Search found 50 matches

by Sarah_Coufal_3k
Sat Dec 07, 2019 1:42 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: acid & bases to memorize
Replies: 3
Views: 28

Re: acid & bases to memorize

I think the best way is to memorize the strong acids and bases and if you come across one that is not on that list, it is weak. Fundametals J has a table as well that lists them. Strong Acids: HCl HI HBr H2So4 HNO3 HCLO4 HCLO3 Strong Bases: these include basically all of the group one metals + hydro...
by Sarah_Coufal_3k
Sat Dec 07, 2019 1:22 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Naming Coordination Compounds on Final
Replies: 2
Views: 25

Re: Naming Coordination Compounds on Final

Yes, it is probably most efficient to memorize those so you can write out compound names correctly
by Sarah_Coufal_3k
Thu Dec 05, 2019 5:34 pm
Forum: *Titrations & Titration Calculations
Topic: Confusion
Replies: 1
Views: 25

Re: Confusion

He was saying that 14B will start with titrations and finding out molarity when it is a weak acid/base not strong one
by Sarah_Coufal_3k
Thu Dec 05, 2019 5:32 pm
Forum: General Science Questions
Topic: Final
Replies: 2
Views: 16

Re: Final

cumulative final
by Sarah_Coufal_3k
Wed Dec 04, 2019 1:42 pm
Forum: Naming
Topic: latin names
Replies: 3
Views: 23

Re: latin names

When the overall complex in brackets is negative add -ate to the end of the transition metal name. However, in iron make it ferrate. (example of another would be nickel-nickelate)
by Sarah_Coufal_3k
Wed Dec 04, 2019 1:34 pm
Forum: Naming
Topic: Tips on Naming
Replies: 5
Views: 34

Re: Tips on Naming

A lot of resources on Lavelle's website!!
by Sarah_Coufal_3k
Sat Nov 30, 2019 11:50 pm
Forum: Student Social/Study Group
Topic: Preparing for the final
Replies: 25
Views: 136

Re: Preparing for the final

I think the TA review sessions help a lot, try to go to as may as you can even on the same subject for reinforcement etc.
by Sarah_Coufal_3k
Sat Nov 30, 2019 11:47 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: strong or weak base?
Replies: 13
Views: 40

Re: strong or weak base?

inorganic acids are. often much stronger than organic acids as well. Also there is a helpful table about strong acids and bases in the textbook. I believe it's in fundamentals J
by Sarah_Coufal_3k
Sat Nov 30, 2019 11:43 pm
Forum: Naming
Topic: Naming
Replies: 4
Views: 19

Re: Naming

I think it's because the overall compound has a negative charge. Usually when a transition metal is used it has an overall positive charge so it's odd when it's negative. Lavelle said adding -ate to transition metals sounds weird too so use that to remember it's an odd compound with an overall negat...
by Sarah_Coufal_3k
Sat Nov 30, 2019 10:59 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Content
Replies: 14
Views: 65

Re: Final Exam Content

Will the final have emphasis on material post midterm and discussion tests. Or is it a likely split between everything we learned?
by Sarah_Coufal_3k
Sat Nov 30, 2019 10:58 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2 Grades
Replies: 10
Views: 73

Re: Test 2 Grades

The grades are up on myUCLA !
by Sarah_Coufal_3k
Sun Nov 24, 2019 7:41 pm
Forum: Lewis Acids & Bases
Topic: Proton acceptor and proton donor?
Replies: 33
Views: 96

Re: Proton acceptor and proton donor?

Acids are proton donors. Bases are proton acceptors. Something that is acidic has a lot of protons in it, because the acids lost them (i.e donated) in the solution.
by Sarah_Coufal_3k
Sun Nov 24, 2019 7:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs linear
Replies: 56
Views: 187

Re: Bent vs linear

Bent has 1 or 2 lone pairs- either AX2E or AX2E2. They are bent because the lone pairs repel the electrons on the bonded atoms.
by Sarah_Coufal_3k
Sun Nov 24, 2019 7:35 pm
Forum: Trends in The Periodic Table
Topic: Pneumonic devices for trends
Replies: 4
Views: 32

Re: Pneumonic devices for trends

I do the arrow thing as well. I draw an arrow going from bottom to top on the side, and left to right. Lastly a diagonal aloo from bottom left to top right. These are all for increasing electronegativity and ionization energy.
by Sarah_Coufal_3k
Sun Nov 24, 2019 7:26 pm
Forum: Administrative Questions and Class Announcements
Topic: final exam
Replies: 9
Views: 51

Re: final exam

^ there is more information about the final on his syllabus
by Sarah_Coufal_3k
Wed Nov 20, 2019 5:26 pm
Forum: Hybridization
Topic: hybridization on the test?
Replies: 10
Views: 67

hybridization on the test?

Is Hybridization on the test? or is it only until sigma and pi bonds?
by Sarah_Coufal_3k
Sun Nov 17, 2019 4:27 pm
Forum: Sigma & Pi Bonds
Topic: Sigma V Pi
Replies: 5
Views: 22

Re: Sigma V Pi

Dr. Lavelle said he will go over this more in depth on Monday as well
by Sarah_Coufal_3k
Sun Nov 17, 2019 4:22 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: AXE formula
Replies: 32
Views: 1443

Re: AXE formula

Yes you can, and they will. usually be the same. Looking at the AXE formula, X is number of bonded pairs to central atoms and E is number of lone pairs. With this you can understand the number of electron densities but also the number of bonded atoms. So you can use both to figure out the shape and ...
by Sarah_Coufal_3k
Sun Nov 17, 2019 4:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR repulsion model
Replies: 8
Views: 34

Re: VSEPR repulsion model

As said above, the strength of repulsion would affect the angles, which will also affect the shape. a lone pair lone pair would have greater repulsion and so the bond angle would be larger because they can't get as close to each other
by Sarah_Coufal_3k
Sun Nov 17, 2019 4:15 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: AXE
Replies: 5
Views: 34

Re: AXE

I believe Dr. Lavelle said that molecules with the same AXE formula have the similar molecular shape so yes. For Example AX4 is usually tetrahedral and AX2E1 is usually trigonal pyramidal
by Sarah_Coufal_3k
Thu Nov 14, 2019 6:57 pm
Forum: Bond Lengths & Energies
Topic: Week 7 Homework
Replies: 15
Views: 124

Re: Week 7 Homework

I think anything not on the midterm to the beginning of the new outline is ok
by Sarah_Coufal_3k
Sun Nov 10, 2019 2:03 pm
Forum: Dipole Moments
Topic: Dipoles between the same elements
Replies: 3
Views: 22

Re: Dipoles between the same elements

Molecules like O2 ad Br2 and F2 etc. do not have dipoles. This is because they have the same electronegativity so each atom pulls the electrons an equal amount towards their own nucleus. Dipoles occurs when an atom pulls the electrons towards it more than another atom
by Sarah_Coufal_3k
Sun Nov 10, 2019 2:00 pm
Forum: Octet Exceptions
Topic: octet exceptions
Replies: 11
Views: 94

Re: octet exceptions

Basically most elements in period 3 and beyond. This is because there is now the D sub shell that can be filled. In addition Boron can be satisfied with either 8 or 6 electrons.
by Sarah_Coufal_3k
Sun Nov 10, 2019 1:53 pm
Forum: Dipole Moments
Topic: Boiling Point
Replies: 11
Views: 55

Re: Boiling Point

When a bond is stronger, it needs more energy to be broken. There is more energy in higher temperature. So when a bond is really strong, it needs more energy to be broken (and go to different state) i.e it has a higher boiling point/melting point. Similarly when a bond is weak, it needs little energ...
by Sarah_Coufal_3k
Fri Nov 08, 2019 9:54 am
Forum: Administrative Questions and Class Announcements
Topic: Homework
Replies: 2
Views: 27

Homework

Can homework this week be from the chemical bonds section? (outline 3, section 2 of the textbook)
by Sarah_Coufal_3k
Fri Nov 08, 2019 9:47 am
Forum: Lewis Structures
Topic: Midterm grades
Replies: 26
Views: 195

Re: Midterm grades

At least a week
by Sarah_Coufal_3k
Sun Nov 03, 2019 5:23 pm
Forum: Lewis Structures
Topic: More stable structures
Replies: 2
Views: 23

Re: More stable structures

I think the question on the exam may make it clear whether it wants multiple versions. For example if it is talking about resonance or if it says "make the lowest energy structure". Some lewis structure have the same formal charge when changed and others are variable. I think when you are ...
by Sarah_Coufal_3k
Sun Nov 03, 2019 5:20 pm
Forum: Octet Exceptions
Topic: Radical
Replies: 6
Views: 32

Re: Radical

A radical is an atom, molecule, or ion with at least one unpaired electron. This is highly reactive, because this single electron is unstable and the molecule doesn't want it.
by Sarah_Coufal_3k
Sun Nov 03, 2019 12:34 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configurations of ions
Replies: 4
Views: 29

Re: Electron configurations of ions

It's mainly so you won't mess up and remove it from the wrong shell. This is especially important when you get to the fourth row and start using the D block. Because you would fill up an electron from low to high energy, 4S starts out lower energy than 3d, but once 3d has an electron now it's a lowe...
by Sarah_Coufal_3k
Sat Nov 02, 2019 9:07 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: delta V. in. Heisenberg questions
Replies: 2
Views: 26

delta V. in. Heisenberg questions

In 1.B.27,the question says: a bowling ball of 8 .00kg is being rolled down an alley lane at 5.00 +/- 5.0 m/s. what is the minimum uncertainty in its position? For uncertainty in velocity (delta v), would it be 10 or 5? I thought it would be 10. because the range is from 0-10, however the solutions ...
by Sarah_Coufal_3k
Mon Oct 28, 2019 10:32 am
Forum: General Science Questions
Topic: midterm review sessions
Replies: 1
Views: 29

midterm review sessions

In light of classes being canceled, are the step-up programs/ midterm review sessions still happening today?
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:49 pm
Forum: Properties of Light
Topic: Threshold Frequency
Replies: 5
Views: 35

Re: Threshold Frequency

I believe Threshold Frequency is the amount of energy of a photon required to displace an electron on a metal surface. The photon needs to at least match the threshold, which will result in a kinetic energy of 0.
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:47 pm
Forum: Trends in The Periodic Table
Topic: Location of elements
Replies: 12
Views: 75

Re: Location of elements

You should probably know the groupings, because that might help determine how they react with other elements/atoms.
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:45 pm
Forum: Trends in The Periodic Table
Topic: bond length
Replies: 9
Views: 58

Re: bond length

I think he was just talking about the different types to inform us. Also to show how the length can be shorter when attraction is greater. I think he just used the numbers to help us understand better, not have a way to calculate it.
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:42 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Order of electron configuration
Replies: 6
Views: 32

Re: Order of electron configuration

After Atomic number 20 (i.e. 20 electrons) 3d has a slightly lower energy level and you want to fill them from low to high. So do 3d and then 4s
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:38 pm
Forum: Resonance Structures
Topic: defintion
Replies: 7
Views: 60

Re: defintion

Resonance structures are different versions of lewis structures for the same molecule and there are equivalent models.
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:30 pm
Forum: Ionic & Covalent Bonds
Topic: ground state electron configurations
Replies: 3
Views: 52

Re: ground state electron configurations

If it is in a plus 3 state, shouldn't we subtract 3 electrons instead of add?
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:26 pm
Forum: Ionic & Covalent Bonds
Topic: What topic are we on?
Replies: 11
Views: 91

Re: What topic are we on?

Because it's a transition week you can either turn in homework on either Quantum or Chemical bonds
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:22 pm
Forum: Ionic & Covalent Bonds
Topic: Octet Rule
Replies: 6
Views: 41

Re: Octet Rule

They don't have enough electrons to begin with to then go form an octet. It would take a lot of energy to do so I think. Hydrogen can only have two in its first shell, so it has its own version of the octet rule
by Sarah_Coufal_3k
Wed Oct 23, 2019 11:20 pm
Forum: Lewis Structures
Topic: lewis drawings
Replies: 8
Views: 76

Re: lewis drawings

I think a problem on a test would be to draw out the lewis structure, but it would only ask for one way. But all variations would get credit. I would ask Dr. Lavelle to be sure.
by Sarah_Coufal_3k
Sun Oct 13, 2019 5:35 pm
Forum: Properties of Light
Topic: 'light intensity'
Replies: 8
Views: 49

Re: 'light intensity'

I think increasing intensity of light only increases the amplitude/height of a wave but does not change wavelength or the energy emitted. So more photons would be emitted but the energy of each photon wouldn't change. To change the energy of a light wave, the frequency has to change. As we learned, ...
by Sarah_Coufal_3k
Sun Oct 13, 2019 5:25 pm
Forum: DeBroglie Equation
Topic: Diffraction patterns
Replies: 4
Views: 32

Re: Diffraction patterns

I'm not sure how to identify them. But constructive interference occurs when two light sourced are in phase with each other, such as peak on peak. This can result in bigger peaks. Destructive interference occurs when the light waves are not in phase with each other and as a result are smaller peaks
by Sarah_Coufal_3k
Sun Oct 13, 2019 5:21 pm
Forum: Significant Figures
Topic: When to apply Sig Figs
Replies: 6
Views: 28

Re: When to apply Sig Figs

during your calculations, do not round to sig figs until the final answer. I think when you are doing a problem you can write the number as 3.456.. to show you have the rest of the number saved in you calculator and are going from that
by Sarah_Coufal_3k
Sun Oct 13, 2019 5:16 pm
Forum: Significant Figures
Topic: How Many Sig Figs
Replies: 7
Views: 57

Re: How Many Sig Figs

On Lavelle's main page of his website there is a document that answers a bunch of questions about sig figs. One thing I noticed that was important was in addition and subtraction go by the fewest number of decimal places. But in multiplication and division just the fewest number of sig figs
by Sarah_Coufal_3k
Sun Oct 13, 2019 5:08 pm
Forum: SI Units, Unit Conversions
Topic: Unit conversion
Replies: 15
Views: 130

Re: Unit conversion

I think the best way to do conversions like this is to use dimensional analysis. nm to meters to angstroms. I think also be aware of what your answer looks like. For example, if you are going. from nm to angstroms thats going. from 10^-9 to 10^-10. An angstrom is smaller scale, and there are more an...
by Sarah_Coufal_3k
Sun Oct 06, 2019 4:50 pm
Forum: Properties of Light
Topic: unit change
Replies: 4
Views: 37

Re: unit change

It's the units of Hz. 5 Hz and 5 s^-1 and 5 cycles per second are all the same/
by Sarah_Coufal_3k
Sun Oct 06, 2019 4:48 pm
Forum: Limiting Reactant Calculations
Topic: Reactant vs. Reagent
Replies: 4
Views: 37

Re: Reactant vs. Reagent

For the sake of our class, I think it's reagents/reactants on the left side and products on the right side.
by Sarah_Coufal_3k
Sun Oct 06, 2019 4:44 pm
Forum: Limiting Reactant Calculations
Topic: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
Replies: 68
Views: 1314

Re: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]

I don't think you have to show as many steps as in discussion. However, if you mess up the final answer, but show your correct process, you might receive partial credit.
by Sarah_Coufal_3k
Sun Oct 06, 2019 4:41 pm
Forum: SI Units, Unit Conversions
Topic: Unit Conversions
Replies: 11
Views: 107

Re: Unit Conversions

1mole of atoms is 6.022 * 10^23, which is Avogadro's number. To convert atoms to moles, you take the number of atoms and divide by Avogadro's number. A easy analogy is: Think of 36 eggs and you want to know how many dozens. you divide the number of eggs by the number that represents the dozen which ...
by Sarah_Coufal_3k
Sun Oct 06, 2019 4:33 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Theoretical vs. Actual Yield
Replies: 38
Views: 316

Re: Theoretical vs. Actual Yield

Theoretical yield is the maximum amount of product you could get out of a reaction. I don't think actual yield can ever be more than theoretical. Products can get stuck in the beaker and tubes when doing a reaction or measuring, so it will be less than the maximum. Then you can divide the actual yie...

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