Search found 100 matches
- Fri Mar 12, 2021 4:40 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Sapling #20
- Replies: 4
- Views: 240
Re: Sapling #20
For this question, we can use some concepts from 14A. We can tell that N2 would be a linear molecule, so we can then choose which molar heat capacity at constant volume to use. Then we can use this to find the heat required.
- Fri Mar 12, 2021 4:38 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: When to use Platinum
- Replies: 14
- Views: 712
Re: When to use Platinum
When the textbook says that the oxidized and reduced species are both in the solution, that means we need a metal to act as a conductor and help the two half-reactions happen. Whenever the two species are in solution, it is safe to assume that Pt should be used.
- Fri Mar 12, 2021 4:34 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Rate Laws for Slow Step/Overall
- Replies: 14
- Views: 830
Re: Rate Laws for Slow Step/Overall
There was a similar question in the sapling homework which tapped into this concept. Since the intermediates will not be included in the reaction, you can use the other fast reactions to substitute it and find the rate law.
- Fri Mar 12, 2021 4:23 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Catalyst
- Replies: 30
- Views: 1923
Re: Catalyst
Since catalysts help the rate of the reaction and are not actually a part of it, they would not be included in the overall reaction. They are consumed and produced later so they do not show up.
- Fri Mar 12, 2021 4:19 pm
- Forum: Zero Order Reactions
- Topic: kind of reaction
- Replies: 25
- Views: 1025
Re: kind of reaction
a zero order reaction is a reaction where it only depends on the rate constant rather than the concentrations of the reactants, since zero order means that there is a linear relationship between the concentration and time.
- Thu Mar 04, 2021 5:32 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Constructing Cell Diagrams
- Replies: 4
- Views: 197
Re: Constructing Cell Diagrams
I believe that when the two sides are in solution rather than solid, we would have to add solid conducting metal in order to have the redox reaction take place. With this we would add the Pt(s). Hope this helps!
- Thu Mar 04, 2021 5:28 pm
- Forum: First Order Reactions
- Topic: 1st Order Reactions
- Replies: 29
- Views: 1747
Re: 1st Order Reactions
When we plot a 1st order reaction, the y axis is actually the ln[A] rather than just A. The ln[A] give us this linear relationship while just [A] vs time gives us a decreasing exponential function. With this, they both still show us a 1st order reaction. I hope this helps!
- Thu Mar 04, 2021 5:26 pm
- Forum: Second Order Reactions
- Topic: half life for second-order reactions
- Replies: 9
- Views: 519
Re: half life for second-order reactions
It is important to note the difference between 1st order and 2nd order half life equations. Since the half life of 2nd order reactions depends on the initial concentration, while the 1st order only depends on k, we can not just multiply by time. Hope this helps!
- Thu Mar 04, 2021 5:19 pm
- Forum: Zero Order Reactions
- Topic: Half life
- Replies: 20
- Views: 893
Re: Half life
To calculate a half-life for a zero order reaction, the equation would be t(1/2)=[A]0/2k. In lecture yesterday, he derived this from the integrated rate law for zero order. It is important to note that the half life zero order rate depends on the concentration of [A] initial.
- Thu Mar 04, 2021 5:16 pm
- Forum: Balancing Redox Reactions
- Topic: adding H+ and H2O
- Replies: 9
- Views: 684
Re: adding H+ and H2O
In an acidic solution, when we are balancing the O and H, we would add H20 to one side and then H+ to the other side in order to get it in acidic solution. We can then balance the charges and the O and H using this method. If it were to be in basic solution, we can then add an equal amount of OH- to...
- Thu Feb 25, 2021 12:27 pm
- Forum: Balancing Redox Reactions
- Topic: E naught
- Replies: 15
- Views: 854
Re: E naught
Yes, since E naught is an intensive property, the standard potential of the cell will not change no matter how many times the reaction occurs. Similar to density, we then would not have to multiply it when balancing the redox equations.
- Thu Feb 25, 2021 12:25 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Oxidation Agent
- Replies: 12
- Views: 563
Re: Oxidation Agent
In order to determine the order of best oxidizing agents, we can look at it as "which species will be most likely to take the electrons away" or has the most potential to be reduced. With this, we would look to see which species has the highest reduction potential in order to see which wou...
- Thu Feb 25, 2021 12:22 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: E cell vs Ecell naught
- Replies: 25
- Views: 1509
Re: E cell vs Ecell naught
The E cell naught is the value in standard conditions -- 1 atm, 25 Celsius, 1M. The E cell gives us the value of E in a given cell at any given time/condition. With this, we can use these two concepts and link them in the nernst equation, E cell = E cell naught - RT/nf lnQ.
- Thu Feb 25, 2021 12:15 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing Agent and Reducing Agent
- Replies: 7
- Views: 348
Re: Oxidizing Agent and Reducing Agent
I like to think of oxidizing/reducing agent as the species that causes oxidization or reduction to happen. When we have an oxidizing agent, we know that it is causing the other species to be oxidized, so in turn, it is being reduced. So, since it is being reduced it is gaining an electron, which is ...
- Thu Feb 25, 2021 12:12 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 30
- Views: 1263
Re: Salt Bridge
In the cell, when we follow where the electrons are going, we can see that without anything to neutralize the charges on either side of the cell, there would be a build up of charges. With this, in order to allow the transfer of electrons to continue, we have to have a salt bridge that allows ions t...
- Tue Feb 16, 2021 9:53 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: When q=w
- Replies: 9
- Views: 407
Re: When q=w
q would equal -w when the change in internal energy or delta U is zero. This makes sense since this would typically occur in an isothermal reversible expansion, so it is at a constant temperature. The system is doing work and losing energy, and energy is replaced by heat flow or q into the system.
- Tue Feb 16, 2021 9:50 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: w and q relationship
- Replies: 2
- Views: 173
Re: w and q relationship
These sections are right after each other as they both relate to the equation delta U = w + q. When there is no other source, q would be zero, so delta U would equal w, while when the only source of energy transfer is heat, then w is 0, so delta U equals q.
- Tue Feb 16, 2021 9:48 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: G° vs G
- Replies: 30
- Views: 2364
Re: G° vs G
the delta G(0) value is just the delta G value but at standard conditions for a certain system. With this, there are different equations that we can use to relate these values. We can relate the delta G(0) value to a system at equilibrium, while we can use the delta G value in the equation, not at e...
- Tue Feb 16, 2021 9:45 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Textbook 4.37
- Replies: 2
- Views: 154
Re: Textbook 4.37
For b and c we can reference the equation, delta G = delta H(0) -TdeltaS(0). With delta H and delta S, they are dependent on each other in order to see the delta G value. So just given these values we can not tell anything. With the equation -deltaG(sys)/T=deltaS(tot), we can see that the delta G wo...
- Tue Feb 16, 2021 9:32 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Which R value to choose
- Replies: 13
- Views: 1363
Re: Which R value to choose
hey, with choosing the correct R-value, it is important to look at the units and the context of the question. One R value relates to energy while one is related to the ideal gas law. When using PV=nRT, we would use the .0821 value, since this relates it to Lxatm/Kxmol in order to cancel. When relati...
- Thu Feb 11, 2021 10:15 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneous in Reverse
- Replies: 3
- Views: 147
Re: Spontaneous in Reverse
I believe that a reaction that occurs spontaneously in reverse means that the reaction proceeding in the reverse direction is more favorable than the reaction that is proceeding in the forward reaction. Gibb's free energy will be negative for these spontaneous reactions in reverse and positive for t...
- Thu Feb 11, 2021 10:11 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Free Energy
- Replies: 49
- Views: 1809
Re: Free Energy
Hey a state function only considers the initial and final states of a reaction or value, so the "path" taken to get to a certain point doesn't matter only if the initial and final states are the same. With this, free energy is a state function in that the change in free energy for a reacti...
- Thu Feb 11, 2021 10:08 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Equations
- Replies: 8
- Views: 307
Re: Equations
I believe that the integral equations used to derive equations like the work equations and the temperature dependence on entropy were just shown to demonstrate the conceptual aspect of reversible reactions and how the area under the curve plays a role in it. I believe it is important to understand w...
- Thu Feb 11, 2021 10:05 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: residual vs. thermal entropy
- Replies: 6
- Views: 333
Re: residual vs. thermal entropy
In terms of an isolated system, the difference between residual and thermal entropy lies in what is considered when calculating it. In residual entropy, we assume that the system is at 0 kelvin, so there is no additional thermal heat or movement from the particles, and the entropy simply lies in the...
- Thu Feb 11, 2021 10:01 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Delta G and Spontaneity
- Replies: 10
- Views: 719
Re: Delta G and Spontaneity
When we think of the word "spontaneity" we can relate this to a reaction or process where energy is not needed for the reaction to go forward (not including the activation energy). With this, when we think of Gibbs free energy, we can also think about the change in entropy of the universe....
- Tue Feb 02, 2021 5:57 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Postive vs. negative work
- Replies: 18
- Views: 884
Re: Postive vs. negative work
Hey, when work is being done by the system, it would be a negative value since the system is using energy and it is being transferred to the surroundings. When work is being done on the system, energy is transferred from the surroundings to the system which account for the positive work value since ...
- Tue Feb 02, 2021 5:40 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Constant Pressure in Open Systems
- Replies: 8
- Views: 237
Re: Constant Pressure in Open Systems
Hey, I believe that when considering an open system, we can assume that it has the ability to exchange/transfer matter and energy. Pressure within the system will be equal to that of the surroundings since it is exposed. With this, since the pressure in the system is equal to the surroundings we can...
- Tue Feb 02, 2021 5:37 pm
- Forum: Calculating Work of Expansion
- Topic: Work on surrounding
- Replies: 12
- Views: 391
Re: Work on surrounding
When looking at whether or not the system is performing work on the surroundings, we would only consider the reactants/products that are in the gas state, since a solid or liquid does not have a significant change in the volume or pressure, so no expansion/compression (work) is being done by the sys...
- Tue Feb 02, 2021 5:32 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Significance of open, closed, isolated
- Replies: 22
- Views: 1014
Re: Significance of open, closed, isolated
Hey, I believe that the significance in knowing the difference between the different systems lies in what it can tell us about the transfer of energy, or lack thereof, and what variables in the system remain constant. When a system is open, matter and energy can be transferred into the surroundings,...
- Tue Feb 02, 2021 5:27 pm
- Forum: Calculating Work of Expansion
- Topic: sapling question 14
- Replies: 2
- Views: 79
Re: sapling question 14
Hey, I believe when choosing which R value to use, we have to see what we are looking for. Since the question is asking for the Joules, then we know to use the 8.314 since this value's units include J/KxMol, while other R values may not have what we are looking for. Hope that helps.
- Mon Jan 25, 2021 2:10 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: constant p calorimeter vs. constant v calorimeter
- Replies: 3
- Views: 100
Re: constant p calorimeter vs. constant v calorimeter
In the problem-solving process, it is important to realize which of these constants we should use when solving a certain problem. In the lecture, Dr. Lavelle mentions how they are slightly different values due to the fact that one requires more heat or energy, leading to a higher value. With Cp, sin...
- Mon Jan 25, 2021 2:05 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Ice melting
- Replies: 5
- Views: 299
Re: Ice melting
Just to add on, when increasing temperature, we can say that we are releasing energy from the system to the surroundings which fits the definition of an exothermic reaction, since the system is losing heat, or releasing heat. With this, ice melting would be an endothermic reaction since it is requir...
- Mon Jan 25, 2021 2:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Catalysts and equilibrium
- Replies: 4
- Views: 72
Re: Catalysts and equilibrium
I believe that when adding a catalyst, we are simply increasing the rate of the reaction. Lowering the energy required for a reaction to take place will help increase the forward or reverse reactions, but the concentrations will still approach the equilibrium constant at a specific temperature.
- Mon Jan 25, 2021 2:00 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Exothermic rxn
- Replies: 9
- Views: 341
Re: Exothermic rxn
I believe that when he said the change in heat was positive he was referencing the heat of the surroundings. Just to add on to what was said before, since q(system) + q(surroundings)=0, we can see that a negative change in heat in the system (an exothermic reaction), would result in a positive chang...
- Mon Jan 25, 2021 1:58 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Molar heat Capacity
- Replies: 3
- Views: 148
Re: Molar heat Capacity
Hey! I believe that when writing molar heat capacity, or specific heat capacity, the Celsius and Kelvin are interchangeable since it would be the same value anyways. In other words, the change in celsius would be the same value as the change in Kelvin which is why we can switch them out for the unit...
- Wed Jan 20, 2021 12:19 pm
- Forum: General Science Questions
- Topic: Polyprotic Acids
- Replies: 6
- Views: 362
Re: Polyprotic Acids
Yeah I believe that we can just focus on the Ka1 of the polyprotic acid. The Ka1 is usually always higher than the other K values of the polyprotic acid. This means that its dissociation will have the greatest affect on the pH of the solution. For example, in H3PO4, the dissociation of the first hyd...
- Wed Jan 20, 2021 12:14 pm
- Forum: Phase Changes & Related Calculations
- Topic: Endothermic v. Exothermic
- Replies: 139
- Views: 9245
Re: Endothermic v. Exothermic
I do not believe that there are any exceptions to the rule, and you are correct. This is due to the nature of "delta H" itself. Delta H is the change in enthalpy. So, when you have a positive value, it tells us that the enthalpy in the products is higher than the reactants, which mean it r...
- Wed Jan 20, 2021 12:09 pm
- Forum: Phase Changes & Related Calculations
- Topic: Adding Heat but Temp remains constant
- Replies: 11
- Views: 354
Re: Adding Heat but Temp remains constant
Hello! I had this question myself, so I am not entirely sure. I believe that the heat being added in a phase change is absorbed by the molecules themselves, causing the bonds to break. After this happens, as more heat is added, then the temperature begins to rise after the bonds are broken since the...
- Wed Jan 20, 2021 11:59 am
- Forum: Phase Changes & Related Calculations
- Topic: ionization percentage
- Replies: 10
- Views: 415
Re: ionization percentage
Just to add on, since the percent ionization is calculated through [H3O+] or [OH-]/ the acid or base, the percent ionization gives us valuable information that tells us whether or not a base or acid is strong (strong acids or bases are going to dissociates 100%, which makes sense since that will inf...
- Wed Jan 20, 2021 11:52 am
- Forum: Phase Changes & Related Calculations
- Topic: Steam causing severe burns
- Replies: 5
- Views: 169
Re: Steam causing severe burns
Hey! Yeah I believe what you said is correct. Since water does have strong hydrogen bonds, it is harder, or requires more heat in order to break its bonds and make water go through a phase change from liquid to vapor, explaining the high heat of vaporization. In other molecules which do not have as ...
- Mon Jan 11, 2021 4:45 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Textbook Problem 5.J.5 part B
- Replies: 5
- Views: 291
Re: Textbook Problem 5.J.5 part B
Hello! An increase in total pressure from a decrease in volume would cause the reactants to be favored since there are less moles of gas on the left than there are on the right since Carbon is not included in the reaction since it is a solid. To add on, it would go this way since more pressure would...
- Mon Jan 11, 2021 4:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Super acids and super bases
- Replies: 4
- Views: 182
Re: Super acids and super bases
Hello!
I believe that we only have to know from pH 0 to 14. Though, I am curious about what situations we would have a super acid or base. Are there any examples that anybody knows? Hope this helps!
I believe that we only have to know from pH 0 to 14. Though, I am curious about what situations we would have a super acid or base. Are there any examples that anybody knows? Hope this helps!
- Mon Jan 11, 2021 4:27 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Adding Helium
- Replies: 10
- Views: 844
Re: Adding Helium
Hello! Helium along with other inert gases, or gases that are not included in the reaction, do not effect the concentrations/partial pressures of the reactants and products. With this, there is no effect on reaction and it would remain at equilibrium. Although adding it adds overall to the pressure ...
- Mon Jan 11, 2021 4:22 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: ICE Table
- Replies: 9
- Views: 400
Re: ICE Table
Hello! Just to add on, the direction in which the reaction is moving -- whether that's towards the reactants or the products -- dictates which species are getting the nx or -nx in the ICE table. Usually, in some practice questions they will give you the initial concentration, so you can assume the s...
- Mon Jan 11, 2021 4:11 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Hydronium and Hydroxide
- Replies: 4
- Views: 135
Re: Hydronium and Hydroxide
Hello! I believe that you wouldn't assume the concentration of either to be 0. Since kw will always be 1.0x10^-14 at 25 degrees celsius, you can use that to determine each of the concentrations. For example, in the example given in lecture today, we found the concentration of H3O+ through the concen...
- Thu Jan 07, 2021 1:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: concentration or partial pressure
- Replies: 7
- Views: 301
Re: concentration or partial pressure
Hey!
Since the question gives you the molarity and the kc of the reaction, then no conversions are needed for the gas since the Kc value is based on the concentrations that they give you. I believe you would only have to change Kc to Kp if they asked you to. Hope this helps!
Since the question gives you the molarity and the kc of the reaction, then no conversions are needed for the gas since the Kc value is based on the concentrations that they give you. I believe you would only have to change Kc to Kp if they asked you to. Hope this helps!
- Thu Jan 07, 2021 1:34 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: How do you know when to use Kc vs Kp?
- Replies: 9
- Views: 500
Re: How do you know when to use Kc vs Kp?
I believe that, depending on context, we can decide to use Kc or Kp. When a question is given in all partial pressures, then it would be safe to assume to use Kp, while if given in aq, then use Kc. I would not convert anything unless the question asks, since it is possible to convert the Kp to Kc. H...
- Thu Jan 07, 2021 1:28 pm
- Forum: Ideal Gases
- Topic: Ideal vs real gases
- Replies: 12
- Views: 571
Re: Ideal vs real gases
Ideal gases have a set of rules that are not likely to occur in real life. This includes the fact that all atoms and molecules in the gas are not interacting with each other, and are moving randomly. With this, in comparison to real gases, ideal gases are used in calculations such as with the ideal ...
- Thu Jan 07, 2021 1:23 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Why doesn't pressure change affect K?
- Replies: 5
- Views: 2797
Re: Why doesn't pressure change affect K?
Hey! A change in pressure would not affect the equilibrium constant since it would affect the concentration of the reactants and products and shift the reaction a certain way. With this, however, although the concentrations of the reactants and products are different from equilibrium, it is the same...
- Thu Jan 07, 2021 1:18 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: names for reaction quotient Q
- Replies: 19
- Views: 459
Re: names for reaction quotient Q
Hey! With Qp and Qc, they are both calculated in the same way and represent the reaction quotient at anytime in a reaction. They are basically the same, but Qp represents the reaction quotient for the partial pressure while Qc represents the reaction quotient for the concentration of the reaction. W...
- Thu Dec 10, 2020 2:57 pm
- Forum: Ionic & Covalent Bonds
- Topic: CO2 vs CS2
- Replies: 8
- Views: 1374
Re: CO2 vs CS2
Hey! Just to add on, it is important to note the periodic trends that we have been going over. When comparing O and S, we can see that O would have a smaller atomic radius. This means that it would have a stronger electronegativity, since its protons can hold on to its electrons better due to less s...
- Thu Dec 10, 2020 2:54 pm
- Forum: Lewis Acids & Bases
- Topic: Difference between a Lewis Base and Bronsted Base
- Replies: 3
- Views: 1111
Re: Difference between a Lewis Base and Bronsted Base
Hey! The difference between a Bronsted base and a lewis base lies in what we are focusing on. The bronsted base is concerned with accepting an H+ ion, while a lewis base is concerned with the donation of an electron pair. It is important to note that every Bronsted base is a lewis base, but not ever...
- Thu Dec 10, 2020 2:45 pm
- Forum: Electronegativity
- Topic: ionic bonds
- Replies: 13
- Views: 592
Re: ionic bonds
Hey! The answer would be BaBr2, since the difference in electronegativity would be much higher than BeBr2. By looking at the trends, Ba is much lower than Be in column 2, meaning it has a much larger radius, and therefore, less electronegativity. This would result in a higher difference in electrone...
- Thu Dec 10, 2020 2:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 4
- Views: 355
Re: Bond Angles
Hey! I believe in one of the lectures, Dr. Lavelle talks about how the difference between these is that in the tetrahedral molecule, the atoms occupy more than one plane. With this, it can maximize the bond angles, since if it was all in one plane the angles would be 90 degrees. Also, adding on, the...
- Thu Dec 10, 2020 2:34 pm
- Forum: Electronegativity
- Topic: solubility
- Replies: 7
- Views: 397
Re: solubility
Hey! Having more ionic character is going to allow for higher solubility due to the difference in electronegativity. Having a larger difference in electronegativity means that these electric charges can interact with the polar bonds from the H2O. For example, in NaCl, the Na+ ions can interact with ...
- Wed Dec 02, 2020 10:48 am
- Forum: Bronsted Acids & Bases
- Topic: Bronsted Acids vs Strong Acids
- Replies: 4
- Views: 203
Re: Bronsted Acids vs Strong Acids
Hey! It is important to note the definition of Bronsted acids which donate protons. With this, although he did state strong acids in today's lecture, I believe that an acid that donates a proton is considered a bronsted acid, even if it is weak. Although many acids are weak, they still can donate pr...
- Wed Dec 02, 2020 9:01 am
- Forum: Biological Examples
- Topic: Enzyme Function
- Replies: 9
- Views: 437
Enzyme Function
Hi I am not sure if this has been answered before but near the end of lecture from Monday, Dr. Lavelle mentioned a few examples of transition metals and their biological significance. One of these was Mn, Ni, Cu, and Zn and their impact on enzyme function. How do these transition metals play a role ...
- Wed Dec 02, 2020 8:52 am
- Forum: Naming
- Topic: Lecture Example [Co(Nh3)5 Cl]Cl2H2O
- Replies: 8
- Views: 296
Re: Lecture Example [Co(Nh3)5 Cl]Cl2H2O
Hey!
To answer the question above, I believe that when naming coordination compounds within the brackets, so within the coordination sphere, you would go in alphabetical order of the ligands followed by the transition metal ion. Feel free to correct me if I am wrong. Hope this helps!
To answer the question above, I believe that when naming coordination compounds within the brackets, so within the coordination sphere, you would go in alphabetical order of the ligands followed by the transition metal ion. Feel free to correct me if I am wrong. Hope this helps!
- Wed Dec 02, 2020 8:44 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination numbers and shapes
- Replies: 3
- Views: 303
Re: Coordination numbers and shapes
Hey! Just to add on, the coordination number represents the number of bonds that are formed by a specific cation, or transition metal. With this, we can use this information and the information we know about the shapes of molecules (i.e. coordination # of 6 being octahedral, # 4 being square planar ...
- Wed Dec 02, 2020 8:38 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Neutral ligands
- Replies: 4
- Views: 1361
Re: Neutral ligands
Hey! Just to add on, these neutral ligands are usually bonded to cation transition metals and when we know that a ligand is neutral, we can then use that information to calculate the charge of the transition metal, given the charge of the entire compound. A few more examples can include NO, CH3NH2, ...
- Wed Nov 25, 2020 11:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bonds
- Replies: 4
- Views: 108
Re: Bonds
Hey! Just adding on to what has been said before, since double and triple bonds equate to one electron density, then it's helpful to think that these electrons stay in the same place that they would if it were a single bond, therefore, not changing the shape. When we have a different amount of elect...
- Wed Nov 25, 2020 10:59 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: When Ligands appear?
- Replies: 3
- Views: 195
Re: When Ligands appear?
Hey! Ligands are the molecules that has electron lone pairs and donates them to form coordinate bonds. These ligands then form coordinate compounds with transition metals, which have various different uses. I believe that one of the most important things to remember about ligands and "when"...
- Wed Nov 25, 2020 4:36 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Lecture 24 Question
- Replies: 2
- Views: 110
Re: Lecture 24 Question
Hey! I think that what Dr. Lavelle was saying is just that these e- rich molecules can displace the H20 molecules, but depending on how much is added, the TM can still be bonded with the H20 at the same time. The TM has a certain amount of molecules that it can bond with and as more e- rich molecule...
- Wed Nov 25, 2020 4:29 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: EDTA example in 11/25 lecture
- Replies: 5
- Views: 262
Re: EDTA example in 11/25 lecture
Hey! To answer the question above, I believe that the 6 atoms would be from the two N atoms and the 4 negatively charged single bonded O's. I believe this is because these O's have pairs of electrons to give since they are negatively charged in comparison to the double bonded O's. Please correct me ...
- Wed Nov 25, 2020 4:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: H2O VSEPR
- Replies: 27
- Views: 1177
Re: H2O VSEPR
Hey!
Although there are 4 bonding regions for H20, there are still 2 lone pairs. This makes the shape of the molecule bent since the two lone pairs are pushing the electrons from the two bonded atoms. Also, this would make the angles between the molecules less than 109.5. Hope this helps!
Although there are 4 bonding regions for H20, there are still 2 lone pairs. This makes the shape of the molecule bent since the two lone pairs are pushing the electrons from the two bonded atoms. Also, this would make the angles between the molecules less than 109.5. Hope this helps!
- Mon Nov 16, 2020 7:38 pm
- Forum: Dipole Moments
- Topic: London Dispersion Forces
- Replies: 10
- Views: 790
Re: London Dispersion Forces
Hey! All molecules exhibit london dispersion forces, but correct me if I am wrong, I believe that CH3CHO would also exhibit dipole dipole interactions since it is a polar molecule. It would not exhibit hydrogen bonds since none of the Hydrogens are bonded to a highly electronegative molecule, N, O, ...
- Mon Nov 16, 2020 7:28 pm
- Forum: Ionic & Covalent Bonds
- Topic: textbook problem 2D3 and 2D5
- Replies: 3
- Views: 105
Re: textbook problem 2D3 and 2D5
Hey! Without knowing the actual electronegativity values, we can still use periodic trends to predict what the question is asking. For example for 2D5.d, since we know that O has a greater electronegativity than S just due to periodic trends and its location on the periodic table, we can assume that...
- Mon Nov 16, 2020 7:23 pm
- Forum: Electronegativity
- Topic: Periodic trend
- Replies: 17
- Views: 857
Re: Periodic trend
Hey! Just to add on to what has been said, electronegativity is highest in the top right of the periodic table due to the fact that the atoms are more tightly held. When we go across a period to the right, there is higher nuclear charge holding the electrons closer, and therefore, increasing electro...
- Mon Nov 16, 2020 7:20 pm
- Forum: Ionic & Covalent Bonds
- Topic: KBr vs NaBr ionic character
- Replies: 4
- Views: 761
Re: KBr vs NaBr ionic character
Hey! I believe that KBr would have a greater ionic character than NaBr due to the fact that it has a bigger difference in electronegativity with Br due to size. Having a greater difference in electronegativity means that there would be a higher attraction between the two atoms, and therefore, more i...
- Mon Nov 16, 2020 7:14 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Textbook Problem 2A.5
- Replies: 2
- Views: 131
Re: Textbook Problem 2A.5
Hey! In lecture Dr. Lavelle talked about how copper is an exception to the rules that we normally follow in electron configurations. I believe that having a full d orbital would be more energetically preferred than having the 3d8, which explains why it would take away from the 4s orbital leaving the...
- Wed Nov 11, 2020 12:56 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Textbook problem 1.D.13
- Replies: 3
- Views: 173
Re: Textbook problem 1.D.13
Hey! The ml quantum describes the electron in an atom and its spin state. With this, this depends on which orbital that the electron is in. We are given that the electron is in a 6d state which means that we are in the d orbital. Since the d orbital has an l value of 2, there would be 5 possible val...
- Wed Nov 11, 2020 12:52 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Textbook Question 2A.21 part D)
- Replies: 2
- Views: 224
Re: Textbook Question 2A.21 part D)
Hey! I believe that the electron configuration for Ag+ would be [Kr]4d^10, since the atom would be more stable filling up this orbital rather than having two unpaired electrons. I think that it is better to minimize the amount of unpaired electrons since this would cause the atom to be less stable. ...
- Wed Nov 11, 2020 12:46 pm
- Forum: Lewis Structures
- Topic: Hydrogen in Lewis Structures
- Replies: 5
- Views: 235
Re: Hydrogen in Lewis Structures
Hey!
I believe that hydrogen can not have more than two electrons in its lewis structure since it occupies the 1s orbital. This does not allow to have more than two electrons. Hope that helps and feel free to correct me if I am wrong!
I believe that hydrogen can not have more than two electrons in its lewis structure since it occupies the 1s orbital. This does not allow to have more than two electrons. Hope that helps and feel free to correct me if I am wrong!
- Wed Nov 11, 2020 1:41 am
- Forum: Bond Lengths & Energies
- Topic: Bond Strengths
- Replies: 10
- Views: 430
Re: Bond Strengths
Hey! Feel free to correct me if I am wrong, and this may vary, but I believe that number of bonds would have the most effect on bond strength, then size, then lone pairs. I believe that they each have their own effect depending on the situation, but for the most part, for example, a triple bond is g...
- Wed Nov 11, 2020 1:32 am
- Forum: Ionic & Covalent Bonds
- Topic: 2A.15
- Replies: 2
- Views: 119
Re: 2A.15
Hey!
I believe the Ga would prefer the 3+ charge as it has 3 valence electrons similar to Al. It may be more energetically favored for the atom to lose the 3 electrons rather than gain 5. Hope that helps!
I believe the Ga would prefer the 3+ charge as it has 3 valence electrons similar to Al. It may be more energetically favored for the atom to lose the 3 electrons rather than gain 5. Hope that helps!
- Wed Nov 11, 2020 1:28 am
- Forum: Lewis Structures
- Topic: 2C #7B
- Replies: 2
- Views: 45
Re: 2C #7B
Hey! To determine the number of electron pairs in ICl4^-1, we should draw out its lewis structure. Also, in order to find out how many electron pairs there should be, we would multiply the amount of valence electrons in each molecule, so 7 for iodine and (7x4) for the Cl and 1 for the negative charg...
- Wed Nov 11, 2020 1:18 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Intermolecular Interactions' Strengths
- Replies: 3
- Views: 171
Re: Intermolecular Interactions' Strengths
Hey! This is a really good question and I was kinda confused about this too. I am thinking it is in this order due to the state that these molecules are in -- that is, dipole-dipole being less temporary than the other two types. I believe they are all -2kj/mol for strength, but the dipole-dipole int...
- Wed Nov 11, 2020 1:13 am
- Forum: Lewis Structures
- Topic: Lewis Structure for NO+
- Replies: 3
- Views: 384
Re: Lewis Structure for NO+
Hey! Correct me if I am wrong but if we were to keep a double bond between the nitrogen and oxygen, then the octet for the nitrogen would not be complete, and would therefore, be more unstable than if there was the triple bond with the positive charge on the oxygen. I believe having the octet is pri...
- Wed Nov 04, 2020 11:13 am
- Forum: Lewis Structures
- Topic: Lewis Acid-Base
- Replies: 6
- Views: 224
Re: Lewis Acid-Base
Hey!
Boron is an exception to the octet rule and can only form 3 bonds, so by making a double bond, it would not work. This is why when forming the lewis acid base with fluorine, that fluorine is giving both of its electrons to form a coordinate covalent bond. Hope this helps :)
Boron is an exception to the octet rule and can only form 3 bonds, so by making a double bond, it would not work. This is why when forming the lewis acid base with fluorine, that fluorine is giving both of its electrons to form a coordinate covalent bond. Hope this helps :)
- Wed Nov 04, 2020 11:10 am
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge and Stability
- Replies: 7
- Views: 162
Re: Formal Charge and Stability
Hello! With lewis structures, when calculating the formal charges, we want to minimize the charges as much as possible. In a resonance structure, since they are just changing positions, I believe the formal charges would be the same; however, if adding double or triple bonds and manipulating it in t...
- Wed Nov 04, 2020 11:05 am
- Forum: Ionic & Covalent Bonds
- Topic: SO4 covalent bond
- Replies: 6
- Views: 158
Re: SO4 covalent bond
Hey! At this point in lecture Dr. Lavelle was just showing us the way calculating formal charge can help us find more stable molecules. With the double bonds, the formal charges are minimized, making it more stable. I believe this way is more preferred as stable molecules are usually good. Hope this...
- Wed Nov 04, 2020 11:01 am
- Forum: Octet Exceptions
- Topic: Radicals
- Replies: 5
- Views: 118
Re: Radicals
Hey!
I think some examples of radicals that we ingest are in fatty foods, or foods with lots of hydrocarbon chains. When we eat them, they are oxidized which can cause them to form free radicals leading to some un-fun results. Lecture today is gonna make me try to eat healthier now. :/
I think some examples of radicals that we ingest are in fatty foods, or foods with lots of hydrocarbon chains. When we eat them, they are oxidized which can cause them to form free radicals leading to some un-fun results. Lecture today is gonna make me try to eat healthier now. :/
- Wed Nov 04, 2020 10:55 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: F orbitals?
- Replies: 21
- Views: 668
Re: F orbitals?
Hi,
To show which orbital each electron is in for the p orbital, we wrote it as 2px^2 2py^2 etc... and for d it was xy yz and zx, but I am just wondering what it would be for the f orbital? I don't think that we would have to know it, but just curious. :)
Thanks
To show which orbital each electron is in for the p orbital, we wrote it as 2px^2 2py^2 etc... and for d it was xy yz and zx, but I am just wondering what it would be for the f orbital? I don't think that we would have to know it, but just curious. :)
Thanks
- Wed Nov 04, 2020 10:51 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: numbers in electron configuration
- Replies: 5
- Views: 114
Re: numbers in electron configuration
Hey! Just to add on, as the value of "n" increases, or the principal quantum number, since it is at a higher energy level, this allows for more orbitals (s, p, d, f), which are represented by the letter l. Also, the number in the exponent spot represents the number of electrons in the orbi...
- Wed Nov 04, 2020 10:33 am
- Forum: Octet Exceptions
- Topic: Radicals
- Replies: 5
- Views: 164
Radicals
Hey! Today in lecture Dr. Lavelle mentioned the radial -OH, and how it can form inside biological systems, and ultimately, damaged our DNA. I am just sort of curious on how this -OH would form inside of us, what it would do, and what specific outcomes would come about if we were vitamin deficient. T...
- Fri Oct 30, 2020 10:08 am
- Forum: Photoelectric Effect
- Topic: Sampling HW Q4
- Replies: 5
- Views: 226
Re: Sampling HW Q4
Hey! Like the others said, (E=hv) - (work function) = kinetic energy(1/2mv^2). Since they give us kinetic energy and the frequency, we can find the work function by subtracting the E by the kinetic energy. I would also like to add on that for the rest of question 4, it asks for the maximum amount of...
- Fri Oct 30, 2020 9:53 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configurations
- Replies: 15
- Views: 443
Re: Electron Configurations
Hi! I believe Dr. Lavelle mentioned that the first way is better just because it mentions which orbital the electron is occupying, so it is more detailed and shows us the behavior of the electron, and more specifically Hund's rule, as they occupy different orbitals first. Since both of these ways ar...
- Fri Oct 30, 2020 9:47 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Energy Level Excited
- Replies: 8
- Views: 362
Re: Energy Level Excited
Hi! I believe some others touched on the idea of the energy levels, but I think it is important to mention the way in which energy is quantized. When an electron is "excited," meaning absorbing the energy from photons of light at the right wavelengths, it will excite the electron to specif...
- Fri Oct 30, 2020 9:40 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions in Electron Configurations: Filling out Half/Full d-shell
- Replies: 4
- Views: 194
Re: Exceptions in Electron Configurations: Filling out Half/Full d-shell
Hey! Just to add on, I think that it is a special case with the half filled and full d-shell, since in only these circumstances is that it would be more stable to have the filled d-orbital with one less in the 4s orbital, rather than having an empty 4s block. I believe the same thing would not occur...
- Fri Oct 30, 2020 9:33 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 1E 25
- Replies: 4
- Views: 139
Re: 1E 25
Hey! I am pretty sure that the "valence shell configuration" refers to the "shortcut" configuration with the nearest noble gas, since the valence shell only refers to the electrons that occupy the outermost shell, and not all of the electrons that make up the atom. It would adher...
- Wed Oct 21, 2020 11:25 pm
- Forum: Properties of Electrons
- Topic: intensity vs energy
- Replies: 29
- Views: 3115
Re: intensity vs energy
Hey! The intensity of light relates to the amount of photons, but does not have an impact on the overall energy. Like what Tessa said, the photoelectric effect showed how intensity had no effect on the ejection of electrons, but rather the frequency did. Depending on what electrons we are trying to ...
- Wed Oct 21, 2020 11:17 pm
- Forum: *Shrodinger Equation
- Topic: X,Y,Z axis
- Replies: 4
- Views: 705
Re: X,Y,Z axis
hey!
I understand how the axes work with the x y z, but I am a bit lost on the idea behind the d orbital and how electrons can inhabit 2 axes at the same time? Like xy, yz, and zx. I am just not quite understanding the concept behind being on the x and y axis at the same time.
I understand how the axes work with the x y z, but I am a bit lost on the idea behind the d orbital and how electrons can inhabit 2 axes at the same time? Like xy, yz, and zx. I am just not quite understanding the concept behind being on the x and y axis at the same time.
- Wed Oct 21, 2020 11:01 pm
- Forum: Properties of Light
- Topic: wave vs particle
- Replies: 3
- Views: 81
Re: wave vs particle
hey! Just to add on, although waves and particles are, many times, associated together with the equations and concepts that we learn, they have very distinct characteristics. Like what Marcus said, scientists believed electrons behaved as particles (as in just shoot through the slits). However, they...
- Wed Oct 21, 2020 10:39 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic vs Molecular Spectroscopy
- Replies: 3
- Views: 69
Re: Atomic vs Molecular Spectroscopy
Hey! I believe that, to the core, the two concepts are pretty similar. I think that the difference lies in where the electron is, that is, whether it is being excited within a single atom or in a molecule. I think that in one of the modules, one of the questions asked about molecular spectroscopy, a...
- Wed Oct 21, 2020 10:32 pm
- Forum: Properties of Light
- Topic: Sapling Weeks 2-4 Question 4
- Replies: 3
- Views: 177
Re: Sapling Weeks 2-4 Question 4
Hey!
I think that all of your work is correct, but 5.63x10^-4cm would be 5.63x10^-6 m instead of 10^-2 meters.
Hope that helped!
I think that all of your work is correct, but 5.63x10^-4cm would be 5.63x10^-6 m instead of 10^-2 meters.
Hope that helped!
- Tue Oct 13, 2020 1:14 pm
- Forum: DeBroglie Equation
- Topic: DeBroglie Concept Help
- Replies: 4
- Views: 217
Re: DeBroglie Concept Help
Hey! De Broglie's concept refers to the duality of wave and particle characteristics. I believe all things/particles exhibit wave-like properties. By using the equation, with anything with mass, we are able to calculate the wave that it gives off. However, large objects such as a ball, emit waves th...
- Tue Oct 13, 2020 12:50 pm
- Forum: Properties of Electrons
- Topic: Wavelike characteristics of objects
- Replies: 4
- Views: 188
Re: Wavelike characteristics of objects
Hey! Yes! When we reference the De Brogile equation when calculating the wavelength of something like a baseball, the wavelength is too small to observe (the calculation would be around something to 10^-34 m depending on the weight of the ball), making it hard to know if it exists. However, I think ...
- Tue Oct 13, 2020 12:30 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra Post-Module Question 41
- Replies: 3
- Views: 46
Re: Atomic Spectra Post-Module Question 41
Hey! Transitioning from n = 4 to n = 2 emits less energy than transition from n = 5 to n = 1. n = 5 to n = 1 falls through more energy levels to the primary levels, having a higher energy than n = 4 to n = 2. With this, using the equation e = hc/wavelength, and e = hv, a higher energy would mean a s...
- Tue Oct 13, 2020 12:15 pm
- Forum: Properties of Light
- Topic: Gamma Rays
- Replies: 5
- Views: 157
Re: Gamma Rays
Hey! When analyzing the electromagnetic spectrum, we can see that UV rays are around 10^-7 to 10^-8 meters, with x-rays being 10^-8 to 10^-12 meters, and gamma being 10^-12 meters and smaller. With this, due to the energy equation e = ch/wavelength or e = hv, we can see that the smaller the waveleng...
- Tue Oct 13, 2020 11:50 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Atomic Spectra Post Assessment #41
- Replies: 2
- Views: 54
Re: Atomic Spectra Post Assessment #41
Hello! The correct answer, B, makes sense since a transition from n = 4 to n = 2, would not emit as much energy as a transition from n = 5 to n = 1. With this, this would also mean that the wavelengths from the transition from n = 4 to n = 1 would be longer than the wavelengths from the transition f...