https://users.stlcc.edu/gkrishnan/rateunits.htm
here is a helpful link to organize which units go with each order of reaction!
Search found 100 matches
- Sat Mar 14, 2020 5:39 pm
- Forum: Zero Order Reactions
- Topic: units of k
- Replies: 5
- Views: 471
- Sat Mar 14, 2020 5:36 pm
- Forum: Ideal Gases
- Topic: Kc
- Replies: 7
- Views: 582
Re: Kc
You'd use concentration of products over reactants for gaseous and aqueous, not liquid and solid.
- Sat Mar 14, 2020 5:20 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2 Concentration Cell
- Replies: 3
- Views: 242
Re: Test 2 Concentration Cell
It would be anode concentration over cathode concentration.
- Sat Mar 14, 2020 5:16 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: pseudo rate law
- Replies: 13
- Views: 1019
Re: pseudo rate law
I believe that the pseudo rate law is essentially increasing all but one of the reactant concentrations, making them basically constant. This makes small changes in the small concentration significant by isolating it.
- Sat Mar 14, 2020 5:14 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Where to find the final exam
- Replies: 5
- Views: 393
Re: Where to find the final exam
Lavelle is doing the exam through CCLE, so printing out and scanning isn't needed, since it will all be online
- Sun Mar 08, 2020 10:11 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius Equation Variables
- Replies: 4
- Views: 394
Re: Arrhenius Equation Variables
PranaviKolla2B wrote:Does the Arrhenius equation simply tell us the effect of temperature on the rate constant?
Yes, the Arrhenius equation is used to measure/calculate what happens to the rate constant (and the rate of the reaction) when a change in temperature occurs.
- Sun Mar 08, 2020 10:08 pm
- Forum: Balancing Redox Reactions
- Topic: Why do we flip E for oxidation?
- Replies: 13
- Views: 1085
Re: Why do we flip E for oxidation?
If using the equation E(cell) = E(cathode) - E(anode) and using reduction values found in the appendix or on the sheet he will give us on the test, then I'm pretty sure that there is no need to flip the anode cell potential value when accounting for oxidation. In this case you would not need to chan...
- Sun Mar 08, 2020 9:58 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Temperature
- Replies: 4
- Views: 274
Re: Temperature
At a higher temperature, it is more likely that moving particles will collide with each other with enough energy to surpass the activation energy barrier. Therefore, the reaction will be faster.
- Sun Mar 08, 2020 9:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2 Grades
- Replies: 22
- Views: 1153
Re: Test 2 Grades
You could also check your grades on myucla regularly, since the TA's might input test 2 grades prior to discussion session
- Sun Mar 08, 2020 9:53 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Molecularity
- Replies: 3
- Views: 225
Re: Molecularity
molecularity according to the textbook is the number of reactant molecules, atoms, or ions that take part in a specific elementary reaction.
- Sun Mar 01, 2020 10:23 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: salt bridge
- Replies: 9
- Views: 577
Re: salt bridge
a salt bridge allows the electrons to go from the cathode to the anode to prevent charge buildup
- Sun Mar 01, 2020 9:48 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrochemical Series
- Replies: 5
- Views: 426
Re: Electrochemical Series
The electrochemical series is Chapter 6M.2 and basically lays out the relative strengths of oxidizing and reducing agents.
- Sun Mar 01, 2020 9:45 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 4
- Views: 340
Re: Nernst Equation
I believe we use the Nernst equation to find the cell potential at any point in a reaction
- Sun Mar 01, 2020 9:20 pm
- Forum: General Science Questions
- Topic: Review Sessions for Test 2
- Replies: 4
- Views: 446
Re: Review Sessions for Test 2
there are no big review sessions by the TA's and UA's but office hours and the step up/workshop sessions in young and covel are very helpful
- Sun Mar 01, 2020 9:16 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: first order
- Replies: 8
- Views: 612
Re: first order
First order reactions has a linear rate and depends on one concentration
- Sun Feb 23, 2020 8:18 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram
- Replies: 4
- Views: 225
Re: Cell Diagram
My TA explained that cell diagrams look like this:
s | g | aq || aq | g | s
and the electrons go left to right (from the anode to the cathode)
s | g | aq || aq | g | s
and the electrons go left to right (from the anode to the cathode)
- Sun Feb 23, 2020 8:12 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff Equation
- Replies: 7
- Views: 505
Re: Van't Hoff Equation
I think we use Van't Hoff when trying to calculate how K is affected by a change in temperature
- Sun Feb 23, 2020 8:10 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing redox
- Replies: 6
- Views: 480
Re: Balancing redox
chari_maya 3B wrote:If it is alkaline, why would you balance it first acidically?
You would have to balance the hydrogens with H+ first in order to balance out the charges, and then cancel the extra protons with OH-
- Sun Feb 23, 2020 8:05 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Reactions: Acid vs Base
- Replies: 3
- Views: 319
Re: Balancing Reactions: Acid vs Base
Balancing acidic and alkaline reactions are mostly the same, but balancing alkaline reactions have an additional step. in a basic reaction, after balancing the reaction with protons (H+), you have to also balance out the protons with OH-.
- Sun Feb 23, 2020 8:01 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cell diagram
- Replies: 2
- Views: 174
Re: cell diagram
My TA explained that cell diagrams look like:
s | g | aq || aq | g | s
where | indicates a phase change and || is a salt bridge
also, the anode is on the left of the salt bridge and cathode is on the right of the salt bridge
s | g | aq || aq | g | s
where | indicates a phase change and || is a salt bridge
also, the anode is on the left of the salt bridge and cathode is on the right of the salt bridge
- Sun Feb 16, 2020 9:28 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated versus closed
- Replies: 7
- Views: 580
Re: Isolated versus closed
Isolated: does not exchange matter or energy with surroundings
Closed: can exchange energy with surroundings, but not mass
Closed: can exchange energy with surroundings, but not mass
- Sun Feb 16, 2020 9:24 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2
- Replies: 11
- Views: 699
Re: Test 2
I'm pretty sure it's not cumulative, it probably will be on material from after the midterm, but he'll definitely confirm the topics closer to the test.
- Sun Feb 16, 2020 9:19 pm
- Forum: Calculating Work of Expansion
- Topic: Irreversible and Reversible Expanision
- Replies: 9
- Views: 635
Re: Irreversible and Reversible Expanision
How can you differentiate when to use -nRlnV2/V1 versus using -PV? I feel like I always get mixed up when I should use which equation. Any tips for knowing which one to use when? https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=160&t=58744&p=221113&hilit=helpful&sid=b6cc45c218434...
- Sun Feb 16, 2020 9:16 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isochoric
- Replies: 8
- Views: 566
Re: Isochoric
isochoric: constant volume
isobaric: constant pressure
isothermic: constant temperature
isobaric: constant pressure
isothermic: constant temperature
- Tue Feb 11, 2020 9:38 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: 4H.5
- Replies: 4
- Views: 558
Re: 4H.5
for b, pentene has more entropy than cyclopentane because cyclopentane is a rigid ring that is not that flexible, while pentene is more flexible (thus having more entropy).
- Sun Feb 09, 2020 10:28 pm
- Forum: Student Social/Study Group
- Topic: Number of Chemistry Community Posts
- Replies: 45
- Views: 2403
Re: Number of Chemistry Community Posts
ashwathinair wrote:Sometimes I post multiple times on the same thread - is this counted as separate posts or as just one?
I think it would count as multiple posts, but for a definite answer I'd ask your TA since they give the credit at the end of the quarter.
- Sun Feb 09, 2020 10:26 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Specific Heat Capacity
- Replies: 5
- Views: 164
Re: Specific Heat Capacity
You use specific heat capacity when trying to find the heat required to raise the temperature of one gram of a substance by 1 degree Celsius.
Molar heat capacity is used to find heat required to raise the temperature of one mole of the substance.
Molar heat capacity is used to find heat required to raise the temperature of one mole of the substance.
- Sun Feb 09, 2020 10:13 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: qp=deltaH
- Replies: 6
- Views: 353
Re: qp=deltaH
qp is equal to delta h when a system is at constant pressure, so no nonexpansion work is being done.
- Sun Feb 09, 2020 10:11 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong Acids
- Replies: 6
- Views: 290
Re: Strong Acids
From what I remember from 14a,
Strong acids include: HCl, HNO3, H2SO4, HBr, HI, HClO4
Strong bases are mostly bases that include OH in the chemical formula (ex: NaOH, KOH)
Strong acids include: HCl, HNO3, H2SO4, HBr, HI, HClO4
Strong bases are mostly bases that include OH in the chemical formula (ex: NaOH, KOH)
- Sun Feb 09, 2020 10:09 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Cv and Cp
- Replies: 3
- Views: 86
Re: Cv and Cp
Use Cv when the system is at a constant volume, and Cp when the system is at a constant pressure, I'm pretty sure it'll either be stated in the problem or will be able to be inferred by other info.
- Sun Feb 02, 2020 7:35 pm
- Forum: Phase Changes & Related Calculations
- Topic: State functions
- Replies: 7
- Views: 432
Re: State functions
State functions can be added or subtracted, which allows us to calculate changes in values of the system
- Sun Feb 02, 2020 6:52 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calorimeter vs. Bomb Calorimeter
- Replies: 4
- Views: 279
Re: Calorimeter vs. Bomb Calorimeter
a regular calorimeter is thermally insulated, while the bomb calorimeter is an insulated container completely immersed in a metal box of water. in addition, a constant pressure calorimeter is used to calculate change in enthalpy, while a bomb calorimeter (constant volume) is used to calculate the ch...
- Sun Feb 02, 2020 6:24 pm
- Forum: General Science Questions
- Topic: Midterm
- Replies: 17
- Views: 927
Re: Midterm
i'm pretty sure that Dr. Lavelle does not have any past exams in the test bank, but going to the midterm review sessions that he has set up help drastically with understanding concepts or for practicing problems.
- Sun Feb 02, 2020 6:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ka approximation
- Replies: 6
- Views: 493
Re: Ka approximation
you would divide the x amount (found using ice table) by the original concentration and multiply by 100. If this percentage is less than 5%, then the approximation is valid.
- Wed Jan 29, 2020 1:25 pm
- Forum: Calculating Work of Expansion
- Topic: Irreversible vs. Reversible Reactions
- Replies: 6
- Views: 331
Re: Irreversible vs. Reversible Reactions
During reversible reactions, products and reactants are always being made (going back and forth), while in irreversible reactions products can't revert back to what it was as a reactant. I also think that during reversible reactions, the system stays at equilibrium, and during irreversible reactions...
- Sun Jan 26, 2020 6:57 pm
- Forum: Phase Changes & Related Calculations
- Topic: State function
- Replies: 4
- Views: 113
Re: State function
Heat is not a state function because it is dependent on the path of the reaction, while enthalpy is a state function because it does not depend on the path of the system but is dependent on initial and end results.
- Sun Jan 26, 2020 6:53 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta U
- Replies: 3
- Views: 167
Re: Delta U
Delta h is change in enthalpy, while delta u is the change within the internal energy of the system.
- Sun Jan 26, 2020 6:49 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Gas Constant
- Replies: 13
- Views: 521
Re: Gas Constant
The gas constant depends on which measurement that the question uses (J, atm, bar, or torr usually) and it will be on the equations sheet.
- Sun Jan 26, 2020 6:42 pm
- Forum: Phase Changes & Related Calculations
- Topic: work and heat
- Replies: 3
- Views: 208
Re: work and heat
Work is not a state function because it depends on the path from the initial to final states of the reaction. Heat is not a state function because it depends on the paths of each individual state.
- Sun Jan 26, 2020 6:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Internal energy = State function
- Replies: 4
- Views: 235
Re: Internal energy = State function
Internal energy is a state function I believe because it is independent of the path of the process in question. It has different values at each different state of the system.
- Sun Jan 19, 2020 8:51 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic vs. endothermic
- Replies: 2
- Views: 92
Re: Exothermic vs. endothermic
Think of heat in a endothermic reaction as a reactant (need heat to reaction to proceed) and in a exothermic reaction as a product (reaction produces heat). For exothermic, if K decreases when temperature increases, the reaction shifts to the left, and if K increases when temperature decreases, the ...
- Sun Jan 19, 2020 8:25 pm
- Forum: General Science Questions
- Topic: Acids
- Replies: 3
- Views: 129
Re: Acids
When referring to Bronsted acids and bases, we refer to proton donors (acids) and proton acceptors (bases).
Lewis acids and bases are electron pair acceptors (acids) and electron pair donors (bases).
Lewis acids and bases are electron pair acceptors (acids) and electron pair donors (bases).
- Sun Jan 19, 2020 8:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Q
- Replies: 14
- Views: 318
Re: K vs Q
K is the equilibrium constant of an reaction that is already at equilibrium, while Q (reaction quotient) is used when the reaction is not already at equilibrium. Q is also used to show in which direction the reaction shifts (for example, when K>Q, then the reaction shifts to the right).
- Sun Jan 19, 2020 8:17 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Not including solids and liquids
- Replies: 7
- Views: 275
Re: Not including solids and liquids
Solids and liquids are not used in calculating an equilibrium constant, only gasses and aqueous solutions are considered. This is because the activity of the pure solids and liquids are considered to be 1, so it would not affect the equilibrium equation (their concentrations do not change throughout...
- Sun Jan 19, 2020 8:14 pm
- Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
- Topic: Titration
- Replies: 2
- Views: 645
Re: Titration
the equivalence point shows where the amount of titrant neutralizes the analyte solution.
- Sun Jan 12, 2020 6:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Reaction Quotient Q
- Replies: 6
- Views: 145
Re: Reaction Quotient Q
We use the reaction quotient Q when the reaction is not in equilibrium, to figure out which way the reaction shifts. Use K when the reaction is at equilibrium.
- Sun Jan 12, 2020 6:20 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Application of La Chatelier's
- Replies: 3
- Views: 127
Re: Application of La Chatelier's
You would use Le Chatelier's Principle when the physical parameters of a reaction changes (including temperature, concentration, and pressure). Le Chatelier's basically tells us what happens to the reaction as these changes occur (i.e. if the reaction shifts to the right or the left).
- Sun Jan 12, 2020 6:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K units
- Replies: 3
- Views: 88
Re: K units
when calculating for K, the calculation expression is in a ratio, and all of the units cancel each other out. K therefore also has no units.
- Sun Jan 12, 2020 6:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating K
- Replies: 9
- Views: 204
Re: Calculating K
Water is not accounted for when calculating for K because it does not affect the equilibrium of the reaction. Pure solids and pure liquids usually do not affect K and are not included in its calculation expression.
- Sun Jan 12, 2020 6:09 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Chatelier's Principle
- Replies: 7
- Views: 210
Re: Chatelier's Principle
Chatelier's Principle is, as Professor Lavelle said in class, chemical reactions adjusting to minimize the effect of change. This change usually refers to changing physical parameters of temperature, pressure, or concentration.
- Sun Dec 08, 2019 12:02 am
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Acidosis
- Replies: 3
- Views: 351
Re: Acidosis
Respiratory acidosis is a surplus of carbon dioxide in the bloodstream, and since CO2 is acidic, it lowers the pH of blood to be acidic. This happens when a person is suffocating, or not breathing out the CO2 they produce. Therefore, acidosis may be deadly because the pH of blood should not be acidi...
- Sat Dec 07, 2019 11:45 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: oxygen in acid strength
- Replies: 1
- Views: 256
Re: oxygen in acid strength
Acids that contain oxygen are under the "oxoacid" group, which means that the more oxygen atoms that are present, the more acidic the compound is (because of high electronegativity). When comparing two oxoacids, the molecule with a larger number of oxygen atoms would be more acidic. I'm no...
- Sat Dec 07, 2019 9:48 pm
- Forum: Lewis Structures
- Topic: Expanded Octets
- Replies: 2
- Views: 252
Re: Expanded Octets
Period 3 elements and lower can have an expanded octet because it is able to utilize its d-orbital to also hold electrons.
- Sat Dec 07, 2019 9:45 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: resonance in relation to pH
- Replies: 2
- Views: 217
Re: resonance in relation to pH
I believe that if a molecule has resonance, it has a lower pka, and thus making it more acidic.
- Sat Dec 07, 2019 9:36 pm
- Forum: Bronsted Acids & Bases
- Topic: Strong Acids and Bases
- Replies: 8
- Views: 529
Re: Strong Acids and Bases
Lyndon gave us this list during his last workshop session:
Strong acids: HCl, HBr, HI, HNO3, H2SO4, HClO4
Strong bases: LiOH, NaOH, KOH, RbOH, ScOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
Strong acids: HCl, HBr, HI, HNO3, H2SO4, HClO4
Strong bases: LiOH, NaOH, KOH, RbOH, ScOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
- Sun Dec 01, 2019 8:24 pm
- Forum: Bronsted Acids & Bases
- Topic: Water as an acid and base
- Replies: 7
- Views: 566
Water as an acid and base
How does water act as both a Bronsted acid and a base?
- Sun Dec 01, 2019 3:48 pm
- Forum: Trends in The Periodic Table
- Topic: Nitrogen
- Replies: 7
- Views: 564
Re: Nitrogen
Electron affinity is the likelihood of an atom gaining an electron. Since Nitrogen's 2p shell is has 3 up-spin electrons, making it half full, it would not want to take on another electron because it would make the atom less stable. Half full and completely full subshells are more stable than partia...
- Sun Dec 01, 2019 3:42 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Characteristics of a polydentate ligand
- Replies: 3
- Views: 129
Re: Characteristics of a polydentate ligand
A polydentate ligand has to have more than 2 lewis base sites, for example having more than 2 donor electron pairs that bind to the central atom.
- Sun Dec 01, 2019 3:12 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Water
- Replies: 5
- Views: 327
Re: Water
I think water is considered to be a constant in the equilibrium constant formula (it is considered to be 1) because it shouldn't affect the equilibrium of the reactants.
- Sun Dec 01, 2019 2:30 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: What is kA value?
- Replies: 5
- Views: 542
Re: What is kA value?
kA is the acid dissociation constant, and larger values for kA means that the acid is stronger and dissociates better, while smaller values for kA means that the acid is weaker and does not dissociate as well.
- Wed Nov 20, 2019 4:11 pm
- Forum: Electronegativity
- Topic: electronegativity of hydrogen
- Replies: 3
- Views: 312
Re: electronegativity of hydrogen
Hydrogen is not very electronegative. In terms of periodic trends, electronegativity goes up as you go up a group as period numbers increase (towards fluorine).
- Wed Nov 20, 2019 3:56 pm
- Forum: Bond Lengths & Energies
- Topic: Boiling Points
- Replies: 3
- Views: 758
Re: Boiling Points
Why does NO2 have a higher boiling point than N2O? I am confused because NO2 is a radical. NO2 has a higher boiling point because it is more polarizable, which means it has stronger van der waals forces. Since NO2 has more electrons than N2O, it is bigger and more polarizable. I don't think it has ...
- Wed Nov 20, 2019 3:47 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape vs. Geometry
- Replies: 5
- Views: 311
Re: Molecular Shape vs. Geometry
From what I understand, the geometry is counting up all the areas of electron density, while the shape involves how the areas of electron density from the lone pairs affects the overall shape of the molecule. For example, H20 would have a tetrahedral geometry (because it would have 4 areas of electr...
- Wed Nov 20, 2019 3:40 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: Boiling Point
- Replies: 7
- Views: 535
Re: Boiling Point
I think SO2 would have a higher boiling point because it has more electrons than O3, therefore making it more polarizable. Since it is more polarizable, it has stronger van der waals forces, which take more energy to break, causing SO2 to have a higher boiling point.
- Wed Nov 20, 2019 3:32 pm
- Forum: Lewis Structures
- Topic: XeO2F2 Lewis Structure
- Replies: 2
- Views: 698
Re: XeO2F2 Lewis Structure
If an element is in the third period or lower, it can have an expanded octet because it can utilize d-orbitals.
- Sat Nov 16, 2019 7:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Melting Points
- Replies: 7
- Views: 447
Re: Melting Points
You should probably know which types of bonds are stronger than others, because the stronger the bond, the higher the melting/boiling point. For example, ion-ion being the strongest bond and induced dipole-induced dipole being the weakest.
- Sat Nov 16, 2019 7:22 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability
- Replies: 5
- Views: 463
Re: Polarizability
You would calculate the difference in electronegativity between the atoms. Polar molecules usually also have a dipole moment, or a difference in partial charges within the molecule.
- Sat Nov 16, 2019 7:12 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Definition
- Replies: 2
- Views: 321
Re: Definition
What exactly is polarizability and how are we supposed to apply it? Like, what is its purpose because I'm kind of confused? Polarizability is how an electron cloud is distorted by an outside electric field. The bigger the atomic radius of an atom, the more polarizable it is because the positive nuc...
- Sat Nov 16, 2019 7:01 pm
- Forum: Dipole Moments
- Topic: Dipole Moment
- Replies: 3
- Views: 108
Re: Dipole Moment
A dipole moment happens when there is a separation of partial charges within a molecule, which happens when there is a big difference in electronegativity. For example, in H20, there is a dipole moment pointing towards oxygen because oxygen has a much higher electronegativity than hydrogen.
- Mon Nov 11, 2019 8:50 pm
- Forum: Einstein Equation
- Topic: E=hv vs E=pc?
- Replies: 8
- Views: 1636
Re: E=hv vs E=pc?
E=hv is used to find the energy of a photon using Planck's constant and frequency of light.
E=pc is used to find the energy of a photon using the speed of light and the momentum of a photon. I'm pretty sure we only use E=pc when momentum of the photon is provided.
E=pc is used to find the energy of a photon using the speed of light and the momentum of a photon. I'm pretty sure we only use E=pc when momentum of the photon is provided.
- Sun Nov 10, 2019 8:18 pm
- Forum: Dipole Moments
- Topic: Dipole
- Replies: 1
- Views: 100
Re: Dipole
You can tell by the difference in electronegativity I think. If one atom in a molecule has a high electronegativity and another atom in the molecule has a low electronegativity, then there is a dipole moment. So basically one side is more positive and one side is more negative. The dipole moment is ...
- Sun Nov 10, 2019 8:06 pm
- Forum: DeBroglie Equation
- Topic: De Broglie Equation Derivation and Use
- Replies: 7
- Views: 1135
Re: De Broglie Equation Derivation and Use
You use de Broglie's equation to find the wavelength of a particle that has resting mass (not light/photons).
- Wed Nov 06, 2019 11:39 pm
- Forum: Resonance Structures
- Topic: resonance hybrid
- Replies: 6
- Views: 348
Re: resonance hybrid
Lavelle does not expect us to draw the hybrid I think, because he didn't show it in class. So it's preferred that you draw all of the different resonance structures.
- Tue Nov 05, 2019 9:25 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Uncertainty in Position
- Replies: 4
- Views: 382
Re: Heisenberg Uncertainty in Position
I'm pretty sure you'd multiply by 2 to account for both -5 and +5
- Mon Nov 04, 2019 4:33 pm
- Forum: DeBroglie Equation
- Topic: de Broglie vs electromagnetic radiation
- Replies: 3
- Views: 188
Re: de Broglie vs electromagnetic radiation
You would use de Broglie's to find the wavelength (or describe wave properties) of an object that has resting mass (not light), and you would use E=hv to find the energy of a photon (light).
- Sun Nov 03, 2019 8:20 pm
- Forum: Lewis Structures
- Topic: Resonance Structure
- Replies: 4
- Views: 254
Re: Resonance Structure
In the review session today on bonding/structures, he told us to either draw all of the resonance structures (and state that there is a hybrid), or to draw the actual hybrid of the structures
- Sun Nov 03, 2019 3:32 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electron Configuration
- Replies: 7
- Views: 401
Re: Electron Configuration
Yes, because a half filled or a completely filled configuration is more stable than a partially filled.
- Sun Nov 03, 2019 3:18 pm
- Forum: *Shrodinger Equation
- Topic: H ψ = E ψ
- Replies: 2
- Views: 263
Re: H ψ = E ψ
The H is the Hamiltonian which is just an operator that acts on the ψ. The ψ describes the system mathematically and E is energy. In the review, the problem that was used as an example basically just gave you the H and you had to plug it into the equation and not solve. I think we just have to know...
- Sun Nov 03, 2019 1:51 pm
- Forum: Trends in The Periodic Table
- Topic: Exceptions
- Replies: 4
- Views: 106
Re: Exceptions
Usually, the electron affinity trend is that EA increases from left to right across the groups, but noble gasses (He, Ne, Ar, etc) have lower EA than the rest of the group.
- Sun Nov 03, 2019 1:44 pm
- Forum: Lewis Structures
- Topic: Lewis Structure for N2O
- Replies: 2
- Views: 480
Lewis Structure for N2O
Can someone please help walk me through how to draw the lowest energy Lewis Structure for N2O with N as the central atom? (12c on the dino nuggets midterm practice). I was a little confused when they explained it in the review session. Thanks!
- Thu Oct 24, 2019 11:16 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Electron Configurations (p-orbital)
- Replies: 5
- Views: 200
Re: Electron Configurations (p-orbital)
I don't believe that we have to separate px, py, and pz when writing electron configurations. I think Lavelle does it in class to show that each is a different orientation, but when writing configurations on hw or on tests, I haven't been splitting them up.
- Thu Oct 24, 2019 10:59 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electron Affinity
- Replies: 5
- Views: 283
Re: Electron Affinity
Electron affinity is when an atom (in the gaseous phase) takes on an electron to form an anion (a negative ion). Basically, a neutral charged atom gains an electron, and the electron's negative charge makes the atom's net charge negative. Also, the prompt will probably tell you if the atom is gaseou...
- Thu Oct 24, 2019 10:05 pm
- Forum: Properties of Electrons
- Topic: Anions and Cations
- Replies: 4
- Views: 178
Re: Anions and Cations
Anions are bigger than their parent atoms because there is more negative electronic charge than positive charge, so there is more electron repulsion. Cations are smaller than their parent atoms because the bigger positive charge from the nucleus makes the attraction of the electrons stronger, thus s...
- Thu Oct 24, 2019 9:45 pm
- Forum: *Particle in a Box
- Topic: TEST 2
- Replies: 14
- Views: 1299
Re: TEST 2
I was advised that the best way to study is by reading the chapters in the book and by doing all of the suggested problems on the syllabus
- Tue Oct 22, 2019 10:08 pm
- Forum: Einstein Equation
- Topic: Used for Photons Only
- Replies: 6
- Views: 318
Re: Used for Photons Only
E=hv is the equation used to solve for the energy of a particle of light, which is a photon.
- Sun Oct 20, 2019 5:14 pm
- Forum: Einstein Equation
- Topic: When do we use the Einstein Equation?
- Replies: 14
- Views: 752
Re: When do we use the Einstein Equation?
I'm pretty sure we use E=hv to find the energy of a photon
- Fri Oct 18, 2019 10:30 am
- Forum: DeBroglie Equation
- Topic: Photon Equation
- Replies: 4
- Views: 204
Re: Photon Equation
Lavelle explained in class that since photons do not have mass (because light doesn't have mass), so they obtain all of their energy from their momentum. So, instead of calculating momentum (p) by multiplying velocity by resting mass, the photon's momentum will probably be given to you in the questi...
- Thu Oct 17, 2019 10:46 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty Value
- Replies: 8
- Views: 213
Re: Uncertainty Value
the uncertainty value is 0.2 because the actual value would lie between 2.34 - 2.36.
- Thu Oct 17, 2019 9:51 pm
- Forum: Photoelectric Effect
- Topic: E = pc
- Replies: 3
- Views: 114
Re: E = pc
I think that you use E = pc when mass is not considered (maybe like a photon, because Lavelle said in class that photons do not have mass, but they have momentum).
- Thu Oct 17, 2019 9:45 pm
- Forum: Significant Figures
- Topic: Tests and Significant Figures
- Replies: 6
- Views: 311
Re: Tests and Significant Figures
this past test i don't think that the graders took off if you had the wrong amount of significant digits, my TA said he wasn't taking off for sig figs this test
- Sun Oct 13, 2019 8:02 pm
- Forum: SI Units, Unit Conversions
- Topic: knowing how many sig figs to use
- Replies: 17
- Views: 764
Re: knowing how many sig figs to use
I was recommended to keep as many digits as possible until the very end. This last test, our TA told us that he wasn't placing a heavy emphasis on sig figs so we shouldn't worry about it, but they might start counting it in the future.
- Sun Oct 13, 2019 7:57 pm
- Forum: Balancing Chemical Reactions
- Topic: Writing out equations
- Replies: 9
- Views: 525
Re: Writing out equations
According to the Hill System, you're supposed to put C carbon first, then Hydrogen, then all the other elements in alphabetical order. But if there is no Carbon the formula, then all the elements are written in alphabetical order.
- Thu Oct 10, 2019 11:36 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 Grading
- Replies: 12
- Views: 917
Re: Test 1 Grading
the amount of points that each question was worth was put on the test but they do give partial credit if you did the right work but got the wrong answer
- Thu Oct 10, 2019 10:39 am
- Forum: Empirical & Molecular Formulas
- Topic: How to format formulas
- Replies: 4
- Views: 449
Re: How to format formulas
Usually for the homework problems, when asking for molecular or empirical formulas, the mass percentage composition or the amount in grams of each element is listed out in the order that the resulting compound will be in.
- Wed Oct 09, 2019 2:52 pm
- Forum: Balancing Chemical Reactions
- Topic: Fractions
- Replies: 34
- Views: 1350
Re: Fractions
You should multiply all coefficients to make them whole integers, especially if the question is asking for a molecular or empirical formula.
- Sat Oct 05, 2019 10:53 pm
- Forum: SI Units, Unit Conversions
- Topic: How units of mass effect Scientific notation
- Replies: 3
- Views: 158
Re: How units of mass effect Scientific notation
10^3 = 1000 while 10^-3= 0.001
When you see a negative, it just means to move the decimal to the left, while a positive exponent means to move the decimal to the right
When you see a negative, it just means to move the decimal to the left, while a positive exponent means to move the decimal to the right
- Thu Oct 03, 2019 9:33 am
- Forum: Significant Figures
- Topic: rounding in sig figs
- Replies: 5
- Views: 316
Re: rounding in sig figs
Professor Lavelle also has a link on his website (https://lavelle.chem.ucla.edu/wp-conten ... OUT_SF.pdf) that is really helpful for figuring out sig figs :)
- Wed Oct 02, 2019 3:50 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Solubility Rules Memorization ?
- Replies: 3
- Views: 275
Re: Solubility Rules Memorization ?
For a couple of the examples given in my discussion last week where we were practicing writing out and balancing chemical equations, we weren't given states of matter, but for those questions, it was easier to use context clues to figure it out. It might be a little harder to figure out which reacta...
- Wed Oct 02, 2019 3:39 pm
- Forum: SI Units, Unit Conversions
- Topic: Difference between Chem Community HW and Textbook HW
- Replies: 5
- Views: 185
Re: Difference between Chem Community HW and Textbook HW
I'm pretty sure that hand-written homework from the textbook is collected at your discussion (except this week) and chemistry community posts are due on Sundays.
- Wed Oct 02, 2019 3:29 pm
- Forum: Balancing Chemical Reactions
- Topic: Combustion [ENDORSED]
- Replies: 3
- Views: 218
Combustion [ENDORSED]
Just making sure: when writing out combustion reactions, it's implied that we add oxygen as a reagent and CO2 and H20 as products, right?