Search found 102 matches
- Mon Mar 08, 2021 7:59 am
- Forum: Biological Examples
- Topic: Enzymes
- Replies: 13
- Views: 1711
Re: Enzymes
What defines an enzyme as homogeneous or heterogeneous?
- Mon Mar 08, 2021 7:58 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Activation energy on graphs [ENDORSED]
- Replies: 2
- Views: 191
Activation energy on graphs [ENDORSED]
Are activation energies for endergonic reactions higher in the forward or reverse direction? How about exergonic reactions?
- Mon Mar 08, 2021 7:55 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridges
- Replies: 12
- Views: 534
Re: Salt Bridges
The salt bridge completes the circuit and allows the flow of electrons to continue by reducing charge buildup which would hinder the cell potential.
- Mon Mar 08, 2021 7:52 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Reaction Mechanisms
- Replies: 4
- Views: 318
Reaction Mechanisms
How can we tell if something is the slow step or is that experimental data that is given to us?
- Mon Mar 08, 2021 7:51 am
- Forum: Zero Order Reactions
- Topic: Sapling Question
- Replies: 9
- Views: 460
Re: Sapling Question
You can see that C changes throughout the experiment at seemingly random intervals while other variables are changing as well, showing that its concentrations has no effect on the rate law
- Mon Mar 01, 2021 11:51 am
- Forum: Zero Order Reactions
- Topic: Zero order
- Replies: 8
- Views: 607
Zero order
How can a reaction be completely independent of the concentrations of reactants?
- Mon Mar 01, 2021 11:50 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: How to determine n and k with experimental data that is not doubled
- Replies: 2
- Views: 201
How to determine n and k with experimental data that is not doubled
How do we find the relationships between different rates if the concentrations or rates are not doubled exactly or raised by the same factor?
- Mon Mar 01, 2021 11:47 am
- Forum: First Order Reactions
- Topic: Reverse reactions
- Replies: 2
- Views: 148
Reverse reactions
How do reverse reactions complicate our rate law calculations and how do we remove products from a reaction as they are formed? Or is this more of a hypothetical situation that doesn't reflect real experiment.
- Mon Mar 01, 2021 11:42 am
- Forum: First Order Reactions
- Topic: Half Life caluclations
- Replies: 6
- Views: 353
Half Life caluclations
How do you determine how many half lifes there are between 2 different concentrations?
- Mon Mar 01, 2021 11:40 am
- Forum: First Order Reactions
- Topic: Difference between Difffernetial and Integrated rate law
- Replies: 2
- Views: 388
Difference between Difffernetial and Integrated rate law
What is the main difference between differential and integrated rate law and what are the uses of each
- Mon Feb 22, 2021 12:47 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in NFE
- Replies: 64
- Views: 2918
Re: n in NFE
You can find n by looking at the redox reaction and the number of electrons that cancel out on each side of the reaction
- Mon Feb 22, 2021 12:44 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation @ equilibrium
- Replies: 6
- Views: 341
Nernst Equation @ equilibrium
Is the Nernst equation similar to the delta G where at equilibrium E can be set to 0 and used to find E naught?
- Mon Feb 22, 2021 12:42 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Recharging batteries
- Replies: 3
- Views: 286
Recharging batteries
So are recharging batteries just using electricity to favor the reverse reaction and cell potential? How does recharging batteries affect the sign of E and does this change the cell diagram in any way?
- Mon Feb 22, 2021 12:33 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Molecularity [ENDORSED]
- Replies: 1
- Views: 159
Molecularity [ENDORSED]
Often times, there are reactions that use more than 3 molecules, do we have to know anything about molecularities past 3 and how would we determine the related equations with those molecularities.
- Mon Feb 22, 2021 12:30 pm
- Forum: Second Order Reactions
- Topic: 2nd order Half Life [ENDORSED]
- Replies: 1
- Views: 203
2nd order Half Life [ENDORSED]
Hello, I was just wondering how half-life increases with concentration in 2nd order reactions and wouldn't that mean that half-life is never reached?
- Mon Feb 15, 2021 7:56 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Difference between E and E^o
- Replies: 4
- Views: 757
Difference between E and E^o
What is the main difference between E and E^o?
- Mon Feb 15, 2021 7:54 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff [ENDORSED]
- Replies: 6
- Views: 510
Re: Van't Hoff [ENDORSED]
We can use the Vant Hoff Equation when we know the different temperatures we are using, delta H, and the original equilibrium constant.
- Mon Feb 15, 2021 7:53 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: When to put Pt(s) in a cell [ENDORSED]
- Replies: 4
- Views: 270
When to put Pt(s) in a cell [ENDORSED]
There are a lot of examples in the book with platinum starting or ending a cell diagram. What are the rules regarding using platinum in a cell?
- Mon Feb 15, 2021 7:51 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Types
- Replies: 2
- Views: 166
Cell Types
What is the difference between Galvanic, Voltaic, and Electrolytic cells?
- Mon Feb 15, 2021 7:50 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation Number Guide
- Replies: 2
- Views: 412
Oxidation Number Guide
How do we find oxidation numbers and is it useful to make a lewis structure before attempting?
- Mon Feb 08, 2021 1:19 pm
- Forum: Calculating Work of Expansion
- Topic: Lecture #14 Diagram
- Replies: 1
- Views: 109
Re: Lecture #14 Diagram
Isothermal reversible expansion is where the surrounding external pressure is made to match the pressure of the system. The internal pressure starts at 3 atm so we know that external pressure is 3atm and will slowly decrease to match the internal pressure of the system until it makes it to the final...
- Mon Feb 08, 2021 1:17 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: What is residual entropy?
- Replies: 16
- Views: 4779
Re: What is residual entropy?
Residual entropy is the disorder present within a system that is implicit with the different positions the molecules within the substance can occupy. This can be quantified by the equation W=possible oritenations^number of particles
- Mon Feb 08, 2021 1:14 pm
- Forum: Van't Hoff Equation
- Topic: Outline 4 problems
- Replies: 3
- Views: 307
Outline 4 problems
For the Outline 4 problems for 5J, I found the correct answers without using the Van't hoff equation? Do we just need top understand the Van't hoff equation at a conceptual level?
- Mon Feb 08, 2021 1:11 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy and Phase Changes
- Replies: 5
- Views: 262
Re: Entropy and Phase Changes
Gases and liquids are at higher temperatures than solids which leads to increased thermal entropy. That means there is more movement and possible positions for the molecules due to the different constraints of each phase.
- Mon Feb 08, 2021 1:08 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneity
- Replies: 5
- Views: 293
Spontaneity
Why are increases in entropy spontaneous but increases in Gibbs free energy are not spontaneous when the two are related in an equation delta G=delta H - Tdelta S
- Mon Feb 01, 2021 4:54 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Memorizing molar entropies
- Replies: 15
- Views: 556
Memorizing molar entropies
Should we memorize any molar entropies so we can calculate standard reaction entropies or will those values be given to us?
- Mon Feb 01, 2021 4:48 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 5/2R vs 3/2R
- Replies: 8
- Views: 7755
Re: 5/2R vs 3/2R
What are the different heat capacities involving R of different types of molecules and is the general rule +1 R for constant pressure.
- Mon Feb 01, 2021 4:43 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Constant W [ENDORSED]
- Replies: 1
- Views: 157
Constant W [ENDORSED]
How do we evaluate W? I am very confused on how W is calculated for the Boltzmann Equation in different forms.
- Mon Feb 01, 2021 4:36 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Constant Pressure in Open Systems
- Replies: 8
- Views: 251
Re: Constant Pressure in Open Systems
When it's an open container in the normal atmosphere, can we just assume that the pressure is at 1 atm or does that have to be given to us?
- Mon Feb 01, 2021 4:34 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: 4H.9
- Replies: 3
- Views: 314
Re: 4H.9
I actually believe that the container with monoatomic gas phase molecules will have higher entropy because there are more particles present.
- Wed Jan 27, 2021 4:04 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes
- Replies: 6
- Views: 270
Re: Phase Changes
The plateau parts of the heat curve reference the energy it takes for the substance to phase change, correct? In other words, they show the enthalpy of fusion and vaporization right?
- Wed Jan 27, 2021 3:58 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4.31: Hess's Law vs. Bond Enthalpies
- Replies: 2
- Views: 153
Re: 4.31: Hess's Law vs. Bond Enthalpies
You are absolutely correct, bond enthalpies are calculated based on the average of many bond enthalpies between different bonds of that type which leads to the discepancy.
- Wed Jan 27, 2021 3:55 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 5J.5 d
- Replies: 6
- Views: 527
Re: 5J.5 d
When pressure is added to a system, a system prefers the side of the reaction that will lead to the least amount of gas phase molecules which can be determined by the stoichiometric coefficients and adding them up on each side.
- Wed Jan 27, 2021 11:33 am
- Forum: Calculating Work of Expansion
- Topic: Difference between reversible and irreversible expansion
- Replies: 4
- Views: 176
Difference between reversible and irreversible expansion
What is the difference between irreversible and reversible expansion?
- Mon Jan 25, 2021 10:52 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Approximating Method for ICE Table
- Replies: 4
- Views: 270
Approximating Method for ICE Table
How small does K have to be to use the approximation method on ICE tables?
- Wed Jan 20, 2021 1:38 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy vs heat
- Replies: 31
- Views: 2215
Re: Enthalpy vs heat
Enthalpy is at constant pressure and is often equal to heat when there are no other factors at play to my understanding.
- Wed Jan 20, 2021 1:37 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: pH in relation to pKa
- Replies: 6
- Views: 278
pH in relation to pKa
What is the relationship of pH and pKa in regards to whether the acid is predominantly charged or neutral at a certain pH level?
- Wed Jan 20, 2021 1:34 pm
- Forum: Phase Changes & Related Calculations
- Topic: 4e.3 sample problem bond enthalpy
- Replies: 2
- Views: 173
Re: 4e.3 sample problem bond enthalpy
The slightly confusing part of this section is that the practice problems assigned for this section regarding the first part of the section about bound enthalpies and less about the temperature part of the section.
- Wed Jan 20, 2021 1:31 pm
- Forum: Phase Changes & Related Calculations
- Topic: Lecture #7 Question
- Replies: 7
- Views: 161
Re: Lecture #7 Question
In the process of steam going back to liquid water, it is releasing a lot of heat energy as water has a large enthalpy of vaporization, causing a much more severe burn than the water of the same temperature that does not have to release energy stored due to enthalpy of vaporization.
- Tue Jan 19, 2021 4:37 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4D.9
- Replies: 3
- Views: 150
4D.9
Why is the answer positive for 4D.9 when the calculated delta-H was negative
- Mon Jan 11, 2021 12:32 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: change in temp and k
- Replies: 6
- Views: 357
Re: change in temp and k
It is also useful to think that if temperature affected Q, then Q would go along with K, which would negate LeChatelier's principle as Q wouldn't have anything adapt to if it were to move with K.
- Mon Jan 11, 2021 12:28 pm
- Forum: Ideal Gases
- Topic: Q and K relationship
- Replies: 22
- Views: 771
Re: Q and K relationship
It is also pretty helpful to think that the inequality sign will be open to the side that the reaction favors. So a less-than sign would signify a favoring of the products side of the equilibrium because the sign opens up to the right side. (and vis-versa) =)
- Mon Jan 11, 2021 12:24 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: H2O
- Replies: 44
- Views: 1886
Re: H2O
In acid and base reactions where it is reacting with water, the water is in such excess that it is considered pure so it is not included in the calculations for chemical equilibrium constants.
- Mon Jan 11, 2021 12:17 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Temperature Affecting Acids and bases
- Replies: 4
- Views: 123
Temperature Affecting Acids and bases
How does the temperature affect acid and base reactions? How do we know if a reaction with acids and bases are exothermic or endothermic?
- Mon Jan 11, 2021 12:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Difference between Amphoteric and Amphiprotic
- Replies: 5
- Views: 199
Difference between Amphoteric and Amphiprotic
I am posting this here, because ther is no acid and base section for 14B. But, what is the difference between amphoteric and amphrotic?
- Tue Jan 05, 2021 4:20 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Qc vs Kc
- Replies: 15
- Views: 5223
Re: Qc vs Kc
Q is just the same calculation as K, just at a certain point in time and does not necessarily have to be at equilibrium, correct?
- Tue Jan 05, 2021 4:16 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Textbook Problem 5.61 Part F
- Replies: 3
- Views: 206
Re: Textbook Problem 5.61 Part F
Pure solids and liquids are not taken into consideration in problems dealing with equilibrium. Aqueous solutions are taken into consideration only by concentration since it is not in a gaseous state.
- Tue Jan 05, 2021 4:12 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Temperature Affecting K
- Replies: 2
- Views: 90
Temperature Affecting K
How does the temperature change K, I know that partial pressures take into consideration temperature thus changing K but when Kc is calculated with concentrations in mol/L how does that take into consideration temperature?
- Tue Jan 05, 2021 4:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium is shifted to the right/left
- Replies: 9
- Views: 920
Re: Equilibrium is shifted to the right/left
To make it easier, you can just remember that the right side of a chemical reaction formula is products and the left side of the formula is reactants to help visualize the phenomena.
- Tue Jan 05, 2021 4:06 pm
- Forum: Ideal Gases
- Topic: Units of Temperature
- Replies: 82
- Views: 3342
Re: Units of Temperature
When converting between Celsius and Kelvin, you have to add or subtract how many degrees to Celsius to convert it into Kelvin again? And when converting from Fahrenheit, would it be easier to convert it into celsius first?
Re: -ate
-ate is used for when a coordination compound has an overall negative charge, in other words, an anion. For instance, if a coordination compound with iron has a negative charge, it would become ferrate.
- Mon Dec 07, 2020 12:48 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Deciding which part of the salt affects pH
- Replies: 4
- Views: 224
Deciding which part of the salt affects pH
I am having slight trouble figuring out which part of the salt affects the pH of the solution. In other words, how do I know if a salt is going to turn a solution acidic or basic.
- Mon Dec 07, 2020 12:40 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bonds and Covalent Bonds
- Replies: 7
- Views: 785
Re: Coordinate Covalent Bonds and Covalent Bonds
A coordinate covalent bond is also the bond used when dealing with Lewis acids and bases. A Lewis acid can accept electrons while a lewis base gives off electrons. These can then form a coordinate covalent bond where both electrons involved in bonding are coming from the Lewis base.
- Mon Dec 07, 2020 12:37 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: 6c.19 f
- Replies: 4
- Views: 288
Re: 6c.19 f
I believe the more elctronegative one is more able to stabilize the resulting ion so it is easier for the acid to lose its hydrogen when put into solution.
- Mon Dec 07, 2020 12:33 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Definition of Ka and pKa
- Replies: 2
- Views: 541
Definition of Ka and pKa
What is the meaning of Ka and pKa? what do these values represent and how do they help us when dealing with acids and bases?
- Wed Dec 02, 2020 12:23 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: How to find Oxidation Numbers
- Replies: 4
- Views: 278
How to find Oxidation Numbers
How do I find the charges associated with different ligands in coordination compounds. How am I supposed to logically din out that CN has a charge of -1 and that SO4 has a charge of -2? Are these supposed to be memorized or is there a way to find them without memorization?
- Mon Nov 30, 2020 12:45 pm
- Forum: Industrial Examples
- Topic: Coordination compounds as Chemotherapy drugs
- Replies: 9
- Views: 1766
Re: Coordination compounds as Chemotherapy drugs
It is important to recognize the difference between cisplatin and translation and just know that the structure of the compound leads to its effectiveness as a chemotherapy drug, where cisplatin has the ability to cause cell death through its attachment to two adjacent guanine bases while transplatin...
- Mon Nov 30, 2020 12:40 pm
- Forum: Bronsted Acids & Bases
- Topic: Main Difference
- Replies: 8
- Views: 583
Re: Main Difference
Are there examples of acids and bases that fit the Bronsted definition and not the Lewis definition and vise versa? Because the definitions use different subatomic particles as definers but aren't they often interchangeable as electrons are often connected to protons?
- Mon Nov 30, 2020 12:38 pm
- Forum: Hybridization
- Topic: How to find the hybridization
- Replies: 14
- Views: 681
Re: How to find the hybridization
Clarifying question: If an atom with 3 p orbitals only hybridizes to an sp2 level, this means that there is an unhybridized p orbital still correct? Does the unhybrized orbital have any properties that distinguish it from the hybridized ones?
- Mon Nov 30, 2020 12:34 pm
- Forum: Biological Examples
- Topic: Hemoglobin vs. Myoglobin
- Replies: 30
- Views: 1219
Re: Hemoglobin vs. Myoglobin
Hemoglobin is a protein that is found in the blood that carries oxygen while myoglobin is found in muscles. This is why blood has a red color and is also why muscle tissue or meat from animal products have a red color. This is due to the natural red color that results from the iron in each protein. ...
- Mon Nov 30, 2020 12:31 pm
- Forum: Naming
- Topic: Bis-, Tris-, etc
- Replies: 6
- Views: 266
Re: Bis-, Tris-, etc
I am slightly confused as the previous 2 replies have given a slightly different take on the topic. Does the "bis" go in front of the "di" or does it replace "di" as in is it bisdiethylene... or bisethylene....
- Wed Nov 25, 2020 12:00 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination number
- Replies: 9
- Views: 355
Re: Coordination number
The coordination number is based off the number of bonds, as shown in lecture, so I believe while ligand number is a useful indicator as to what the coordination number is, if there is a double bond somewhere, the bonds must be the final determiner of the coordination number.
- Wed Nov 25, 2020 11:58 am
- Forum: Industrial Examples
- Topic: Cisplatin Vs. Transplatin
- Replies: 7
- Views: 1399
Re: Cisplatin Vs. Transplatin
The Cisplatin has 2 Chlorines on the same side which gives it the strength to stay onto the two adjacent guanine nitrogenous bases. With the translation only having one chlorine on each side, it is more easily removed from the DNA strand. It is much less effective as a treatment, thus cisplatin is u...
- Wed Nov 25, 2020 11:55 am
- Forum: Biological Examples
- Topic: Why Cisplatin is considered "general"
- Replies: 4
- Views: 221
Re: Why Cisplatin is considered "general"
As he said in lecture, cisplatin is general because it cannot distinguish between cancer and healthy cells, thus the DNA in both types of cells are affected. This can kill of healthy cells which can lead to the patient feeling serious side effects. However, it is important to note that the rapid red...
- Wed Nov 25, 2020 11:53 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Cisplatin vs. Transplatin
- Replies: 4
- Views: 214
Re: Cisplatin vs. Transplatin
I think the Cl's are singly bonded to the Platinum so that would be a sigma bond which is flexible. I think the cis and trans varieties of the coordination compound are just due to the flexibility of the bonds, as you mentioned. I do not know how electron repulsion would work into the formation of t...
- Wed Nov 25, 2020 11:51 am
- Forum: Naming
- Topic: Nomenclature
- Replies: 5
- Views: 477
Re: Nomenclature
There is a very helpful section on nomenclature with a guide for naming different compounds in the textbook. I find that the steps outlined in the section were fairly effective when naming different compounds. There is a nomenclature question in sapling so I think it is important to have somewhat of...
- Mon Nov 16, 2020 9:30 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 7 Sapling
- Replies: 12
- Views: 675
Week 7 Sapling
Will there be Week 7 Sapling HW? Aren't we supposed to have a sapling unit every week? Or has it just not been posted quite yet?
- Mon Nov 16, 2020 12:47 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis acids and Bases
- Replies: 6
- Views: 198
Re: Lewis acids and Bases
These types of molecules often form a coordinate covalent bond where the lewis acid takes on 2 electrons from the lewis base.
- Mon Nov 16, 2020 12:45 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trigonal Pyramidal Shape in the Sulfite Ion
- Replies: 4
- Views: 502
Re: Trigonal Pyramidal Shape in the Sulfite Ion
In the textbook, there is a very useful guide showing a general formula for each molecular shape based on atoms surrounding a central atom and lone pairs. It would give sulfate a VSEPR formula of AX3E which would be a trigonal pyramidal due to the extra lone pair on the suflur.
- Mon Nov 16, 2020 12:40 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Periodic Table Trends
- Replies: 4
- Views: 355
Periodic Table Trends
What are the trends for polarizability and polarizing power on the Periodic Table?
- Mon Nov 16, 2020 12:35 pm
- Forum: Dipole Moments
- Topic: Dipole Moment
- Replies: 7
- Views: 349
Re: Dipole Moment
Is it valid to say that pretty much most asymmetrical molecules have a somewhat polar nature? In other words, do most molecules that are asymmetric have a dipole moment?
- Mon Nov 16, 2020 12:32 pm
- Forum: Hybridization
- Topic: Hybrid Orbitals
- Replies: 2
- Views: 264
Hybrid Orbitals
Hello, I'm fairly confused regarding how to determine what hybrid orbitals are being used when bonding. What factors are in play when determining the hybrid? How many atoms are bonding? Multiplicity of bonds? The current electron configuration? How do all of these contribute to determining hyrbridiz...
- Mon Nov 09, 2020 12:16 pm
- Forum: Bond Lengths & Energies
- Topic: Hydrogen Bonding
- Replies: 13
- Views: 1023
Re: Hydrogen Bonding
Are hydrogen bonds permanent like other bonds or are they more of a temporary phenomenon like induced dipoles?
- Mon Nov 09, 2020 12:10 pm
- Forum: Octet Exceptions
- Topic: Identifying Radicals
- Replies: 24
- Views: 1104
Re: Identifying Radicals
Often times, molecules that would have radicals are shown as ions to subtract or add electrons to get rid of the radical, however, if a molecule has an odd amount of electrons, you would know that there is a radical because there is one electron without another electron to form a bonding pair or a l...
- Mon Nov 09, 2020 12:06 pm
- Forum: Bond Lengths & Energies
- Topic: bond lengths
- Replies: 9
- Views: 423
Re: bond lengths
Bond lengths can also vary based on atomic radii. Larger atoms will implicitly have larger bond lengths because there is more distance between the two atoms due to the large electron cloud surrounding the large atom. This is also affected by the aforementioned amount of bonds, where triple bonds are...
- Mon Nov 09, 2020 12:03 pm
- Forum: Dipole Moments
- Topic: Definition of Dipole
- Replies: 7
- Views: 365
Re: Definition of Dipole
Clarifying question, is the major difference between dipole and induced dipole the permanence? Like, is a dipole a property of a molecule while induced dipoles only happen when in the proximity of other molecules or ions that can cause distortions?
- Mon Nov 09, 2020 11:59 am
- Forum: Ionic & Covalent Bonds
- Topic: The ionic model
- Replies: 7
- Views: 173
Re: The ionic model
Since the electrons within the atoms of the ion are distorted due to attractive and repulsive forces due to electromagnetic charge, this causes a shared nature between the electrons, leading to a "covalent character"
- Tue Nov 03, 2020 4:14 pm
- Forum: Lewis Structures
- Topic: NO3- example in lecture
- Replies: 4
- Views: 109
Re: NO3- example in lecture
I often use atoms that outnumber the other atoms in a molecule as the outer ones surrounding the central atom due to symmetry reasons. It wouldn't make sense for O to be a central atom because that would throw off the molecule's symmetry.
- Tue Nov 03, 2020 3:53 pm
- Forum: Resonance Structures
- Topic: Resonance Structures Question
- Replies: 2
- Views: 99
Resonance Structures Question
Hello, I am slightly confused regarding resonance structures. Do they have to minimize formal charges? So in other words, are some possibilities for Lewis structures not included in the resonance hybrid because they are not optimized in the sense that their formal charges are unrealistic?
- Tue Nov 03, 2020 3:45 pm
- Forum: Ionic & Covalent Bonds
- Topic: Main group elements
- Replies: 8
- Views: 625
Re: Main group elements
Some main group elements form covalent bonds while others don't. When the electronegativity surpasses a difference of 2, it is more realistic to represent the bond between those two elements with an ionic bond.
- Tue Nov 03, 2020 3:40 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Lengths
- Replies: 10
- Views: 767
Bond Lengths
I am confused regarding bond lengths as in lecture, Professor said that actual bond length is experimentally determined as is between the lengths of bonds present in the molecule. Why do we represent individual double and single bonds if they are all the same length?
- Tue Nov 03, 2020 3:34 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge and Lewis Structures
- Replies: 10
- Views: 478
Re: Formal Charge and Lewis Structures
I think formal charges help point us in the correct direction for correct Lewis structures and show us if we can expand past the octect rule in certain situations to minimize formal charge.
- Tue Oct 27, 2020 10:08 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Sapling Homework #8 - Which number do we assign to n(1) versus n(2)
- Replies: 4
- Views: 210
Re: Sapling Homework #8 - Which number do we assign to n(1) versus n(2)
I find it useful to think of n1 as initial and n2 as final. Where it depends on whether it is emission or absorption. When it is emission, the Balmer or Lyman series energy line would be n2 because the electron is going back down to lower energy levels to release or emit that stream of photons. When...
- Tue Oct 27, 2020 10:03 pm
- Forum: *Shrodinger Equation
- Topic: Sapling week 2/3
- Replies: 12
- Views: 1188
Re: Sapling week 2/3
This is a photoelectric effect question. You would enter in your known values for frequency and kinetic energy to find the work function I assume. That would lead you with 3.50×10−19J=(6.626x10^-34)(1.32×1015 Hz) - (work function). From there just solve for work function through algebra.
- Tue Oct 27, 2020 9:59 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Chromium and Copper
- Replies: 5
- Views: 272
Re: Chromium and Copper
The s block is left open for chromium and copper. Is the s-orbital electron a single valence electron or is it underneath the d-orbital electrons. If it is the only electron outside, doesn't that mean these groups of metals have different bonding properties than expected?
- Tue Oct 27, 2020 9:56 pm
- Forum: DeBroglie Equation
- Topic: Diffraction Pattern
- Replies: 9
- Views: 376
Re: Diffraction Pattern
I have an additional question regarding diffraction patterns, as said in the above comment, diffraction patterns are similar to pebbles in water. My question is are diffraction patterns the same thing as spectral lines or they completely different concepts. Are diffraction patterns more just for sho...
- Tue Oct 27, 2020 9:52 pm
- Forum: Einstein Equation
- Topic: E=pc vs E=hv
- Replies: 15
- Views: 731
Re: E=pc vs E=hv
I believe the Einstein equation E=hv is much more relevant for our purposes, relating energy to frequency. While both are used in energy calculations, I have not used E=pc in any textbook or sapling question so far.
- Tue Oct 20, 2020 11:32 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Differences in Rydberg Equation versus equation to find "En" from Friday's lecture
- Replies: 3
- Views: 134
Re: Differences in Rydberg Equation versus equation to find "En" from Friday's lecture
I believe they are interchangeable. He basically used the other formula to split up the process into 2 logical steps rather than the combined formula that can cause some confusion. The other formula finds energy which can be put into delta E=E final - E initial. I believe they will achieve the same ...
- Tue Oct 20, 2020 11:26 am
- Forum: DeBroglie Equation
- Topic: De Broglie wavelength vs. wavelength
- Replies: 7
- Views: 540
Re: De Broglie wavelength vs. wavelength
DeBroglie wavelengths are applicable to matter and photons while c=frequency * wavelength is only applicable to electromagnetic radiation and light. De broglie wavelengths can be for electrons, atoms, and even larger things like baseballs, while it is impossible to find that type of wavelength for t...
- Tue Oct 20, 2020 11:22 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Sapling Question Number 7
- Replies: 3
- Views: 126
Re: Sapling Question Number 7
M is the magnetic quantum number which specifies which individual orbitals to my understanding. There are (2l+1) orbitals. For instance for n=3 l=2 m can equal -2,-1, 0, 1, 2. Up to two electrons fit in each orbital.
- Tue Oct 20, 2020 11:17 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Sapling Q 26
- Replies: 2
- Views: 64
Re: Sapling Q 26
The mass of an atom of helium is 6.64x10^-27 kg so plug that into m(delta v) * (delta x) > h/4pi. You get 6.64x10^-27 kg(delta v) * (1.4 x10^-10m) > h/4pi. You would just solve for delta v. The answer would be 56.7 m/s
- Tue Oct 20, 2020 11:07 am
- Forum: Einstein Equation
- Topic: Enthalpy of Fusion Sapling Question 7
- Replies: 1
- Views: 69
Enthalpy of Fusion Sapling Question 7
Hello, I was wondering what enthalpy of fusion is for the Sapling homework. Is it something we have not covered yet or just an additional piece of information we can use to solve the problem with our current knowledge of this unit? The question goes as follows: How many photons with a wavelength of ...
- Tue Oct 13, 2020 7:33 pm
- Forum: DeBroglie Equation
- Topic: Focus 1 Textbook Problem 1B: #19
- Replies: 2
- Views: 127
Re: Focus 1 Textbook Problem 1B: #19
For the last part of the problem, at 3 sig figs, the wavelengths of the proton and neutron are identical so there is no percent difference..
- Tue Oct 13, 2020 7:30 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Uncertainty Principle
- Replies: 2
- Views: 199
Re: Heisenberg Uncertainty Principle
Often times you are using either delta p or delta x to find the other value so unless you have made a miscalculation, I don't believe it is possible for (delta p)(delta x) to be smaller that .5 h-bar.
In other words, when delta x increases delta p decreases and vice versa.
In other words, when delta x increases delta p decreases and vice versa.
- Tue Oct 13, 2020 7:27 pm
- Forum: Photoelectric Effect
- Topic: Textbook Question 1B15
- Replies: 4
- Views: 153
Re: Textbook Question 1B15
For the parts after you can use the equation 1/2(Mass of electron)(Velocity^2)=(Planck's constant)(Frequency)-(Work Function). For part b, plug in 0 on the left side and put in the Hz into frequency to fin the work function. For part c, Use the work function and Kinetic energy to find Frequency and ...
- Mon Oct 12, 2020 7:46 pm
- Forum: Photoelectric Effect
- Topic: Units (eV)
- Replies: 5
- Views: 251
Re: Units (eV)
Is the electron volt just a different way to measure energy or are there situations in which using the eV more useful than just Joules?
- Mon Oct 12, 2020 7:44 pm
- Forum: Properties of Light
- Topic: Quanta and Photons
- Replies: 19
- Views: 312
Re: Quanta and Photons
I believe a transferable unit of H20 would be the smallest unit possible. In this case, that would be a single molecule of water since on a very small scale, we are dealing with discrete numbers where they often have to be a specific value like integers in this case. In addition, this concept can be...
- Mon Oct 05, 2020 7:50 pm
- Forum: Limiting Reactant Calculations
- Topic: Determining Limiting Reactant
- Replies: 7
- Views: 163
Determining Limiting Reactant
Is there an easy way to find which reactant is the limiting reactant? Like is there a way we are supposed to be finding which reactant limits the reaction? So far I have been dividing the limiting reactant by its stoichiometric coefficient and multiplying it by the other reactant's coefficient to fi...
- Mon Oct 05, 2020 7:44 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect Module
- Replies: 6
- Views: 154
Re: Photoelectric Effect Module
Since there is a 1 to 1 ratio from photon to electron, the energy from the photons need to exceed a work function or minimum threshold right? So if that energy goes past what is needed, that is what become the kinetic energy that shoots the electron out. My main question is does intensity of the lig...
- Mon Oct 05, 2020 7:35 pm
- Forum: SI Units, Unit Conversions
- Topic: Conversion of grams to moles and millimoles to moles.
- Replies: 9
- Views: 3842
Re: Conversion of grams to moles and millimoles to moles.
You can convert from grams to moles by finding the molar mass of the atom or molecule that you are trying to find moles for and dividing the grams by the molar mass. For instance: If you have 32.0 grams of O2, you would simply divide 32/by 32 because 16(the molar mass of oxygen) x 2(atoms). This wou...