Search found 87 matches

by Shannon Asay 1C
Sat Feb 22, 2020 12:16 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram Example
Replies: 3
Views: 20

Cell Diagram Example

In the cell diagram we did in class, why was Pt(s) only in contact with the aqueous iron solution and not the copper?
by Shannon Asay 1C
Sat Feb 22, 2020 12:15 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: ln K equation
Replies: 1
Views: 28

Re: ln K equation

I believe the graph you are talking about shows the temperature dependence of K, and the slope of the line is -delta H/R.
by Shannon Asay 1C
Sat Feb 22, 2020 12:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 5
Views: 21

Salt Bridge

How does the salt bridge keep the charge from building up?
by Shannon Asay 1C
Sat Feb 22, 2020 12:09 pm
Forum: Balancing Redox Reactions
Topic: Calculating the reaction Gibbs free energy
Replies: 7
Views: 35

Re: Calculating the reaction Gibbs free energy

n refers to the number of electrons that are transferred in the balanced chemical equation.
by Shannon Asay 1C
Sat Feb 22, 2020 12:07 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Max Potential
Replies: 2
Views: 11

Max Potential

How is the max potential calculated and why does it occur when very little current flows?
by Shannon Asay 1C
Wed Feb 12, 2020 4:28 pm
Forum: Phase Changes & Related Calculations
Topic: Delta H Fusion
Replies: 8
Views: 48

Delta H Fusion

When calculating enthalpies of melting ice, why do we have to divide the process into multiple steps?
by Shannon Asay 1C
Wed Feb 12, 2020 4:25 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: pizza rolls question 2D
Replies: 2
Views: 23

Re: pizza rolls question 2D

The equation of Q is Q=[NH3][H2S]. The molarity of NH3 is 1.47mol/2L and the molarity of H2S is 2.85mol/2L. Multiply those together and you'll get Q which is 1.05.
by Shannon Asay 1C
Wed Feb 12, 2020 4:22 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: THe first law definition
Replies: 5
Views: 36

Re: THe first law definition

The first law is basically just conservation of energy. It's shown by the equation delta u=q + w. It's saying that the internal energy of an isolated system is constant.
by Shannon Asay 1C
Wed Feb 12, 2020 4:20 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Laws of thermodynamics
Replies: 2
Views: 25

Re: Laws of thermodynamics

The 2nd law says that systems spontaneously go towards states of maximum entropy, which is shown by the equation, delta s=q/T. This is also demonstrated by Gibbs free energy equation because systems that are exothermic and have high entropy are spontaneous. For the third law, it's saying that as the...
by Shannon Asay 1C
Wed Feb 12, 2020 4:15 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal Reversible
Replies: 6
Views: 31

Re: Isothermal Reversible

I believe so, because all the equations we learned for reversible reactions relied on there being no change in temperature with the surroundings.
by Shannon Asay 1C
Sat Feb 08, 2020 1:31 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Microstates
Replies: 6
Views: 30

Microstates

Are micro states always dependent on the number of bonds? Would we have to calculate the entropy of more complex molecules?
by Shannon Asay 1C
Sat Feb 08, 2020 1:28 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Perfect Crystal
Replies: 3
Views: 7

Perfect Crystal

What did Dr. Lavelle mean when he said that if a system can be prepared in only 1 way, then S=kBlnW=0? And how did this relate to the third law of thermodynamics?
by Shannon Asay 1C
Sat Feb 08, 2020 1:20 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Spontaneous rxns
Replies: 3
Views: 22

Re: Spontaneous rxns

I believe if volume is the only variable that changes, then yes, the volume would need to increase for the entropy to increase (for the reaction to be spontaneous).
by Shannon Asay 1C
Sat Feb 08, 2020 1:19 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy
Replies: 3
Views: 14

Re: Entropy

Entropy is an extensive property because it depends on the amount of substance available. However, it is also a state property because it doesn't matter the pathway it takes to get there, but the final minus initial states.
by Shannon Asay 1C
Fri Feb 07, 2020 10:52 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous Reaction
Replies: 8
Views: 31

Re: Spontaneous Reaction

Yes, when delta G is negative, the reaction is spontaneous. Dr. Lavelle proved this today when he showed how the entropy of the universe would increase.
by Shannon Asay 1C
Tue Jan 28, 2020 1:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Neutralization Reactions
Replies: 2
Views: 19

Neutralization Reactions

For calculating the heat given off by a neutralization reaction, would you always use the specific heat capacity of water to calculate it?
by Shannon Asay 1C
Tue Jan 28, 2020 1:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta U
Replies: 6
Views: 31

Delta U

What does delta u stand for and how do you calculate for it?
by Shannon Asay 1C
Tue Jan 28, 2020 1:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta H and Delta U Relation
Replies: 2
Views: 16

Delta H and Delta U Relation

What does it mean that when the volume of the reactants equals the volume of products, delta h is equal to delta u?
by Shannon Asay 1C
Tue Jan 28, 2020 1:30 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Delta T
Replies: 4
Views: 25

Delta T

In calculating the enthalpy of a system, why is it that the delta T for an exothermic reaction is positive?
by Shannon Asay 1C
Tue Jan 28, 2020 1:27 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimetry
Replies: 4
Views: 29

Calorimetry

How does the experiment work to calculate enthalpy using the bomb calorimeter?
by Shannon Asay 1C
Fri Jan 24, 2020 2:32 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy Accuracy
Replies: 6
Views: 17

Bond Enthalpy Accuracy

Why is using bond enthalpies the least accurate method for calculating delta H?
by Shannon Asay 1C
Fri Jan 24, 2020 2:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Delta H
Replies: 3
Views: 21

Calculating Delta H

Lavelle brought up that there were 4 methods for calculating delta H, what was the 4th method he mentioned in lecture today?
by Shannon Asay 1C
Fri Jan 24, 2020 2:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Steam
Replies: 5
Views: 20

Steam

Could someone reiterate why steam causes more severe burns? How does the energy relate to this?
by Shannon Asay 1C
Fri Jan 24, 2020 2:27 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Pressure and Enthalpy
Replies: 5
Views: 24

Pressure and Enthalpy

How does the pressure of the surrounding environment affect the enthalpy of the system?
by Shannon Asay 1C
Fri Jan 24, 2020 2:23 pm
Forum: Administrative Questions and Class Announcements
Topic: homework for week 4
Replies: 11
Views: 82

Re: homework for week 4

I believe so. I think it's just anything he's covered in lecture over the week, so thermodynamics should be fine!
by Shannon Asay 1C
Tue Jan 14, 2020 5:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Including gasses for Q vs K
Replies: 2
Views: 24

Re: Including gasses for Q vs K

I'm pretty sure for that question you're still solving for Qc for aqueous phase materials, and partial pressure for the gaseous phase molecules. I think solving for concentration or pressure depends on what the question is asking for.
by Shannon Asay 1C
Tue Jan 14, 2020 5:33 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5.33
Replies: 6
Views: 32

Re: 5.33

It would increase the formation of X because the reaction is endothermic and an increase in the temperature would increase the k value. This means an increase in the number of products.
by Shannon Asay 1C
Tue Jan 14, 2020 5:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Weak Acids/Bases
Replies: 2
Views: 21

Re: Weak Acids/Bases

Weaker acids don't dissociate completely, like strong acids do, so there is a lower concentration of H+. Because of this, weak acids have a higher pH, because they aren't as acidic as strong acids in the same concentration.
by Shannon Asay 1C
Tue Jan 14, 2020 5:29 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5j #11
Replies: 4
Views: 25

Re: 5j #11

So In 5J.11 b, the equation is X2->2X, where x is a halogen. In this equation, it is essentially breaking a bond, which means it requires energy and is endothermic. In an endothermic reaction, when you raise the temperature, the value of k increases. If k increases, that means the equilibria is favo...
by Shannon Asay 1C
Tue Jan 14, 2020 5:25 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: HW 5j #5
Replies: 4
Views: 27

Re: HW 5j #5

I'm not entirely sure why either but I'm guessing it's because the number of moles of gas on either side of the equation doesn't change so one side isn't strongly favored.
by Shannon Asay 1C
Tue Jan 14, 2020 5:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 1
Replies: 7
Views: 45

Test 1

Will topics using or related to Gibbs free energy equation be on the first test?
by Shannon Asay 1C
Wed Jan 08, 2020 1:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure vs. Concentration
Replies: 4
Views: 23

Partial Pressure vs. Concentration

How would you know whether to solve for Kp or Kc?
by Shannon Asay 1C
Wed Jan 08, 2020 1:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Module: Chemical Equilibrium Part 3
Replies: 2
Views: 20

Module: Chemical Equilibrium Part 3

When solving an ICE table and solving for x, when do you know you can simplify a quadratic or cubed equation, and why can you do that?
by Shannon Asay 1C
Wed Jan 08, 2020 1:50 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 3
Views: 25

Le Chatelier's Principle

What is Le Chatelier's Principle and what effects cause changes to the equilibria. For example, how can you produce more product?
by Shannon Asay 1C
Wed Jan 08, 2020 1:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solvents
Replies: 5
Views: 33

Solvents

Why are solvents not included in the equilibrium expression equation?
by Shannon Asay 1C
Wed Jan 08, 2020 1:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Small K value and Large K value
Replies: 10
Views: 57

Re: Small K value and Large K value

It strongly favors the formation of products if K>10^3 and it strongly favors the formation of reactants when K<10^-3.
by Shannon Asay 1C
Tue Dec 03, 2019 3:03 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook 9C.9
Replies: 2
Views: 37

Textbook 9C.9

9C.9) With the help of Table 9C.1, determine the coordination number of the metal ion in each of the following complexes: (a) [NiCl4]2–; (b) [Ag(NH3)2]+; (c) [PtCl2(en)2]2+; (d) [Cr(edta)]-. Could someone help me understand why c and d are both 6? This is what the answer key says: c) 6 (en is bident...
by Shannon Asay 1C
Tue Dec 03, 2019 2:54 pm
Forum: Amphoteric Compounds
Topic: Textbook 6A.17
Replies: 3
Views: 39

Textbook 6A.17

State whether the following oxides are acidic, basic, or amphoteric: (a) BaO; (b) SO3; (c) As2O3; (d) Bi2O3.

How do we tell when it's amphoteric or not?
by Shannon Asay 1C
Tue Dec 03, 2019 2:44 pm
Forum: Lewis Acids & Bases
Topic: Textbook 6C.17
Replies: 1
Views: 34

Textbook 6C.17

6C.17) Which is the stronger base, the hypobromite ion, BrO-, or morphine, C17H19O3N? Justify your answer.

Why is hypobromite the stronger base?
by Shannon Asay 1C
Tue Dec 03, 2019 2:32 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Percentage Deprotonation
Replies: 2
Views: 15

Percentage Deprotonation

What is the percentage deprotonation for a molecule and how do you calculate it?
by Shannon Asay 1C
Tue Dec 03, 2019 11:51 am
Forum: Lewis Acids & Bases
Topic: Bronsted v Lewis acids and bases
Replies: 1
Views: 17

Re: Bronsted v Lewis acids and bases

Bronsted and Lewis acids and bases are essentially referring to the same things, they're just different ways of describing an acid or a base. A Bronsted acid is a proton donor and a Lewis acid is an electron pair acceptor. A Bronsted base is a proton acceptor and a Lewis base is an electron pair don...
by Shannon Asay 1C
Sun Dec 01, 2019 10:34 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids - Example from Lecture
Replies: 6
Views: 48

Strength of Acids - Example from Lecture

In the example from lecture Wednesday, Dr. Lavelle said that trichloroacetic acid, CCl3COOH, was stronger than acetic acid, CH3COOH. Could someone re-explain why that is?
by Shannon Asay 1C
Sun Dec 01, 2019 10:32 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strong vs Weak Acids
Replies: 7
Views: 46

Strong vs Weak Acids

What properties make an acid strong versus weak?
by Shannon Asay 1C
Sun Dec 01, 2019 10:29 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Textbook Problem 6B.1
Replies: 1
Views: 23

Textbook Problem 6B.1

6b.1) The molar concentration of HCl in hydrochloric acid is reduced to 12% of its initial value by dilution. What is the difference in the pH values of the two solutions?

How would you go about starting this problem?
by Shannon Asay 1C
Sun Dec 01, 2019 10:28 am
Forum: Hybridization
Topic: Hybridization of Carbon and Nitrogen
Replies: 2
Views: 25

Hybridization of Carbon and Nitrogen

Can someone explain the hybridization of carbon in CH2O and the hybridization of nitrogen in NH3?
by Shannon Asay 1C
Sun Dec 01, 2019 10:25 am
Forum: Conjugate Acids & Bases
Topic: Conjugate acids
Replies: 3
Views: 19

Re: Conjugate acids

The conjugate acid, in the products, is the compound that receives the proton and the conjugate base is the one that had given up the proton in the reactants. For example, with the equation, H2SO4 + H20 -> H30+ + HSO4-, the acid would be the H2SO4, the base would be H20, the conjugate acid would be ...
by Shannon Asay 1C
Sat Nov 23, 2019 4:17 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook Problem 9C.7
Replies: 1
Views: 23

Textbook Problem 9C.7

Could I get some help with this question?

9C.7) Which of the following isomers of diaminobenzene can form chelating complexes? Explain your reasoning.
Screen Shot 2019-11-23 at 4.15.44 PM.png
by Shannon Asay 1C
Sat Nov 23, 2019 4:07 pm
Forum: Biological Examples
Topic: Myoglobin
Replies: 3
Views: 32

Myoglobin

How does myoglobin work to transport O2 in muscle tissue?
by Shannon Asay 1C
Sat Nov 23, 2019 4:06 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelates
Replies: 2
Views: 26

Chelates

What is a chelate and how does it work?
by Shannon Asay 1C
Sat Nov 23, 2019 4:06 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 2
Views: 28

Cisplatin

How does cisplatin work to stop cell division?
by Shannon Asay 1C
Sat Nov 23, 2019 4:05 pm
Forum: Hybridization
Topic: Sigma and Pi Bonds
Replies: 6
Views: 39

Sigma and Pi Bonds

Why is a sigma bond more stable than a pi bond?
by Shannon Asay 1C
Thu Nov 14, 2019 12:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: difference between trigonal planar and tetrahedral
Replies: 4
Views: 26

Re: difference between trigonal planar and tetrahedral

Trigonal planar has 3 bonded pairs attached to the central atom and tetrahedral has 4 bonded pairs attached to the central atom.
by Shannon Asay 1C
Thu Nov 14, 2019 11:22 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: question concerning london dispersion forces and molecular formula
Replies: 2
Views: 22

Re: question concerning london dispersion forces and molecular formula

C18H38 has a higher molar mass than C5H12. The polarizability is higher for atoms with larger molecular weights. This has nothing to do with the mass, however, it's because the number of electrons increases as the mass does which allows for more polarizability of the electrons.
by Shannon Asay 1C
Thu Nov 14, 2019 11:18 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle
Replies: 9
Views: 50

Re: Bond Angle

It's because the lone pair of electrons over the central atom pushes the other electrons away from it, making the bond angles slightly smaller.
by Shannon Asay 1C
Thu Nov 14, 2019 11:12 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: London vs Dipole induced dipole
Replies: 2
Views: 15

Re: London vs Dipole induced dipole

Dr. Lavelle was saying that London forces were the same as induced dipole-induced dipole reactions, not dipole-induced dipole reactions. So the book is correct in saying that London forces are between nonpolar molecules and dipole-induced dipoles are between polar molecules and nonpolar molecules.
by Shannon Asay 1C
Wed Nov 13, 2019 4:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR model angles
Replies: 7
Views: 42

Re: VSEPR model angles

I'm assuming that we will have to know the angles for the test.
by Shannon Asay 1C
Fri Nov 08, 2019 5:21 pm
Forum: Dipole Moments
Topic: Electric Dipole Moment
Replies: 2
Views: 22

Electric Dipole Moment

What is an electric dipole moment?
by Shannon Asay 1C
Fri Nov 08, 2019 5:16 pm
Forum: Dipole Moments
Topic: Hydrogen Bonds
Replies: 6
Views: 48

Hydrogen Bonds

Why are hydrogen bonds stronger than normal dipole-dipole interactions?
by Shannon Asay 1C
Fri Nov 08, 2019 4:00 pm
Forum: Electronegativity
Topic: Periodic Trend
Replies: 13
Views: 85

Re: Periodic Trend

Electronegativity increases up a group and across a period, going towards Fluorine, which is the most electronegative element. Electronegativity refers to an atom's ability to attract electrons, and since Fluorine only needs one more electron to complete its valence shell and have a full stable octe...
by Shannon Asay 1C
Fri Nov 08, 2019 2:45 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: Shape of Molecule
Replies: 5
Views: 29

Re: Shape of Molecule

Yes, that's correct. For example, two molecules, like pentane and 2,2-Dimethylpropane, both have the molecular formula C5H12. They have the same number of electrons, so their shape influences the strength of attraction. Certain shapes allow the molecules to get closer so they can have stronger induc...
by Shannon Asay 1C
Tue Nov 05, 2019 11:08 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing Strength of Cations
Replies: 8
Views: 52

Polarizing Strength of Cations

Why do smaller cations have higher polarizing powers?
by Shannon Asay 1C
Wed Oct 30, 2019 9:11 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 4
Views: 26

Drawing Lewis Structures

What are some general rules for drawing Lewis structures?
by Shannon Asay 1C
Wed Oct 30, 2019 9:07 pm
Forum: Coordinate Covalent Bonds
Topic: coordinate covalent bonds
Replies: 3
Views: 25

coordinate covalent bonds

Could someone go over what coordinate covalent bonds are and why they occur?
by Shannon Asay 1C
Wed Oct 30, 2019 8:49 pm
Forum: Ionic & Covalent Bonds
Topic: Radicals
Replies: 9
Views: 60

Re: Radicals

Radicals are compounds with unpaired electrons. They're highly reactive because of this. In bodies, radicals can damage DNA because they react with it.
by Shannon Asay 1C
Wed Oct 30, 2019 4:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How many VE- in a cation? 2A.17
Replies: 2
Views: 37

Re: How many VE- in a cation? 2A.17

a) Mn 4+ would have 3 valence electrons, as it normally would have 7, including those in the d-orbital, but since you remove 4 electrons to have the net positive 4 charge, it would have 3. You can see this by counting across the period on the periodic table. b) Rh 3+ would have 6 valence electrons b...
by Shannon Asay 1C
Wed Oct 30, 2019 4:17 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 8
Views: 33

Re: Electron Affinity

Electron affinity is the energy released when an electron is added to a gas-phase atom. The general trend is that it increases as you go across a period and up a group.
by Shannon Asay 1C
Fri Oct 25, 2019 11:38 am
Forum: Resonance Structures
Topic: Delocalization
Replies: 3
Views: 26

Delocalization

What is the meaning of electron delocalization in resonance structures?
by Shannon Asay 1C
Fri Oct 25, 2019 11:29 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Number of Valence Electrons
Replies: 5
Views: 59

Re: Number of Valence Electrons

I believe it would have 7 valence electrons because you include the electrons from the d and s orbital.
by Shannon Asay 1C
Fri Oct 25, 2019 11:26 am
Forum: Lewis Structures
Topic: Exceptions to the Octet Rule
Replies: 2
Views: 26

Exceptions to the Octet Rule

How is phosphorus in phosphorus pentachloride able to have more than an octet in its bonding structure?
by Shannon Asay 1C
Fri Oct 25, 2019 11:22 am
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 4
Views: 31

Electron Affinity

Could someone explain the periodic trend for electron affinity?
by Shannon Asay 1C
Fri Oct 25, 2019 11:17 am
Forum: Formal Charge and Oxidation Numbers
Topic: Electron Affinity and Formal Charge
Replies: 3
Views: 25

Electron Affinity and Formal Charge

In lecture today, Dr. Lavelle mentioned something about electron affinity and formal charge, did anyone catch what the last thing he said about that was?
by Shannon Asay 1C
Fri Oct 25, 2019 11:07 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Writing e- Configurations
Replies: 15
Views: 100

Re: Writing e- Configurations

I think either one would be marked as correct on a midterm, it's just the noble gas abbreviation makes it easier especially when you get further down on the periodic table when there are more shells.
by Shannon Asay 1C
Sat Oct 19, 2019 11:52 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum Numbers
Replies: 9
Views: 54

Quantum Numbers

What are the differences between the angular momentum quantum number and the magnetic quantum number and how do you calculate them?
by Shannon Asay 1C
Sat Oct 19, 2019 11:26 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 6
Views: 39

Nodal Planes

What are nodal planes exactly and why do the s- orbitals not have them?
by Shannon Asay 1C
Sat Oct 19, 2019 11:10 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Stern and Gerlach Experiment
Replies: 1
Views: 11

Stern and Gerlach Experiment

Could someone help me understand the Stern and Gerlach Experiment a bit better and what they discovered about electrons from it?
by Shannon Asay 1C
Tue Oct 15, 2019 4:31 pm
Forum: Einstein Equation
Topic: HW 1B. 7
Replies: 6
Views: 122

Re: HW 1B. 7

So the two equations are E=hv and c=(wavelength)(v). If we solve for frequency in the speed of light equation, we get v=c/wavelength. You can plug that in for the frequency of the energy equation to get E=(h*c)/(wavelength)
by Shannon Asay 1C
Tue Oct 15, 2019 4:26 pm
Forum: Properties of Light
Topic: Relationships
Replies: 2
Views: 29

Re: Relationships

Yeah you're correct, the wavelength and frequency are inversely proportional so as one goes up the other goes down. That's seen with this equation: c=(wavelength)(frequency). Energy and frequency are directly proportional, as seen by this equation: E=hv. When one goes up, the other does as well.
by Shannon Asay 1C
Fri Oct 11, 2019 6:26 pm
Forum: Properties of Light
Topic: Photoelectric effect- post assessment questions #29 and 30
Replies: 2
Views: 20

Re: Photoelectric effect- post assessment questions #29 and 30

For #30, I used the equation E(photon)-E(energy to remove an electron)=Ek(electron). For the kinetic energy of the electron (Ek), I plugged in the number I calculated from #28 which was 1.99x10^-19 and for E(energy to remove an electron), I plugged in the value I calculated for #29 which was 2.501x1...
by Shannon Asay 1C
Fri Oct 11, 2019 6:09 pm
Forum: Properties of Electrons
Topic: Wave Properties of Electrons
Replies: 4
Views: 51

Wave Properties of Electrons

I had some trouble understanding in today's lecture how electron's exhibit wave-like properties and I was wondering if someone could help explain that a bit better?
by Shannon Asay 1C
Fri Oct 11, 2019 5:51 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Negative Energy Value for Hydrogen Energy Levels
Replies: 2
Views: 27

Re: Negative Energy Value for Hydrogen Energy Levels

The electrons have negative energies according to Rydberg's equation because we take our reference point off an electron that has been completely removed and is no longer interacting with the nucleus as E=0. The minus sign is because the electron's energy has decreased and the energy is released as ...
by Shannon Asay 1C
Fri Oct 11, 2019 5:46 pm
Forum: Properties of Light
Topic: Photoelectric effect- post assessment questions #29 and 30
Replies: 2
Views: 20

Re: Photoelectric effect- post assessment questions #29 and 30

For #29, I took the work function for sodium given in the problem, 150.6 kJ/mol and multiplied that by 1000 to get the joules/mole. Then, I divided that by Avogadro's constant to get the energy per electron which should be 2.501x10^-19 J.
by Shannon Asay 1C
Fri Oct 11, 2019 5:28 pm
Forum: Photoelectric Effect
Topic: HW problem 1B.5
Replies: 1
Views: 20

Re: HW problem 1B.5

A keV is a kiloelectron volt, there is a conversion to get it in joules in the back of the textbook. To start the problem, I converted keV to Joules, then used the E=hv equation to solve for frequency, and then you can just divide the speed of light by the frequency to get the wavelength.
by Shannon Asay 1C
Sun Sep 29, 2019 4:17 pm
Forum: Significant Figures
Topic: Constants and Sig Figs
Replies: 4
Views: 58

Re: Constants and Sig Figs

From my other chem classes, constants did not come into play in the final answer, you'd typically go with the same amount of sig figs as the original question states. So to answer your question, your answer would not be limited to 4 sig figs.
by Shannon Asay 1C
Sun Sep 29, 2019 3:41 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.17
Replies: 2
Views: 39

Re: G.17

I followed the same process as you, solving for the moles given the molarity and volume, and then using the molar mass to convert to grams. I got the same answers as you for both a and b.
by Shannon Asay 1C
Sun Sep 29, 2019 3:37 pm
Forum: Significant Figures
Topic: Rounding the elements
Replies: 12
Views: 124

Re: Rounding the elements

I personally use 1.01 for hydrogen and 16 for oxygen, but I think it's fine to use whatever number is on the periodic table.
by Shannon Asay 1C
Sun Sep 29, 2019 2:38 pm
Forum: Limiting Reactant Calculations
Topic: Homework Problem M.11
Replies: 3
Views: 73

Homework Problem M.11

"A reaction vessel contains 5.77g of white phosphorus and 5.77g of oxygen. The first reaction to take place is the formation of phosphorus(III) oxide, P4O6: P4(s) + 3O2(g)->P4O6(s). If enough oxygen is present, the oxygen can react further with this oxide to produce phosphorus(V) oxide, P4O10: ...
by Shannon Asay 1C
Sun Sep 29, 2019 2:25 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Precision and Accuracy
Replies: 3
Views: 76

Re: Precision and Accuracy

You could have precision and not accuracy if you got a set of measurements close to one another, but the known value for the measurement is off from what you experimentally got. It could be due to a variety of reasons, like if your scale wasn't calibrated properly before you started your experiment.

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