Search found 63 matches

by Mikayla Kwok 3K
Fri Jan 15, 2021 4:30 pm
Forum: General Science Questions
Topic: pH to PKa
Replies: 3
Views: 24

Re: pH to PKa

I think we will learn this later, but you can get pKa from pH and pH from pKa by rearranging the Henderson-Hasselbalch equation, pH = pKa + log([base]/[acid]).
by Mikayla Kwok 3K
Fri Jan 15, 2021 4:26 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Ionization vs Protonation
Replies: 2
Views: 8

Re: Ionization vs Protonation

Ionization is the process of dissociating into ions, as an acid would dissociate into H+ and its conjugate base. Protonation is the process of receiving a H+ ion, just as a base may receive a proton. I think this is why percent ionization is for acids and percent protonation is for bases.
by Mikayla Kwok 3K
Fri Jan 15, 2021 4:00 pm
Forum: General Science Questions
Topic: Significant Figures and Rounding
Replies: 3
Views: 19

Re: Significant Figures and Rounding

I just wanted to add that I think we have been rounding values throughout calculations, because we are implementing different sigfig rules. We are using the classic multiplication sigfig rules but also the log sigfig rules, which would require you to round at different points in the problem. This wo...
by Mikayla Kwok 3K
Fri Jan 15, 2021 3:52 pm
Forum: Administrative Questions and Class Announcements
Topic: acids and bases on the midterm
Replies: 6
Views: 31

Re: acids and bases on the midterm

I think we are expected to know a lot of 14A acid-base content (like strong acids and bases, identifying acids and bases, etc.). It seems like you need to use a lot of this foundational information to do the 14B problems.
by Mikayla Kwok 3K
Fri Jan 15, 2021 3:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #3
Replies: 5
Views: 30

Re: Sapling #3

Your last equation should read 53.3 = 4x^2/(0.3-x)(0.3-x). This is because you are squaring (2x), not just the (x) in the equilibrium expression.
by Mikayla Kwok 3K
Fri Jan 15, 2021 3:46 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: What is autoprotolysis? lavelle's lecture 1/15 [ENDORSED]
Replies: 7
Views: 37

Re: What is autoprotolysis? lavelle's lecture 1/15 [ENDORSED]

Autoprotolysis is the self-ionization of water. The reaction is 2H2O <----> H3O+ + OH-.
by Mikayla Kwok 3K
Wed Jan 06, 2021 11:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Boundaries for high and low K values
Replies: 3
Views: 22

Re: Boundaries for high and low K values

I think it is technically correct to use K<1 and K>1 to determine equilibrium shifts, but you would have to describe the equilibrium as "slightly" rather than "strongly" favoring one direction. However, using K<10^-3 and K<10^3 is especially helpful when doing ICE tables, because...
by Mikayla Kwok 3K
Wed Jan 06, 2021 11:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constant dependence on concentrations
Replies: 3
Views: 24

Re: Equilibrium constant dependence on concentrations

I think the equilibrium constant is only dependent on temperature. This means changing the concentrations and volume would not change the value of the equilibrium constant if the temperature remains the same.
by Mikayla Kwok 3K
Wed Jan 06, 2021 11:16 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Halogens
Replies: 6
Views: 65

Re: Halogens

I agree with Karl. I don't think that a reaction involving a halogen is automatically exothermic. For instance, 2HCl -> H2 + Cl2 is endothermic.
by Mikayla Kwok 3K
Wed Jan 06, 2021 10:54 pm
Forum: Ideal Gases
Topic: Ideal Gas Law Question
Replies: 11
Views: 52

Re: Ideal Gas Law Question

I don't think temperature is a constant in the ideal gas law equation, because it is not a fixed value. It can be any value based on the circumstances given in the problem. When you are trying to convert between concentration and partial pressure in a practice problem, you just input the temperature...
by Mikayla Kwok 3K
Wed Jan 06, 2021 10:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How do you know when to use Kc vs Kp?
Replies: 9
Views: 46

Re: How do you know when to use Kc vs Kp?

I believe if at least one of the species involved in the reaction is aqueous, you should use Kc, because you cannot convert the concentration of an aqueous species to partial pressure. However, if the species are all in the gas phase, you can use either Kc or Kp, and the problem probably would speci...
by Mikayla Kwok 3K
Fri Dec 11, 2020 4:25 pm
Forum: Naming
Topic: "ate" and "ic"
Replies: 4
Views: 42

Re: "ate" and "ic"

Just to add to what Anirudh said, I believe an acid with the name "hydro___ic acid" has no oxygen atoms, while an acid with the name "___ic acid" is an oxyacid and has oxygen atoms.
by Mikayla Kwok 3K
Fri Dec 11, 2020 4:18 pm
Forum: Electronegativity
Topic: help with a periodic trend problem?
Replies: 3
Views: 46

Re: help with a periodic trend problem?

I think MgS is the answer, because Mg2+ is a small, highly charged cation, which makes it very polarizing, and S2- is a relatively large anion, which makes it polarizable. These characteristics cause the Mg2+ ion to pull more electrons from S2- into a shared region, which gives the ionic bond more c...
by Mikayla Kwok 3K
Fri Dec 11, 2020 4:06 pm
Forum: Einstein Equation
Topic: units for E=hv
Replies: 11
Views: 107

Re: units for E=hv

I think E=hv is used for electromagnetic radiation, so it should be generally used with the units J/photon. However, if the problem makes a comment about one atom being associated with one photon, I think that's when you would use J/atom.
by Mikayla Kwok 3K
Fri Dec 11, 2020 4:04 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid Strength of Oxoacids
Replies: 2
Views: 50

Re: Acid Strength of Oxoacids

You can also justify the textbook's answer by thinking about the structures in terms of resonance rather than electronegativity, because having more oxygen atoms in the acid provides more resonance options for one acid, which makes its anion more stable and, therefore, makes the acid stronger.
by Mikayla Kwok 3K
Fri Dec 11, 2020 3:58 pm
Forum: Air Pollution & Acid Rain
Topic: pH of hard water
Replies: 4
Views: 50

Re: pH of hard water

I think hard water is alkaline, because it contains a bunch of minerals with cations.
by Mikayla Kwok 3K
Fri Dec 04, 2020 6:42 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Stability of Anions Resulting From Acids
Replies: 3
Views: 42

Re: Stability of Anions Resulting From Acids

I think HOF is the stronger acid. Because HFO, HClO, HBrO, and HIO all have to break the same H-O bond to dissolve, we cannot judge acid strengths based on bond lengths. Instead, we have to compare anion stabilities. As you said, FO- is more more stable than ClO-, because F is more electronegative, ...
by Mikayla Kwok 3K
Fri Dec 04, 2020 6:26 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: exchanging H for Cl allows for resonance
Replies: 2
Views: 31

Re: exchanging H for Cl allows for resonance

I don't think replacing the H atoms with Cl enabled more resonance, because both CH3COOH and CCl3COOH have a C-O bond and a C=O bond, both of which experience resonance. However, the CCl3COO- anion is still more stable, because Cl is more electronegative than H. The three electronegative Cl atoms pu...
by Mikayla Kwok 3K
Fri Dec 04, 2020 6:18 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: calculating
Replies: 2
Views: 35

Re: calculating

I don't think the H3O+ concentration is always the same. A problem may ask you to find the H3O+ concentration based on a given pH, so the H3O+ concentration would depend on the given pH. Another problem may ask you to find the pH based on the given H3O+ concentration. In that case, the H3O+ concentr...
by Mikayla Kwok 3K
Fri Dec 04, 2020 6:11 pm
Forum: Conjugate Acids & Bases
Topic: Definition of "Conjugate"
Replies: 5
Views: 45

Re: Definition of "Conjugate"

A conjugate acid is the compound formed from the base after the base receives the proton donated by the acid. A conjugate base is the compound formed from the acid after having given away its proton to the base. For instance, in the reaction NH3 + H2O --> NH4+ + OH-, NH3+ is the base, H2O is the aci...
by Mikayla Kwok 3K
Fri Dec 04, 2020 6:07 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH Question
Replies: 2
Views: 35

Re: pH Question

I am not completely sure about my answer, but pure water has a pH and a pOH of 7, which means that even though it is a pure substance, not a solution, it still has a [OH-] and [H3O+] of 10^-7. Adding a solute in would just manipulate the concentrations by increasing one and decreasing the other, not...
by Mikayla Kwok 3K
Wed Nov 25, 2020 10:27 pm
Forum: Naming
Topic: chelating ligand
Replies: 7
Views: 71

Re: chelating ligand

I believe you would have to draw the lewis structure of the molecule first if given the molecular formula, but after that, you can find out whether the ligand has multiple atoms with attachment sites (lone pairs), single bonds for rotation abilities, and spacers between the atoms with lone pairs tha...
by Mikayla Kwok 3K
Wed Nov 25, 2020 10:19 pm
Forum: Biological Examples
Topic: Cisplatin Cell Division Question
Replies: 2
Views: 34

Re: Cisplatin Cell Division Question

I think Dr. Lavelle says that cisplatin bonds to the DNA strand tightly and kind of acts as a blockade. When the replicating protein attaches to the DNA strand and moves along it for replication, it is stopped by this ligand and cannot proceed through to copy the rest of the strand. I believe he say...
by Mikayla Kwok 3K
Wed Nov 25, 2020 10:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bonds
Replies: 4
Views: 31

Re: Bonds

Bond multiplicity does not affect molecular shape, because single, double, and triple bonds all constitute a single electron density, or region where the electrons are located. The number of electron densities affect the molecular shape, not the number of bonds attached to the central atom. Experime...
by Mikayla Kwok 3K
Wed Nov 25, 2020 9:53 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordinate Compounds
Replies: 5
Views: 55

Re: Coordinate Compounds

I don't think you need a transition metal to form a coordination compound, just a Lewis acid and a Lewis base (one species to donate a lone pair and another to accept a lone pair). The Lewis acid is usually a transition metal cation though, because it has more empty valence orbitals to accept lone p...
by Mikayla Kwok 3K
Wed Nov 25, 2020 9:46 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand bonding
Replies: 1
Views: 37

Re: Ligand bonding

I am not completely sure about this answer, but I think a ligand can form two bonds with the TM if it is bidentate. If you are wondering about a ligand forming a double bond, as in two bonds from a single atom within the ligand to the TM, I don't think this is possible, because Dr. Lavelle mentions ...
by Mikayla Kwok 3K
Wed Nov 25, 2020 9:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling Question #12
Replies: 2
Views: 23

Re: Sapling Question #12

I drew this structure and got it correct. Did you scroll down and answer the other two questions? They ask about hybridization and polarity. Maybe either of those two questions was answered incorrectly.
by Mikayla Kwok 3K
Sun Nov 22, 2020 6:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 6
Views: 37

Re: Lone Pairs

I think he's saying that lone pairs occupy more space than bonding pairs. This is because they are only attracted to one nucleus, which makes them more loosely held and more expandable. This is also why when a molecule has a lone pair, the bond angles between the other atoms decrease.
by Mikayla Kwok 3K
Sun Nov 22, 2020 6:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Remembering Molecular Shapes
Replies: 4
Views: 31

Re: Remembering Molecular Shapes

I went to Justin's workshop this weekend, and he recommended using this website (http://intro.chem.okstate.edu/1314F00/Lecture/Chapter10/VSEPR.html) to get familiar with molecular shapes. They have rotating 3-D models to help with spatial recognition. With more practice, I think we should be able to...
by Mikayla Kwok 3K
Sun Nov 22, 2020 6:00 pm
Forum: Lewis Structures
Topic: # of electrons in expanded valence
Replies: 6
Views: 51

Re: # of electrons in expanded valence

I think the question is asking you to find the valence of the atom with the expanded octet. This means you should count the total number of valence electrons on the atom with the expanded octet, and your answer should be greater than 8.
by Mikayla Kwok 3K
Sun Nov 22, 2020 5:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 39

Re: Bond Angles

I think this is true! In order for the bond angle to decrease to less than 109.5 degrees on one end of the molecule, the other side must increase (due to the electron repulsion from the lone pair, which occupies more space). However, we do not list this expanded bond angle. I am not exactly sure why...
by Mikayla Kwok 3K
Sun Nov 22, 2020 5:46 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Effective Nuclear Charge
Replies: 3
Views: 62

Re: Effective Nuclear Charge

I think because s-orbitals are spherical and have no nodal planes, the probability of finding an electron at the nucleus is not technically zero. Thus, electrons in the s-orbital can penetrate to the nucleus of the atom. This causes more effective shielding, making electrons farther away from this s...
by Mikayla Kwok 3K
Sun Nov 15, 2020 12:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: D orbital
Replies: 4
Views: 27

Re: D orbital

4s does have a lower energy than 3d when no electrons are in the 3d subshell, but once the 4s and 3d subshells are occupied (which happens after Z=20), 3d has the lower energy.
by Mikayla Kwok 3K
Sun Nov 15, 2020 11:28 am
Forum: Lewis Structures
Topic: Cl Breaking Octet
Replies: 2
Views: 15

Re: Cl Breaking Octet

I think because it has a d subshell to fill, the maximum number of valence electrons in can have is 18 (s[2] + p[6] + d[10] = 18). However, it looks like it is rare for Cl to accommodate more than 10 or 12.
by Mikayla Kwok 3K
Sun Nov 15, 2020 11:24 am
Forum: Trends in The Periodic Table
Topic: UA Riya Week 5 Question 4B
Replies: 2
Views: 19

Re: UA Riya Week 5 Question 4B

I think this ineffective shielding is caused by the fact that the d and f subshells are unable to completely shield the nuclear charge, because these subshells have more nodes. This causes Ga to have a larger ionization energy than Al because of the 3d subshell between them. This also causes Tl to h...
by Mikayla Kwok 3K
Sun Nov 15, 2020 11:14 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electron Configurations
Replies: 9
Views: 76

Re: Writing Electron Configurations

I think he wrote it in that order, because it is easier to visualize the removal of electrons. It is true that you fill electrons in that order so that the configuration reads [Kr] 5s^2 4d^10. However, when removing electrons from this atom, you remove 5s electrons first and then 4d electrons, becau...
by Mikayla Kwok 3K
Sun Nov 15, 2020 11:08 am
Forum: Ionic & Covalent Bonds
Topic: Hydrogen and Covalent Bonds
Replies: 3
Views: 31

Re: Hydrogen and Covalent Bonds

Covalent bonds are intramolecular forces, and hydrogen bonds are intermolecular forces. To compare their strengths is not typical because they are completely different forces. However, if you did want to compare them, hydrogen bonds are strong, because the bonded elements have such a great electrone...
by Mikayla Kwok 3K
Sun Nov 08, 2020 5:19 pm
Forum: Quantum Numbers and The H-Atom
Topic: Pauli Exclusion Principle
Replies: 6
Views: 22

Re: Pauli Exclusion Principle

Each orbital can only have two electrons, because two electrons can have the same orbital in the same subshell of the same shell but still be distinct from each other due to having opposite spins (+1/2 or -1/2). Because there are only two possible spins, there can only be two electrons in each orbit...
by Mikayla Kwok 3K
Sun Nov 08, 2020 5:15 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Parallel electrons
Replies: 7
Views: 53

Re: Parallel electrons

The parallel electrons in Hund's rule is just stating that when distributing electrons into different orbitals, every electron in the half-filled orbitals have the same spin (like all three electrons in the 2p^3 subshell) would be either spin-up (+1/2) or spin-down(-1/2). This is because electrons w...
by Mikayla Kwok 3K
Sun Nov 08, 2020 5:00 pm
Forum: Coordinate Covalent Bonds
Topic: formation of coordinate covalent bonds
Replies: 4
Views: 49

Re: formation of coordinate covalent bonds

I think atoms like hydrogen, helium, lithium, and beryllium are more likely to give up electrons to form an ionic bond, but not to form a coordinate covalent bond. From what I understand, Lewis bases are usually molecules and polyatomic ions, like NH3 and and OH-.
by Mikayla Kwok 3K
Sun Nov 08, 2020 4:49 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Covalent character vs. Ionic character
Replies: 4
Views: 47

Re: Covalent character vs. Ionic character

I just wanted to add that almost all bonds have ionic and covalent characters! In the lecture, Dr. Lavelle says that a molecule made up of atoms of the same element (like a diatomic molecule) do not have ionic character, because the electron are shared relatively equally between the atoms.
by Mikayla Kwok 3K
Sun Nov 08, 2020 4:45 pm
Forum: Bond Lengths & Energies
Topic: bond lengths
Replies: 9
Views: 37

Re: bond lengths

The greater the number of bonds at one location, the shorter the bond length. Double bonds are shorter than single bonds, and triple bonds are shorter than single bonds.
by Mikayla Kwok 3K
Sun Nov 01, 2020 5:59 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Unusual Electron Configuration
Replies: 3
Views: 47

Re: Unusual Electron Configuration

I also wanted to add Dr. Lavelle said in his lectures that as the shells increase, more exceptions appear regarding the energy of subshells in the d-block. This is mainly because the difference in energies between shells becomes smaller and smaller. Thus, when you get to transition metals lower in t...
by Mikayla Kwok 3K
Sun Nov 01, 2020 5:49 pm
Forum: Bond Lengths & Energies
Topic: ionization energy
Replies: 6
Views: 74

Re: ionization energy

Oxygen has 2 e- in the 2px orbital, while nitrogen has only 1 e- in each of the 2p orbitals. The electron repulsion in the 2px orbital of oxygen makes the outer electrons more loosely held, so oxygen requires less energy to be removed an electron than nitrogen. Meanwhile, oxygen has a lower ionizati...
by Mikayla Kwok 3K
Sun Nov 01, 2020 5:42 pm
Forum: Properties of Electrons
Topic: ion radius size
Replies: 3
Views: 45

Re: ion radius size

Like atomic radii, ionic radii increase down groups and to the left of the periods.
by Mikayla Kwok 3K
Sun Nov 01, 2020 5:40 pm
Forum: Trends in The Periodic Table
Topic: Electron Shielding Question
Replies: 5
Views: 40

Re: Electron Shielding Question

Shielding causes the outermost electrons to be more loosely held due to the lower effective nuclear charge. Thus, shielding can lower the ionization energy of atoms, by making these loosely held electrons more likely to be removed, and increase the size of atoms, by not pulling the outer electrons t...
by Mikayla Kwok 3K
Sun Nov 01, 2020 5:36 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number (orientation)
Replies: 2
Views: 30

Re: Magnetic Quantum Number (orientation)

I just wanted to add that we don't know which magnetic quantum number represents which orientation unless the problem assigns specific magnetic quantum numbers to specific orbital. For instance, one problem may say ml = 0 is the px orbital, while another may say ml = 0 is the py orbital.
by Mikayla Kwok 3K
Sun Oct 25, 2020 2:05 pm
Forum: *Shrodinger Equation
Topic: Schrodinger's Wave Function and Equation
Replies: 2
Views: 34

Re: Schrodinger's Wave Function and Equation

I just wanted to add that Justin also emphasized using diagrams of the s and p orbitals to interpret what is meant by different regions in the orbitals having symmetric or asymmetric probabilities of finding electrons. I don't think learning any calculations about wave functions will be necessary fo...
by Mikayla Kwok 3K
Sun Oct 25, 2020 1:58 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectroscopy v. Molecular Spectroscopy
Replies: 1
Views: 39

Re: Atomic Spectroscopy v. Molecular Spectroscopy

Atomic spectroscopy is based on the excitation an electron in an atom to emit light. From my understanding, molecular spectroscopy is based on the excitation of an electron in a molecule to emit light. The process of experimentation is similar, but I believe molecular spectroscopy is a little more c...
by Mikayla Kwok 3K
Sun Oct 25, 2020 1:51 pm
Forum: Student Social/Study Group
Topic: Fundamental Topics for Midterm
Replies: 3
Views: 50

Re: Fundamental Topics for Midterm

I think if you look at the outlines on Dr. Lavelle's website, we will be tested on all the bullet points listed in Outline 1 and all the bullet points except the last eight listed in Outline 2. This includes the audio-visual lessons, but not all the fundamentals in the textbook.
by Mikayla Kwok 3K
Thu Oct 22, 2020 3:51 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Energy of H-Atom Equations
Replies: 3
Views: 66

Re: Energy of H-Atom Equations

In the equation v (frequency) = R [ 1/(n1^2) - 1/(n2^2) ], n1 is the initial energy level, and n2 is the final energy level. The reason why this equation looks like we are doing the initial-final rather than final-initial is because we manipulated the original deltaE = -hR/(n2^2) - (-hR/(n1^2)) equa...
by Mikayla Kwok 3K
Thu Oct 22, 2020 3:40 pm
Forum: *Shrodinger Equation
Topic: Hamiltonian
Replies: 3
Views: 51

Re: Hamiltonian

I agree with what Tamara said about the Hamiltonian representing the double derivative, so H \Psi is the double derivative of the wave function. However, I'm pretty sure we have to think about the Hamiltonian as an operator, not a variable, so it represents a mathematical function being done to a va...
by Mikayla Kwok 3K
Tue Oct 13, 2020 1:46 am
Forum: Photoelectric Effect
Topic: Microwaves being harmful?
Replies: 3
Views: 43

Re: Microwaves being harmful?

From what I've read, microwaves are not harmful in the sense that that they can alter your DNA and cause cancer, which is a common myth. The type of radiation that does this damage is ionizing radiation, which includes x-rays and gamma rays (high frequency). Microwaves are non-ionizing radiation. Th...
by Mikayla Kwok 3K
Tue Oct 13, 2020 1:22 am
Forum: Photoelectric Effect
Topic: What does increasing the frequency of light look like for the particle model?
Replies: 3
Views: 40

Re: What does increasing the frequency of light look like for the particle model?

I am not completely sure either, but I do not think you can actually visualize a photon's frequency. Frequency is measured by Hz, so the frequency of a photon is still determined by the number of cycles per second, which is supposed to be characteristic of the wave model. From what I understand, eve...
by Mikayla Kwok 3K
Tue Oct 13, 2020 1:05 am
Forum: Photoelectric Effect
Topic: Detector in Photoelectric Experiment
Replies: 4
Views: 29

Re: Detector in Photoelectric Experiment

I think Dr. Lavelle mentioned this briefly in one of the lectures. I believe he said that the detector is connected to an external energy source that gives the detector a slightly positive charge, so if the energy of the incoming photon is exactly equal to the energy to remove an electron, the barel...
by Mikayla Kwok 3K
Tue Oct 13, 2020 12:40 am
Forum: SI Units, Unit Conversions
Topic: Rounding answers
Replies: 7
Views: 83

Re: Rounding answers

Just an additional note about rounding that was new to me upon entering this class: when you round based on the smallest number of sig figs and the digit immediately after your last is 5, you do not always round up. You round to the nearest even number. For instance, if you get an exact answer of 2....
by Mikayla Kwok 3K
Tue Oct 13, 2020 12:28 am
Forum: Photoelectric Effect
Topic: Textbook 1A.11 question
Replies: 2
Views: 41

Re: Textbook 1A.11 question

To add to Faaizah's answer, the Lyman series comes from when an excited electron comes back down to the n=1 energy level, while the Balmer series comes from when an excited electron comes back down to the n=2 energy level. The Lyman series is a result of directing UV radiation at hydrogen, while the...
by Mikayla Kwok 3K
Sun Oct 11, 2020 1:54 pm
Forum: General Science Questions
Topic: Chemical formulas.
Replies: 3
Views: 78

Re: Chemical formulas.

In our lectures, I think Dr. Lavelle mentioned that we will learn about the nomenclature of compounds later, but if you need help, you can look through Fundamental D in the textbook (page F29). As for the problem you're asking, magnesium sulfate is an ionic compound. The magnesium ion has a 2+ charg...
by Mikayla Kwok 3K
Tue Oct 06, 2020 9:52 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units
Replies: 9
Views: 107

Re: Formula Units

Formula units are the smallest units of an ionic compound (or network covalent solid compound). If you want to think about it in analogies, formula unit is to ionic compound as molecule is to covalent compound or as atom is to element.
by Mikayla Kwok 3K
Tue Oct 06, 2020 9:46 pm
Forum: SI Units, Unit Conversions
Topic: Problem E1, use of conversion factor?
Replies: 3
Views: 34

Re: Problem E1, use of conversion factor?

1.) Start with the given 1.00 mol Ag. 2.) Convert this from moles to number of atoms by multiplying 1.00 mol Ag by 6.022*10^23 Ag atoms/1 mol Ag (Avogadro's number). 3.) Because the given radius of each atom is 144 pm, the diameter would be 288 pm per Ag atom. To find the length of all the Ag atoms ...
by Mikayla Kwok 3K
Tue Oct 06, 2020 9:38 pm
Forum: DeBroglie Equation
Topic: E = pc [ENDORSED]
Replies: 2
Views: 68

Re: E = pc [ENDORSED]

Hi! I'm also still trying to grasp the logic behind each value, but here is what I can explain as far as the derivation and use of the formula. The formula is derived from E=hv (energy = Planck's constant*frequency) and c=[lambda]*v (speed of light = wavelength*frequency). By isolating v in the latt...
by Mikayla Kwok 3K
Tue Oct 06, 2020 9:14 pm
Forum: Empirical & Molecular Formulas
Topic: Fundamentals E. 29
Replies: 3
Views: 50

Re: Fundamentals E. 29

1.) Start with what is given: 8.61 g CuCl2*4H2O. 2.) Convert g to moles by dividing 8.61 g CuCl2*4H2O by the molar mass (206.47 g/mol CuCl2*4H2O). (At this point, you should get ~ 0.41701 mol CuCl2*4H2O.) 3.) Because there are 2 chloride ions (see the subscript 2 in CuCl2) in a single formula unit, ...
by Mikayla Kwok 3K
Tue Oct 06, 2020 8:46 pm
Forum: Properties of Light
Topic: Work Function Explanation
Replies: 3
Views: 46

Re: Work Function Explanation

Ryan's definition is the most straightforward, but you can also think of the work function as the threshold energy to remove an electron. If the incoming photon's energy does not match or exceed work function, the electron from the metal cannot overcome the binding energy between itself and the atom...

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