Search found 104 matches
- Sat Mar 13, 2021 11:23 pm
- Forum: General Rate Laws
- Topic: Writing Rate Laws
- Replies: 2
- Views: 283
Writing Rate Laws
Hello, I was wondering if someone could explain to me how to go about writing rate laws for when k is the rate constant, as I struggled on that part of the question on question 7 on week 9 and 10 of Sapling?
- Sat Mar 13, 2021 11:13 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Direction of Current Flow
- Replies: 2
- Views: 197
Direction of Current Flow
Hello, I am a bit lost on how to go about determining the direction of current flow of a cell and was wondering if someone could explain to me in simple terms how direction flow is determined?
- Sat Mar 13, 2021 11:05 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Identifying Catalysts in a reaction
- Replies: 5
- Views: 470
Identifying Catalysts in a reaction
Hello, I am a bit lost on one of the points on the outline stating that we need to be able to identify catalysts in a reaction, from what I know its usually written above the yield arrow of a reaction, but I was wondering if there if something I am missing or if that is the only idea we need to unde...
- Sat Mar 13, 2021 10:41 pm
- Forum: General Rate Laws
- Topic: Determining Order of Reactants
- Replies: 2
- Views: 211
Determining Order of Reactants
Hello, I am struggling a bit to identify the order of a reactant in a reaction, a part of the question asked on question 7 of Weeks 9 and 10 on Sapling, and I was wondering if anyone could help explain to me in basic terms of how I would go about finding the order of reactants for a given reaction?
- Sat Mar 13, 2021 10:33 pm
- Forum: Ideal Gases
- Topic: Torr as a Unit of Pressure
- Replies: 8
- Views: 868
Torr as a Unit of Pressure
Hello, I have seen some mentions of the unit torr in the textbook as a unit for pressure in the ideal gas equation and I was wondering if we are required to ever use this unit in chemical equilibrium problems or if we should know how to convert this unit as I have seen the unit only in the text an n...
- Sun Mar 07, 2021 10:49 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Determining The Favored Side of an Equilibrium Product
- Replies: 12
- Views: 1311
Determining The Favored Side of an Equilibrium Product
Hello, I may be missing something from my notes but I know that when determining which direction the reaction is proceeding in an equilibrium question we solve for Q, but I was wondering if someone could tell me the basis we use to state the direction of the reaction based on this Q?
- Sun Mar 07, 2021 9:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Making X Negligible
- Replies: 6
- Views: 690
Making X Negligible
Hello, I just have a question as to why we cannot make X negligible in quadratic and cubic equations in equilibrium concentration problems when K is greater than 10^-4?
- Sun Mar 07, 2021 9:12 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Rust and Sea Water
- Replies: 8
- Views: 544
Rust and Sea Water
Hello, I was wondering if someone could explain one of the last concepts covered in electrochemistry that I do not really understand and that is, why is it that sea water causes rusting faster than pure water?
- Sun Mar 07, 2021 8:23 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridges
- Replies: 12
- Views: 635
Salt Bridges
Hello, I am a bit lost on Electrochemistry and was wondering if someone could just explain the significance of the salt bridge in a reaction or what its purpose is in electron transfer?
- Sun Mar 07, 2021 8:12 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Favoring Direction of Equilibrium
- Replies: 5
- Views: 380
Favoring Direction of Equilibrium
Hello, I am reviewing Outline 1 and I just needed some confirmation on whether the reactants or product is favored when K is less than 10^3 and grater than 10^-3, as I assume that it would simply mean that neither is favored, but I am unsure if this is correct?
- Sun Feb 28, 2021 10:54 pm
- Forum: Balancing Redox Reactions
- Topic: Canceling Out Added Electrons in Half Reactions
- Replies: 10
- Views: 1531
Canceling Out Added Electrons in Half Reactions
Hello, I am a bit lost on balancing redox reactions as I have looked at some explanations and I have seen the use of adding electrons in order to balance the equation and I was a bit lost and was wondering if someone could explain how these added electrons will later be canceled out in order to reco...
- Sun Feb 28, 2021 10:39 pm
- Forum: Balancing Redox Reactions
- Topic: Finding Anodes and Cathodes
- Replies: 2
- Views: 179
Finding Anodes and Cathodes
Hello, I found myself lost determining anodes and cathodes from the chart of Standard Reduction Potentials, and I was wondering if someone could tell me what I should look for in order to determine the two?
- Sun Feb 28, 2021 9:58 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: The Faraday Constant and The Nernst Equation
- Replies: 4
- Views: 490
The Faraday Constant and The Nernst Equation
Hello, I would I just like some clarification on the Faraday constant as I saw in one of the Sapling feedback responses they included the Nernst Equation, but with no indication of the Faraday constant, so I am wondering if there are instances when we should exclude the constant, or should we always...
- Sun Feb 28, 2021 9:28 pm
- Forum: Balancing Redox Reactions
- Topic: Shortened Notation Clarification
- Replies: 1
- Views: 178
Shortened Notation Clarification
Hello, I am a bit lost on writing shortened notation of a redox reaction, as I greatly struggled to find the correct notation on Sapling 3 for weeks 7-8, and I was wondering if someone could explain how shortened notation should be written or a general rule to follow?
- Sun Feb 28, 2021 8:42 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation Clarification
- Replies: 5
- Views: 303
Nernst Equation Clarification
Hello, I've seen two variations of the Nernst equation and I was wondering if there is a difference between the two and if they can only be applied in certain cases as one case uses RT and the other uses the constant 0.05916?
- Sun Feb 21, 2021 10:33 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cell Significance
- Replies: 2
- Views: 184
Galvanic Cell Significance
Hello, I just had a question regarding the galvanic cell introduced in Wednesday's lecture and I was wondering how exactly galvanic cells affect the chemical reaction involving electric current or rather the significance of the galvanic cell?
- Sun Feb 21, 2021 10:05 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Liquids and Solids in Equilibrium Calculations
- Replies: 12
- Views: 767
Liquids and Solids in Equilibrium Calculations
Hello, I am currently reviewing Outline 1 and I was wondering if someone could confirm or deny that in calculating constants, are liquids and solids completely ignored in solving for the equilibrium constant?
- Sun Feb 21, 2021 9:17 pm
- Forum: Phase Changes & Related Calculations
- Topic: Textbook Problem 4A1 part C
- Replies: 3
- Views: 325
Textbook Problem 4A1 part C
Hello, I am a bit confused on the reasoning of this question and I was wondering if someone could explain to me why in the question 4A1 part C, the system of a bomb calorimeter in which benzene is burned is considered an isolated system?
- Sun Feb 21, 2021 9:03 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Favoring of a Process
- Replies: 2
- Views: 210
Favoring of a Process
Hello, I was wondering if someone could remind me exactly what determines whether the forward or reverse reaction is favored when doing Gibbs Free Energy calculations that indicate whether delta H or delta S will dominate?
- Sun Feb 21, 2021 8:59 pm
- Forum: Balancing Redox Reactions
- Topic: "Leo" Oxidation Numbers
- Replies: 26
- Views: 1271
"Leo" Oxidation Numbers
Hello, I am a but lost on some of the material from last Wednesday's lecture when the notes state that a loss of electrons causes "'Leo' oxidation numbers" to increase. I was wondering if someone could explain what this term means or the significance of this term "leo" in describ...
- Sun Feb 14, 2021 11:25 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Units for Gibbs Free Energy Calculations
- Replies: 6
- Views: 434
Units for Gibbs Free Energy Calculations
Hello, I was just wondering when we solve a Gibbs Free Energy problem, whether it be for G, H, or S should the answer always be in kilojoules?
- Sun Feb 14, 2021 11:17 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Phase Changes of Delta H and Delta S
- Replies: 3
- Views: 2129
Phase Changes of Delta H and Delta S
Hello, I would just like some clarification on phase changes of H and S and I was just wondering if someone could explain just how I should think about phase changes, as presented in Sapling week 5 and 6 question 3.
- Sun Feb 14, 2021 10:13 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneity of a System
- Replies: 38
- Views: 3114
Spontaneity of a System
Hello, I am a bit lost on spontaneity of a reaction and I was wondering if someone could explain how to determine when a reaction is spontaneous in simple terms?
- Sun Feb 14, 2021 9:49 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Determining the Sign of S
- Replies: 8
- Views: 509
Determining the Sign of S
Hello, I am just a bit lost on determining the sign of delta S and I was wondering if the sign is dependent on certain aspects of the reaction, or is it simply determined by the result of the calculation?
- Sun Feb 14, 2021 9:42 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Residual Entropy
- Replies: 5
- Views: 490
Residual Entropy
Hello, I was a bit lost doing the first Sapling problem of week 5 and 6 involving determining which molecules have residual structure and I was wondering what exactly I should look for and what exactly residual entropy is?
- Sun Feb 07, 2021 10:32 pm
- Forum: Calculating Work of Expansion
- Topic: Negative Work
- Replies: 5
- Views: 245
Negative Work
Hello, after completing the week 3 and 4 Sapling homework I found myself a bit lost in that I did not understand why values for including work and q were often negative values, and I was wondering if someone could explain why these equations involving work yield a negative answer?
- Sun Feb 07, 2021 10:28 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Explaining Enthalpies
- Replies: 7
- Views: 476
Explaining Enthalpies
Hello, I am struggling to understand the general meaning of enthalpies and was wondering if someone could explain exactly what this process entails.
- Sun Feb 07, 2021 10:08 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: The Three Systems and the 1st Law of Thermodynamics
- Replies: 1
- Views: 78
The Three Systems and the 1st Law of Thermodynamics
Hello, I just need some clarification on the First Law of Thermodynamics as I was wondering, do only isolated systems model or represent the first law since their energy always remains constant? Or can other systems also follow this law?
- Sun Feb 07, 2021 9:32 pm
- Forum: Calculating Work of Expansion
- Topic: R constant of an Ideal Gas
- Replies: 16
- Views: 870
R constant of an Ideal Gas
Hello, I found myself a bit lost on the Sapling homework when working on work equations as I was always unsure of which R constant to insert for the Ideal Gas Law, and I was wondering if someone could explain how to know which R value to use when solving these questions.
- Sun Feb 07, 2021 9:20 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Extensive Properties
- Replies: 10
- Views: 549
Extensive Properties
Hello, I was just wondering if someone could explain the significance of heat capacities being extensive properties? I have heard it in lecture but I do not really understand the meaning of the statement.
- Sun Jan 31, 2021 11:01 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure's Impact on Chemical Equilibria
- Replies: 2
- Views: 172
Pressure's Impact on Chemical Equilibria
Hello, I was just wondering if someone could explain to me how pressure affects chemical equilibria equations? I am having a bit of difficulty understanding how it affects equilibrium.
- Sun Jan 31, 2021 10:51 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Closed vs Isolated Systems
- Replies: 4
- Views: 246
Closed vs Isolated Systems
Hello, I was wondering if someone could explain to me the difference between closed and isolated systems as I am having trouble differentiating the two.
- Sun Jan 31, 2021 10:37 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Clarification on pKw
- Replies: 15
- Views: 4029
Clarification on pKw
Hello, I need some clarification on the meaning of pKw, and I was wondering if pKw is supposed to always equal 14 or is it like other K values that can be different depending on the equilibrium question at hand?
- Sun Jan 31, 2021 10:24 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Solving for Cubic Equations
- Replies: 13
- Views: 1223
Solving for Cubic Equations
Hello, I was wondering if making X negligible when solving equilibrium questions is possible with other scenarios than a cubic equation? I do understand that the K value must be extremely small, but is a cubic set up the only time we can make X negligible?
- Sun Jan 31, 2021 10:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solving for Heterogeneous Equilibria
- Replies: 4
- Views: 251
Solving for Heterogeneous Equilibria
Hello, I realized I may have mixed myself up but I was just wondering if when we solve chemical equilibria questions for heterogeneous equilibria, we do not include the solids or liquids correct?
- Sun Jan 24, 2021 6:57 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Charge of Predominant Species
- Replies: 5
- Views: 240
Charge of Predominant Species
Hello, I was a bit lost doing Sapling Problems 9 and 10 of week 2 and I was wondering if someone could explain what would make the predominant species at a certain pH charged, neutral, or unknown?
- Sun Jan 24, 2021 6:54 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Ionization Constant of water
- Replies: 4
- Views: 266
Ionization Constant of water
Hello, during week 2, the ionization constant of water(1.0x10^-14) was given to us, and I was wondering what the significance of this constant is and if we need to have this memorized for future exams?
- Sun Jan 24, 2021 6:46 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Difference between Strong and Weak acids and bases
- Replies: 3
- Views: 216
Difference between Strong and Weak acids and bases
Hello, I am struggling with differentiating the processes for solving equilibria problems of weak and strong acids and bases problems and I was wondering if someone could explain the key differences in solving for weak or strong acid and bases problems?
- Sun Jan 24, 2021 6:24 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Determining pH
- Replies: 18
- Views: 948
Determining pH
Hello, I am a bit lost on determining the pH of acids and bases and was wondering when one knows that taking the -log will wield the pH or the pOH?
- Sun Jan 24, 2021 6:08 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Best Method for Finding Enthalpy Changes
- Replies: 6
- Views: 330
Best Method for Finding Enthalpy Changes
Hello, in Friday's lecture, professor said that the second method (using bond enthalpies to calculate enthalpy change) was the least favorable method of the three to find enthalpy change, and I was wondering if one of the other two methods was considered the best?
- Sun Jan 17, 2021 3:55 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: The Quadratic equation
- Replies: 7
- Views: 561
The Quadratic equation
Hello, I am a bit lost on the applications of the quadratic equation in chemical equilibrium and I was wondering if this equation can be applied to other scenarios besides finding molar concentration?
- Sun Jan 17, 2021 3:51 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Autoprotolysis Constant of Water
- Replies: 7
- Views: 327
Autoprotolysis Constant of Water
In the first lecture of week 2, Professor Lavelle mentions the autoprotolysis constant of water being 1.0x10^-14, and I was wondering if this is an important constant we need to remember, or is it a constant that we only need for certain problems and will likely be given to us?
- Sun Jan 17, 2021 3:35 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Hess's Law
- Replies: 1
- Views: 126
Hess's Law
Hello, I saw on one of the Sapling feedbacks from week 1 that a chemical equilibrium problem required the use of Hess's Law. I may have missed this at some point and was wondering if someone could explain to me in basic terms what this law does.
- Sun Jan 17, 2021 3:23 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc vs. Q
- Replies: 5
- Views: 243
Kc vs. Q
Hello, I believe I may be getting my variables mixed up, but I was wondering if the equilibrium constant Kc and the reaction quotient referred to the same value?
- Sun Jan 17, 2021 3:04 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Box method
- Replies: 5
- Views: 1317
ICE Box method
Hello, I am having a bit of difficulty understanding how to use the ice box and was wondering if someone could explain how I would use it in these chemical equilibrium problems?
- Sun Jan 10, 2021 2:28 am
- Forum: Ideal Gases
- Topic: P over R in the Ideal Gas Law
- Replies: 4
- Views: 208
P over R in the Ideal Gas Law
Hello, I am just a bit confused on the functionality of the Ideal Gas Law and was wondering if when using the law in a calculation, it would be safe to assume that P/R is directly proportional to K?
- Sun Jan 10, 2021 2:23 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Reactions at Equilibrium
- Replies: 6
- Views: 304
Reactions at Equilibrium
Hello, I just had a question regarding chemical equilibrium and was wondering if it is correct to assume that although the concentrations of reactant and product are not changing at equilibrium, reactants and products are still forming at the molecular level?
- Sun Jan 10, 2021 2:09 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Response of Equilibria to Change
- Replies: 8
- Views: 297
Response of Equilibria to Change
Hello, I was reviewing the response of equilibria to change and was wondering if the only change that causes K to change is a change in temperature?
- Wed Jan 06, 2021 8:35 pm
- Forum: Ideal Gases
- Topic: Ideal Gas Law Question
- Replies: 11
- Views: 470
Ideal Gas Law Question
Hello, I am just a bit confused and was wondering, in the equation for the ideal gas law PV=nRT, why is the temperature T regarded as a constant?
- Mon Jan 04, 2021 2:56 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Liquids and Equilibrium Constants
- Replies: 2
- Views: 151
Liquids and Equilibrium Constants
Hello, I just need some confirmation on today's lecture and I was wondering that since pure substances are not included in K expression, and since gases have a partial pressure constant Kp, do liquids simply not have any form of equilibrium constant?
- Sat Dec 12, 2020 1:47 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configurations of Ions
- Replies: 3
- Views: 327
Electron Configurations of Ions
Hello, I was just wondering if electron configurations of ions are done by simply doing the same electron configuration except adding or removing an electron from the last orbital?
- Thu Dec 10, 2020 8:38 pm
- Forum: Lewis Structures
- Topic: Exceptions to the Ocetet
- Replies: 1
- Views: 257
Exceptions to the Ocetet
Hello, I'm a bit lost on the exceptions to the octet rule, and I was wondering if someone could just give me a general rule to know when an atom is exempt from the rule?
- Wed Dec 09, 2020 3:02 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: The Stern and Gerlach Experiment
- Replies: 2
- Views: 281
The Stern and Gerlach Experiment
Hello, I was just wondering if there is anything we need to know about the Stern and Gerlach Experiment beyond the fact that it was used to discover the electron spin( the 4th quantum number) of an electron in an orbital?
- Tue Dec 08, 2020 1:57 pm
- Forum: Balancing Chemical Reactions
- Topic: Knowing the names of molecules
- Replies: 4
- Views: 388
Knowing the names of molecules
Hello, I was just wondering if we are asked to balance a chemical reaction and the product is given in the form of a name such as iron(III) oxide, are we still going to be provided with the chemical formula as well , or do we have to know what the chemical formula is? And if not, how would I go abou...
- Mon Dec 07, 2020 5:45 pm
- Forum: Bronsted Acids & Bases
- Topic: CLarification on Acids
- Replies: 2
- Views: 146
CLarification on Acids
Hello, I'm just a tad lost on what makes a molecule more or less acidic, is it the gain or loss of protons or is it solely based on the pH of the molecule?
- Sun Dec 06, 2020 8:28 pm
- Forum: Bronsted Acids & Bases
- Topic: Acids as proton donors
- Replies: 4
- Views: 323
Acids as proton donors
Hello, when the notes state that a Bronsted acid is a proton donor, does that equate to the same idea as a Lewis acid being called an electron recipient? Or are the two different?
- Sun Dec 06, 2020 8:15 pm
- Forum: Bronsted Acids & Bases
- Topic: Relative acidity
- Replies: 3
- Views: 195
Relative acidity
Hello, I would just like some clarification on how the strength of acids are determined and I was wondering in particular are weaker acids more likely to lose their H+ or are strong acids more likely to do so?
- Sun Dec 06, 2020 7:07 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Tips on determining coordination number
- Replies: 5
- Views: 389
Tips on determining coordination number
Hello, I was wondering if anyone could give me any tips on determining the coordination number of atoms, or just clarify if the only thing we need to determine a coordination number is to know the number of bonds to the atom?
- Sun Dec 06, 2020 6:51 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Sigma and Pi bond rotation
- Replies: 5
- Views: 1209
Sigma and Pi bond rotation
Hello, I would just like to clear something up from my notes and was wondering that since sigma bonds allow for the bound atom to rotate and pi bonds do not allow their bound atom to rotate, does that mean when both bonds are together, say in a double or triple bond, does that mean the bound atom do...
- Sun Dec 06, 2020 6:22 pm
- Forum: Hybridization
- Topic: Clarification on Hybridization
- Replies: 2
- Views: 98
Clarification on Hybridization
Hello, I've been reviewing for finals and found I understood very little on hybridization and I was just wondering if someone could briefly explain how I should approach problems that ask how to determine the hybridization of an atom?
- Sun Nov 29, 2020 4:19 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent Shape molecules
- Replies: 7
- Views: 1118
Bent Shape molecules
Hello, I was wondering if I could get some help with determining molecular shape, more specifically the bent shape, and I was wondering if someone could explain what makes a molecule form the bent shape?
- Sun Nov 29, 2020 4:07 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands
- Replies: 4
- Views: 357
Ligands
Ligands are considered any electron rich species, so my question is when do we consider a species to be electron rich so that it can also be considered a ligand?
- Sun Nov 29, 2020 3:43 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 5
- Views: 312
Bond Angles
Hello, I was looking over past notes and saw that we are expected to know when bond angles are greater or less than a certain common bond angle and I was hoping someone could explain how we would go about doing this?
- Sun Nov 29, 2020 3:38 am
- Forum: Lewis Structures
- Topic: Tips on drawing Lewis structures
- Replies: 21
- Views: 2456
Tips on drawing Lewis structures
Hello, after seeing my midterm score I believe I may not be very keen on drawing Lewis structures and I was wondering if anyone could give me some tips or a basic outline that will help me draw Lewis structures in the future. Thanks in advance!
- Mon Nov 23, 2020 6:49 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Nonpolar molecules
- Replies: 3
- Views: 366
Nonpolar molecules
Hello, I am just a bit lost on non-polar molecules and was wondering if someone could explain what makes these molecules non-polar, thanks!
- Sun Nov 22, 2020 7:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bonds in depictions of molecular shape
- Replies: 3
- Views: 207
Bonds in depictions of molecular shape
Hello, I would just like some clarification on when we draw molecular shape, and I was wondering if for the three dimensional depictions do dashed lines indicate a bond with an atom facing behind the rest of the molecule and then do bold bonds indicate a bond with an atom closest to your view?
- Thu Nov 19, 2020 1:47 pm
- Forum: Lewis Structures
- Topic: Single electron in a Lewis Structure
- Replies: 6
- Views: 537
Single electron in a Lewis Structure
Hello, I am a little lost on making Lewis structures and was wondering if it is possible to have an unpaired electron in a Lewis structure?
- Wed Nov 18, 2020 11:28 pm
- Forum: Lewis Structures
- Topic: Difference between Lewis acids and bases and cations and anions
- Replies: 2
- Views: 123
Difference between Lewis acids and bases and cations and anions
Is there a difference between Lewis acids and bases and cations and anions? Because I have noticed they seem to have the same properties of either donating or accepting electrons and I would just like some clarification on the difference between the two. Thanks!
- Wed Nov 18, 2020 11:08 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Schrodinger's Wave Function Equation
- Replies: 4
- Views: 328
Schrodinger's Wave Function Equation
Will we ever need to make calculations using the Schrodinger's wave function equation? Or will we only need it to describe atomic orbitals?
- Wed Nov 18, 2020 10:29 pm
- Forum: Dipole Moments
- Topic: Dipole-Dipole vs. Dipole--Induced Dipole
- Replies: 1
- Views: 124
Dipole-Dipole vs. Dipole--Induced Dipole
Hello, I had a question regarding dipole-dipole and dipole-induced dipole interactions, which is in regards to their value of -2kJ per mol. So my question is that is the value of dipole-dipole interactions and dipole-induced interactions exactly the same? Or is the dipole-induced dipole slightly les...
- Sun Nov 15, 2020 7:33 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Clarification on the 4th quantum number
- Replies: 5
- Views: 415
Clarification on the 4th quantum number
Concerning quantum numbers, will we ever be asked to determine the spin of the fourth quantum number ms? Or will we only be asked if a certain ms is possible in a set of all four quantum numbers?
- Sun Nov 15, 2020 6:55 pm
- Forum: Dipole Moments
- Topic: Sapling #13
- Replies: 9
- Views: 654
Re: Sapling #13
I solved this using the N, O, and F rule of hydrogen bonding by locating and counting all the possible points on the structure where a hydrogen bond could occur and that total should give you your answer as the question implies that the water molecules would bond to urea using hydrogen bonds.
- Sun Nov 15, 2020 6:11 pm
- Forum: Bond Lengths & Energies
- Topic: Hydrogen Bonds
- Replies: 17
- Views: 957
Hydrogen Bonds
In determining hydrogen bonds, in addition to bonding with N, O, and F, is a hydrogen atom bonding with another hydrogen atom considered a hydrogen bond?
- Sun Nov 15, 2020 4:55 pm
- Forum: Octet Exceptions
- Topic: Clarification on octet exceptions
- Replies: 3
- Views: 196
Clarification on octet exceptions
Hello, I just need some clarification on octet exceptions and was wondering if there are any exceptions to the octet rule we need to know besides the first three elements of the periodic table?
- Mon Nov 09, 2020 7:58 pm
- Forum: Dipole Moments
- Topic: Dipole Moment Units
- Replies: 2
- Views: 109
Dipole Moment Units
If we are ever asked about dipole moments on the midterm or final, is coulombs or debye a preferred unit or is using either acceptable?
- Sun Nov 08, 2020 5:38 am
- Forum: Trends in The Periodic Table
- Topic: Understanding trends in the Periodic Table
- Replies: 2
- Views: 850
Understanding trends in the Periodic Table
Hello, I am just a bit lost on understanding the various elements grouped by last occupied shells, and I was wondering if anyone could explain in simple terms how to navigate/find the various s, p, and d blocks, and maybe provide an easy method to grasp the trends in the periodic table? Thanks!
- Sun Nov 08, 2020 4:46 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Energy of an electron
- Replies: 1
- Views: 112
Energy of an electron
I just need some clarification on the amount of energy of an electron depending on its location on the orbitals of an atom. So my question is: Is the energy of an electron highest when it is in the orbital closest to the nucleus, or when it is the farthest orbital away from the nucleus as a valence ...
- Sun Nov 08, 2020 4:33 am
- Forum: Ionic & Covalent Bonds
- Topic: Salts and molecules
- Replies: 4
- Views: 218
Salts and molecules
During Friday's lecture, professor in an example called some elements forming ionic bonds a salt, and elements forming covalent bonds a molecule. Is it safe to say any elements forming ionic bonds are salts and any elements forming covalent bonds are called molecules?
- Sun Nov 08, 2020 12:55 am
- Forum: Student Social/Study Group
- Topic: Studying From Home
- Replies: 91
- Views: 10844
Re: Studying From Home
Personally, I find myself being mostly distracted by my phone while at home and being at home can lower your sense of urgency to do your work. I would recommend removing your phone from your workspace, and if that's not possible then try to set screen time limits on the apps that distract you. I'd a...
- Thu Nov 05, 2020 1:17 am
- Forum: Octet Exceptions
- Topic: Group 13 Elements
- Replies: 13
- Views: 565
Re: Group 13 Elements
Yes, I believe all elements in group 13 do not have to form an octet when forming bonds as they are exempt from the octet rule.
- Sat Oct 31, 2020 1:35 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Nodal Planes
- Replies: 10
- Views: 634
Nodal Planes
Hi, would someone mind elaborating/explaining what nodal planes are and their involvement in quantum numbers?
- Sat Oct 31, 2020 1:04 am
- Forum: Properties of Electrons
- Topic: Constructive vs Destructive
- Replies: 6
- Views: 378
Re: Constructive vs Destructive
I believe this topic is related to the diffraction patterns of light in the experiment covered in the wave properties of electrons module, as the interaction of waves after they passed through the two slits of the barrier can produce constructive or destructive results depending on how the waves of ...
- Wed Oct 28, 2020 9:18 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Delta E and negative symbol
- Replies: 3
- Views: 269
Re: Delta E and negative symbol
I believe you generally should make it positive because the negative symbol simply indicates that the energy of light is being emitted and the electron is slowly returning to ground state, and not an actual negative quantity.
- Wed Oct 28, 2020 9:07 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Midterm Questions
- Replies: 4
- Views: 213
Re: Midterm Questions
There will be 12 questions on the midterm, but Professor wrote it as 11+1 in his email, so one may be extra credit or a free question but I am not sure.
- Wed Oct 28, 2020 8:12 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect post module
- Replies: 4
- Views: 249
Re: Photoelectric Effect post module
For this problem, since the question says the kinetic energy is zero, we can reason that the energy of a photon hitting the metal surface is equal to the threshold energy. And with this idea, you simply use the given energy 3.607x10^-19J and the equation E=hc/wavelength and solve for wavelength. I h...
- Mon Oct 26, 2020 10:38 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Core Electrons
- Replies: 1
- Views: 128
Core Electrons
Hi, I was just looking for a brief explanation/clarification on core electrons as mentioned in today's lecture about writing electron structures. When you use a core electron in writing a configuration, do you have to use the element that is at the end of the previous row? Or can you use any previou...
- Fri Oct 23, 2020 4:15 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: 1B.9 Question
- Replies: 2
- Views: 180
Re: 1B.9 Question
For this question, you first need to determine the total energy per photon of the lamp using the equation E=hv(E=hc/lambda). Using this equation you should get: E=(6.626x10^-34J*s)(2.998x10^8m/s)/(420x10^-9m)=4.7x10^-19J*photon^-1. Using the given information that the lamp is rated at 32W(J*s^-1) we...
- Thu Oct 22, 2020 11:34 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Fundamental G Problem Help
- Replies: 3
- Views: 318
Re: Fundamental G Problem Help
In order to solve this problem, I started off by using the equation M initial x V initial=M final x V final, and with this equation you plug in all known values to find that M final is unknown, meaning you must solve for it and you should get 0.05 moles per liter. From here, you use this molarity an...
- Thu Oct 22, 2020 12:56 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: MT #6
- Replies: 2
- Views: 134
Re: MT #6
I believe your only error in this solution is when you solve for the uncertainty in momentum you said it was 8.1746x10^-9, and when I calculated the uncertainty I did exactly the same process as you did and got the uncertainty in momentum to be 8.1746x10^-6. And using this value I solved for the unc...
- Wed Oct 21, 2020 12:36 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Question 20 from Heisenberg Module
- Replies: 2
- Views: 87
Re: Question 20 from Heisenberg Module
I am not certain if there is a constant or number to compare to the uncertainty of the kinetic energy, but for this problem I simply looked at the two kinetic energies that we were asked to solve for and I realized that the exponents of the portion in scientific notation were of the opposite sign, w...
- Mon Oct 19, 2020 10:25 pm
- Forum: Properties of Light
- Topic: 1B.7
- Replies: 1
- Views: 118
Re: 1B.7
This number 3.37x10^-19 J is not a constant you need to memorize, it is the energy emitted by a single excited sodium atom when it generates a photon, which is the solution found in part A of 1.7, and is significant as it is used in this problem to find the amount of energy emitted by 5.00 mg of the...
- Fri Oct 16, 2020 9:57 pm
- Forum: DeBroglie Equation
- Topic: Post-Module Conversion Questions
- Replies: 3
- Views: 431
Re: Post-Module Conversion Questions
In this question, you do convert 125km*hr^-1 to m*s^-1: 125km*hr^-1x(1hr/60min)x(1min/60sec)x(1000m/1km)=34.7m*s^-1. And then you simply use this speed in Debroglie's wave equation to find the wavelength :Wavelength=h/p=h/mv. Wavelength= (6.626*10^-34J*S)/((275kg)(34.7m*s^-1))= 6.94*10^-38m.
- Thu Oct 15, 2020 8:33 pm
- Forum: Photoelectric Effect
- Topic: 1B #7 part b
- Replies: 5
- Views: 220
Re: 1B #7 part b
In part B, you are asked to calculate the amount of energy emitted by 5.00mg of sodium at the given wavelength, and in order to do this, you simply convert the 5.00mg of sodium to moles(you must first convert mg to g) and then to particles and then multiply this result by the energy emitted from a s...
- Wed Oct 14, 2020 5:25 pm
- Forum: Properties of Light
- Topic: Photoelectric Effect -Post Assessment #23
- Replies: 2
- Views: 59
Re: Photoelectric Effect -Post Assessment #23
The two words are "wave" and "particle", and photons is not the answer because the question is asking about how the results of the effect were interpreted, and it was interpreted using a detector to detect electrons emitted by the photons striking them, meaning electrons were bei...
- Tue Oct 13, 2020 8:05 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric effect post-test #34
- Replies: 3
- Views: 185
Re: Photoelectric effect post-test #34
In order to solve this problem you basically need to find the energy of the photons and subtract the threshold energy from the energy of the photons in order to find the excess energy, which is the kinetic energy. First you must calculate the frequency of the light, by dividing the speed of light(c)...
- Mon Oct 12, 2020 8:38 pm
- Forum: Photoelectric Effect
- Topic: Electromagnetic Spectrum
- Replies: 2
- Views: 158
Electromagnetic Spectrum
Are we required to memorize the wavelengths for each part of the electromagnetic spectrum? Because on the post-assessment module for Atomic Spectra, question 44 asks what region the wavelength of this solution would fall under and I was just wondering if we would have to know which region by heart.
- Fri Oct 09, 2020 9:16 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect Module Assesment #29
- Replies: 1
- Views: 87
Re: Photoelectric Effect Module Assesment #29
I had trouble with this problem too, the issue here is the given work function of 150.6kJ/mol. This work function is the threshold energy to remove an electron, but I realized that it is given in kilojoules and only applies to a mole of an atom. Therefore, I converted kilojoules to joules (150600J) ...
- Thu Oct 08, 2020 7:28 pm
- Forum: SI Units, Unit Conversions
- Topic: Do I need to do very single textbook question on the syllabus?
- Replies: 34
- Views: 1871
Re: Do I need to do very single textbook question on the syllabus?
You do not have to do every single question, you may only do the ones that you think you should do as they are not being collected, but remember that Lavelle does pull some questions from the textbook homework and places them on exams.
- Thu Oct 08, 2020 7:20 pm
- Forum: Balancing Chemical Reactions
- Topic: Question H 7d
- Replies: 3
- Views: 185
Re: Question H 7d
The copper metal is not included in the chemical reaction as it is a catalyst, meaning it is used to simply speed up the chemical reaction going on in the equation. But the copper catalyst can be represented on the top of the arrow in between the reactants and the product.
- Wed Oct 07, 2020 5:50 pm
- Forum: Significant Figures
- Topic: Sapling Question 2
- Replies: 14
- Views: 549
Re: Sapling Question 2
Sapling is correct here because if 291.7 was put into the scientific notation of 2.917x10^-2, the decimal would move to the left instead of the right when you take it out of scientific notation, meaning that if the exponent of the notation was -2, then the number would be 0.02917 and not 291.7. So, ...