Alfred Barrion 2H
Fri Mar 13, 2020 9:06 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: U vs H
Replies: 15
Views: 269

Re: U vs H

Delta U is change in internal energy while delta H is a change in enthalpy.
by Alfred Barrion 2H
Fri Mar 13, 2020 9:05 pm
Forum: Student Social/Study Group
Topic: final?
Replies: 7
Views: 203

Re: final?

His last email said that he would be telling us by tomorrow the format of the final. All I know is that its open book and online.
by Alfred Barrion 2H
Fri Mar 13, 2020 9:00 pm
Forum: Administrative Questions and Class Announcements
Topic: take home FINAL DEADLINE
Replies: 15
Views: 306

Re: take home FINAL DEADLINE

I think the take home final will be in the same time period as the regular final.
by Alfred Barrion 2H
Fri Mar 13, 2020 8:25 pm
Forum: Balancing Redox Reactions
Topic: intensive and extensive
Replies: 3
Views: 28

Re: intensive and extensive

Intensive properties are not affected by changes in matter. Extensive properties change when the amount of matter changes.
by Alfred Barrion 2H
Fri Mar 13, 2020 4:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 280
Views: 134600

Re: Saying Thank You to Dr. Lavelle

Dr. Lavelle, Thank you so much for exposing me to the world of chemistry in my short first year at UCLA. I am so grateful for the way you taught chemistry and worked so hard to coordinate office hours, step-up sessions, and workshops. To all of the TAs and UAs reading this. Thank you from the bottom...
by Alfred Barrion 2H
Fri Mar 13, 2020 4:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 11
Views: 143

Re: Final

The final should be up around Sunday! Lavelle has been finalizing things so be sure to check his emails.
by Alfred Barrion 2H
Fri Mar 13, 2020 4:45 pm
Forum: Administrative Questions and Class Announcements
Topic: "Open Book" Final?
Replies: 30
Views: 758

Re: "Open Book" Final?

We can use our books in pdf or physically, as well as any notes we have prepared.
by Alfred Barrion 2H
Thu Mar 12, 2020 9:46 pm
Forum: Administrative Questions and Class Announcements
Topic: review session packets
Replies: 4
Views: 63

Re: review session packets

I think they will be posted in the same thread where the worksheet was posted.
by Alfred Barrion 2H
Thu Mar 12, 2020 9:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram
Replies: 4
Views: 68

Re: Cell Diagram

The comma is for something in the same phase, such as two aqueous. The | is used to separate substances in different phases.
by Alfred Barrion 2H
Thu Mar 12, 2020 3:19 pm
Forum: Balancing Redox Reactions
Topic: Test 2 Return
Replies: 20
Views: 338

Re: Test 2 Return

I would ask your TA for more information to pick up Test 2
by Alfred Barrion 2H
Thu Mar 12, 2020 3:12 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts and Rates
Replies: 10
Views: 131

Re: Catalysts and Rates

Catalysts help speed up reactions though.
by Alfred Barrion 2H
Thu Mar 12, 2020 3:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 11
Views: 58

Re: salt bridge

Salt bridges help with electron flow and neutralizing the solutions in a galvanic cell.
by Alfred Barrion 2H
Thu Mar 12, 2020 3:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Format because I posted in 14A by accident
Replies: 8
Views: 126

Re: Format because I posted in 14A by accident

In the email he said that the final will be shorter and open book. My TA said that it would be collected online.
by Alfred Barrion 2H
Thu Mar 12, 2020 1:43 pm
Forum: First Order Reactions
Topic: equation derivations
Replies: 9
Views: 112

Re: equation derivations

We wouldn't necessarily use the derivations on the exam, but knowing how the derivation occurs and how it leads to a specific equation would be valuable in decoding a certain question.
by Alfred Barrion 2H
Thu Mar 12, 2020 1:42 pm
Forum: First Order Reactions
Topic: Half Life Equations
Replies: 10
Views: 66

Re: Half Life Equations

They are typically provided on the list of given equations!
by Alfred Barrion 2H
Thu Mar 12, 2020 1:41 pm
Forum: Administrative Questions and Class Announcements
Topic: Take Home Final
Replies: 16
Views: 272

Re: Take Home Final

I feel like we would have to print the final out and scan it, I'm waiting for an update as well!
by Alfred Barrion 2H
Tue Mar 10, 2020 11:45 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework 10
Replies: 11
Views: 125

Re: Homework 10

Lavelle's email said you can send a picture to your TA.
by Alfred Barrion 2H
Mon Mar 09, 2020 1:54 pm
Forum: General Science Questions
Topic: Who makes the Final
Replies: 23
Views: 378

Re: Who makes the Final

I think that Lavelle is in control of what goes on the final.
by Alfred Barrion 2H
Mon Mar 09, 2020 1:54 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Kelvin or Celsius?
Replies: 47
Views: 960

Re: Kelvin or Celsius?

You should use Kelvin since it matches with the gas constant R to cancel out.
by Alfred Barrion 2H
Mon Mar 09, 2020 1:52 pm
Forum: First Order Reactions
Topic: Difference between first and second order
Replies: 6
Views: 44

Re: Difference between first and second order

A first order reaction depends on the concentration of one of the reactants. A second order reaction is the square of the concentration of a single reactant.
by Alfred Barrion 2H
Mon Mar 09, 2020 1:48 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Relationship Between Ecell and K
Replies: 9
Views: 105

Re: Relationship Between Ecell and K

When Ecell > 0, then K>1.
When Ecell < 0, then K<1
by Alfred Barrion 2H
Tue Mar 03, 2020 12:30 pm
Forum: Second Order Reactions
Topic: [A] v. Time
Replies: 16
Views: 174

Re: [A] v. Time

The graph of [A] v. Time would be linear.
by Alfred Barrion 2H
Sun Mar 01, 2020 11:44 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: intermediate
Replies: 22
Views: 664

Re: intermediate

An intermediate is formed and then used up during a reaction, so it cant be used in rate law.
by Alfred Barrion 2H
Sun Mar 01, 2020 11:42 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Voltage
Replies: 6
Views: 60

Re: Voltage

You should use a positive sign, especially when regarding voltage because it can determine if a charge is positive or negative.
by Alfred Barrion 2H
Sun Mar 01, 2020 11:33 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics in Test 2?
Replies: 13
Views: 118

Re: Kinetics in Test 2?

Only the second part of thermodynamics and electrochemistry is covered in test 2.
by Alfred Barrion 2H
Sun Mar 01, 2020 11:30 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Favorability
Replies: 4
Views: 54

Re: Favorability

Kinetics is used to tell the rate of a reaction, instead you can use thermodynamics to determine if a rxn is favorable.
by Alfred Barrion 2H
Sun Mar 01, 2020 11:28 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: units
Replies: 11
Views: 129

Re: units

Typically the unit for rates is mol per liter per time unit.
by Alfred Barrion 2H
Sun Mar 01, 2020 11:20 pm
Forum: Administrative Questions and Class Announcements
Topic: what to know for test 2
Replies: 10
Views: 110

Re: what to know for test 2

I'm pretty sure that test 2 covers all of electrochemistry and the second page of the thermodynamics outline (not covered in the midterm)
by Alfred Barrion 2H
Sun Jan 19, 2020 10:14 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pKa
Replies: 13
Views: 87

Re: pKa

the lower the pKa = the stronger the acid
by Alfred Barrion 2H
Sun Jan 19, 2020 9:55 pm
Forum: Ideal Gases
Topic: ICE Tables
Replies: 8
Views: 98

Re: ICE Tables

you use -x typically for the reactants and +x for the products
by Alfred Barrion 2H
Sun Jan 19, 2020 9:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Q
Replies: 14
Views: 84

Re: K vs Q

k is used when at equilibrium and q is used when not in equilibrium
by Alfred Barrion 2H
Sun Jan 12, 2020 4:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for Kc and Kp
Replies: 3
Views: 38

Re: Units for Kc and Kp

We dont include units for Kp because its a constant.
by Alfred Barrion 2H
Sun Jan 12, 2020 3:56 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and direction
Replies: 4
Views: 41

Q and direction

How does Q let us predict the direction that an equilibrium practice will go through?
by Alfred Barrion 2H
Sun Jan 12, 2020 3:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between Kc and Kp??
Replies: 2
Views: 26

Difference between Kc and Kp??

Hi, I really don't get how to differentiate between Kc and Kp.
by Alfred Barrion 2H
Sun Jan 12, 2020 3:52 pm
Forum: Ideal Gases
Topic: R in PV=nRT
Replies: 34
Views: 664

Re: R in PV=nRT

R is the gas constant, and depending on the units you have in your problem you have to choose a certain R value.
R = 8.314 J·K-1·mol-1 = 8.206 x 10-2 L·atm·K-1·mol-1 = 8.314 x 10-2 L·bar·K-1·mol-1
= 62.364 L·Torr·K-1·mol-1
by Alfred Barrion 2H
Sun Jan 12, 2020 3:51 pm
Forum: Ideal Gases
Topic: Topics on Test 1
Replies: 37
Views: 417

Re: Topics on Test 1

Most likely outline 1 and some of outline 2, whatever he covers right before the test is on the test I think.
by Alfred Barrion 2H
Sun Dec 08, 2019 12:31 am
Forum: Biological Examples
Topic: Important Complexes and their Biological Significance
Replies: 2
Views: 103

Re: Important Complexes and their Biological Significance

We went over porphyrin ligands and the effects in hemoglobin in lecture so I think its fair game for the final.
by Alfred Barrion 2H
Sun Dec 08, 2019 12:28 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: CO2 in blood
Replies: 1
Views: 40

Re: CO2 in blood

Well more H3O+ in the blood would lower pH not make it higher.
by Alfred Barrion 2H
Sun Dec 08, 2019 12:14 am
Forum: Naming
Topic: Ferrate and Cuprate? [ENDORSED]
Replies: 5
Views: 167

Re: Ferrate and Cuprate? [ENDORSED]

You use ferrate and cuprate when naming a coordination compound.
by Alfred Barrion 2H
Sat Dec 07, 2019 11:51 pm
Forum: Naming
Topic: IUPAC Name Convention
Replies: 1
Views: 30

Re: IUPAC Name Convention

Dr Lavelle said you can use IUPAC or the regular naming as long as you stay consistent with it.
by Alfred Barrion 2H
Sat Dec 07, 2019 11:50 pm
Forum: Ionic & Covalent Bonds
Topic: Coulombs equation
Replies: 1
Views: 111

Re: Coulombs equation

q1 and q2 stand for the charges on the interacting objects.
by Alfred Barrion 2H
Sat Dec 07, 2019 11:46 pm
Forum: Student Social/Study Group
Topic: Study websites besides quizlet
Replies: 3
Views: 152

Re: Study websites besides quizlet

I really like using adobe spark for flashcards, its really customizable.
by Alfred Barrion 2H
Sat Dec 07, 2019 11:45 pm
Forum: Student Social/Study Group
Topic: Equilibrium
Replies: 3
Views: 77

Re: Equilibrium

I dont think we need to know equilibrium that deep, but we did talk about k constants in lecture. We're only expected to do calculations on weak acids/bases though.
by Alfred Barrion 2H
Sat Dec 07, 2019 3:39 pm
Forum: Biological Examples
Topic: cisplatin vs transplatin?
Replies: 2
Views: 51

cisplatin vs transplatin?

Whats the difference between cisplatin and transplatin?
by Alfred Barrion 2H
Sat Dec 07, 2019 3:36 pm
Forum: Naming
Topic: Biological Functions
Replies: 2
Views: 65

Re: Biological Functions

Cisplatin can be used in chemotherapy treatment by stopping cell division but I'm not quite sure if it's naturally occurring...
by Alfred Barrion 2H
Sun Dec 01, 2019 6:32 pm
Forum: Student Social/Study Group
Topic: Final Studying
Replies: 8
Views: 103

Re: Final Studying

For the final, try going to as much review sessions as possible that are focused on topics that you need the most help on. I recommend looking for some of the worksheets that the UAs make they're really helpful!
by Alfred Barrion 2H
Sun Dec 01, 2019 6:30 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Relative acidity
Replies: 7
Views: 176

Re: Relative acidity

Bond length is a component of relative acidity. Since the bond length in HI is longer and weaker compared to the short and strong bond in HF, HI is able to dissociate much easier in a solution compared to HF.
by Alfred Barrion 2H
Sun Dec 01, 2019 6:26 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: equation breakdown
Replies: 2
Views: 30

Re: equation breakdown

The pH equation is on a logarithmic scale and is -log[H+]
You basically find the negative log of the concentration of H+ in a solution to find the pH in a strong acid.
by Alfred Barrion 2H
Sun Dec 01, 2019 6:23 pm
Forum: Lewis Acids & Bases
Topic: Difference between Lewis and Bronsted Acids?
Replies: 2
Views: 40

Difference between Lewis and Bronsted Acids?

Hi can someone tell me how Lewis and Bronsted acids are different or similar?
by Alfred Barrion 2H
Sun Dec 01, 2019 6:12 pm
Forum: Student Social/Study Group
Topic: Study Strategies
Replies: 6
Views: 105

Re: Study Strategies

I feel like you should go to the review sessions for topic that you need the most help in. Also office hours too!!
by Alfred Barrion 2H
Sun Dec 01, 2019 6:10 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating pH for Weak Acids and Bases
Replies: 1
Views: 27

Re: Calculating pH for Weak Acids and Bases

I think we'll be going over ICE tables in 14B. Lavelle said we should know how to calculate pH for strong acids and bases, but i think we just need to know K value for weak acids and bases.
by Alfred Barrion 2H
Sun Dec 01, 2019 6:08 pm
Forum: Biological Examples
Topic: EDTA
Replies: 3
Views: 83

Re: EDTA

EDTA can remove metals from a solution. So if your blood had elevated levels of a deadly metal such as mercury, EDTA can help remove it from your bloodstream.
by Alfred Barrion 2H
Sun Nov 24, 2019 11:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape of carbon Dioxide
Replies: 10
Views: 99

Re: Molecular shape of carbon Dioxide

The molecular shape of carbon dioxide is linear bc there's no lone pairs and it has 2 domains.
by Alfred Barrion 2H
Sun Nov 24, 2019 11:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron pair geometry
Replies: 1
Views: 43

Re: Electron pair geometry

the electron pair geometry for NCl2 is tetrahedral since there are 4 domains.
the molecular geometry is bent
by Alfred Barrion 2H
Sun Nov 24, 2019 11:47 pm
Forum: Hybridization
Topic: Hybridization Formulas
Replies: 2
Views: 49

Re: Hybridization Formulas

You have to count the atoms around the atom you're looking at in a molecule.
If there are 4 atoms around the central atom, you'd have sp3
If there are 3 atoms around the central atom, youd have sp2
If there are 2 atoms around the central atom, youd have sp1
by Alfred Barrion 2H
Sun Nov 24, 2019 11:44 pm
Forum: Hybridization
Topic: Sigma and Pi Bonds
Replies: 21
Views: 151

Re: Sigma and Pi Bonds

Usually a sigma bond occurs in single bonds, double bonds and triple bonds.
pi bonds are found in double and triple bond.
Each bond type has a sigma bond
Ex. Double bond=one sigma, one pi
Triple bond: one sigma, two pi
by Alfred Barrion 2H
Sun Nov 24, 2019 11:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Hydrogen Bonding
Replies: 13
Views: 155

Re: Hydrogen Bonding

Yes, hydrogen bonding should have a partial positive or negative charge.
by Alfred Barrion 2H
Wed Nov 20, 2019 3:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Do we need to know the pentagonal bipyramidal model for Test 2?
Replies: 6
Views: 87

Re: Do we need to know the pentagonal bipyramidal model for Test 2?

I don't think you need to know pentagonal bipyramid because its not THAT common, but its nice to know more VSEPR shapes!
by Alfred Barrion 2H
Wed Nov 20, 2019 3:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles in Square Pyramidal and T-Shaped
Replies: 4
Views: 74

Re: Bond Angles in Square Pyramidal and T-Shaped

In a square pyramidal all angles are <90 degrees
In a t-shape the angles are <90 degrees
by Alfred Barrion 2H
Wed Nov 20, 2019 3:09 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Boiling/melting points
Replies: 5
Views: 53

Re: Boiling/melting points

Depending on the IMFs that the molecules have you can compare them to determine which molecule has a higher boiling or melting point.
by Alfred Barrion 2H
Sun Nov 03, 2019 11:22 pm
Forum: Trends in The Periodic Table
Topic: ionization energy vs electronegativity
Replies: 4
Views: 70

ionization energy vs electronegativity

Both have the same trend on the periodic table, but what is the difference between the two?
by Alfred Barrion 2H
Sun Nov 03, 2019 11:21 pm
Forum: Quantum Numbers and The H-Atom
Topic: magnetic quantum number
Replies: 5
Views: 56

Re: magnetic quantum number

The magnetic quantum number, ml tells you the number of orbitals and the way its oriented in a sub shell. it ranges from -l to l.
by Alfred Barrion 2H
Sun Nov 03, 2019 11:18 pm
Forum: Resonance Structures
Topic: Bond lengths
Replies: 11
Views: 134

Bond lengths

Why is it when there is a resonance structure, all of the bond lengths are the same even though there's double and single bonds.
by Alfred Barrion 2H
Sun Nov 03, 2019 11:15 pm
Forum: Formal Charge and Oxidation Numbers
Topic: central atom
Replies: 21
Views: 242

Re: central atom

You would want the formal charge on the central atom to be closer to zero because its supposed to be the least electronegative.
by Alfred Barrion 2H
Sun Nov 03, 2019 11:13 pm
Forum: General Science Questions
Topic: Study Tactics
Replies: 5
Views: 101

Re: Study Tactics

I would focus on lewis structures and resonance because it plays a huge role in drawing a stable structure!
by Alfred Barrion 2H
Sun Oct 27, 2019 11:58 pm
Forum: Ionic & Covalent Bonds
Topic: Anions and Cations
Replies: 4
Views: 40

Anions and Cations

Why do certain elements make anions and others make cations?
by Alfred Barrion 2H
Sun Oct 27, 2019 11:40 pm
Forum: Bond Lengths & Energies
Topic: Double bond vs single bonds
Replies: 4
Views: 78

Double bond vs single bonds

Why are double bond lengths shorter than single bond lengths?
by Alfred Barrion 2H
Sun Oct 27, 2019 11:39 pm
Forum: Electronegativity
Topic: Fluorine's Electronegativity
Replies: 6
Views: 117

Fluorine's Electronegativity

Why is Fluorine touted as the most electronegative atom? What makes it so electronegative?
by Alfred Barrion 2H
Sun Oct 27, 2019 11:35 pm
Forum: Ionic & Covalent Bonds
Topic: Confusion with covalent
Replies: 3
Views: 37

Confusion with covalent

Why do shared atoms want to be at a noble gas configuration?
by Alfred Barrion 2H
Sun Oct 27, 2019 11:34 pm
Forum: Lewis Structures
Topic: Valence Shells
Replies: 2
Views: 36

Valence Shells

Why exactly can P, S, and Cl have more than 8 valence electrons?
by Alfred Barrion 2H
Sun Oct 20, 2019 10:53 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 8
Views: 107

Re: Ionization Energy

As you remove more electrons from an atom, the attraction between electrons and the nucleus increase because repulsion decreases. So as you go through successive ionization energies, more energy is required to remove electrons due to the lack of repulsion.
by Alfred Barrion 2H
Sun Oct 20, 2019 10:37 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions to the rules
Replies: 3
Views: 45

Exceptions to the rules

Why does Cr and Cu not follow the rules for electron configuration? Why isn't the s block completely filled?
by Alfred Barrion 2H
Sun Oct 20, 2019 10:32 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Spin
Replies: 2
Views: 31

Re: Electron Spin

We draw arrows going up first because each electron must enter an empty orbital first before going into the same orbital because of repulsion (two electrons repel). By putting the arrows up before down, it shows how we can minimize repulsion in a specific element.
by Alfred Barrion 2H
Sun Oct 20, 2019 10:27 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electron Configurations
Replies: 2
Views: 39

Re: Writing Electron Configurations

In some answers, the orders may be reversed due to some exceptions in the Aufbau principle in elements such as Cr and Cu.
by Alfred Barrion 2H
Sun Oct 20, 2019 10:23 pm
Forum: DeBroglie Equation
Topic: Conversion Units for 1B.21
Replies: 3
Views: 56

Re: Conversion Units for 1B.21

For ounce to grams use 1 ounce = 28.3 g
For mph to m/s use 1 mph = 0.447 m/s
by Alfred Barrion 2H
Sun Oct 13, 2019 11:43 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Class example
Replies: 2
Views: 27

Re: Class example

The change in energy was negative because we went from a high to low energy level (n=4 to n=2). When finding the frequency, we made the energy positive because you can't have a negative value of Hertz as your answer, since a wave's frequency can not be -6.17*10^14 per second.
by Alfred Barrion 2H
Sun Oct 13, 2019 11:35 pm
Forum: Properties of Light
Topic: Spectroscopic Analysis
Replies: 1
Views: 17

Re: Spectroscopic Analysis

Spectroscopic analysis is the analysis of light emitted by a certain substance. We can use a device called a spectrometer to analyze light (it involves the use of a prism to separate different wavelengths of light). This gives us spectral lines that allow us to analyze light further.
by Alfred Barrion 2H
Sun Oct 13, 2019 9:04 pm
Forum: Properties of Light
Topic: Baler v. Lyman Series
Replies: 10
Views: 153

Re: Baler v. Lyman Series

The Balmer series is found in the visible region of the hydrogen spectral lines and goes from n=3,4,5,... to n=1
The Lyman series is found in the ultraviolet series of the hydrogen spectra and goes from n=2,3,4,... to n=2
by Alfred Barrion 2H
Sun Oct 13, 2019 8:58 pm
Forum: Properties of Electrons
Topic: electron size
Replies: 3
Views: 34

Re: electron size

The diameter of an electron is approximately < 10−18 m.
by Alfred Barrion 2H
Sun Oct 13, 2019 8:54 pm
Forum: Properties of Light
Topic: Wavelength
Replies: 3
Views: 25

Re: Wavelength

When a wavelength is shorter, its frequency is higher therefore there is more energy. Using the equation E=hc/lambda (lambda is the wavelength), a shorter wavelength would make energy hbiggergher, and a longer wavelength would make energy smaller.
by Alfred Barrion 2H
Thu Oct 03, 2019 11:31 pm
Forum: Significant Figures
Topic: How would sig figs be used in a problem?
Replies: 7
Views: 70

Re: How would sig figs be used in a problem?

Problems usually require us to use the least amount of sig figs from the "given" in the problem. Say you get a problem that gives you the following info: 0.179 M AgNO3 and 0.50 L. You would only round your answer to the least amount of sig figs given in the problem, this being 2 sig figs f...
by Alfred Barrion 2H
Thu Oct 03, 2019 11:12 pm
Forum: Molarity, Solutions, Dilutions
Topic: Solutions vs. Dilutions
Replies: 4
Views: 94

Re: Solutions vs. Dilutions

Dilution problems typically use the term "stock solution" when one wants to dilute a certain compound. For example a problem might say you have a stock solution of 12.0 M NaOH and it would want you to figure out how much stock solution is needed to get 250. mL of 2.0 M NaOH. The word "...
by Alfred Barrion 2H
Thu Oct 03, 2019 11:04 pm
Forum: Empirical & Molecular Formulas
Topic: What decimal place to round to when taking masses from the Periodic Table?
Replies: 19
Views: 399

Re: What decimal place to round to when taking masses from the Periodic Table?

For more accuracy, you should use all decimal places on the periodic table that is provided. Feel free to round to the amount of sig figs needed at the end of the problem.
by Alfred Barrion 2H
Thu Oct 03, 2019 11:01 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Aqueous, solid, gas
Replies: 11
Views: 205

Re: Aqueous, solid, gas

You can usually tell if something is solid or gas by looking through the problem you are doing (it is normally given) and it is usually marked on the periodic table. You can determine if a solution is aqueous if you see that it is being dissolved in water or if ions/precipitates are involved in a pr...
by Alfred Barrion 2H
Thu Oct 03, 2019 8:38 pm
Forum: Significant Figures
Topic: Sig figs in intermediate steps??
Replies: 5
Views: 76

Sig figs in intermediate steps??

Hi all, It's been a long time since I've taken chem, but I was wondering if you need to keep on using sig figs on the intermediate steps of a problem. Say your answer has to be 3 sig figs, do I have to keep on using 3 sig figs for each step in the middle of the problem or implement it in the end? Th...

Go to advanced search