## Search found 98 matches

Mon Jan 25, 2021 5:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Matthew's Workshop - Week 1
Replies: 3
Views: 205

### Re: Matthew's Workshop - Week 1

Hi,

This post was extremely helpful thank you so much for the extra practice! :))
However, I was wondering if Matthew was able to get 1.3 for 2b. I divided 1/(.35)(.45) and got 6.3. Can someone explain how he got 1.3? Thank you!
Sat Jan 23, 2021 10:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Exercise 6B Question 5d
Replies: 1
Views: 4

### Re: Exercise 6B Question 5d

I have attached my work below :))
Sat Jan 23, 2021 10:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4.31 text [ENDORSED]
Replies: 2
Views: 30

### 4.31 text[ENDORSED]

4.31 Water gas is an inexpensive, low-grade fuel that can be made from coal. (a) Is the production of water gas exothermic or endothermic? The reaction is C(s) 1 H2O(g) ¡ CO(g) 1 H2(g) (b) Calculate the enthalpy change for the production of 200. L of hydrogen at 500. Torr and 65 8C by this reaction ...
Sat Jan 23, 2021 2:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 1 Questions from the textbook
Replies: 2
Views: 24

### Midterm 1 Questions from the textbook

Does anybody know which problems from 4D to focus on for midterm 1?
Sat Jan 23, 2021 2:12 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: 4d3
Replies: 1
Views: 13

### 4d3

4D.3 The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise from 22.113 8C to 22.799 8C. The calorimeter assembly is known to have a total heat capacity (calorimet...
Mon Jan 18, 2021 1:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKa
Replies: 4
Views: 21

### pKa

why is it that with lower pKa the stronger the acid?
Mon Jan 18, 2021 12:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Polyprotic Acids
Replies: 3
Views: 21

### Polyprotic Acids

Why is it that for polyprotic acids, all deprotonations are weak and insignificant?
Fri Jan 15, 2021 10:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6.19a
Replies: 1
Views: 16

### 6.19a

6.19 Hemoglobin (Hb) molecules in blood carry O2 molecules from the lungs, where the concentration of oxygen is high, to the tissues where it is low (see the Interlude following Focus 5). In the tissues the equilibrium H3O1(aq) 1 HbO 2 2 (aq) ∆ HHb(aq) 1 H2O(l) 1 O2(aq) releases oxygen. When muscles...
Fri Jan 15, 2021 6:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: percentage protonation for codeine
Replies: 1
Views: 15

### percentage protonation for codeine

6D.5 Calculate the pH, pOH, and percentage protonation of solute in each of the following aqueous solutions: (a) 0.057 m NH3(aq); (b) 0.162 m NH2OH(aq); (c) 0.35 m (CH3)3N(aq); (d) 0.0073 m codeine, given that the pKa of its conjugate acid is 8.21. Did anyone get 1.5% for the percentage protonation ...
Fri Jan 15, 2021 5:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D1 - tables?
Replies: 2
Views: 17

### 6D1 - tables?

For question 6D1 in the textbook, am I allowed to use table 6C1 and 6C2? 6D.1 Calculate the pH, pOH, and percentage deprotonation of each of the following aqueous solutions: (a) 0.20 m CH3COOH(aq); (b) 0.20 m CCl3COOH(aq); (c) 0.20 m HCOOH(aq). (d) Explain any differences in pH on the basis of molec...
Fri Jan 15, 2021 4:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6c7
Replies: 1
Views: 15

### 6c7

6C.7 Use data from Tables 6C.1 and 6C.2 to place the following
acids in order of increasing strength: HNO2, HClO2, +
NH3OH,
(CH3)2NH2+

I cant seem to find the pka or pkb for the last two, does anyone have the same problem?
Fri Jan 15, 2021 11:46 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Hydronium concentrations less than 10^-7
Replies: 2
Views: 19

### Hydronium concentrations less than 10^-7

Why did Lavelle add 10^-10 to 10^-7 in today's lecture? (10/15)
Fri Jan 15, 2021 11:23 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm 1
Replies: 24
Views: 129

### Midterm 1

Are Outline 1 and Outline 2 going to be the only sections tested in Midterm 1?
Wed Jan 13, 2021 8:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Why is the concentration of Ba2+ the same as barium hydroxide?
Replies: 7
Views: 35

### Why is the concentration of Ba2+ the same as barium hydroxide?

6A.23 Calculate the molar concentration of Ba(OH)2(aq)
and the molar concentrations of Ba21, OH2, and H3O1 in an
aqueous solution that contains 0.43 g of Ba(OH)2 in 0.100 L of
solution

Why is the concentration of Ba2+ the same as barium hydroxide?
Sun Jan 10, 2021 5:34 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Halogens
Replies: 6
Views: 73

### Re: Halogens

Oops, sorry y'all I read the question wrong. I was wondering why X2 --> 2X was endothermic and the textbook states that X is a halogen so I thought endothermic reactions were directly linked with halogens. But in reality, because that molecule is being broken, it requires an input of energy, making ...
Thu Jan 07, 2021 3:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.35
Replies: 2
Views: 26

### 5.35

5.35 The following plot shows how the partial pressures of reactant and products vary with time for the decomposition of compound A into compounds B and C. All three compounds are gases. Use this plot to do the following: (a) Write a balanced chemical equation for the reaction. (b) Calculate the equ...
Thu Jan 07, 2021 3:03 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5.33
Replies: 3
Views: 12

### 5.33

Why does increasing temperature increase the products, when not given if the reaction is exo or endothermic? Is it because all the other options do not make sense? Question: Which of the following changes will produce the composition shown? (a) Increasing the temperature. (b) Adding X atoms. (c) Dec...
Wed Jan 06, 2021 5:10 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Halogens
Replies: 6
Views: 73

### Halogens

How is it that with a presence of a HALOGEN, the reaction is exothermic?
Wed Jan 06, 2021 10:52 am
Forum: Equilibrium Constants & Calculating Concentrations
Replies: 7
Views: 34

If I get two positive numbers from my using the quadratic formula to find X, how do I know which one to use? Do I have to plug those numbers into the quadratic equation again to see which one is true?
Wed Jan 06, 2021 10:16 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc vs Kp
Replies: 4
Views: 35

### Kc vs Kp

If given concentrations of reactants and products and the question asks to calculate Kp why don't you convert those molarity concentrations into bars or atm? I thought that if given concentrations and asked for Kp, you would have to use the Ideal Gas Law. Why don't you?
Wed Dec 16, 2020 11:51 pm
Forum: Quantum Numbers and The H-Atom
Topic: London Dispersion Forces
Replies: 7
Views: 65

### Re: London Dispersion Forces

induced dipole induced dipole
- since there are uneven movement of electrons in molecules they create temporary dipole moments
Wed Dec 16, 2020 11:50 pm
Forum: Naming
Topic: Latin names
Replies: 10
Views: 65

### Re: Latin names

latin names only for anions
Wed Dec 16, 2020 11:49 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: How many values of the quantum number l are possible when n = 7?
Replies: 3
Views: 37

### Re: How many values of the quantum number l are possible when n = 7?

l = 1,2,3,4,5,6

l = 1,2,3,... (n-1)
Wed Dec 16, 2020 11:48 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cis Trans Isomers
Replies: 7
Views: 53

### Re: Cis Trans Isomers

cis on the same side and trans on opposite (molecules with lone pairs) - refer to cisplatin as an example
Wed Dec 16, 2020 11:46 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: shape
Replies: 6
Views: 37

### Re: shape

We do not need to know if it's tetrahedral or square planar yet but we do know that myoglobin is made out of a square planar with poryphorin.
Wed Dec 16, 2020 11:45 pm
Forum: Biological Examples
Topic: Hemoglobin vs. Myoglobin
Replies: 29
Views: 225

### Re: Hemoglobin vs. Myoglobin

Hemoglobin is able to transport 4 molecules of oxygen whereas myoglobin transfers one. This is because hemogloblin is made out of four myoglobins.
Wed Dec 09, 2020 2:01 pm
Forum: Bronsted Acids & Bases
Topic: Sulphurous acid > carbonic acid
Replies: 1
Views: 23

### Sulphurous acid > carbonic acid

Why is sulphurous acid stronger than carbonic acid?
Wed Dec 09, 2020 10:43 am
Forum: Identifying Acidic & Basic Salts
Topic: Titration - Lecture 10B
Replies: 1
Views: 30

### Titration - Lecture 10B

Why does the titration reaction written by lavelle in lecture have the equilibrium arrows? Aren't the really strong acids and bases? Does the one arrow only apply to singular acids and bases?
Tue Dec 08, 2020 9:55 pm
Forum: Shape, Structure, Coordination Number, Ligands
Replies: 1
Views: 47

For linkage isomerism, how do you know which preference of interaction is stronger?
Sat Dec 05, 2020 11:28 pm
Forum: Hybridization
Topic: pi bonds
Replies: 6
Views: 90

### pi bonds

how would you find the unhybridized orbitals using electron configuration? what would be the pi bonds for CH3CN?
Sat Dec 05, 2020 11:03 pm
Forum: Bronsted Acids & Bases
Topic: Neutralization Reactions
Replies: 1
Views: 30

### Neutralization Reactions

Why are there coefficients in front of NH3, H+, NH4+ in the neutralization reaction for the formation of ammonium phosphate?
Sat Dec 05, 2020 9:27 pm
Forum: Bronsted Acids & Bases
Topic: CH3COOH vs HCl
Replies: 2
Views: 37

### CH3COOH vs HCl

Why is CH3COOH considered to be a weaker acid than HCl? Since it lost its acidic Hydrogen atom, shouldn't that still be considered a strong acid? Does that mean you disregard the fact that there is only one acidic Hydrogen atom in acetic acid and consider all 4 Hydrogen atoms, when looking for depro...
Sat Dec 05, 2020 9:19 pm
Forum: Bronsted Acids & Bases
Topic: Identification
Replies: 3
Views: 61

### Identification

How would you identify acids and bases? For example, what would be the explanation for why HNO3 would be an acid?
Sat Dec 05, 2020 9:09 pm
Forum: Bronsted Acids & Bases
Topic: CH3COOH vs NH3
Replies: 2
Views: 41

### CH3COOH vs NH3

Why are molecules such as CH3COOH willing to donate a H proton compared to molecules such as NH3? Is the CH3COOH not stable in that form?
Thu Dec 03, 2020 11:24 am
Forum: Bronsted Acids & Bases
Topic: Bronsted Acids Strength
Replies: 3
Views: 28

### Bronsted Acids Strength

Why is it that with longer bond from Br in Hydrobromic acid makes it stronger compared to HCl? I thought that with longer bond length, the atoms would not be closer to each other and therefore not as strong.
Fri Nov 27, 2020 10:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: How do you know if atoms lie in the same plane?
Replies: 5
Views: 41

### How do you know if atoms lie in the same plane?

How do you know if atoms lie in the same plane? Is it by bond angles? So if they share similar bond angles, they lie in the same plane?
Fri Nov 27, 2020 10:49 pm
Forum: Hybridization
Topic: Terminal Atoms
Replies: 1
Views: 29

### Terminal Atoms

In the textbook, it says that terminal atoms such as Cl have not been regarded as hybridized, why is that?
Tue Nov 24, 2020 4:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Number of Questions on the Final
Replies: 1
Views: 25

### Number of Questions on the Final

How many questions are usually on the final?
Tue Nov 24, 2020 2:32 pm
Forum: Hybridization
Topic: Increasing s-character
Replies: 1
Views: 37

### Increasing s-character

2F.15 Noting that the bond angle of an sp3 hybridized atom is 109.5 and that of an sp 2 hybridized atom is 120 8, do you expect the bond angle between two hybrid orbitals to increase or decrease as the s-character of the hybrids is increased? Can someone explain why the bond angle would increase wit...
Tue Nov 24, 2020 10:49 am
Forum: Administrative Questions and Class Announcements
Topic: CHEM14B Asynchronous
Replies: 5
Views: 98

### CHEM14B Asynchronous

Does anybody know if CHEM14B with Lavelle is asynchronous?
Thu Nov 19, 2020 8:40 am
Forum: Bond Lengths & Energies
Topic: Interaction Potential Energy
Replies: 3
Views: 40

### Interaction Potential Energy

What is interaction potential energy and why is it negative?
Thu Nov 19, 2020 8:13 am
Forum: Quantum Numbers and The H-Atom
Topic: quantum number f
Replies: 6
Views: 72

### quantum number f

Can period 5 elements have the subshell f? Since it can equal to 0,1,2,3,4
Wed Nov 18, 2020 12:24 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 11
Views: 83

### Resonance

Why aren't all resonance structures equal?
Tue Nov 17, 2020 6:20 pm
Forum: Lewis Structures
Topic: (CH3)2SO
Replies: 1
Views: 27

### (CH3)2SO

Would we know how to draw lewis structures like (CH3)2SO?
Tue Nov 17, 2020 6:15 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Hybridization
Replies: 1
Views: 7

### Hybridization

do we need to know about hybridization?
Tue Nov 17, 2020 11:53 am
Forum: Ionic & Covalent Bonds
Topic: Covalent molecule - polarizability and en
Replies: 2
Views: 10

### Covalent molecule - polarizability and en

Why would you draw AlCl3 as a covalent molecule?
Sat Nov 14, 2020 3:59 pm
Forum: Trends in The Periodic Table
Topic: Diagonal Relationships
Replies: 3
Views: 20

### Diagonal Relationships

Do we need to know about diagonal relationships in the periodic table?
Sat Nov 14, 2020 11:22 am
Forum: Dipole Moments
Topic: Strength of intermolecular forces
Replies: 3
Views: 46

### Strength of intermolecular forces

What does this mean "The reason for the very rapid falling off of the dipole–dipole interaction is that as the distance between molecules increases, the opposite partial charges on each molecule appear to merge and cancel, whereas in the interaction between a point charge and a dipole, only the...
Fri Nov 13, 2020 5:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Lecture #18
Replies: 3
Views: 25

### Lecture #18

Does Midterm 2 cover material up to the lecture on Wednesday of week 6?
Fri Nov 13, 2020 3:07 pm
Forum: Dipole Moments
Topic: Fluctuating electron density
Replies: 2
Views: 14

### Fluctuating electron density

Why is it that some time later the fluctuating electron density is different?
Thu Nov 12, 2020 5:40 pm
Forum: Lewis Structures
Topic: Resonance Hybrid
Replies: 5
Views: 52

### Resonance Hybrid

https://pin.it/7L5UBKN

In this problem what does it mean by dominant contribution resonance hybrid mean? How would you go about this problem?
Wed Nov 11, 2020 3:55 pm
Forum: Ionic & Covalent Bonds
Topic: Ions
Replies: 6
Views: 34

### Ions

Are we required to remember the molecular formula for nitrite, nitrate, phosphate ions?
Tue Nov 10, 2020 6:51 pm
Forum: Dipole Moments
Topic: Interactions Between Ions and Molecules
Replies: 7
Views: 57

### Interactions Between Ions and Molecules

Why are ion and ion interactions stronger?
Tue Nov 10, 2020 6:23 pm
Forum: Dipole Moments
Topic: Negative Energy
Replies: 4
Views: 55

### Negative Energy

What does Lavelle mean when he says energy is released? Does that mean energy is released when a molecule and another molecule interact with each other? Or does he mean that the energy is positive when trying to break a bond and negative when create a bond?
Tue Nov 10, 2020 5:53 pm
Forum: Dipole Moments
Topic: Debye
Replies: 2
Views: 22

### Debye

What does the unit debye mean? Is it the charge or strength of the pulling of electrons between the covalent bond? Or the overall charge?
Wed Nov 04, 2020 9:04 pm
Forum: Ionic & Covalent Bonds
Topic: Ions
Replies: 5
Views: 51

### Ions

Do ions lose their electrons from the s state first or p state or d state?
Tue Nov 03, 2020 9:46 am
Forum: Trends in The Periodic Table
Topic: d-block properties
Replies: 1
Views: 43

### d-block properties

Why does Fe form Fe 2+ and Fe 3+ and why does Cu for Cu+ and Cu2+? I get how iron and copper can form Fe 2+ and Cu 2+ since they have 2 electrons in the s state but why would Fe lose 3 electrons and why would copper lose 1? The book mentioned something about different oxidation states, but I don't c...
Tue Nov 03, 2020 9:29 am
Forum: Trends in The Periodic Table
Topic: Inert-pair effect
Replies: 4
Views: 43

### Inert-pair effect

Does anybody understand the inert-pair effect and why it occurs?
Tue Nov 03, 2020 8:41 am
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 5
Views: 28

### Ionization Energy

Why is the second ionization energy of an atom always higher than its first ionization energy?
Mon Nov 02, 2020 10:48 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ms
Replies: 4
Views: 44

### Ms

If the spin state switches from +1/2 to -1/2 in a given orbital, does that mean the atom is in an excited state? For question 1E7, the Nitrogen is shown to have different direction of spins, up, down, up. The question asks if this atom is in excited or ground state.
Mon Nov 02, 2020 10:33 am
Forum: Quantum Numbers and The H-Atom
Topic: Multielectron vs H-atom
Replies: 4
Views: 40

### Multielectron vs H-atom

Which of the following increase when an electron in a lithium atom undergoes a transition from the 1s-orbital to a 2p-orbital? (a) Energy of the electron. (b) Value of n. (c) Value of l. (d) Radius of the atom. Which answers would be different for a hydrogen atom and in what way would they be differ...
Mon Nov 02, 2020 10:25 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Exceptions
Replies: 3
Views: 18

### Electron Configuration Exceptions

"The experimental electron configuration of chromium is [Ar]3d^54s^1 instead of [Ar]3d^1 4s^2 , and that of copper is [Ar]3d^10 4s^1 instead of [Ar]3d^9 4s^2 . This apparent discrepancy occurs because the half-complete subshell configuration d5 and the complete subshell configuration d10 turn o...
Mon Nov 02, 2020 10:10 am
Forum: Einstein Equation
Topic: Sapling Q. 6
Replies: 7
Views: 100

### Re: Sapling Q. 6

Since it is excited to n=6 that means it start either from n =1, 2, 3, 4, or 5. This then means that there will be 5 spectral lines since there are only 5 energy levels to start from. To find the max you would have to start from the highest starting energy level (n=5) to n=6. Use the formula E = -hR...
Mon Nov 02, 2020 10:06 am
Forum: Trends in The Periodic Table
Topic: Oxygen vs Nitrogen and Fluorine
Replies: 4
Views: 38

### Re: Oxygen vs Nitrogen and Fluorine

Nitrogen and Fluorine have higher nuclear charge since that have more electrons. This stronger charge makes it harder for them to lose an electron; electrons are more tightly held. This then means that they have lower ionization energy. Additionally they would have higher electron affinity, wanting ...
Mon Nov 02, 2020 10:01 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: difference in p orbitals
Replies: 8
Views: 54

### Re: difference in p orbitals

The px, py, and pz is specifying which orbital the electron is at in the p orbital. We know that the s orbital has only one orbital, the p orbital has 3 orbitals which can hold 6 electrons. Those three orbitals in the p subshell is px, py, and pz. If asked to draw the electrons in these subshells th...
Mon Nov 02, 2020 9:27 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: The word "energy" used in different scenarios
Replies: 3
Views: 42

### The word "energy" used in different scenarios

When the book refers to higher energy or lower energy, does it mean the energy of the electron or the energy of the atom? Or does it refer to energy level? For example, the book mentions energies in orbitals are degenerate in H-atoms, what does the word "energy" mean in this context? Anoth...
Mon Nov 02, 2020 9:23 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital Energies
Replies: 1
Views: 46

### Orbital Energies

"r is the distance of electron 1 from the nucleus, r is the distance of electron 2 from 12 the nucleus, and r12 is the distance between the two electrons. The two terms with nega- tive signs (indicating that the potential energy decreases as r1 or r2 decreases when the electron approaches the n...
Thu Oct 29, 2020 10:31 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra
Replies: 4
Views: 45

### Atomic Spectra

What does it mean by "given off as a photon" in the statement "High energy electrons drop to lower energy level, difference in energy is given off as a photon". I thought the energy of photon is what causes the excitement or transition of energy levels.
Thu Oct 29, 2020 9:52 am
Forum: Einstein Equation
Topic: E=pv and E=pc
Replies: 6
Views: 115

### E=pv and E=pc

Where did E=pv and E=pc come from? What are they supposed to be? A part of einstein's equation? What is it trying to prove or associate?
Thu Oct 29, 2020 9:50 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg's
Replies: 7
Views: 56

### Rydberg's

Is Rydberg's equation only used for H atoms?
Tue Oct 27, 2020 5:45 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 13
Views: 119

### Photoelectric Effect

Even if the energy of the photon is less than the work function does the energy still get absorbed, regardless if it does not eject an electron? (in photoelectric effect)
Mon Oct 26, 2020 4:31 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 4s and 3d
Replies: 14
Views: 104

### 4s and 3d

What is the reason for why 3d goes before 4s other than the fact from how it is arranged in the periodic table?
Mon Oct 26, 2020 8:02 am
Forum: Administrative Questions and Class Announcements
Topic: Workshops
Replies: 2
Views: 28

### Workshops

Hi!
I was wondering the difference between Workshops and Step-Up Sessions, do I have to sign up to join a Workshop meeting? And if I do, where?
Sat Oct 24, 2020 9:50 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: n2 vs n1
Replies: 2
Views: 27

### n2 vs n1

Sapling HW "A red line is observed at 656.3 nm in the spectrum of atomic hydrogen. Determine the values of n for the beginning and ending energy levels of the electron during the emission of energy that leads to this spectral line". I understand that since the wavelength is in the visible ...
Fri Oct 23, 2020 3:13 pm
Forum: *Shrodinger Equation
Topic: Understanding of Shrodinger Equation
Replies: 3
Views: 55

### Understanding of Shrodinger Equation

I am not too sure about what Schrodinger Equation means, but to my understanding, is the following statement correct? So, each wave function gives rise to different electron densities. And when you square the wave function (Hamiltonian in the formula) it gives you that specific electron density (whe...
Wed Oct 21, 2020 6:34 pm
Forum: *Shrodinger Equation
Topic: Material on Midterm [ENDORSED]
Replies: 1
Views: 67

### Material on Midterm[ENDORSED]

Hi,

I was just wondering what numbers in 1D exercises only covers material up to 1D2? (since Professor Lavelle sent an email saying its topics to 1D.2)
Tue Oct 20, 2020 5:07 pm
Forum: Photoelectric Effect
Topic: Intensity Proportional to Number of Photons?
Replies: 4
Views: 38

### Intensity Proportional to Number of Photons?

In Professor Lavelle's lecture, he stated that the intensity is proportional to the number of photons, but I thought it would be the energy in each photon and not the number; since it is a one photon to one electron interaction. Can someone please clarify this for me please?
Mon Oct 19, 2020 4:13 pm
Forum: Photoelectric Effect
Topic: When to use E = h(nu) and not to
Replies: 3
Views: 35

### When to use E = h(nu) and not to

Hi, I don't if I am understanding this correctly, can someone verify if the following statement is true? To my understanding E = h(nu) can only be applied to find the energy in joules of a photon, however, this formula can be applied to find the energy required to remove an electron only if the kine...
Fri Oct 16, 2020 3:10 pm
Forum: Properties of Electrons
Topic: Wave Properties of Electrons
Replies: 4
Views: 35

### Wave Properties of Electrons

What does Professor Lavelle mean when he says "waves cancel each other out"?
Thu Oct 15, 2020 5:54 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Spectral Lines / Rydeberg's
Replies: 2
Views: 34

### Re: Spectral Lines / Rydeberg's

Oh wait, never mind. In Professor's Lavelle website, the "Solutions Manual Error" pdf states that n2 should be n=1.
Thu Oct 15, 2020 1:48 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Spectral Lines / Rydeberg's
Replies: 2
Views: 34

### Spectral Lines / Rydeberg's

Question 1.A.15: "In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line." Should the answer be n2 = 3 and n1 = 1, since...
Wed Oct 14, 2020 7:55 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Series
Replies: 2
Views: 67

### Series

"For the Lyman series, the lower energy level is n=1; for the Balmer series, n=2; for the Paschen series, n=3; and for the Brackett series, n=4." Can someone explain the concept of these series? Does it mean that for the Paschen series, the electron starts at the energy level n=3, then get...
Wed Oct 14, 2020 10:14 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg
Replies: 2
Views: 29

### Heisenberg

What is the difference between a quantitative and qualitative statement?
Tue Oct 13, 2020 5:04 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Electromagnetic Spectrum
Replies: 5
Views: 38

### Electromagnetic Spectrum

Does anyone know if we have to remember the frequencies/wavelengths of the electromagnetic spectrum? Or will it always be given for midterms?
Tue Oct 13, 2020 4:03 pm
Forum: Photoelectric Effect
Topic: Work Function
Replies: 4
Views: 28

### Work Function

In the post assessment in Photoelectric Effect #28, the work function units given is kJ.mol^-1, does this mean that to find the threshold energy or energy required to remove an electron from the work function, you divide by Avogadro's number?
Tue Oct 06, 2020 10:48 pm
Forum: DeBroglie Equation
Topic: Wave Properties of Electrons Module #34
Replies: 1
Views: 25

### Wave Properties of Electrons Module #34

Question: 23. In some experiments electrons display particle-like properties and in other experiments electrons display wave-like properties. True or false?

Why is this "True"?
Tue Oct 06, 2020 10:13 pm
Forum: DeBroglie Equation
Topic: Wave Properties of Electrons and The De Broglie Equation #34
Replies: 1
Views: 36

### Wave Properties of Electrons and The De Broglie Equation #34

Question 34. "If an electron (mass 9.11 x 10-31 kg) has an associated wavelength of 7.28 x 10-9 m, what is its speed? Is your answer reasonable, why?" A. 1.00 x 10-5 m.s-1. Yes. 1.00 x 10-5 m.s-1 is reasonable for e- as it is less than the speed of light, c = 3.0 x 108m.s-1. B.1.00 x 10-5 ...
Tue Oct 06, 2020 6:13 pm
Forum: Properties of Light
Topic: Photoelectric Effect
Replies: 3
Views: 35

### Photoelectric Effect

19. Which one of following is not describing the photoelectric effect?
A. E (photon) – E (remove e-) = E (excess)
B. E (photon) – E (remove e-) = EK (e-) C. hv - work function = 1/2mv2
D. λv = c
E. None of the above
Mon Oct 05, 2020 5:42 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question About HW G17 Pt. b
Replies: 2
Views: 59

### Re: Question About HW G17 Pt. b

CuSO4 is stated to be an aq solution which means that by taking the amount of mol of CuSO4 x H20 you can figure out the mass of CuSO4 x 5H2O. CuSO4 (aq) is the same as CuSO4 x 5H2O, however, CuSO4 is not the same as CuSO4 (aq)

Here is how I figure it out: https://pin.it/2sLkaxX

Hope this helps!
Mon Oct 05, 2020 3:56 pm
Forum: Empirical & Molecular Formulas
Topic: Percent comp calculations
Replies: 5
Views: 79

### Re: Percent comp calculations

Hi! You can always find the mass percentage composition by the mass of each element then dividing the mass of the entire molecule and multiplying it by 100. E.g. Find the mass percentage composition of C,H, O, from C6H12O6. Let's find the mass of the the entire glucose molecule (C6H12O6) 1. You calc...
Mon Oct 05, 2020 3:22 pm
Forum: Student Social/Study Group
Topic: GroupMe for Chem 14A
Replies: 1
Views: 68

### Re: GroupMe for Chem 14A

Yes, there is!

Mon Oct 05, 2020 3:17 pm
Forum: SI Units, Unit Conversions
Topic: E1
Replies: 5
Views: 76

### Re: E1

Use the formula for converting formula units (atoms, molecules, ions, etc.) and moles. N = nNA N: the number of atoms, ions, molecules, objects n: amount of moles in the substance NA: Avogadro's number (6.02 x 10^23) Remember that the length of one atom is equal to its diameter (d = 2r) Here is how ...
Mon Oct 05, 2020 3:10 pm
Forum: Empirical & Molecular Formulas
Topic: Fundamentals L. 39
Replies: 7
Views: 100

### Re: Fundamentals L. 39

Here is how I did it: https://pin.it/7A48fBS

Remember the law of conservation of mass. Mass of REACTANTS must equal to mass of PRODUCTS in a chemical equation.
Mon Oct 05, 2020 2:57 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G23 [ENDORSED]
Replies: 3
Views: 51

### Re: Fundamentals G23[ENDORSED]

Hi!

Make sure you are using the numbers from your calculator and not round as you go.

Here is what I did:

https://pin.it/3XHNgTi
Mon Oct 05, 2020 2:49 pm
Forum: Balancing Chemical Reactions
Topic: Combustion
Replies: 14
Views: 189

### Re: Combustion

He associates this type of chemical reaction that involves, O2 as one of the reactants and CO2 and H2O as the products, to the words "combustion, burning, and oxidation". So if in a question you see any of those three words, you would know how to write the chemical reaction.
Mon Oct 05, 2020 2:45 pm
Forum: Limiting Reactant Calculations
Topic: Sapling Homework Question 10
Replies: 16
Views: 239

### Re: Sapling Homework Question 10

Hi,
to start off you need to find the molecular formulas of each!
https://pin.it/4BEtNTy
Mon Oct 05, 2020 2:15 pm
Forum: Significant Figures
Topic: M.3
Replies: 4
Views: 43

### Re: M.3

Hi Cecilia, the three sig figs from the answer (93.1%) may be based from the amount of sig figs form CO2 (17.5g). Here is the question: When limestone, which is principally CaCO3, is heated, carbon dioxide and quicklime, CaO, are produced by the reaction CaCO3(s) --> CaO(s) + CO2(g). If 17.5 g of CO...
Thu Oct 01, 2020 1:30 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Reactions [ENDORSED]
Replies: 6
Views: 326

### Balancing Chemical Reactions[ENDORSED]

I came across this question while doing the Fundamental problems of H and I do not understand how to balance the second stage chemical reaction: "In one stage in the commercial production of iron metal in a blast furnace, the iron(III) oxide, Fe2O3, reacts with carbon monoxide to form solid Fe3...