Search found 103 matches
- Mon Mar 09, 2020 2:16 pm
- Forum: Environment, Ozone, CFCs
- Topic: Catalysts and angular dependence
- Replies: 5
- Views: 807
Re: Catalysts and angular dependence
While that does make sense, Dr. Lavelle said that it just lowers the value of Ea and the equation, so I am unsure.
- Mon Mar 09, 2020 2:16 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Microscopic Reversibility
- Replies: 3
- Views: 274
Re: Microscopic Reversibility
Microscopic reversibility means if you do the forward process of a reaction mechanism, you will have A & B as your intermediate. If you do the reverse process of the reaction mechanism, you will still have A & B. Microscopic reversibility is when the intermediates are the same for both forwa...
- Mon Mar 09, 2020 2:14 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Identifying Catalysts
- Replies: 6
- Views: 406
Re: Identifying Catalysts
We identify a catalyst by this method:
Look for a reactant that is used and then reformed (taking it out of the overall reaction). This is what a catalyst is. It is originally there and used, but then reformed at a later stage.
Look for a reactant that is used and then reformed (taking it out of the overall reaction). This is what a catalyst is. It is originally there and used, but then reformed at a later stage.
- Mon Mar 09, 2020 2:13 pm
- Forum: General Rate Laws
- Topic: general questions
- Replies: 3
- Views: 284
Re: general questions
Yes this is correct, however the rate laws are always positive, that's why the - is included within the reactants.
- Mon Mar 09, 2020 2:12 pm
- Forum: General Rate Laws
- Topic: Graphs of rate laws
- Replies: 8
- Views: 1000
Re: Graphs of rate laws
If you graph [R] v time & get a straight line: zero order
if you graph ln[R] v time & get a straight line: first order
if you graph 1/[R] v time & get a straight line: second order
if you graph ln[R] v time & get a straight line: first order
if you graph 1/[R] v time & get a straight line: second order
- Mon Mar 09, 2020 2:11 pm
- Forum: *Enzyme Kinetics
- Topic: Lecture 3/6
- Replies: 2
- Views: 361
Re: Lecture 3/6
We covered Ahrenniu's equation, which can be found within the book.
- Mon Mar 09, 2020 2:11 pm
- Forum: General Rate Laws
- Topic: integrated rate law vs general
- Replies: 8
- Views: 730
Re: integrated rate law vs general
Integrated rate law is the rate within a time period so you can see the rate at that time, but the general rate law is just the rate vs the conc. of reactants.
- Mon Mar 09, 2020 2:10 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Kelvin or Celsius?
- Replies: 86
- Views: 5242
Re: Kelvin or Celsius?
You use Kelvin because you must match the units within the R (gas constant) which uses kelvin.
- Mon Mar 09, 2020 2:09 pm
- Forum: General Science Questions
- Topic: Who makes the Final
- Replies: 23
- Views: 1374
Re: Who makes the Final
Lavelle makes the final.
- Mon Mar 09, 2020 2:09 pm
- Forum: Biological Examples
- Topic: Catalysts
- Replies: 7
- Views: 833
Re: Catalysts
NO is the only catalyst and O2 is simply just a reactant because it is not reformed in the products.
- Mon Mar 09, 2020 2:08 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Steady-State Approach
- Replies: 4
- Views: 299
Re: Steady-State Approach
It won't be covered on the final. He did say there are some homework questions on it, but it is not going to be tested.
- Tue Feb 25, 2020 2:17 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: standard potential of a redox reaction
- Replies: 3
- Views: 293
Re: standard potential of a redox reaction
E Is an intensive property, so you do not multiply the E value when the equation is multiplied.
- Tue Feb 25, 2020 2:16 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: identifying strong reducing/oxidizing agents
- Replies: 3
- Views: 313
Re: identifying strong reducing/oxidizing agents
If they are highly positive, they are a strong reducer. If they are highly negative, it is a strong oxidizer.
- Tue Feb 25, 2020 2:13 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Concentration Cells
- Replies: 2
- Views: 191
Re: Concentration Cells
Salt bridges cannot be used because since it is the same molecules on both sides, the salt bridge wouldn't move anything. Porous disks allows for the higher concentration to diffuse into the lower.
- Tue Feb 25, 2020 2:10 pm
- Forum: Balancing Redox Reactions
- Topic: Which equation do we flip?
- Replies: 6
- Views: 377
Re: Which equation do we flip?
You flip the equation that is being oxidized. For a galvanic cell, the E has to be positive, so whichever will make it positive.
- Tue Feb 25, 2020 2:09 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Midterm question Q3B
- Replies: 2
- Views: 282
Re: Midterm question Q3B
For this question, delta H will be the largest for the most moles because its J/mol. Delta H impacts delta T, so B, which has the most moles, is the correct answer.
- Mon Feb 17, 2020 11:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: HW7
- Replies: 14
- Views: 800
Re: HW7
The end of thermodynamics to electrochemistry is perfectly fine for the homework!
- Mon Feb 17, 2020 11:15 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Van't Hoff
- Replies: 6
- Views: 296
Re: Van't Hoff
When using this equation, it assumes that the pressure / volume is constant.
- Mon Feb 17, 2020 11:14 pm
- Forum: Van't Hoff Equation
- Topic: When to Use Vant Hoff
- Replies: 5
- Views: 368
Re: When to Use Vant Hoff
This equation is used when you have a reaction at two different temperatures with two different k values. It is used to solve for T2/K2 or T1/K1
- Mon Feb 17, 2020 11:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Is this course curved?
- Replies: 7
- Views: 535
Re: Is this course curved?
While the final exams are not curved, I do believe that at the very end, it depends on whether or not the top person did in the class to determine the grade of everyone else.
- Mon Feb 17, 2020 11:11 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: G vs G knot
- Replies: 15
- Views: 1653
Re: G vs G knot
G Knot is for when the things are at standard state in the world. G is just the G at that specific states.
- Mon Feb 10, 2020 2:18 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: S=kB*lnw equation
- Replies: 4
- Views: 888
Re: S=kB*lnw equation
Yes, it is given on the formula sheet. It is the Blotzman constant.
- Mon Feb 10, 2020 2:17 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Intensive vs. Extensive
- Replies: 15
- Views: 1314
Re: Intensive vs. Extensive
Intensive properties do not rely on the quantity of matter while extensive properties due depend on the quantity of matter.
- Mon Feb 10, 2020 2:17 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: Using Cv and Cp
- Replies: 4
- Views: 241
Re: Using Cv and Cp
Constant volume uses Cv and Constant pressure uses Cp. Cv is normally used though.
- Mon Feb 10, 2020 2:16 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isothermal delta H
- Replies: 2
- Views: 185
Re: Isothermal delta H
Nope, Delta H is always equal to q, but q is not always equal to Delta H. Therefore, Delta H is only equal to q when p is constant.
- Mon Feb 10, 2020 2:15 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneous delta G
- Replies: 7
- Views: 406
Re: Spontaneous delta G
WE set delta G to zero in the practice problem because by setting it to 0, it gave us the minimum temperature needed to make the reaction spontaneous, therefore answering the question.
- Mon Feb 03, 2020 11:30 pm
- Forum: Phase Changes & Related Calculations
- Topic: -w vs w
- Replies: 15
- Views: 625
Re: -w vs w
When w is positive, work is being done on the system & when w is negative. the system is doing work. For example, today the system pushed the piston outwards, doing work on the system, making w negative.
- Mon Feb 03, 2020 11:29 pm
- Forum: Calculating Work of Expansion
- Topic: Integrals
- Replies: 2
- Views: 81
Re: Integrals
You just need to know that if pressure is constant, the integral results in P (delta)T & if pressure is not it results in nrtln(v2/v1).
- Mon Feb 03, 2020 11:28 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat capacity
- Replies: 3
- Views: 114
Re: Heat capacity
Heat capacity is the amount of heat required to raise 1g of substance up by one temperature.
- Mon Feb 03, 2020 11:27 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated// Energy
- Replies: 11
- Views: 563
Re: Isolated// Energy
For the system as a whole, there cannot be an exchange in energy because its isolated so the energy is constant.
- Mon Feb 03, 2020 11:27 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: endo vs exo
- Replies: 8
- Views: 187
Re: endo vs exo
Breaking a bond requires energy to overcome the bond strength while forming a bond requires energy to be released.
- Tue Jan 28, 2020 2:29 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Best Method of the 3 Given?
- Replies: 7
- Views: 223
Re: Best Method of the 3 Given?
The normal method would be Method 1. It has the exact enthalpies and would give you the right answer. When doing bond enthalpies, its different because each molecules would have different and its jut an average. So method 1/3 are the best.
- Tue Jan 28, 2020 2:27 pm
- Forum: Phase Changes & Related Calculations
- Topic: Change in Temperature
- Replies: 10
- Views: 252
Re: Change in Temperature
Yes, temperature is a factor that changes the equilibrium constant. For example, if temperature increases in a reaction, the equilibrium constant will change.
- Tue Jan 28, 2020 2:26 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Test 2
- Replies: 7
- Views: 216
Re: Test 2
Test 2 will only cover the information that comes after the midterm and up until test 2!
- Tue Jan 28, 2020 2:25 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Adding Enthalpies
- Replies: 5
- Views: 191
Re: Adding Enthalpies
No, instead of multiplying, you add the enthalpies together. If its reverse, you just switch the sign of the enthalpy, and if you double it, you double enthalpy! Hope this helps.
- Tue Jan 28, 2020 2:24 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 11
- Views: 358
Re: Hess's Law
In multi-step reactions, the enthalpies are able to be added together because enthalpy is a state function (meaning the path to get there doesn't matter, its just the value). So you need to just add the enthalpies together.
- Sun Jan 19, 2020 1:57 pm
- Forum: Ideal Gases
- Topic: ICE Table
- Replies: 11
- Views: 793
Re: ICE Table
You use an ice table to calculate the concentrations of all molecules in a reaction at equilibrium. You set up the table with Initial, Change, Equilibrium going vertical and the molecules involved in the equilibrium constant going horizontally. You list the initials, the changes, and then the equili...
- Sun Jan 19, 2020 1:55 pm
- Forum: Ideal Gases
- Topic: R Constant
- Replies: 7
- Views: 241
Re: R Constant
R is the universal gas constant and has the units of the other variables (L, atm, etc...)
- Sun Jan 19, 2020 1:54 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure
- Replies: 5
- Views: 219
Re: Pressure
It depends on which side of the equation has more moles of gas. If the reactants have more moles of gas and pressure is increased, the reaction will shift to the right to lower the pressure and re-reach equilibrium.
- Sun Jan 19, 2020 1:53 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Quadratic Equation
- Replies: 8
- Views: 351
Re: Quadratic Equation
We use the quadratic equation in terms of chemical equilibrium when we are estimating the equilibrium point of a reaction through an ICE Table. If we are unable to use the "x is small" approximation, you must then use the quadratic equation to solve for x.
- Sun Jan 19, 2020 1:52 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic vs. exothermic
- Replies: 5
- Views: 211
Re: Endothermic vs. exothermic
In an endothermic reaction, heat is technically considered a reactant because it takes heat to cause the reaction to occur.. So I we add more reactant, it will force equilibrium to shift to the right, creating more product.
- Mon Jan 13, 2020 12:30 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction shifts right or left?
- Replies: 14
- Views: 1516
Re: Reaction shifts right or left?
Yes. Exactly that. If the reaction is shifted to the left, more reactants are created and if the reaction is shifted to the right, more products are formed.
- Mon Jan 13, 2020 12:29 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in Pressure
- Replies: 6
- Views: 177
Re: Change in Pressure
When the pressure is decreased, the reaction will proceed in the direction that has more moles of gas because it will want to increase the pressure to re-reach equilibrium.
- Mon Jan 13, 2020 12:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units for K
- Replies: 21
- Views: 606
Re: Units for K
K has no units as hen you do all the calculations, the units cancel out. Furthermore, this is because K is just a constant.
- Mon Jan 13, 2020 12:27 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc
- Replies: 5
- Views: 220
Re: Kc
Solids & liquids are excluded when solving for Kc. Only gases and aqueous solutions are included.
- Mon Jan 13, 2020 12:26 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q=K
- Replies: 14
- Views: 611
Re: Q=K
Q is just the system quotient at any time. If q ends up equaling K that means that the reaction is at equilibrium. If K>Q the forward reaction is favored & if K<Q then the backwards reaction is favored.
- Thu Jan 09, 2020 10:05 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G3
- Replies: 8
- Views: 313
Re: 5G3
Yes. All gases should be included in the equilibrium constant.
- Thu Jan 09, 2020 10:03 am
- Forum: Ideal Gases
- Topic: K and Q
- Replies: 13
- Views: 330
Re: K and Q
If the question asks you to solve for the equilibrium constant, that is when you use Kc. If the question asks you to determine whether the reaction is at equilibrium or will proceed forwards/backwards, that's when you compare Kc to Q
- Thu Jan 09, 2020 10:02 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Changing Kc [ENDORSED]
- Replies: 4
- Views: 145
Re: Changing Kc [ENDORSED]
A change in pressure & or volume results in a change in the opposite. These just cause the reaction to go forward or backward and then eventually re-reach equilibrium. Temperature causes the molecules to speed up while nothing else is changing, causing more of them to hit each other.
- Thu Jan 09, 2020 10:01 am
- Forum: Ideal Gases
- Topic: Understanding Q
- Replies: 19
- Views: 690
Re: Understanding Q
Yes. Q and Kc are solved the completely same way. Q is just to tell if the reaction is at equilibrium or not.
- Thu Jan 09, 2020 10:00 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: units of K
- Replies: 10
- Views: 496
Re: units of K
There are no units for K as the units tend to cancel out.
- Sun Dec 08, 2019 9:49 am
- Forum: Biological Examples
- Topic: Formulas for acid rain
- Replies: 2
- Views: 270
Re: Formulas for acid rain
H20 + CO2 -> H2CO3
- Tue Dec 03, 2019 12:47 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: dipole dipole
- Replies: 7
- Views: 398
Re: dipole dipole
Yes. Dipole-Dipole IMFs means that both of the molecules have a dipole moment.
- Tue Dec 03, 2019 12:42 pm
- Forum: Hybridization
- Topic: Triple Bond Hybridization
- Replies: 4
- Views: 187
Re: Triple Bond Hybridization
A triple bond has a hybridization of sp because the central atom (which will have one triple bond and one other area of electron density) creates two areas of electron density, which has the hybridization of sp.
- Tue Dec 03, 2019 12:39 pm
- Forum: *Particle in a Box
- Topic: Hydrogen Atom
- Replies: 7
- Views: 1068
Re: Hydrogen Atom
When a hydrogen absorbs, the energy is positive because it is adding it to the molecule, requiring energy.
- Tue Dec 03, 2019 12:38 pm
- Forum: Dipole Moments
- Topic: Melting points
- Replies: 15
- Views: 1282
Re: Melting points
A double bond has nothing to do with melting point because melting point has to do with intermolecular forces rather than molecular bonds.
- Tue Dec 03, 2019 12:31 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: pKa vs Ka
- Replies: 6
- Views: 445
Re: pKa vs Ka
Ka is the disassociation factor while pKa is the pH of the Ka factor. For example. If an acid has a pKa of 1.0x10^-7, the pKa will be 7.
- Mon Nov 25, 2019 11:15 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Cis and Trans
- Replies: 6
- Views: 477
Re: Cis and Trans
Cis & Trans relate to when the same molecule just has different bonding sites for outer elements. Trans is when they are diagonal and Cis is when they are on the same side. This is extremely important to biological compounds as it can totally change the function because shape is influenced. Howe...
- Mon Nov 25, 2019 11:14 am
- Forum: Administrative Questions and Class Announcements
- Topic: Week 9 Homework
- Replies: 2
- Views: 200
Re: Week 9 Homework
Week 9 homework is on Coordination and Biological Compounds & the beginning of Acids/Bases.
- Mon Nov 25, 2019 11:12 am
- Forum: Bond Lengths & Energies
- Topic: Hydrogen Bonding and Dispersion
- Replies: 5
- Views: 355
Re: Hydrogen Bonding and Dispersion
Dispersion occurs between two non polar molecules. When two non polar molecules get close into contact, the electrons will cause an induced-dipole onto both molecules, making one side positive and one slightly negative. This yields them to be attracted to each other, creating LDF aka dispersion. H b...
- Mon Nov 25, 2019 11:10 am
- Forum: Hybridization
- Topic: Sigma and Pi Bonds
- Replies: 5
- Views: 284
Re: Sigma and Pi Bonds
Sigma bonds can be rotated amongst their axises & orbitals, while pi bongs cannot. Sigma bonds are always formed first before the pi bonds, signifying why a single bond only has one sigma bond and no pi bonds. However with double and triple bonds, there is only one sigma bond and two pi bonds.
- Mon Nov 25, 2019 11:08 am
- Forum: Sigma & Pi Bonds
- Topic: Pi Bonding
- Replies: 6
- Views: 376
Re: Pi Bonding
S orbitals are the only orbital that are unable to form pi bonds because they can rotate no matter what due to the spherical structure. P/d/f orbitals can form pi bonds because they can form double and triple bonds. Therefore, yes, f orbitals can contain pi bonds.
- Sun Nov 17, 2019 5:44 pm
- Forum: Electronegativity
- Topic: Bond type for FeO2?
- Replies: 3
- Views: 855
Re: Bond type for FeO2?
Officially, FeO2 is considered a polar covalent bond. However, it shows extreme ionic character due to the electronegativity difference (~1.6).
- Sun Nov 17, 2019 5:43 pm
- Forum: Hybridization
- Topic: test 2
- Replies: 8
- Views: 468
Re: test 2
Hybridization is not on the test, but the pi and sigma bonds will be discussed about in a small section of lecture on Monday. They will be on the test.
- Sun Nov 17, 2019 5:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar molecules
- Replies: 2
- Views: 183
Re: Polar molecules
An electrostatic potential is just a synonym of electric field. Electric fields contain both positive and negative parts. Therefore, a polar molecule, which has both positive and negative side, will be attracted to an electric field.
- Sun Nov 17, 2019 5:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Radicals for VSEPR
- Replies: 3
- Views: 262
Re: Radicals for VSEPR
Dr. Lavelle said that Radicals (meaning the lone electron that is not in a lone pair) counts as one area of electron density. Due to this, in VSEPR Theory, one electron is equivalent to a double bond and a single bond and a lone pair.
- Sun Nov 17, 2019 5:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 2
- Replies: 19
- Views: 831
Re: Test 2
While the bond angles and shape do not have to be drawn correctly (because you can tell the shape based on bonding pairs / lone pairs), it would be extremely helpful to draw them as close as possible. If the question specifically asks for the lewis structure, then it does need to be drawn correctly.
- Tue Nov 12, 2019 1:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2 Review Sessions?
- Replies: 6
- Views: 335
Re: Test 2 Review Sessions?
Dr Lavelle has not released them. He will most likely release the dates & times for them around a week prior to the test. Watch out as they will be coming soon!
- Tue Nov 12, 2019 1:56 pm
- Forum: Dipole Moments
- Topic: Temporary Dipoles
- Replies: 5
- Views: 280
Re: Temporary Dipoles
A temporary dipole is a dipole created by a non polar molecule. For example N3 which has two Nitrogen atoms triple bonded to each other (both with one lone pair) can create a temporary dipole on itself do to electron dispersion. The e- will not always be completely stable, so sometimes one of the N'...
- Tue Nov 12, 2019 1:54 pm
- Forum: Lewis Structures
- Topic: Exceptions
- Replies: 5
- Views: 165
Re: Exceptions
Some examples include: I, Xe, S, etc...
- Tue Nov 12, 2019 1:54 pm
- Forum: DeBroglie Equation
- Topic: When to Use
- Replies: 8
- Views: 471
Re: When to Use
The equation is used at any time you are asked the wavelength of a particle with mass. Whether it is a baseball or neutron, both contain mass and follow the De Bregolie equation.
- Tue Nov 12, 2019 1:53 pm
- Forum: Student Social/Study Group
- Topic: Test 2
- Replies: 7
- Views: 456
Re: Test 2
Personally, I believe that the test will cover two more topics: Molecular Structure/Shape & Coordination Compounds & their biological importance, But I do not know. We will have to wait and see. It will not cover any topics that were on the midterm though.
- Tue Nov 05, 2019 3:44 pm
- Forum: Ionic & Covalent Bonds
- Topic: molecular polarity
- Replies: 3
- Views: 212
Re: molecular polarity
The reason that CO is more polar than BO is due to the electronegativity difference between both elements. CO has a great electronegativity difference, so it is more polar than BO.
- Tue Nov 05, 2019 3:43 pm
- Forum: Resonance Structures
- Topic: 2C.5 c
- Replies: 1
- Views: 103
Re: 2C.5 c
The resonance structure is the same exact structure, but the double bond with the O and N is just placed with the second oxygen attached to the [N]
- Tue Nov 05, 2019 3:41 pm
- Forum: Properties of Electrons
- Topic: Multi-electron atom
- Replies: 2
- Views: 193
Re: Multi-electron atom
Some factors impacting the energy of electron in a multi-electron atom are:
Electron-Electron repulsion
Shielding
Penetration
Zeff
Electron-Electron repulsion
Shielding
Penetration
Zeff
- Tue Nov 05, 2019 3:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2D.3
- Replies: 3
- Views: 247
Re: 2D.3
We would not need to memorize this. You find out the ionic character through the electronegativity difference. The difference between c is 1.39, and typically, anything equal to or less than 1.5 is determined to have more covalent character.
- Tue Nov 05, 2019 3:39 pm
- Forum: Lewis Structures
- Topic: 2C3.c
- Replies: 1
- Views: 60
Re: 2C3.c
Hello! This is kind of something that you have to get the hang of, but you can tell that the H is going to be attached to the Cl because of how the molecular formula is formatted. HCl, a common known molecule, is together. If the H was attached to the central atom, then the Cl would have probably be...
- Mon Oct 28, 2019 1:20 pm
- Forum: Bond Lengths & Energies
- Topic: Single bond vs double bond
- Replies: 14
- Views: 841
Re: Single bond vs double bond
These are the lengths of both bonds. The double bond is shorter than the single bond because double bonds are stronger, holding the two atoms closer together, decreasing the distance.
- Mon Oct 28, 2019 1:19 pm
- Forum: Photoelectric Effect
- Topic: kinetic energy
- Replies: 6
- Views: 301
Re: kinetic energy
The kinetic energy equation will be supplied, but you should know how to use it and what the results means.
- Mon Oct 28, 2019 1:19 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Multi-electron atoms
- Replies: 6
- Views: 205
Re: Multi-electron atoms
Nodal planes are where the electron density is zero. This means that there are absolutely no electrons there.
- Mon Oct 28, 2019 1:18 pm
- Forum: Trends in The Periodic Table
- Topic: reactivity
- Replies: 3
- Views: 98
Re: reactivity
S-block elements tend to be a lot more reactive than p-block due to their ability to remove electrons with ease. This allows them to share them with other elements, making them really reactive, while p-blocks do not like to lose electrons, making their reactivity much lower.
- Mon Oct 28, 2019 1:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electron configuration for ions
- Replies: 2
- Views: 71
Re: Electron configuration for ions
5s2 would lose an electron first because it is considered the furthest one out. 4d10 is not part of valence electrons once you have 5s2.
- Mon Oct 21, 2019 11:53 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Spin
- Replies: 5
- Views: 299
Re: Electron Spin
There are only two electron spins. One is going clockwise and the other is counter clockwise. Two electrons paired by Hund's Rule will have opposite spins.
- Mon Oct 21, 2019 11:52 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Spin and orbitals
- Replies: 4
- Views: 116
Re: Spin and orbitals
The reason we fill up all the parallel electrons first is a) because of electron-electron repulsion and b) an atom wants to be the most stable. If you fill up pairs first, the atom will not be as stable as it would be when filling up separate parallel electrons.
- Mon Oct 21, 2019 11:51 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: S and P orbital
- Replies: 3
- Views: 184
Re: S and P orbital
The only reason that we move an electron from s to d is because the energy difference is not as large, but it makes the atom more stable that way. By removing an atom from the s and moving it to the p orbital, the energy difference would be much larger and the end product would be more unstable than...
- Mon Oct 21, 2019 11:50 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: how to prepare
- Replies: 22
- Views: 836
Re: how to prepare
Attend step-up sessions, but also do not over extend your mind. Study a little day by day until you are understanding it more and more. By this, you will soon be very prepared! Good Luck!
- Mon Oct 21, 2019 11:49 am
- Forum: Significant Figures
- Topic: Sig Figs on Tests
- Replies: 24
- Views: 2178
Re: Sig Figs on Tests
To decide how many sig figs you need to use on the test, look at the problem and see which number has the lowest amount of sig figs. Your answer will have the same as that. Furthermore, some TA's are lenient when grading. Ask them what they think.
- Thu Oct 17, 2019 11:38 pm
- Forum: Properties of Electrons
- Topic: parallel spins
- Replies: 3
- Views: 103
Re: parallel spins
When they have parallel spins, they repulse each other because they both are negatively charged. Kind of like how to south sides of magnets repel each other.
- Thu Oct 17, 2019 11:25 pm
- Forum: Properties of Electrons
- Topic: effective nuclear charge
- Replies: 5
- Views: 332
Re: effective nuclear charge
Effective Nuclear Charge is really important for ionization energies too. If an element has a higher ENC, then the nucleus will hold onto electrons harder, requiring more energy to remove them
- Thu Oct 17, 2019 10:52 pm
- Forum: Einstein Equation
- Topic: unit of energy
- Replies: 7
- Views: 989
Re: unit of energy
keV is an interesting unit. 1 keV is about 1.602x10-19 J.
- Thu Oct 17, 2019 10:51 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty Value
- Replies: 8
- Views: 221
Re: Uncertainty Value
The uncertainty value is 0.2 because you add .1 and subtract .1 from the given value, giving a total uncertainty value of 0.2.
- Thu Oct 17, 2019 10:51 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty Value
- Replies: 8
- Views: 221
Re: Uncertainty Value
The uncertainty value is 0.2 because you add .1 and subtract .1 from the given value, giving a total uncertainty value of 0.2.
- Thu Oct 17, 2019 10:48 pm
- Forum: Properties of Light
- Topic: What are the units of hertz
- Replies: 41
- Views: 1998
Re: What are the units of hertz
The unit for Hz, which is a frequency is s^-1. However, it means cycles per second.
- Thu Oct 10, 2019 9:31 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Conserved in Chem Rxn
- Replies: 5
- Views: 496
Re: Conserved in Chem Rxn
The following are conserved:
Mass
Atoms
Electrons
Protons
All must be conserved in order to have a complete chemical reaction.
Mass
Atoms
Electrons
Protons
All must be conserved in order to have a complete chemical reaction.
- Thu Oct 10, 2019 9:29 am
- Forum: Properties of Light
- Topic: Speed of Light constant
- Replies: 7
- Views: 292
Re: Speed of Light constant
3.00 x 10^8 is acceptable to use in almost all cases since we do not need the specificity that the actual number implies. In a case where any said number could change the result and have a large effect, then you would use the 2.9 value, but we do not have that in this class.
- Thu Oct 10, 2019 9:28 am
- Forum: Significant Figures
- Topic: Are we allowed to round when showing work?
- Replies: 7
- Views: 498
Re: Are we allowed to round when showing work?
Within your work, follow the sig figs, but when using your calculator, do not cut off the rest of the numbers. It will seriously skew your results.
- Thu Oct 10, 2019 9:26 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Electron energy: is it related to physics concepts?
- Replies: 1
- Views: 97
Re: Electron energy: is it related to physics concepts?
These concepts, to my knowledge, are not related. The reason that were reminded of those two equations were because as the variable -> infinity, the result of the equation -> 0. While the two concepts are similar, they are not related. Just a coincidence.
- Thu Oct 10, 2019 9:24 am
- Forum: Properties of Electrons
- Topic: Rydberg formula clarification
- Replies: 3
- Views: 131
Re: Rydberg formula clarification
The Rydberg formula does not give the best explanation for its own use, however, it is one specific scenario. If you are given an electron that jumps from one level to another, and you are told to find the frequency, you can find it easily with that equation.
- Thu Oct 03, 2019 2:11 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: States of Matter
- Replies: 9
- Views: 667
Re: States of Matter
As of right now, they do not matter as much, but in the future they will matter a lot. They are really telling, especially when we get into deeper chemical equations. It is also super helpful for when we do lab and see what state of matter we need to expect.
- Thu Oct 03, 2019 2:08 pm
- Forum: Limiting Reactant Calculations
- Topic: Basic Question
- Replies: 11
- Views: 527
Re: Basic Question
There can only be one or zero limiting reactants. If there were two limiting reactants, both would be in perfect amounts, or perfect proportions, fully completing both amounts of reactants. Therefore, there can only be one. When there is no limiting reactant, it is known as a complete reaction.