Search found 104 matches
- Sat Mar 13, 2021 10:25 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: porous disk
- Replies: 7
- Views: 386
Re: porous disk
Within a cell that uses a salt bridge, the reduction and oxidation reactions are separated and salts flow through the gel-filled tube to either side. In a cell that uses a porous disk, the salts can simply pass through the pores of the disk to get to either side.
- Sat Mar 13, 2021 10:22 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams
- Replies: 8
- Views: 358
Re: Cell Diagrams
I believe that Professor Lavelle said in our last lecture that the order is irrelevant. As long as the anode is on the left and the cathode is on the right, the order is correct. There is no specified order within the cell itself, so no specific order is required for its notation.
- Sat Mar 13, 2021 10:18 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalysts and Intermediates
- Replies: 16
- Views: 708
Re: Catalysts and Intermediates
A catalyst is usually something that is used to form a product in one step and then is produced in another step. In other words, the catalyst will be a reactant in one step and the same species will be a product in another step. Simply put, it is consumed and then produced again in another reaction ...
- Sat Mar 13, 2021 10:11 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalysts
- Replies: 6
- Views: 370
Re: Catalysts
Yes, they are not included in the overall reaction. Catalysts will be consumed in one step (they will interact with other reactants) and produced in a later step (the original catalyst species will be produced). Therefore, we will not use catalysts in the overall rate law for a reaction. I am unsure...
- Sat Mar 13, 2021 10:01 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Equilibrium and Rate Constants
- Replies: 5
- Views: 951
Re: Equilibrium and Rate Constants
The rate constants are not the reaction rates themselves; they simply describe the relationship between the rate of the reaction and the reactant concentration. When the actual rates of the forward and reverse reactions are equal, their rate laws will be equal to each other. If you set the rate laws...
- Sat Mar 13, 2021 9:49 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Free Energy of Activation
- Replies: 4
- Views: 306
Re: Free Energy of Activation
I believe that the free energy of activation refers to the Gibbs free energy. I've seen this as a response on chemistry community before, so I am not entirely sure that this is valid.
- Sat Mar 13, 2021 7:37 pm
- Forum: Student Social/Study Group
- Topic: Equations for the Final
- Replies: 5
- Views: 329
Re: Equations for the Final
josephspindler2H wrote:Conceptually, it's helpful to remember that delta G nought is equal to work max as well as kforward/kreverse=K
When you say "kforward/reverse", you are referring to the reaction rate constants, correct? Also, thanks for the help! :)
- Sat Mar 13, 2021 7:16 pm
- Forum: Student Social/Study Group
- Topic: General tips/hints
- Replies: 5
- Views: 333
Re: General tips/hints
I sometimes struggle with determining which equation(s) from our equation sheet should be used for a certain problem and whether I am using it correctly. To tackle this issue, I have just been doing problems from the book and Sapling. While I have already done the majority of these problems, going o...
- Sat Mar 13, 2021 6:47 pm
- Forum: Student Social/Study Group
- Topic: Equations for the Final
- Replies: 5
- Views: 329
Equations for the Final
Hi there,
I know that we have all of the equations we need on our equations sheet, but are there other equations we must memorize that are not included on this sheet? If so, what are they? I just want to make sure that I already have everything prepared for tomorrow. Thanks a lot!
I know that we have all of the equations we need on our equations sheet, but are there other equations we must memorize that are not included on this sheet? If so, what are they? I just want to make sure that I already have everything prepared for tomorrow. Thanks a lot!
- Sat Mar 13, 2021 6:45 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Kinetics Outline
- Replies: 3
- Views: 293
Re: Kinetics Outline
Activation energy is the amount of energy that is required to bring the energy level of the reactants to the energy level of the transition state. In other words, this is the energy required to get the reaction going. The free energy of activation is the Gibbs free energy, even though this is not ex...
- Sun Mar 07, 2021 10:25 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Solving Multiple Reactant Problems
- Replies: 3
- Views: 223
Re: Solving Multiple Reactant Problems
The overall rate of the reaction will generally be determined by the slowest step of the reaction. Therefore, the overall reaction rate is dependent on the rate of the reactant that has the slowest unique rate.
- Sun Mar 07, 2021 10:12 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Chemical Reactions and Temperature
- Replies: 3
- Views: 215
Re: Chemical Reactions and Temperature
The rate of chemical reactions is generally increased with a rise in temperature as a result of the fact that the kinetic energy of the reactants is being increased. If the reactants possess a greater average kinetic energy, there will be less energy required for the reaction to continue.
- Sun Mar 07, 2021 9:57 pm
- Forum: General Rate Laws
- Topic: Unique Rate
- Replies: 5
- Views: 312
Re: Unique Rate
The unique rate of a reaction is the rate in reference to a single reactant or product. Since reactants turn into products at differing rates, we can look at specific species in order to see how quickly they are appearing/disappearing. Depending on whether you are looking at the reactant or product ...
- Sun Feb 28, 2021 7:51 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox Reactions in Basic Conditions
- Replies: 7
- Views: 479
Re: Balancing Redox Reactions in Basic Conditions
In order to balance a redox reaction, we can use the following steps: - separate half-reactions of the overall reaction - balance each half-reaction: - Begin with elements other than O and H. Balance oxygen atoms by adding H2O to the side that requires them. Do the same for hydrogen using hydrogen i...
- Sun Feb 28, 2021 7:43 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: How Electricity is Quantified
- Replies: 3
- Views: 270
Re: How Electricity is Quantified
Electricity is the flow of electrons within a given system. It can be quantified using charge, current, and potential. Charge is a physical property of matter. Charge causes matter to experience force within a given electromagnetic field. Current is defined as the amount of charge that passes in a s...
- Sun Feb 28, 2021 7:33 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Reduction Potential Clarification
- Replies: 4
- Views: 241
Re: Reduction Potential Clarification
Yes, you change the sign of E when the direction of the half-reaction is flipped. However, if the reaction is multiplied by a constant, E must not be multiplied by this constant (like with free energy values).
- Sun Feb 28, 2021 7:31 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling week 7/8 #5
- Replies: 7
- Views: 851
Re: Sapling week 7/8 #5
It seems that you balanced the reaction correctly. Did you include the correct phases of each species? This is required in the problem and it may be the reason why you aren't getting it right.
- Sun Feb 28, 2021 7:27 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Sapling week 7/8 number 15
- Replies: 3
- Views: 227
Re: Sapling week 7/8 number 15
First, write and balance the half-reactions. After you do this and determine the reduction potentials for each half-reaction, you can determine the overall standard cell potential. After you have the standard cell potential, you can plug values into the Nernst equation and solve. All values are give...
- Sun Feb 21, 2021 9:51 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling Week 7/8 #1
- Replies: 10
- Views: 1981
Re: Sapling Week 7/8 #1
You can start this problem by identifying the oxidation number of the cation. Then, do the same for the anion of the compound. As you probably know, the oxidation number of a pure element (non-ionic) will be zero.
- Sun Feb 21, 2021 9:44 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Trouton's rule
- Replies: 4
- Views: 258
Re: Trouton's rule
Trouton's rule basically states that various types of liquids possess similar entropies of vaporization at their boiling points. The enthalpy of vaporization divided by the boiling point of the liquid is the entropy of vaporization for a particular liquid. I am also unsure of whether we discussed th...
- Sun Feb 21, 2021 9:36 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling week 7/8 #2
- Replies: 5
- Views: 1152
Re: Sapling week 7/8 #2
Combine the respective reactants and products of each reaction. In other words, the reactants of one half-reaction and the reactants of the other half-reaction will combine to be the reactants of the overall reaction (the same applies to the products). After you have done this, balance the overall r...
- Sun Feb 21, 2021 9:32 pm
- Forum: Phase Changes & Related Calculations
- Topic: Textbook Problem 4A1 part C
- Replies: 3
- Views: 216
Re: Textbook Problem 4A1 part C
A bomb calorimeter is considered to be an isolated system because no matter or heat can be exchanged with the surroundings. While the system within the calorimeter can release heat, it is not released to the surroundings.
- Sun Feb 21, 2021 9:26 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling week 7/8 #5
- Replies: 2
- Views: 140
Re: Sapling week 7/8 #5
A good way of initiating this problem is by identifying the oxidation numbers of each element in the reactants and products. This way, you can see which elements have gained or lost electrons.
- Sun Feb 21, 2021 9:23 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling week 7/8 #5
- Replies: 2
- Views: 140
Re: Sapling week 7/8 #5
What issue are you having with this problem, specifically? Just identifying the oxidizing/reducing agents in general?
- Sun Feb 14, 2021 10:18 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneity of a System
- Replies: 38
- Views: 2640
Re: Spontaneity of a System
In terms of Gibbs Free Energy, a reaction will be spontaneous depending on the sign of the value of the free energy change. If the value of Gibbs Free Energy is negative, then the reaction is spontaneous. If the value is positive, then the reverse reaction is spontaneous. A negative Gibbs Free Energ...
- Sun Feb 14, 2021 10:10 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Sapling Weeks 5-6 #3
- Replies: 4
- Views: 245
Re: Sapling Weeks 5-6 #3
You are on the right track! Your reasoning is entirely right, so all you need to do is apply that concept to the problem. If the phase changes from solid to liquid to gas will always have positive values of entropy and enthalpy, then what category would you put these phase changes in? If the same (b...
- Sun Feb 14, 2021 10:05 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Internal Energy Confusion
- Replies: 4
- Views: 189
Re: Internal Energy Confusion
When I am trying to determine whether internal energy is decreasing or increasing, I simply think of what is happening with its constituents (Heat and Work). If applicable, I try to determine whether the heat is leaving/entering the system and whether work is being done on/by the system. This may no...
- Sun Feb 14, 2021 9:59 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Sapling #1
- Replies: 4
- Views: 218
Re: Sapling #1
Yes, this bond formation is a result of formal charge optimization. We are responsible for knowing how to calculate formal charge (as we have done this in the past), but I do not know if this information will be necessary for the upcoming midterm. I hope this helps!
- Sun Feb 14, 2021 9:57 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Determining the Sign of S
- Replies: 8
- Views: 389
Re: Determining the Sign of S
The sign of entropy change is dependent on whether a system has greater or fewer microstates from one state to the next. For example, the entropy of the vaporization of liquid water is positive because the entropy in the gas state is greater than that of the liquid state. In other words, there is a ...
- Sun Feb 07, 2021 8:57 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Molar Heat Capacities at Constant Volume/Pressure
- Replies: 3
- Views: 94
Molar Heat Capacities at Constant Volume/Pressure
Hi there,
Will we need to memorize the molar heat capacities for atoms, linear molecules, and nonlinear molecules in constant pressure and constant volume processes? For example, question 20 of Week 3/4 Sapling shows the molar heat capacities of types of gases at constant volume. Thanks in advance!
Will we need to memorize the molar heat capacities for atoms, linear molecules, and nonlinear molecules in constant pressure and constant volume processes? For example, question 20 of Week 3/4 Sapling shows the molar heat capacities of types of gases at constant volume. Thanks in advance!
- Sun Feb 07, 2021 8:44 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Sapling #20
- Replies: 9
- Views: 413
Re: Sapling #20
We are informed in this scenario that the volume remains constant. If there is no change in volume, work cannot be performed. The value of work is dependent on a change in volume, which does not occur. Since the change in internal energy is equal to the heat plus work (U = Q + W), the change in inte...
- Sun Feb 07, 2021 8:37 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Sap #19 internal energy
- Replies: 4
- Views: 228
Re: Sap #19 internal energy
The internal energy value is negative as a result of the fact that the internal energy of the system decreases in this scenario. Since there is no change in volume (meaning no work is performed), the only change in energy that occurs is the release of heat. Since heat is being released, it is a nega...
- Sun Feb 07, 2021 8:34 pm
- Forum: Calculating Work of Expansion
- Topic: Work of Expansion
- Replies: 2
- Views: 137
Re: Work of Expansion
Work of expansion occurs when a gas performs work on its surroundings, causing the volume of the system to expand. Since the gas performs work on its surroundings against a given external pressure, this value is negative. This can be mathematically expressed as W = -P*(change in volume), where W is ...
- Sun Feb 07, 2021 8:30 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling #12 Week 3/4
- Replies: 1
- Views: 96
Re: Sapling #12 Week 3/4
In order to calculate the heat of combustion per gram of compound B, you must multiply the heat capacity of the calorimeter (C) by the temperature change that occurs in the calorimeter. This value must be divided by the mass of compound B in order to find the heat of combustion per gram. Keep the si...
- Sun Jan 31, 2021 10:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Reflecting on the midterm
- Replies: 17
- Views: 663
Re: Reflecting on the midterm
When I was taking my midterm, I also experienced instances of working through a tedious math problem, receiving the incorrect answer, then trying again. Since this only occurred roughly twice during this midterm, I did not have too much of an issue with time management. However, I have had trouble w...
- Sun Jan 31, 2021 10:10 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Work-/+
- Replies: 9
- Views: 345
Re: Work-/+
The value of work is positive if work is being done ON the system. For example, if the system is being compressed (the volume is reduced by an external force), the work will be positive. The value of work will be negative if the gas of the system is doing work. If the system is expanding (the volume...
- Sun Jan 31, 2021 10:03 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: System and Surrounding
- Replies: 4
- Views: 150
Re: System and Surrounding
The purpose of referring to the surroundings of the system as "the universe" is to place emphasis on the fact that the surroundings are everything other than the system in focus. The equation "system + surroundings = 0" references that heat lost or gained from the surroundings wi...
- Sun Jan 31, 2021 9:10 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Sapling #16
- Replies: 2
- Views: 136
Re: Sapling #16
Yes, we have covered this material. You can solve this problem by keeping the law of conservation of energy in mind, applying the rule "change in internal energy is equal to the work done on/by the system plus the heat transfer into/out of the system).
- Sun Jan 31, 2021 9:08 pm
- Forum: Student Social/Study Group
- Topic: Students Who Have a Job
- Replies: 103
- Views: 8730
Re: Students Who Have a Job
Hi there! I also have a part-time job, working 20-25 hrs a week. I usually maintain a part-time job throughout the quarter with no trouble, but it has been slightly more difficult this quarter as a result of the fact that I am taking an extra class. Working during the pandemic has also added some st...
- Sun Jan 24, 2021 10:37 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: How to find equations
- Replies: 4
- Views: 208
Re: How to find equations
All of the chemical equations you would need are included on the "Constants and Equations" sheet on the class website!
- Sun Jan 24, 2021 10:25 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Determining whether a reaction is Exothermic/Endothermic
- Replies: 4
- Views: 370
Determining whether a reaction is Exothermic/Endothermic
How do you determine whether a reaction is endothermic or exothermic based on the strength of the bonds being broken and formed? For example, #4 on this week's Sapling homework asks you to classify the nature of a reaction based on relative bond strengths. Thanks! :)
- Sun Jan 24, 2021 10:18 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy vs Temperature
- Replies: 4
- Views: 108
Re: Enthalpy vs Temperature
The value of the temperature represents the average kinetic energy of every molecule within a particular system. The absolute enthalpy of a substance represents its total heat energy content. Enthalpy is a state function as a result of the fact that its value depends only on the initial and final co...
- Sun Jan 24, 2021 10:11 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Neutral Solution
- Replies: 9
- Views: 626
Re: Neutral Solution
In neutral water, the concentration of both H3O+ and OH- are 1x10^-7 mol/L.
- Sun Jan 24, 2021 9:58 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Relationship between Ka and pKa
- Replies: 11
- Views: 1033
Re: Relationship between Ka and pKa
The pKa value is a way of indicating the strength of a particular acid. The pKa is the power, or the negative log, of Ka (the acid dissociation constant for a particular compound).
- Sun Jan 17, 2021 10:42 pm
- Forum: Student Social/Study Group
- Topic: Logistics for the Midterm
- Replies: 11
- Views: 646
Re: Logistics for the Midterm
Yes, our midterms will be taken during lecture time. Our first midterm will be held on January 29th in class and TAs will be proctoring the exam (as far as I know). I hope this helps!
- Sun Jan 17, 2021 10:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: cancelling out variables in K eq
- Replies: 4
- Views: 269
Re: cancelling out variables in K eq
In the equation you provided, the values of x would not cancel out. Since they are opposite signs, you would either add one 2x to the other side to produce 4x or subtract one 2x to the other side to produce -4x.
- Sun Jan 17, 2021 10:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Making the Assumption that Change x is Small
- Replies: 4
- Views: 216
Making the Assumption that Change x is Small
When determining equilibrium concentrations, there are times that we can make the assumption that a change in concentration 'x' is very small compared to the initial concentration, allowing us to ultimately ignore it. What is the K value threshold for which we can make this assumption? Is it 10^-3 o...
- Sun Jan 17, 2021 10:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Total pressure calculation
- Replies: 8
- Views: 971
Re: Total pressure calculation
To calculate the total pressure, you must use an ICE table to find each partial pressure of the system. Set the Kp value equal to the partial pressures of the products over the partial pressures of the reactants. Ensure that you have accounted for the changes in pressure that will occur when the rea...
- Sun Jan 17, 2021 10:05 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 2 Question 5
- Replies: 2
- Views: 114
Re: Sapling Week 2 Question 5
Hi there!
I believe that we assume the reaction is at equilibrium as a result of the fact that the problem states the amine is protonated, meaning the reaction has already occurred. I wish I could be more thorough, but that's all the info I'm able to provide!
I believe that we assume the reaction is at equilibrium as a result of the fact that the problem states the amine is protonated, meaning the reaction has already occurred. I wish I could be more thorough, but that's all the info I'm able to provide!
- Sun Jan 10, 2021 10:53 pm
- Forum: Student Social/Study Group
- Topic: Midterms During Lecture
- Replies: 44
- Views: 1741
Midterms During Lecture
Hi there,
I recently saw on Chemistry Community that midterms are being held during lecture this quarter. Is this true? If so, where did this info come from? Thanks a lot, I appreciate it :).
I recently saw on Chemistry Community that midterms are being held during lecture this quarter. Is this true? If so, where did this info come from? Thanks a lot, I appreciate it :).
- Sun Jan 10, 2021 10:47 pm
- Forum: Student Social/Study Group
- Topic: Exam Changes
- Replies: 12
- Views: 450
Re: Exam Changes
Hi there! It was my understanding that we would be taking them during discussion sections still. I haven't heard anything different, but I could be wrong! I looked at the syllabus and it isn't explicitly stated whether or not this is the case.
- Sun Jan 10, 2021 10:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Favoring Products or Reactants
- Replies: 1
- Views: 94
Re: Favoring Products or Reactants
We did not go over this thoroughly in lecture/discussion, but I recall Lavelle stating that this phenomenon is quite rare. There will most likely be some sort of favoritism to the products or reactants in any given reaction, especially when considering the environment in which reactions occur can be...
- Sun Jan 10, 2021 10:16 pm
- Forum: Student Social/Study Group
- Topic: Advice for study
- Replies: 31
- Views: 1113
Re: Advice for study
There are several things that I do to study, but I have found that reading the text is incredibly impactful for understanding the material. I love Lavelle's lectures and Sapling is helpful for practice, but reading the text and completing the assigned problems from the book helps me like nothing else.
- Wed Jan 06, 2021 8:28 pm
- Forum: Student Social/Study Group
- Topic: Groupme for 14B
- Replies: 5
- Views: 180
Groupme for 14B
Hi there,
Sorry if this question has already been asked, but is there a Groupme for Lecture 2 of 14B with Lavelle? If so, I'd be really grateful if you could send the link. Thanks!
Sorry if this question has already been asked, but is there a Groupme for Lecture 2 of 14B with Lavelle? If so, I'd be really grateful if you could send the link. Thanks!
- Wed Dec 16, 2020 10:36 pm
- Forum: Student Social/Study Group
- Topic: Existing 14B Groupme
- Replies: 4
- Views: 363
Existing 14B Groupme
Hi there!
I was wondering if there is an existing 14B Groupme chat that has been created by students just finishing 14A. If not, I would love to create one! Let me know, thanks :)
I was wondering if there is an existing 14B Groupme chat that has been created by students just finishing 14A. If not, I would love to create one! Let me know, thanks :)
- Wed Dec 16, 2020 10:20 pm
- Forum: Student Social/Study Group
- Topic: Winter Break Study Group
- Replies: 6
- Views: 312
Re: Winter Break Study Group
Hi there!
I would also like to be a part of a study group! Creating a Groupme would be really useful, especially if we could share resources to prep for the upcoming quarter. Feel free to contact me!
I would also like to be a part of a study group! Creating a Groupme would be really useful, especially if we could share resources to prep for the upcoming quarter. Feel free to contact me!
- Wed Dec 16, 2020 9:19 pm
- Forum: Student Social/Study Group
- Topic: grade calculation
- Replies: 12
- Views: 682
Re: grade calculation
There's plenty of online calculators that will allow you to put in grades and the weight of grades to estimate your final grade. Google something like "final grade calculator" or "percentage grade calculator". Use the syllabus and grade book to fill them out with the grades we h...
- Wed Dec 16, 2020 6:22 pm
- Forum: General Science Questions
- Topic: final timing
- Replies: 25
- Views: 1191
Re: final timing
Personally, I felt like the time during the final flew by quite fast. I agree that when taking the midterms we had a comfortable amount of time to both answer each question and review responses for accuracy. I don't believe that there was a problem with the time provided, though; I simply feel that ...
- Mon Dec 14, 2020 11:49 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: axial/equatorial
- Replies: 5
- Views: 320
Re: axial/equatorial
An atom in an axial position is perpendicular to the plane of the "ring," or the atoms that lie in the plane with the central atom. Atoms in equatorial positions are around this plane of the ring and are perpendicular to the axial atoms.
- Sun Dec 06, 2020 11:19 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pH vs pOH
- Replies: 9
- Views: 316
Re: pH vs pOH
Yes, there is a pOH scale that exists. The same principles of the pH scale apply to that of the pOH scale, only 7+ is acidic and below 7 is basic. A pOH of 7 still indicates a neutral solution. Hope this helps!
- Sun Dec 06, 2020 11:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle
- Replies: 4
- Views: 112
Re: Bond Angle
I'm not sure if there is a molecular geometry chart provided with bond angles included, but you should memorize the bond angles for common shapes. I do not think we'll be provided with this information on the exam, so it would be best just to have these common bond angles memorized.
- Sun Dec 06, 2020 11:13 pm
- Forum: Student Social/Study Group
- Topic: Naming Coordination Compounds
- Replies: 1
- Views: 65
Naming Coordination Compounds
Hi,
I've been trying to memorize the process of naming coordination compounds, but I am having some trouble doing so. Does anyone have a method they use to remember how to name coordination compounds? If not, an effective way of studying this process? Thanks!
I've been trying to memorize the process of naming coordination compounds, but I am having some trouble doing so. Does anyone have a method they use to remember how to name coordination compounds? If not, an effective way of studying this process? Thanks!
- Sun Dec 06, 2020 10:49 pm
- Forum: *Molecular Orbital Theory Applied To Transition Metals
- Topic: Orbitals and coordination numbers
- Replies: 2
- Views: 566
Re: Orbitals and coordination numbers
Hi, The coordination number is the number of atoms bonded to the transition metal. If there is an atom bonded to the transition metal, it will be included within the brackets of its chemical formula. The transition metal complex can form ionic bonds, but these bonds may not be located on the transit...
- Sun Dec 06, 2020 10:44 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Tips for Coordination #
- Replies: 4
- Views: 171
Re: Tips for Coordination #
Hi there,
The coordination number is simply the number of atoms bonded to the central atom (the transition metal). Everything bonded to the transition metal will be included within brackets. For your example, the coordination number is 4. I hope this helps!
The coordination number is simply the number of atoms bonded to the central atom (the transition metal). Everything bonded to the transition metal will be included within brackets. For your example, the coordination number is 4. I hope this helps!
- Sun Nov 29, 2020 7:05 pm
- Forum: Electronegativity
- Topic: Sapling Week 8 Polarity
- Replies: 5
- Views: 359
Re: Sapling Week 8 Polarity
Due to the fact that a polar bond exists within the molecule, the molecule is polar. There are no other polar bonds in the molecule that cancel out this bond's polarity, so the molecule as a whole is considered to be polar as well. Electrons will be more attracted to the oxygen atom, causing the mol...
- Sun Nov 29, 2020 6:41 pm
- Forum: Student Social/Study Group
- Topic: Studying for Final Exam
- Replies: 57
- Views: 2366
Studying for Final Exam
Hi there,
Out of curiosity, how will you be studying for this final exam? What methods/strategies do you use when studying for the chem final? I study a lot but I often lack organization and efficiency when doing so. Thanks for the help!
Out of curiosity, how will you be studying for this final exam? What methods/strategies do you use when studying for the chem final? I study a lot but I often lack organization and efficiency when doing so. Thanks for the help!
- Sun Nov 29, 2020 5:56 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: molecule shape polarity
- Replies: 5
- Views: 280
Re: molecule shape polarity
To determine the polarity of a molecule, we must first observe the polarities of the bonds within it. When looking at BeCl2, it can be observed that the bonds between the Be and Cl atoms are polar due to differing electronegativities. However, since the molecule only has these two regions of electro...
- Sun Nov 29, 2020 5:50 pm
- Forum: Hybridization
- Topic: Definition of Hybridization
- Replies: 5
- Views: 275
Re: Definition of Hybridization
In response to your first question, orbital hybridization can be defined as the "mixing" of different orbitals to form new, hybridized orbitals that have different energies and shapes than the original components. Hybridization simply tells us what types of bonds exist between atoms.
- Sun Nov 29, 2020 5:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: #13 Sapling Week 8
- Replies: 18
- Views: 552
Re: #13 Sapling Week 8
Four regions of electron density indicate a tetrahedral geometry, so that response would be correct. I am not sure why it marked yours wrong (my response was marked as correct). I hope this helped!
- Sun Nov 22, 2020 11:40 pm
- Forum: Student Social/Study Group
- Topic: Final Format
- Replies: 35
- Views: 1516
Final Format
Hi there,
I know this may be a little early, but does anyone know the general format of the final exam and the allotted time for it? Just trying to get a sense of what it will be like. Thanks!
I know this may be a little early, but does anyone know the general format of the final exam and the allotted time for it? Just trying to get a sense of what it will be like. Thanks!
- Sun Nov 22, 2020 11:24 pm
- Forum: Sigma & Pi Bonds
- Topic: Delocalized pi Bonds
- Replies: 2
- Views: 100
Delocalized pi Bonds
What causes the delocalization of a pi bond? What does a delocalized pi bond entail for the stability of the bond? I've been having a little bit of trouble finding the answer. Thanks a lot!
- Sun Nov 22, 2020 11:12 pm
- Forum: Electronegativity
- Topic: Polarity of Molecules
- Replies: 10
- Views: 535
Polarity of Molecules
When looking at the Lewis structure for a certain molecule, how can we determine its polarity? I know polar bonds occur due to differences in electronegativity between atoms, but how would we determine the polarity of a molecule without knowing the specific electronegativities of its atoms? Thanks!
- Sun Nov 22, 2020 11:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 25
- Views: 883
Bond Angles
Hi there,
For the final exam, will we be required to memorize the bond angles of certain molecular geometry? Thanks!
For the final exam, will we be required to memorize the bond angles of certain molecular geometry? Thanks!
- Sun Nov 22, 2020 10:48 pm
- Forum: Ionic & Covalent Bonds
- Topic: C-H bond polarity
- Replies: 10
- Views: 11369
Re: C-H bond polarity
If you search the difference in electronegativity between the two atoms, it is only 0.35. Since the difference between their electronegativities is so small, we can state that the bond is nonpolar (electrons will be more equally shared). The two atoms have similar electronegativities, therefore the ...
- Sun Nov 15, 2020 10:52 pm
- Forum: Bond Lengths & Energies
- Topic: Bonds and Accepting Electrons
- Replies: 2
- Views: 147
Re: Bonds and Accepting Electrons
I believe that CO2 would be considered a Lewis Acid due to its polarity because of the positive charge that is on the central carbon atom. Since the carbon atom is partially positive while the adjacent oxygen atoms are partially negative, the carbon is able to attract lone pair electrons. Molecules ...
- Sun Nov 15, 2020 10:37 pm
- Forum: Ionic & Covalent Bonds
- Topic: Hydrogen Bonding in Water
- Replies: 2
- Views: 185
Hydrogen Bonding in Water
Hi, In lecture, we were told that a hydrogen atom involved in a hydrogen bond in water is bonded to an electronegative atom (oxygen) while being close to another electronegative atom with a lone pair of electrons. Why must it be close to another electronegative atom with a lone pair? I've tried look...
- Sun Nov 15, 2020 10:24 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Character
- Replies: 3
- Views: 173
Bond Character
Hi there, On one of our Sapling homework problems, we are asked to state whether a bond has "ample" or "overwhelming" bond character. Specifically, we are asked to state whether a carbon-nitrogen bond has ample double-bond character or an overwhelmingly single-bond character (the...
- Sun Nov 15, 2020 9:44 pm
- Forum: Lewis Structures
- Topic: Sapling Week 5/6 HW #3
- Replies: 7
- Views: 201
Re: Sapling Week 5/6 HW #3
If I recall correctly, Dr. Lavelle stated in lecture that we would be provided with the chemical formulas for all given compounds on each midterm. If this was not the case, a good way of differentiating between -ite and -ate is that -ite indicates a low oxidation state while -ate indicates a high ox...
- Sun Nov 15, 2020 9:30 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Best Formal Charge Equations
- Replies: 24
- Views: 990
Re: Best Formal Charge Equations
The way that I calculate the formal charge is by using the following equation:
Formal Charge = (Valence e-) - (Nonbinding Valence e-) - (Bonding e-)*1/2
I suppose that one way to more easily memorize this equation is to memorize its abbreviated form (FC = V - NB - B/2). Hope this helps!
Formal Charge = (Valence e-) - (Nonbinding Valence e-) - (Bonding e-)*1/2
I suppose that one way to more easily memorize this equation is to memorize its abbreviated form (FC = V - NB - B/2). Hope this helps!
- Sun Nov 08, 2020 1:11 pm
- Forum: Ionic & Covalent Bonds
- Topic: Silver Halides
- Replies: 3
- Views: 69
Silver Halides
Hi! In lecture last Friday, it was stated that increasing the covalent character of silver halides like AgF, AgCl, and AgBr makes them less soluble in water. In other words, increasing the size of the anion in these bonds causes the compound to be less soluble, which is a characteristic of salts. Wh...
- Sun Nov 08, 2020 12:58 pm
- Forum: Octet Exceptions
- Topic: Why are there exceptions to the octect rule?
- Replies: 2
- Views: 163
Why are there exceptions to the octect rule?
Hi there, I understand that there are exceptions to the octet rule, but I don't know why this is the case. For example, there are multiple compounds in which Boron only has 6 electrons in place of 8. Wouldn't this cause Boron to be reactive? This has probably already been asked but I couldn't find a...
- Sun Nov 08, 2020 12:52 pm
- Forum: Ionic & Covalent Bonds
- Topic: Classifying Distortion
- Replies: 4
- Views: 150
Classifying Distortion
Hello, While I understand that distortion in an ionic bond occurs because the cation's positive charge attracts the anion's electrons, I do not understand how this distortion is recognized and classified. In other words, how can one experimentally verify that the electron cloud of an element is dist...
- Sun Nov 08, 2020 12:32 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Distortion
- Replies: 8
- Views: 191
Re: Distortion
Hi! When electrons in an atom are distorted, this is due to the positive charge of another element attracting the electrons of said atom. For example, in an ionic bond, the cation exerts an electrostatic attraction on the electrons of the surrounding anion. The positive charge of the cation attracts...
- Sun Nov 08, 2020 12:21 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Character
- Replies: 7
- Views: 363
Re: Covalent Character
Hi there! Covalent bonds can have ionic character because elements within a bond have differing electronegativities. If one element in a bond has a greater electronegativity than the other, it will attract the electron more than the other element, causing the electron to be unevenly shared (having i...
- Sun Nov 01, 2020 7:24 pm
- Forum: Student Social/Study Group
- Topic: Midterm 1
- Replies: 4
- Views: 192
Midterm 1
Hi there,
I doubt that we are, but I was wondering if anyone knew whether we will be reviewing the midterm either in discussion or otherwise after it has been graded. Let me know! Thanks:)
I doubt that we are, but I was wondering if anyone knew whether we will be reviewing the midterm either in discussion or otherwise after it has been graded. Let me know! Thanks:)
- Sun Nov 01, 2020 7:17 pm
- Forum: DeBroglie Equation
- Topic: energy of a photon
- Replies: 7
- Views: 362
Re: energy of a photon
Hi! Since the energy of a photon is equal to its frequency multiplied by Planck's constant, we can rewrite the equation (c = wavelength * frequency) to solve for frequency in terms of wavelength. We can then replace frequency in the E = hv equation with the term from the rewritten (c = wavelength * ...
- Sun Nov 01, 2020 7:09 pm
- Forum: Trends in The Periodic Table
- Topic: Isoelectronic Ions
- Replies: 5
- Views: 152
Re: Isoelectronic Ions
Hi! When two elements are isoelectronic, this signifies that they share the same number of electrons. For example, F- and Ne are isoelectronic, due to the fact that they both possess 10 electrons. While they may have the same number of electrons, this does not mean they share properties. Two element...
- Sun Nov 01, 2020 7:04 pm
- Forum: Trends in The Periodic Table
- Topic: Sapling question 24
- Replies: 3
- Views: 368
Re: Sapling question 24
Hi, Having a high effective nuclear charge signifies that the electrons are more attracted to the nucleus, resulting in a smaller atomic radius. The effective nuclear charge is the net positive charge from the nucleus on an electron. So, having a higher effective nuclear charge means the electrons a...
- Sun Nov 01, 2020 6:53 pm
- Forum: Student Social/Study Group
- Topic: Sappling #26
- Replies: 3
- Views: 208
Re: Sappling #26
Hi there, We can find the minimum uncertainty of velocity when only given this information by using Heisenberg's Uncertainty Principle. We are provided with the information that the position is known within 11 Angstrom. Using the uncertainty principle, the only unknown information remaining is the u...
- Sun Oct 25, 2020 7:40 pm
- Forum: Student Social/Study Group
- Topic: Questions for Midterm 1
- Replies: 5
- Views: 213
Questions for Midterm 1
Hi!
I have heard that the midterm will have 10 questions, but I have not confirmed that this is true. Will there really be 10 questions? If not, do you know how many questions will be on the midterm? Thanks, I appreciate it.
I have heard that the midterm will have 10 questions, but I have not confirmed that this is true. Will there really be 10 questions? If not, do you know how many questions will be on the midterm? Thanks, I appreciate it.
- Sun Oct 25, 2020 7:30 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Effective Nuclear Charge
- Replies: 2
- Views: 87
Effective Nuclear Charge
Hello, It was stated in our lecture on Friday that inner electrons shield outer electrons from electrostatic attraction of the positive nucleus. These outer electrons feel reduced electrostatic attraction, resulting in an "effective nuclear charge". What does this mean exactly? I understan...
- Sun Oct 25, 2020 7:23 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Electrostatic Potential Energy
- Replies: 1
- Views: 87
Electrostatic Potential Energy
Hello!
Can someone describe the concept of electrostatic potential energy to me? We recently covered this in our most previous lecture, but I couldn't quite understand what it is and how it is related to the charges of protons and electrons within an atom. Thanks a lot!
Can someone describe the concept of electrostatic potential energy to me? We recently covered this in our most previous lecture, but I couldn't quite understand what it is and how it is related to the charges of protons and electrons within an atom. Thanks a lot!
- Sun Oct 25, 2020 7:19 pm
- Forum: *Shrodinger Equation
- Topic: Wave Function
- Replies: 5
- Views: 301
Re: Wave Function
Hi! Simply put, the wave function is a mathematical expression that describes the state of an electron. It is a function that defines the probability of a particle's quantum state. This is done by incorporating the following factors: the energy of an electron, the angular momentum, orbital orientati...
- Sun Oct 25, 2020 7:04 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Differing Energies within the Same Shell
- Replies: 1
- Views: 70
Differing Energies within the Same Shell
Hi there!
In the lecture on Friday, we were told that s-electrons have lower energy than p-electrons within the same shell. Additionally, we were told that the energies of the orbitals in the same shell are ranked as such: s<p<d<f. Why is this the case? Thanks!
In the lecture on Friday, we were told that s-electrons have lower energy than p-electrons within the same shell. Additionally, we were told that the energies of the orbitals in the same shell are ranked as such: s<p<d<f. Why is this the case? Thanks!
- Sun Oct 18, 2020 9:50 pm
- Forum: Significant Figures
- Topic: How do I know how many sig figs to use?
- Replies: 6
- Views: 8875
Re: How do I know how many sig figs to use?
Hi there! The amount of sig figs used is dependent on how you completed the problem. With multiplication and division, the lowest number of sig figs used will be the number of sig figs included in your answer. With addition and subtraction, you assign significant figures based on the number of decim...
- Sun Oct 18, 2020 9:44 pm
- Forum: Student Social/Study Group
- Topic: Midterm 1
- Replies: 8
- Views: 236
Midterm 1
Hi!
I was just wondering what content would be included in the midterm. What weeks of material can we expect to see? Thanks a lot.
I was just wondering what content would be included in the midterm. What weeks of material can we expect to see? Thanks a lot.
- Sun Oct 18, 2020 9:27 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Respondus Browser
- Replies: 4
- Views: 101
Respondus Browser
Hi there!
When using respondus, will I have to point my camera down onto the paper I am writing on? If so, will I be able to project my work onto a separate monitor so I can see what I'm doing more clearly! Thank you!
When using respondus, will I have to point my camera down onto the paper I am writing on? If so, will I be able to project my work onto a separate monitor so I can see what I'm doing more clearly! Thank you!
- Sun Oct 18, 2020 9:19 pm
- Forum: Photoelectric Effect
- Topic: Kinetic energy equation
- Replies: 3
- Views: 267
Re: Kinetic energy equation
Hi there,
In this equation, m represents the mass in kilograms of an object. This component of the equation is necessary in order to calculate the kinetic energy. Hope this helps!
In this equation, m represents the mass in kilograms of an object. This component of the equation is necessary in order to calculate the kinetic energy. Hope this helps!
- Sun Oct 18, 2020 9:14 pm
- Forum: Balancing Chemical Reactions
- Topic: Syntax Question
- Replies: 4
- Views: 381
Re: Syntax Question
Hi there!
Yes, both ways of writing signify the same thing. The reason why it is written as (OH)2 instead of O2H2 is that it is the simplified form, nothing more. Hope this helps!
Yes, both ways of writing signify the same thing. The reason why it is written as (OH)2 instead of O2H2 is that it is the simplified form, nothing more. Hope this helps!
- Sun Oct 11, 2020 8:53 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Textbook Homework E9
- Replies: 6
- Views: 179
Re: Textbook Homework E9
Hi there! While watching one of the lectures, I heard that we would be provided with compounds on tests and that we would not be required to memorize them. While I have not seen this written on the syllabus or any other materials, I am fairly confident that we will not have to memorize compounds as ...