Search found 102 matches

Sun Mar 08, 2020 5:25 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: K < >
Replies: 8
Views: 118

Re: K < >

If [products] > [reactants], then K > 1. If [reactants] > [products], then K < 1.
Sun Mar 08, 2020 5:23 pm
Forum: General Science Questions
Topic: Who makes the Final
Replies: 23
Views: 441

Re: Who makes the Final

I believe it's primarily Lavelle with some input from the TAs but I'm not certain.
Sat Mar 07, 2020 4:48 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Terminology for reaction rate constant
Replies: 3
Views: 108

Re: Terminology for reaction rate constant

I'm pretty sure those are all just names for the constant, K.
Sat Mar 07, 2020 11:05 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate-Limiting Step
Replies: 5
Views: 93

Rate-Limiting Step

How do you determine the rate-limiting or slow step? Is it given in the problem which one is slow?
Sat Mar 07, 2020 10:49 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: What is 'A'?
Replies: 5
Views: 98

Re: What is 'A'?

With the Arrhenius equation, we are trying to calculate K, the equilibrium constant.
Sun Mar 01, 2020 8:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell reaction that can only occur in acidic solution
Replies: 1
Views: 38

Re: Cell reaction that can only occur in acidic solution

You are usually told in the question whether it is in an acidic or basic solution.
Sun Mar 01, 2020 8:31 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Ion-selective Electrodes and Corrosion
Replies: 2
Views: 50

Re: Ion-selective Electrodes and Corrosion

I would go off of the topics listed in the outlines on Lavelle's website. These are the topics that may be tested on the exam.
Sun Mar 01, 2020 8:27 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Spontaneity
Replies: 4
Views: 84

Re: Spontaneity

The reaction of diamonds to graphite does occur, and it is spontaneous. It just occurs at an EXTREMELY slow rate.
Sun Mar 01, 2020 1:29 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: HW Question 6N.23 Part A
Replies: 2
Views: 79

HW Question 6N.23 Part A

Suggest two metals that could be used for the cathodic protection of a titanium pipeline. The answer is aluminum or magnesium because both are below titanium in the electrochemical series. My question is what is the result of being below titanium in the series? How does this mean that aluminum or ma...
Sun Mar 01, 2020 12:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: HW Question 6L.7
Replies: 1
Views: 50

HW Question 6L.7

Write the half-reactions and devise a galvanic cell (write a cell diagram) to study each of the following reactions: (a) AgBr(s) --> Ag1(aq) + Br2(aq), a solubility equilibrium (b) H+(aq) + OH-(aq) --> H2O(l), the neutralization reaction (c) Cd(s) + 2 Ni(OH)3 (s) --> Cd(OH)2 (s) + 2 Ni(OH)2 (s), the...
Sun Feb 23, 2020 12:32 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert Conductor
Replies: 1
Views: 21

Re: Inert Conductor

Yes, if there is no conducting solid an inert conductor must be added.
Sat Feb 22, 2020 10:45 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Concentration
Replies: 2
Views: 46

Concentration

How does concentration affect cell potential?
Sat Feb 22, 2020 10:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: single line in cell diagram
Replies: 3
Views: 47

Re: single line in cell diagram

The single line represents a porous disk or wall.
Sat Feb 22, 2020 10:32 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff equation
Replies: 10
Views: 258

Re: Van't Hoff equation

The learning objectives ask you to be able to derive this equation.
Sat Feb 22, 2020 2:14 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff Equation
Replies: 2
Views: 51

Re: Van't Hoff Equation

The Van't Hoff equation relates the change in K to change in temperature given delta H (the change in enthalpy).
Sat Feb 15, 2020 1:21 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Enthalpy
Replies: 12
Views: 308

Re: Enthalpy

Examples of state functions include density, internal energy, enthalpy, and entropy.
Sat Feb 15, 2020 1:16 pm
Forum: Van't Hoff Equation
Topic: What is this? [ENDORSED]
Replies: 7
Views: 150

Re: What is this?[ENDORSED]

The Van't Hoff equation can be used to calculate K at a different temperature if delta H is known.
Sat Feb 15, 2020 11:29 am
Forum: Van't Hoff Equation
Topic: Van't Hoff
Replies: 6
Views: 96

Re: Van't Hoff

The Van't Hoff equation can be used to calculate K at a different temperature if delta H is known.
Sat Feb 15, 2020 11:27 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Potential
Replies: 4
Views: 69

Re: Cell Potential

Cell potential is also known as cell voltage. It is used to measure the voltage difference in two halves of a cell.
Sat Feb 15, 2020 11:24 am
Forum: General Science Questions
Topic: Converting Liters to m^3 ?
Replies: 2
Views: 49

Re: Converting Liters to m^3 ?

1 dm = 0.1 m. A dm is a decimeter.
Sat Feb 15, 2020 11:23 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs free energy
Replies: 5
Views: 79

Re: Gibbs free energy

Gibbs free energy is a state function because it is determined by enthalpy and entropy, which are also state functions.
Sat Feb 08, 2020 1:56 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Molecular Complexity
Replies: 4
Views: 79

Re: Molecular Complexity

Because they have more positions or states that the molecule can be in. They have more atoms and are arranged in a more complicated way than less complex molecules.
Sun Feb 02, 2020 9:31 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Affect of temperature on entropy?
Replies: 5
Views: 72

Re: Affect of temperature on entropy?

Increasing the temperature increases the entropy of a system.
Sat Feb 01, 2020 8:32 pm
Forum: Calculating Work of Expansion
Topic: Reversible and Irreversible
Replies: 5
Views: 59

Reversible and Irreversible

What are reversible and irreversible processes? What do reversible expansion and irreversible expansion mean?
Sat Feb 01, 2020 8:26 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy
Replies: 3
Views: 42

Re: Entropy

This is usually done using the equation: delta G = delta H - T*delta S. Lavelle will likely cover this later.
Sat Jan 25, 2020 11:21 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: sign changes in bond enthalpy
Replies: 5
Views: 65

Re: sign changes in bond enthalpy

Bond enthalpy is positive when bonds are being broken because this process requires energy. Bond enthalpy is negative when bonds are being formed because this process releases energy.
Sat Jan 25, 2020 11:19 am
Forum: Phase Changes & Related Calculations
Topic: Endothermic and Exothermic
Replies: 13
Views: 97

Re: Endothermic and Exothermic

Endothermic reactions use heat as a reactant because they require energy. Exothermic reactions use heat as a product because they release energy.
Fri Jan 24, 2020 5:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14A Final Exam
Replies: 1
Views: 52

Re: Chem 14A Final Exam

Young Hall 3034
Fri Jan 24, 2020 3:10 pm
Forum: General Science Questions
Topic: Fall 2019 final
Replies: 7
Views: 101

Re: Fall 2019 final

Ellen Amico 2L wrote:We have to pick them up ourselves in Young Hall 3034 between 9-5pm.

What day?
Fri Jan 24, 2020 3:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Delta H
Replies: 3
Views: 29

Re: Calculating Delta H

I believe we ran out of time and were unable to go over the last method.
Tue Jan 21, 2020 4:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ice box
Replies: 4
Views: 44

Re: ice box

If the coefficient of the reactant is a number other than 1.
Tue Jan 21, 2020 4:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: using K
Replies: 5
Views: 34

Re: using K

Use Kp if the problem gives units of pressure. Otherwise, assume Kc.
Tue Jan 21, 2020 4:21 pm
Forum: Identifying Acidic & Basic Salts
Topic: Buffer Solution
Replies: 2
Views: 107

Re: Buffer Solution

A buffer solution is a composed of a weak acid and its conjugate base or a weak base and its conjugate acid. Buffers are used to maintain the pH of a solution at a consistent point.
Tue Jan 21, 2020 4:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Gases (units based on K)
Replies: 2
Views: 23

Re: Gases (units based on K)

If you are given pressure units, use Kp. Otherwise, assume Kc.
Sat Jan 18, 2020 5:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6B. 9 Solutions Typo
Replies: 1
Views: 29

6B. 9 Solutions Typo

Is the solutions manual correct for this question? I am getting very different answers when completing the table. Thanks!
Tue Jan 14, 2020 12:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Table
Replies: 8
Views: 97

Re: ICE Table

Yes, you can use it for partial pressures as well as concentrations and amount of moles.
Mon Jan 13, 2020 7:23 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH range
Replies: 4
Views: 128

Re: pH range

Yes, if a solution is VERY acidic or VERY basic.
Mon Jan 13, 2020 7:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Autoprotolysis vs Autoionization
Replies: 2
Views: 22

Re: Autoprotolysis vs Autoionization

An explanation that I found online said that "the key difference between autoionization and autoprotolysis is that autoionization is the conversion of a neutral state of a chemical species into an ionized state whereas autoprotolysis is the transfer of a proton between two identical chemical sp...
Mon Jan 13, 2020 7:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ATP Hydrolysis
Replies: 2
Views: 22

Re: ATP Hydrolysis

The chemical reaction equation for ATP hydrolysis was in some of the textbook questions that were assigned but I don't think Lavelle ever specifically mentioned it in class.
Mon Jan 13, 2020 7:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kw and H3O/OH concentrations
Replies: 5
Views: 53

Re: Kw and H3O/OH concentrations

The concentration of H3O+ is equal to that of OH- when the pH of the solution is 7. When the solution is neutral, the concentration of acid and base essentially cancel one another out.
Sat Jan 11, 2020 9:41 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Hw 5I.1
Replies: 4
Views: 68

Re: Hw 5I.1

No, you do not create an ICE table. You simply set K equal to (BrCl)^2/((Cl2)*(Br2)) and solve for the equilibrium concentration of Br2. This question just involves some simple algebra.
Sat Jan 11, 2020 9:38 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Knowing it's an Equilibrium Reaction
Replies: 4
Views: 44

Re: Knowing it's an Equilibrium Reaction

I believe that at least for this class, we will be told when a reaction is reversible. The double arrow is an easy way to determine this.
Sat Jan 11, 2020 9:36 am
Forum: Ideal Gases
Topic: Solids and Liquids [ENDORSED]
Replies: 10
Views: 126

Re: Solids and Liquids[ENDORSED]

Solids and liquids are considered pure substances. Therefore they have an activity value of 1. So in equilibrium expressions, we do not include them because their value would just be 1.
Sat Jan 11, 2020 9:35 am
Forum: Ideal Gases
Topic: textbook [ENDORSED]
Replies: 2
Views: 38

Re: textbook[ENDORSED]

Yes.
Sat Jan 11, 2020 9:31 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5I.13
Replies: 2
Views: 32

Re: Textbook question 5I.13

For part b, you just substitute F for Cl into the chemical reaction equation from part a (Cl2 --> 2Cl). Using table 5G.2, you can obtain the value of Kc for the new equation. Next, you just make an ICE table and solve for X to find the equilibrium concentrations just like in part a. I'm not sure how...
Fri Jan 10, 2020 7:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5I.13 Part C
Replies: 2
Views: 33

5I.13 Part C

This question asks whether Cl2 or F2 is thermodynamically more stable relative to its atoms at 1000 K. How would you determine this? Thanks!
Fri Jan 10, 2020 5:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pure Substance
Replies: 5
Views: 42

Re: Pure Substance

According to the textbook, "activities are used to take into account deviations from ideal behavior". Since solids and liquids are considered to be completely pure substances, they do not deviate from ideal behavior. Therefore, their activity is equal to 1, not zero.
Sat Dec 07, 2019 5:30 pm
Forum: Naming
Topic: Wrong order
Replies: 4
Views: 79

Re: Wrong order

The ligand names in a coordination compound should be in alphabetical order.
Sat Dec 07, 2019 1:37 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Equations
Replies: 5
Views: 59

Re: Equations

205192823 wrote:Thank you, and also when the equation is pH=-log [H+] it is the same as pH=-log[H3O+]?

Yes
Fri Dec 06, 2019 8:36 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Relative Acidity: e- withdrawing groups
Replies: 2
Views: 117

Relative Acidity: e- withdrawing groups

What exactly is an electron-withdrawing group? Can you give some examples? Thanks.
Fri Dec 06, 2019 8:24 pm
Forum: Naming
Topic: Abbreviations
Replies: 2
Views: 47

Re: Abbreviations

Fri Dec 06, 2019 8:22 pm
Forum: Naming
Topic: Naming Cont
Replies: 3
Views: 43

Re: Naming Cont

First, alphabetize the ligands. Then, write the transition metal cation. Lastly, don't forget the roman numeral at the end of the name. If the complex has a negative charge, add -ate to the end of the metal name.
Fri Dec 06, 2019 8:19 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: HF
Replies: 4
Views: 177

Re: HF

HF also has a relatively large pKa value and a small Ka value, which makes it a weak acid.
Thu Dec 05, 2019 12:54 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: calculating pH
Replies: 4
Views: 84

Re: calculating pH

Arianna Perea 3H wrote:will we only have to calculate problems for strong acid/bases or weak ones as well for the final?

Only strong acids or bases
Tue Dec 03, 2019 9:13 pm
Forum: Lewis Acids & Bases
Topic: How to identify acid vs. base
Replies: 4
Views: 73

How to identify acid vs. base

Question 6A.13 asks to identify whether certain compounds/molecules are Lewis acids or Lewis bases. How can you determine whether a substance is a Lewis acid or base? Thanks!
Sat Nov 30, 2019 8:44 am
Forum: General Science Questions
Topic: test bank
Replies: 2
Views: 52

Re: test bank

The test bank does not have any of Lavelle's previous exams. I checked.
Sat Nov 30, 2019 8:43 am
Forum: General Science Questions
Topic: test taking nervousness
Replies: 19
Views: 375

Re: test taking nervousness

Try to really focus on the content and not the fact that you are taking a test. Just treat the questions like regular practice problems that you have successfully completed in the past. I know this can be difficult but it helps me.
Sat Nov 30, 2019 8:40 am
Forum: Biological Examples
Topic: Cisplatin
Replies: 15
Views: 174

Re: Cisplatin

Emily_4B wrote:would we need to know this on the final?

Yes, you should know it for the final.
Tue Nov 26, 2019 4:29 pm
Forum: Student Social/Study Group
Topic: -ate Nomenclature for final?
Replies: 2
Views: 59

Re: -ate Nomenclature for final?

If a complex has a negative charge, we add -ate to the end of the metal name. However, I do not have anything in my notes about the -ite ending.
Tue Nov 26, 2019 11:31 am
Forum: Amphoteric Compounds
Topic: How can compounds be amphoteric?
Replies: 5
Views: 78

Re: How can compounds be amphoteric?

Amphoteric compounds are those that are able to either accept or donate a proton, depending on what other compounds they react with. For example, HCO3- can either accept a proton and become H2CO3 or donate a proton and become CO3 2-.
Sat Nov 23, 2019 9:02 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 44

Polydentate

How do you determine whether a ligand is polydentate?
Sat Nov 23, 2019 7:30 pm
Forum: Hybridization
Topic: 2F.7
Replies: 1
Views: 28

2F.7

How do you identify the hybrid orbitals used by an atom? I am able to figure out the hybridization of an atom (as in question 2F.5) but am having trouble with this question. Thanks.
Sat Nov 23, 2019 7:04 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 15
Views: 174

Cisplatin

How exactly does cisplatin stop the DNA replication of cancerous cells?
Sat Nov 23, 2019 7:02 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand
Replies: 4
Views: 61

Ligand

What is the definition of a ligand?
Sun Nov 17, 2019 4:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 2
Views: 70

Re: Test 2

My TA sent me this: Test 2 covers all material since midterm up to and including the list below: • Use the Valence-Shell Electron-Pair Repulsion Model (VSEPR) to determine the shape of inorganic, organic, and small biological molecules, cations, and anions. • Use bond dipole moments and shape to det...
Sun Nov 17, 2019 2:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moments
Replies: 4
Views: 80

Dipole moments

How do you determine the direction in which a dipole moment points?
Sun Nov 17, 2019 2:15 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: Quick Run-Through
Replies: 2
Views: 34

Re: Quick Run-Through

Ion-ion interactions are between two ionic molecules. Ion-dipole interactions are between an ion and a polar molecule. Dipole-dipole interactions are between two polar molecules. Dipole-induced dipole interactions are between a polar molecule and a non-polar molecule.
Sun Nov 17, 2019 1:55 pm
Forum: Student Social/Study Group
Topic: Test 2 Study Worksheets
Replies: 9
Views: 328

Re: Test 2 Study Worksheets

There is a peer learning session tomorrow night at Covel. I'm sure they'll provide some kind of practice problems there.
Sat Nov 16, 2019 12:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-shape
Replies: 6
Views: 109

T-shape

Did Dr. Lavelle ever talk about t-shape structures? I don't have it in my notes and a lot of questions include it. Can someone explain this shape?
Sat Nov 16, 2019 12:18 pm
Forum: General Science Questions
Topic: Test 2
Replies: 7
Views: 83

Re: Test 2

It all seems to be mostly concept based. The only numerical content would be the strengths of bonds and bond angle degrees.
Sat Nov 16, 2019 12:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape of ClO2+
Replies: 6
Views: 85

Shape of ClO2+

Referring to question 2E.5. Is ClO2+ trigonal planar or bent? The solution manual includes both in its answer.
Sat Nov 09, 2019 9:51 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: London Dispersion Forces VS. Induced Dipole - Induced Dipole
Replies: 2
Views: 27

Re: London Dispersion Forces VS. Induced Dipole - Induced Dipole

Dispersion forces, induced dipole-induced dipole, LDFs, and Van der Waals forces are all equivalent. These interactions are always present and always attractive.
Sat Nov 09, 2019 9:49 pm
Forum: Bond Lengths & Energies
Topic: Dissociation Energy
Replies: 5
Views: 59

Re: Dissociation Energy

It's the energy required to break the bonds.
Sat Nov 09, 2019 9:48 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarisability Trend
Replies: 3
Views: 53

Re: Polarisability Trend

Larger electron-rich atoms are more polarizable. Usually, on the periodic table, polarizability decreases from left to right increases down a column.
Sat Nov 09, 2019 9:45 pm
Forum: Bond Lengths & Energies
Topic: Dissociation Energy
Replies: 5
Views: 59

Re: Dissociation Energy

Dissociation energy refers to the amount of energy required to break down a molecule into singular atoms.
Sat Nov 09, 2019 7:35 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: Ion-Dipole Forces
Replies: 4
Views: 49

Ion-Dipole Forces

How can you easily determine whether a compound contains ion-dipole forces? Is there some kind of rule to go off of? Thanks!
Fri Nov 08, 2019 1:55 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: Order of strength
Replies: 3
Views: 52

Re: Order of strength

Weakest --> Strongest: London dispersion forces, dipole-dipole forces, hydrogen bonding
Sat Nov 02, 2019 9:28 am
Forum: Resonance Structures
Topic: Tips for drawing resonance structures
Replies: 3
Views: 51

Re: Tips for drawing resonance structures

It's important that you understand how to calculate and use formal charge when drawing resonance structures. This will allow you to select the primary resonance structure of the molecule.
Wed Oct 30, 2019 9:32 pm
Forum: Ionic & Covalent Bonds
Replies: 9
Views: 166

Radicals also only exist for a short amount of time because they are so reactive. Food supplements can react with radicals in the body before they cause damage to DNA, which is why it's important to eat plenty of vitamins and nutrients!
Wed Oct 30, 2019 9:22 pm
Forum: Coordinate Covalent Bonds
Topic: coordinate covalent bonds
Replies: 3
Views: 69

Re: coordinate covalent bonds

A coordinate covalent bond occurs when the shared electrons all come from the same atom. In a simple covalent bond, each atom supplies one electron. Coordinate covalent bonds are common between metals and ligands.
Wed Oct 30, 2019 9:18 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 4
Views: 57

Re: Drawing Lewis Structures

Generally, you would want to place the atom with the lowest electronegativity in the center of your lewis structure. Hydrogen can never be the central atom. To start your diagram, you should count the number of valence electrons for each atom so that you can determine how many electrons you need in ...
Wed Oct 30, 2019 9:14 pm
Forum: Electronegativity
Topic: Electronegativity vs. Electron Affinity
Replies: 7
Views: 96

Electronegativity vs. Electron Affinity

Could someone please explain the conceptual difference between electronegativity and electron affinity? Thanks!
Wed Oct 23, 2019 9:31 pm
Forum: Resonance Structures
Topic: defintion
Replies: 7
Views: 98

Re: defintion

Resonance structures are alternate structures of the same molecule so basically yes, your definition is correct.
Tue Oct 22, 2019 9:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Online Modules
Replies: 7
Views: 95

Online Modules

Does anyone know if there will be videos and modules posted for the new content on Lavelle's website? Was this just for the introductory material? I found the videos and modules very helpful! Thanks.
Tue Oct 22, 2019 9:43 pm
Forum: DeBroglie Equation
Topic: When to use the DeBroglie Equation
Replies: 3
Views: 59

Re: When to use the DeBroglie Equation

It depends on what values you are given in the problem. If you are given the momentum, then use De Broglie's equation but if you are only given the frequency and asked to find the wavelength, then use c=lambda*v. It helps if you start out by writing the values that you have. This way, you can easily...
Tue Oct 22, 2019 9:39 pm
Forum: Quantum Numbers and The H-Atom
Topic: The plus and minus sign on the magnetic quantum #
Replies: 5
Views: 75

Re: The plus and minus sign on the magnetic quantum #

I would say that if the textbook specifically tells you to write the +, then you should write it.
Mon Oct 21, 2019 2:12 pm
Forum: Trends in The Periodic Table
Topic: Focus 1 Exercise 1.13
Replies: 3
Views: 33

Focus 1 Exercise 1.13

This question asks us to explain why the ionization energy for oxygen is lower than that of either nitrogen and fluorine. I do not understand the explanation that the solution manual provides. Can someone explain this anomaly in a different way? Thanks!
Thu Oct 17, 2019 9:30 pm
Forum: Properties of Electrons
Topic: effective nuclear charge
Replies: 5
Views: 71

Re: effective nuclear charge

The higher the effective nuclear charge of an atom, the atom can attract electrons more closely to its nucleus. The tighter an atom's hold is on its electrons, the smaller its atomic radius. In conclusion, a higher effective nuclear charge causes a lower atomic radius.
Thu Oct 17, 2019 5:01 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Replies: 92
Views: 1938

I have been watching the videos posted on Lavelle's website and completing the modules. Then throughout the week, I will read the sections in the textbook and complete all of the homework problems. Good luck!
Thu Oct 17, 2019 4:57 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals
Replies: 2
Views: 32

Re: Orbitals

The number of orbitals is based on the subshell. The s-subshell corresponds to 1 orbital, the p-subshell has 3, d-subshell has 5, and f-subshell has 7. I hope this was helpful!
Wed Oct 16, 2019 6:52 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.23 Homework Question
Replies: 1
Views: 70

1D.23 Homework Question

1D.23 How many orbitals can have the following quantum numbers in an atom? (a)n=2, l=1 (b)n=4, l=2, ml=-2 (c)n=2 (d)n=3, l=2, ml=+1 I understand that the answer to B and D is 1 because they both have 3 quantum numbers that identify a single orbital. Could someone please explain how the answer to A i...
Mon Oct 14, 2019 1:58 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post-Module Question
Replies: 3
Views: 62

Atomic Spectra Post-Module Question

#38 on the Atomic Spectra Post-Module Assessment asks us to calculate the frequency of a photon emitted by a hydrogen atom when an electron makes a transition from the fourth to the second principal quantum level. A. -6.17 x 10^14 Hz B. 1.62 x 10^-15 Hz C. 6.17 x 10^14 Hz D. 2.71 x 10^-52 Hz I keep ...
Fri Oct 11, 2019 12:16 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Clarification
Replies: 3
Views: 47

Re: Photoelectric Effect Clarification

To add on to the previous reply, increasing the intensity of light increases the number of photons, not the energy of the photons. One photon can eject one electron to do so, the photon must have either a short wavelength or high frequency so that the photons have enough energy.
Fri Oct 11, 2019 12:10 pm
Forum: Properties of Electrons
Topic: Multi-Electron Systems
Replies: 4
Views: 49

Re: Multi-Electron Systems

Although it was once thought otherwise, the Bohr Model can only be used for the element of hydrogen, which has only one electron.
Fri Oct 11, 2019 12:07 pm
Forum: DeBroglie Equation
Topic: Frequency and de Broglie Equation Derivation
Replies: 3
Views: 61

Re: Frequency and de Broglie Equation Derivation

The equations used to derive the De Broglie wavelength equation cannot be used for electrons. Lavelle just demonstrated the way that the equation was originally derived so that we would understand where the equation comes from.
Fri Oct 11, 2019 11:55 am
Forum: Properties of Light
Topic: Equations for quantum mechanics
Replies: 3
Views: 52

Re: Equations for quantum mechanics

The equations that we learned on Monday that pertain to light and electromagnetic radiation cannot be used for electrons. They were just used today to demonstrate how De Broglie derived his wavelength equation.
Fri Oct 11, 2019 11:49 am
Forum: DeBroglie Equation
Topic: Measurable V. Non-Measurable
Replies: 5
Views: 83

Re: Measurable V. Non-Measurable

If the De Broglie wavelength value is greater than 10^-15, it is measurable.
Thu Oct 03, 2019 9:51 am
Forum: Molarity, Solutions, Dilutions
Topic: HW E.23
Replies: 3
Views: 30

Re: HW E.23

For parts A and C, you basically do it the same way. You just have to determine the number of ions in the compound. In part A, there is only 1 Cu2+ ion. In part C, there are 6 F- ions because it has a subscript of 6. So you would have to first divide by the molar mass for both parts A and C. Then, m...
Thu Oct 03, 2019 9:48 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Textbook Question E15
Replies: 3
Views: 82

Textbook Question E15

For question E15, would OH be the sulfide of the metal? Or would it be (OH)2? Thanks.
Thu Oct 03, 2019 9:42 am
Forum: SI Units, Unit Conversions
Topic: Finding Molar Mass
Replies: 3
Views: 58

Re: Finding Molar Mass

In this question, you just add to find the molar mass. For Na2CO3 * 10H2O, you would compute 2(22.99) + 12.01 + 3(16) +10(18.02) = 286.19.