Search found 52 matches

by Brynne Burrows 3K
Thu Dec 05, 2019 10:29 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Identify chelate
Replies: 2
Views: 1071

Re: Identify chelate

What is the threshold for the bond angle of a chelating molecule? I have heard the term "spacer atom" but am not sure how this relates to whether a molecule can chelate.
by Brynne Burrows 3K
Wed Dec 04, 2019 12:07 am
Forum: Bronsted Acids & Bases
Topic: Homework Question
Replies: 2
Views: 50

Re: Homework Question

Also, this molecule is not likely to gain more protons because of its stability so it cannot be a Bronsted base (proton acceptor). If you look at the conjugate base SO3]2- this is a stable anion with resonance. It is a conjugate base of a strong acid which will completely dissociate in water and giv...
by Brynne Burrows 3K
Wed Dec 04, 2019 12:01 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Basic or Acidic
Replies: 2
Views: 38

Basic or Acidic

How can we determine if a molecule acts as an acid or a base if there are no hydrogens present in the formula? Is it solely based on the metal or nonmetal present or are there other ways of identifying its characteristics in an aqueous solution?
by Brynne Burrows 3K
Tue Dec 03, 2019 11:50 pm
Forum: Amphoteric Compounds
Topic: Amphoteric vs Amphiprotic
Replies: 9
Views: 99

Re: Amphoteric vs Amphiprotic

Amphiprotic means that a substance can both accept and donate a proton or H+. Amphoteric means that a substance can act as both an acid and a base. All amphoteric substances are amphiprotic because if a molecule can either donate or accept a proton, that means it can act as both an acid or a base. H...
by Brynne Burrows 3K
Tue Dec 03, 2019 11:45 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Hw 6C19
Replies: 3
Views: 55

Re: Hw 6C19

You can look at the anion once the acid has lost its proton and see which anion is more stable due to resonance of the structure or electronegativity, and in this case Chlorine is more electronegative than Phosphorus so chlorine stabilizes the anion more since it is able to withdraw the electrons.
by Brynne Burrows 3K
Tue Dec 03, 2019 11:35 pm
Forum: Biological Examples
Topic: hemoglobin and myoglobin
Replies: 3
Views: 151

Re: hemoglobin and myoglobin

Myoglobin has one heme group and primarily stores oxygen while hemoglobin has 4 heme groups and transports oxygen.
by Brynne Burrows 3K
Thu Nov 28, 2019 12:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test #2 handback
Replies: 11
Views: 158

Re: Test #2 handback

So if I am getting my test back in discussion Friday I will have two days to review it before the final?
by Brynne Burrows 3K
Thu Nov 28, 2019 12:04 pm
Forum: Bronsted Acids & Bases
Topic: Lewis and Bronsted
Replies: 4
Views: 46

Re: Lewis and Bronsted

A Lewis base means that molecule is donating its lone pair, while the Bronsted base accepts a proton. The molecule is still a base either way, it is just the way of wording that changes if its called Lewis or Bronsted.
by Brynne Burrows 3K
Thu Nov 28, 2019 12:01 pm
Forum: Lewis Acids & Bases
Topic: Identifying Acids and Bases
Replies: 8
Views: 132

Re: Identifying Acids and Bases

Strong acids are HCl, H2SO4, HI, HNO3, HBr, and HClO4, weak acids typically have carbon or phosphorus. Some of the strong bases are NaOH, Ba(OH)2, CsOH, and KOH, while weak bases typically have ammines. Nitrogen makes it a weak base because its lone pair can sometimes break the O-H bond in H2O.
by Brynne Burrows 3K
Thu Nov 28, 2019 11:53 am
Forum: Amphoteric Compounds
Topic: Amphoteric
Replies: 8
Views: 102

Re: Amphoteric

I just memorized which elements are amphoteric because the diagonal line is a bit skewed on the periodic table. However elements to the left of that general area are metals and form bases, while elements to the right are nonmetals and form acids.
by Brynne Burrows 3K
Thu Nov 28, 2019 11:48 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Week 9 homework
Replies: 11
Views: 178

Re: Week 9 homework

You would turn in week 9 and 10 at the same time during your next discussion.
by Brynne Burrows 3K
Thu Nov 28, 2019 11:47 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cis vs Trans
Replies: 21
Views: 482

Re: Cis vs Trans

Cis means same side and trans means opposite side, which also means that cis are typically polar charged because there is no cancellation of charges as opposed to trans.
by Brynne Burrows 3K
Mon Nov 18, 2019 8:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E13 part d
Replies: 1
Views: 35

2E13 part d

What is the correct way to draw the Lewis structure for N2O? There can either be a triple bond between the Nitrogen molecules and a single bond between Nitrogen and Oxygen, or a double bond between both N-N and N-O. Should the -1 formal charge be assigned to the Nitrogen atom or Oxygen?
by Brynne Burrows 3K
Mon Nov 18, 2019 8:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: XeF2 Bond Angle and Shape
Replies: 2
Views: 33

Re: XeF2 Bond Angle and Shape

The lone pair electrons spread out equidistant around the equatorial plane and the atoms, as a result, go to either end of the axial plane, as far away from each other as possible. The electron arrangement would appear trigonal bipyramidal while the molecular shape is linear. This is only possible w...
by Brynne Burrows 3K
Mon Nov 18, 2019 8:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Class Curve?
Replies: 4
Views: 97

Re: Class Curve?

I think Lavelle's curve will depend on the overall grades of the students in this quarter's 14A class the percent ranges for letter grades will be determined by his curve for this quarter.
by Brynne Burrows 3K
Mon Nov 18, 2019 8:47 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: Intermolecular Forces in CO2
Replies: 4
Views: 58

Re: Intermolecular Forces in CO2

Since CO2 is a nonpolar molecule, only London dispersion forces are present and therefore would not have dipole-dipole forces. The behavior of the bonds within the molecule, also known as intramolecular forces, does not determine the type of intermolecular forces.
by Brynne Burrows 3K
Mon Nov 18, 2019 8:44 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 7
Views: 94

Re: Test 2

Just to be safe, I would suggest using bent as he taught us.
by Brynne Burrows 3K
Thu Nov 14, 2019 12:11 am
Forum: Administrative Questions and Class Announcements
Topic: Class grading
Replies: 12
Views: 268

Re: Class grading

I know that grades aren't assigned after everything is in the grade book, meaning that he can curve the grades if the average is low.
by Brynne Burrows 3K
Thu Nov 14, 2019 12:05 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: What’s the Difference
Replies: 6
Views: 222

Re: What’s the Difference

Polarizability is the tendency of an anion to be polarized, while polarizing power refers to how much cations can distort the electrons of the anion.
by Brynne Burrows 3K
Thu Nov 14, 2019 12:00 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Problem 2E 7
Replies: 5
Views: 91

Re: Problem 2E 7

005162520 wrote:How would you draw the resonance structure for SOCl2?

S is the central atom, double bonded to the Oxygen atom, single bonded to both Chlorine's, with a lone pair attached to the sulfur.
by Brynne Burrows 3K
Wed Nov 13, 2019 11:56 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: Intermolecular forces
Replies: 10
Views: 147

Re: Intermolecular forces

Most molecules have London forces, which occur between two dipoles, and are the weakest intermolecular forces relative to the others.
by Brynne Burrows 3K
Wed Nov 13, 2019 11:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E9
Replies: 3
Views: 45

Re: 2E9

The lone pair counts as an area of electron density which moves the atoms also bonded to the central atom as far away from each other as possible, which changes the molecule's shape.
by Brynne Burrows 3K
Tue Nov 05, 2019 10:44 am
Forum: Lewis Structures
Topic: Drawing Double Bonds
Replies: 2
Views: 62

Re: Drawing Double Bonds

First make sure the number of lone pairs + bonds on the atom matches the number of valence electrons or is very close so that it results in a low formal charge. Then check if you are maintaining the octet rule on the atoms to know which lone pairs must be taken away.
by Brynne Burrows 3K
Tue Nov 05, 2019 10:42 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: lyman and balmer
Replies: 3
Views: 72

Re: lyman and balmer

If the problem doesn't give you the n final if the electron is losing energy, or they don't give you n initial when an electron is going up levels, then you have to know that Balmer signifies n=2 and Lyman signifies n=1. These will then be plugged into the Rydberg formula to calculate the energy of ...
by Brynne Burrows 3K
Tue Nov 05, 2019 10:37 am
Forum: Octet Exceptions
Topic: Radicals
Replies: 5
Views: 89

Re: Radicals

After drawing the Lewis structure of a molecule you can usually identify a radical because one of the atoms has a single electron due to the odd number of valence electrons that must be accounted for.
by Brynne Burrows 3K
Tue Nov 05, 2019 10:35 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 3
Views: 74

Re: Electron Configuration

When writing electron configuration, 3d always preceeds 4s because it is a lower energy level!
by Brynne Burrows 3K
Tue Nov 05, 2019 10:28 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polar Covalent VS Ionic
Replies: 11
Views: 155

Re: Polar Covalent VS Ionic

Leila_4E wrote:This is really helpful, thank you. I'm also having trouble remembering if the ionic radius trend is different than atomic radius trend?


The ionic radius trend is the same as the atomic radius trend. Decreasing down and to the left.
by Brynne Burrows 3K
Wed Oct 30, 2019 10:23 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Question 1E 1
Replies: 3
Views: 71

Re: Question 1E 1

I don't think the fact that it is a Lithium atom is as significant in this problem as the fact that it is going from the 1s-orbital to the 2p-orbital. This is what tells you that energy will increase, the value of l and n will increase, and the radius will increase because electrons are being added.
by Brynne Burrows 3K
Wed Oct 30, 2019 10:19 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: d block before s block
Replies: 3
Views: 64

Re: d block before s block

I think this partly has to do with an electron being removed from 4s before it would be removed from 3d. The energy level is lower in the 3d shell, so it would come before 4s when 4s has both electrons.
by Brynne Burrows 3K
Wed Oct 30, 2019 10:16 am
Forum: Ionic & Covalent Bonds
Topic: Format of midterm?
Replies: 12
Views: 140

Re: Format of midterm?

I believe the entire test will be free response questions like the first one, but I am not 100% sure.
by Brynne Burrows 3K
Wed Oct 30, 2019 10:14 am
Forum: Lewis Structures
Topic: Formal charge
Replies: 9
Views: 111

Re: Formal charge

aphung1G wrote:Can someone explain how to find the lone pair electrons when trying to find the formal charge?

Whichever pairs of electrons that cannot be replaced by a bond when the Lewis structure is drawn out can be counted as a lone pair. It helps to see the picture in order to determine lone pair electrons.
by Brynne Burrows 3K
Wed Oct 30, 2019 10:10 am
Forum: Ionic & Covalent Bonds
Topic: Atomic and ionic radii
Replies: 3
Views: 51

Re: Atomic and ionic radii

Atomic radius is half the diameter measured across one ground state atom, while ionic radius is half the distance between the nuclei of two ionically bonded atoms.
by Brynne Burrows 3K
Wed Oct 23, 2019 8:58 pm
Forum: DeBroglie Equation
Topic: DeBroglie Equation
Replies: 11
Views: 148

Re: DeBroglie Equation

De Broglie's Equation proves wavelike properties of electrons by finding wavelength, and the equation is Planck's constant/(mass x velocity) is used for this.
by Brynne Burrows 3K
Wed Oct 23, 2019 8:43 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Subshell vs. Orbital
Replies: 9
Views: 160

Re: Subshell vs. Orbital

n correlates to the shell; l correlates to the subshell; ml correlates to the orbital.
by Brynne Burrows 3K
Wed Oct 23, 2019 8:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 177
Views: 13506

Re: Advice from a Medical Student - Part II [ENDORSED]

I love your perspective on being able to take these classes at UCLA and how big of an opportunity this is for us and maybe our last opportunity to learn about this subject material! Thank you so much for sharing and good luck with the rest of your journey!!
by Brynne Burrows 3K
Wed Oct 23, 2019 8:26 pm
Forum: Trends in The Periodic Table
Topic: Electron affinity
Replies: 5
Views: 45

Re: Electron affinity

The elements in the top right of the periodic table have shells that are nearly full, meaning they need few electrons to complete an octet, whereas elements in the bottom left corner of the periodic table need to gain far more electrons in order to have an octet.
by Brynne Burrows 3K
Wed Oct 23, 2019 8:22 pm
Forum: Trends in The Periodic Table
Topic: Exceptions
Replies: 3
Views: 53

Exceptions

What are the exceptions to the trends in the periodic table when talking about ionization energy?
by Brynne Burrows 3K
Mon Oct 14, 2019 10:28 pm
Forum: DeBroglie Equation
Topic: DeBroglie
Replies: 3
Views: 43

Re: DeBroglie

His equation supports the fact that all matter -- if it is small enough -- has wavelike properties. Using Planck's constant and the momentum (mass*velocity) of the object, the wavelength of that object can be found because it has wavelike properties.
by Brynne Burrows 3K
Mon Oct 14, 2019 10:22 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 16
Views: 285

Re: Atomic Radius

Atomic radii are only measured in the ground state, not in the excited state.
by Brynne Burrows 3K
Mon Oct 14, 2019 10:20 pm
Forum: Properties of Electrons
Topic: calculating frequency
Replies: 3
Views: 68

Re: calculating frequency

In terms of frequency, a negative value cannot be obtained because it is the number of waves over a given unit of time. Negative values represent the loss or gain of energy in terms of a change in energy under the Bohr frequency condition.
by Brynne Burrows 3K
Mon Oct 14, 2019 10:16 pm
Forum: Student Social/Study Group
Topic: De Broglie and Heseinberg
Replies: 2
Views: 48

Re: De Broglie and Heseinberg

The mass of one electron is 9.109*10^-28 grams
by Brynne Burrows 3K
Mon Oct 14, 2019 10:12 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Unit keV
Replies: 4
Views: 108

Re: Unit keV

Here is the conversion from keV to J:
E = (140.11*10^3 eV)*(1.6022*10^-19 J/eV) = 2.2513*10^-14 J
by Brynne Burrows 3K
Fri Oct 11, 2019 1:23 am
Forum: Properties of Light
Topic: Emission/line spectrum
Replies: 3
Views: 48

Re: Emission/line spectrum

I think it is more conceptual, but also has to do with calculating the distances between spectral lines as was explained through the sketch during the last lecture. Visible light has smaller gaps between lines whereas ultraviolet has ones farther apart so the value of change in E is greater.
by Brynne Burrows 3K
Fri Oct 11, 2019 1:18 am
Forum: DeBroglie Equation
Topic: How to know which equation to use
Replies: 9
Views: 200

Re: How to know which equation to use

Both of those equations are referring to v as frequency instead of velocity, but you can use velocity in the equation E=1/2Me*Ve.
by Brynne Burrows 3K
Fri Oct 11, 2019 1:16 am
Forum: Einstein Equation
Topic: E=hv
Replies: 43
Views: 4496

Re: E=hv

E in this equation represents the energy of the photon. In some cases, it could also be equal to the energy required to remove an electron if the kinetic energy is 0. This is shown in the formula E(photon) - work function = Kinetic energy. If the Kinetic energy is 0, then the energy of the photon is...
by Brynne Burrows 3K
Fri Oct 11, 2019 1:12 am
Forum: Empirical & Molecular Formulas
Topic: Formula Units
Replies: 10
Views: 168

Re: Formula Units

Formula units are the amount of said material object, such as molecule, atom, compound, etc. The formula units are a quantitative measurement of the amount of any given thing.
by Brynne Burrows 3K
Fri Oct 11, 2019 1:10 am
Forum: Photoelectric Effect
Topic: Wavelengths?
Replies: 8
Views: 159

Re: Wavelengths?

The intensity of the photons hitting the metal surface is not as important as the frequency of the photons hitting the metal. Higher energy light results from the increased frequency, in other words a shorter wavelength, because all of these variables have a proportional relationship to one another.
by Brynne Burrows 3K
Thu Oct 03, 2019 9:58 pm
Forum: SI Units, Unit Conversions
Topic: How to format homework
Replies: 9
Views: 149

Re: How to format homework

On my paper is name, section and lecture #, date, and UID.
by Brynne Burrows 3K
Thu Oct 03, 2019 9:48 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: avogadro number
Replies: 7
Views: 399

Re: avogadro number

The number of units (atoms, molecules, compounds, etc.) in a mole.
by Brynne Burrows 3K
Thu Oct 03, 2019 9:47 pm
Forum: Significant Figures
Topic: Sig Figs on the Test
Replies: 3
Views: 72

Re: Sig Figs on the Test

You should use however many sig figs are given in the original problem, even when considering periodic table molar masses.
by Brynne Burrows 3K
Thu Oct 03, 2019 9:44 pm
Forum: Balancing Chemical Reactions
Topic: Compound names
Replies: 11
Views: 190

Re: Compound names

We will be given the necessary compound names on tests, so no we do not have to memorize them.
by Brynne Burrows 3K
Thu Oct 03, 2019 9:42 pm
Forum: Limiting Reactant Calculations
Topic: Basic Question
Replies: 11
Views: 169

Re: Basic Question

There can only be one limiting reactant in a chemical reaction. Sometimes the reactants are present in equal amounts so there would be none in this case.

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