Search found 105 matches
- Mon Mar 09, 2020 10:20 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ENDGAME Review Session
- Replies: 71
- Views: 5701
Re: ENDGAME Review Session
WE LOVE YOU 3000 TOO LYNDON
- Mon Mar 09, 2020 9:32 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: ln(A) Arrhenius Equation
- Replies: 3
- Views: 269
Re: ln(A) Arrhenius Equation
i think Lavelle said we aren't going to learn how to calculate an actual value for A; just understand what it represents and why it's significant
- Mon Mar 09, 2020 9:31 pm
- Forum: Second Order Reactions
- Topic: 7B.13
- Replies: 5
- Views: 467
Re: 7B.13
Delaney Smith 1C wrote:Wait, how do you solve for k if you don't have [A]t?
you're given the A naught and the half life so you can use the formula for the half life of a second order rxn in order to find k
- Mon Mar 09, 2020 9:24 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: How does K change during compression/expansion?
- Replies: 6
- Views: 945
Re: How does K change during compression/expansion?
the K constant does not change with a change in pressure-- only temperature. however, the reaction will adjust to compensate any disruptions made to the equilibrium. when you decrease the volume the reaction will shift to the side with less moles of gas. if you increase the volume the reaction will ...
- Mon Mar 09, 2020 9:20 pm
- Forum: Ideal Gases
- Topic: Partial Pressure
- Replies: 13
- Views: 756
Re: Partial Pressure
when you decrease the volume of a reaction, you also increase the pressure. thus the reaction will shift towards the side that has fewer moles of gas.
- Mon Mar 09, 2020 9:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Going from pKa to pH
- Replies: 10
- Views: 727
Re: Going from pKa to pH
i don't believe there's any direct conversion to get from pKa to pH. instead you'll have to convert pKa to Ka and make an ICE table to find the concentration of H+. then you can solve the equation and convert H+ to pH.
- Sat Mar 07, 2020 6:47 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Positional Disorder and Thermal Disorder
- Replies: 2
- Views: 347
Re: Positional Disorder and Thermal Disorder
thermal disorder refers to the entropy of motion of molecules. if you add heat to a substance, the molecules move faster and thus thermal disorder increases. positional disorder refers to entropy of a molecule's orientation.
- Sat Mar 07, 2020 6:43 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: the intermediate in a reaction
- Replies: 10
- Views: 710
Re: the intermediate in a reaction
intermediates do not show up in the rate law or overall reaction because they will cancel out on the reactants and products side.
- Fri Mar 06, 2020 7:17 pm
- Forum: Zero Order Reactions
- Topic: Differential v Integrated rate law
- Replies: 3
- Views: 292
Re: Differential v Integrated rate law
i believe if you tried to write the differential rate law as a function of time, you would have to manipulate it into the integrated rate law. the differential rate law equation as is relates rate to concentration
- Fri Mar 06, 2020 7:15 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalyst
- Replies: 2
- Views: 203
Re: Catalyst
no; adding a catalyst lowers activation energy, which increases the rate constant k because the reaction could proceed faster. however, i believe the rates of the forward and reverse reaction would increase proportionally, so mathematically you can see the equilibrium constant K is unaffected
- Fri Mar 06, 2020 7:12 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: units of T
- Replies: 11
- Views: 1089
Re: units of T
i think it is safest to use seconds, even if the problem doesn't specify
- Fri Feb 28, 2020 8:03 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: concentration cells
- Replies: 5
- Views: 385
Re: concentration cells
a concentration cell is comprised of two half cells in which the anode and cathode are the same element but have different concentrations. also E standard=0
- Fri Feb 28, 2020 7:58 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Spontaneity
- Replies: 12
- Views: 951
Re: Spontaneity
when delta G is negative it means the reaction is spontaneous
- Thu Feb 27, 2020 11:24 am
- Forum: Balancing Redox Reactions
- Topic: Half reactions don't have to be redox?
- Replies: 1
- Views: 156
Re: Half reactions don't have to be redox?
i encountered a practice problem that had this situation, i think the half reactions add together to make a bigger half reaction. therefore it doesn't make the reaction a redox.
- Thu Feb 27, 2020 11:22 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: reducing/oxidizing agents
- Replies: 7
- Views: 555
Re: reducing/oxidizing agents
reducing agents cause other species to be reduced and in the process, they themselves become oxidized because they have given an electron in order to reduce the other species.
- Thu Feb 27, 2020 11:21 am
- Forum: General Rate Laws
- Topic: Unique Rate
- Replies: 4
- Views: 368
Re: Unique Rate
because the unique rate sets the rate of change in concentration for species in a reaction over time equal, the unique rate will be the same for each reactant/product
- Sun Feb 23, 2020 11:50 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: porous disc
- Replies: 5
- Views: 427
Re: porous disc
the porous disc has the same effect as a salt bridge as it keeps the charges balances
- Wed Feb 19, 2020 6:55 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: converting T to kelvin
- Replies: 46
- Views: 3557
Re: converting T to kelvin
it's okay to leave the temperature in celsius if you're just finding the change-- it shouldnt make a difference mathematically
- Tue Feb 18, 2020 1:52 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing and Adding together Half-Rxns
- Replies: 6
- Views: 331
Re: Balancing and Adding together Half-Rxns
the charge of electrons must be maintained; same reasoning as to why we balance equations in general
- Tue Feb 18, 2020 1:51 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: ∆G = ∆Gº + RT lnQ
- Replies: 12
- Views: 2626
Re: ∆G = ∆Gº + RT lnQ
delta G is the gibbs free energy under standard conditions
- Tue Feb 18, 2020 1:50 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Van't Hoff Equation
- Replies: 4
- Views: 419
Re: Van't Hoff Equation
van't hoff equation is used to find the K value for different temperatures
- Tue Feb 18, 2020 1:49 pm
- Forum: Van't Hoff Equation
- Topic: Constant delta H
- Replies: 4
- Views: 302
Re: Constant delta H
we are assuming the difference between the final H and initial H to remain constant, and that the temperature change isn't significant enough to affect that
- Fri Feb 14, 2020 5:17 pm
- Forum: Calculating Work of Expansion
- Topic: Determining Expansion Work
- Replies: 4
- Views: 637
Re: Determining Expansion Work
if there was a change in the number of moles, the system had done expansion work (if the volume can change)
- Fri Feb 14, 2020 5:13 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free energy concept
- Replies: 16
- Views: 868
Re: Gibbs Free energy concept
gibbs free energy is basically the energy that is available to do work, hence "free" energy.
- Fri Feb 14, 2020 5:12 pm
- Forum: Phase Changes & Related Calculations
- Topic: Expansion Work
- Replies: 6
- Views: 466
Re: Expansion Work
expansion means there was an increase in volume
- Fri Feb 14, 2020 5:11 pm
- Forum: Phase Changes & Related Calculations
- Topic: Delta H Fusion
- Replies: 9
- Views: 713
Re: Delta H Fusion
the temperature doesn't change during a phase change. you can keep adding heat but the temperature doesn't change. you would need to calculate the energy needed to raise the temperature to the melting point, then find the amount of energy needed to actually melt the substance
- Fri Feb 14, 2020 5:09 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isothermal Reversible
- Replies: 6
- Views: 402
Re: Isothermal Reversible
i think isothermal always means reversible but not necessarily the other way around
- Mon Feb 10, 2020 6:00 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
- Replies: 67
- Views: 5833
Re: Pizza Rolls REVIEW Session DOWNLOAD HERE
can someone explain the lex luthor problem to me? it's number 5. i think for part a, i need to use the 2 entropy equations as well as the equipartition thing. and i'm not sure about b...
- Sun Feb 09, 2020 9:40 am
- Forum: Administrative Questions and Class Announcements
- Topic: memorizing things?
- Replies: 13
- Views: 640
memorizing things?
are there any specific values we need to memorize for this midterm? like heat capacities and whatnot?
- Sat Feb 08, 2020 1:28 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy
- Replies: 3
- Views: 215
Re: Entropy
is it not a state function? if i recall correctly, entropy is in fact a state function because it does not depend on the path followed by the system--just the final and initial state. however, the entropy does depend on the size or amount of moles. entropy=q/T, and q itself is extensive
- Thu Feb 06, 2020 7:55 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: 3rd Law
- Replies: 4
- Views: 136
Re: 3rd Law
as the temperature approaches 0 K, the change in entropy would approach 0. with the example of the perfect crystal, there is no inherent disorder and it must be at 0 K or else there will be some motion within the crystal
- Wed Feb 05, 2020 3:00 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: heat given off by rxn = - heat absorbed by solution
- Replies: 6
- Views: 328
Re: heat given off by rxn = - heat absorbed by solution
the heat given off by the rxn would be absorbed by the surroundings. i'm not sure if you need to know specifically which side the negative is on, as long as one is negative?
- Tue Feb 04, 2020 6:14 pm
- Forum: Calculating Work of Expansion
- Topic: second equation
- Replies: 8
- Views: 268
Re: second equation
if you solve the integral you would get ln( V2/V1).
- Mon Feb 03, 2020 7:56 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Closed Systems
- Replies: 14
- Views: 943
Re: Closed Systems
in a closed system, you can change the energy by doing work/having work done on the system or by changing the temperature
- Sat Feb 01, 2020 9:51 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy vs Change in Internal Energy
- Replies: 4
- Views: 310
Re: Enthalpy vs Change in Internal Energy
internal energy includes heat and work. sometimes change in internal energy is equal to change in enthalpy, and this happens when you are at constant pressure and volume.
- Sat Feb 01, 2020 9:48 am
- Forum: Phase Changes & Related Calculations
- Topic: Internal Energy, U
- Replies: 6
- Views: 314
Re: Internal Energy, U
it's equal if you are at constant pressure and volume.
- Thu Jan 30, 2020 7:06 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Changing the energies of systems
- Replies: 2
- Views: 126
Re: Changing the energies of systems
in an open system, you can add or remove products/reactants. in a closed system, you can change the pressure by compression/expansion (work) or changing the temperature. you cannot change the energy of an isolated system.
- Thu Jan 30, 2020 6:25 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Closed and Isolated
- Replies: 5
- Views: 248
Re: Closed and Isolated
i think there are few, if any, isolated systems in the world. maybe there's such minuscule amount of change that it's negligible?
- Thu Jan 30, 2020 6:22 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond enthalpies
- Replies: 4
- Views: 243
Re: Bond enthalpies
it depends on whether or not the value of bonds formed is greater than that of bonds broken.
- Sun Jan 26, 2020 12:03 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 7
- Views: 334
Re: Hess's Law
hess's law is basically stating that because enthalpy is a state function, enthalpy is additive. you can simply add the enthalpies of reactions; regardless of how many steps a reaction has, the total enthalpy change is just the sum of all changes
- Sun Jan 26, 2020 12:01 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: bond enthalpies
- Replies: 2
- Views: 129
Re: bond enthalpies
you would have to draw out the lewis structures and see which bonds were broken and formed in the products.
- Wed Jan 22, 2020 11:16 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Best Way To Study?
- Replies: 13
- Views: 651
Re: Best Way To Study?
the examples done in lectures are the most accurate representations of what show up in exams. Make sure you thoroughly understand the concepts behind each example so that you are able to recognize what steps to take when you encounter a similar problem on an exam.
- Wed Jan 22, 2020 11:12 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Test 1 Practice Worksheet #5
- Replies: 6
- Views: 273
Re: Test 1 Practice Worksheet #5
i got 8.62
- Tue Jan 21, 2020 11:19 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: H20 in the ICE table
- Replies: 26
- Views: 1512
Re: H20 in the ICE table
leave out pure liquids and solids
- Tue Jan 21, 2020 8:39 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When to Use Q
- Replies: 3
- Views: 168
Re: When to Use Q
wait so for this problem we had to make sure which direction it went in?
- Tue Jan 21, 2020 8:07 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test One Content
- Replies: 6
- Views: 321
Re: Test One Content
homework problems are good practice, i wouldn't bank on them being on the test though. and yes, the test covers outline 1 and 2.
- Tue Jan 21, 2020 7:50 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Grading of Tests
- Replies: 18
- Views: 771
Re: Grading of Tests
you usually get partial credit yeah
- Tue Jan 21, 2020 7:48 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ice box approximation
- Replies: 9
- Views: 344
Re: ice box approximation
if the K value is less than 10^-3, then you can assume x is very small relative to the initial concentration. this makes sense when you think about the formula for K (the concentration of reactants is much greater than that of products). if this is the case, you can disregard the x (that is subtract...
- Sun Jan 19, 2020 11:39 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Box
- Replies: 4
- Views: 157
Re: ICE Box
it's ignored if it's in a liquid state. as a solvent, it's in large excess, the concentration isn't really gonna change so it's not included in the K equation
- Thu Jan 16, 2020 11:28 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc vs Kp
- Replies: 5
- Views: 215
Re: Kc vs Kp
usually Kc is used, but i believe the problem would specify which one to use. you can also tell by the information given by a problem
- Thu Jan 16, 2020 11:27 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Quadratic
- Replies: 10
- Views: 299
Re: Quadratic
i don't think you would get 2 positive answers often, but just in case i'd plug the values back into the ICE table to see which value is more reasonable
- Thu Jan 16, 2020 11:25 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Factos effecting Equilibrium
- Replies: 6
- Views: 259
Re: Factos effecting Equilibrium
change in concentration, pressure (from volume), and temperature. temperature is the only one that affects the K value
- Wed Jan 15, 2020 4:08 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Quotient
- Replies: 11
- Views: 328
Re: Reaction Quotient
if the reaction is not at equilibrium, or if you aren't sure, then you are calculating the reaction quotient. It is the same equation as K. it can be used, when compared to K, to determine which way the reaction is proceeding
- Wed Jan 15, 2020 4:07 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: How to make ICE box
- Replies: 17
- Views: 1271
Re: How to make ICE box
The change would be x if you aren't given the equilibrium concentrations. Unless there are coefficients, then it would be corresponding coefficient times x.
- Fri Jan 10, 2020 4:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: using Kp vs Kc
- Replies: 13
- Views: 1573
Re: using Kp vs Kc
you would use Kp if you are given the partial pressures.
- Fri Jan 10, 2020 4:07 pm
- Forum: Student Social/Study Group
- Topic: Test 1 14B Topics
- Replies: 4
- Views: 250
Re: Test 1 14B Topics
definitely study outline 1, but i'm not sure if some of outline 2 will be covered
- Fri Jan 10, 2020 4:06 pm
- Forum: Ideal Gases
- Topic: Chatelier’s Principle
- Replies: 8
- Views: 253
Re: Chatelier’s Principle
basically the reaction will "adjust" to keep K constant. if you add more products and throw off the equilibrium, the reaction will proceed to the left to form more reactants. Regarding the change in pressure, the reaction will proceed towards the side with less moles of gas; however, it is...
- Fri Jan 10, 2020 4:02 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: K vs Q
- Replies: 9
- Views: 1768
Re: K vs Q
the equation to calculate K and Q is the concentration of products over concentration of reactants. If Q is less than K, that means that there must be more reactants compared to the concentrations at equilibrium. Therefore, the reaction will shift to the right to produce more products. the same logi...
- Fri Jan 10, 2020 3:57 pm
- Forum: Ideal Gases
- Topic: R in PV=nRT
- Replies: 34
- Views: 6702
Re: R in PV=nRT
R is a gas constant and the numerical value depends on the units being used to measure the gas
- Sun Dec 01, 2019 10:24 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Do strong acids dissociate completely in water?
- Replies: 7
- Views: 642
Re: Do strong acids dissociate completely in water?
yes, strong acids dissociate completely in water. whether or not an acid (or a base) ionizes completely in water depends on the polarity. when there is a significant electronegativity difference, there is less electron density associated with hydrogen and it is easier to ionize
- Sun Dec 01, 2019 10:18 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Pka vs Ka
- Replies: 10
- Views: 606
Re: Pka vs Ka
ka is the acid dissociation constant, and pka is the -log of Ka
- Sat Nov 30, 2019 10:07 am
- Forum: Lewis Acids & Bases
- Topic: Proton acceptor and proton donor?
- Replies: 33
- Views: 2170
Re: Proton acceptor and proton donor?
bases are proton acceptors, so they gain a H+. acids are proton donors, so they lose a H+
- Sat Nov 30, 2019 10:06 am
- Forum: Amphoteric Compounds
- Topic: Examples of amphoteric compounds
- Replies: 5
- Views: 342
Re: Examples of amphoteric compounds
i think Lavelle said to memorize the diagonal line of elements on the periodic table.
- Sat Nov 30, 2019 10:05 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Weak Acids and Bases
- Replies: 5
- Views: 700
Re: Weak Acids and Bases
you'll know based on the kb value. i believe there are strong acids and bases you can memorize, and anything else not on that list is a weak acid/base
- Sat Nov 23, 2019 9:59 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate
- Replies: 3
- Views: 171
Re: Polydentate
the best way to be sure would be to draw the structure and see how many bonds the ligand can form. if there can be multiple bonds formed, then the ligand is polydentate
- Sat Nov 23, 2019 9:57 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxidation State
- Replies: 4
- Views: 342
Re: Oxidation State
for monoatomic ions, the oxidation state is the same as the charge, so just look at the periodic table.
- Sat Nov 23, 2019 9:54 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordinate covalent bonds
- Replies: 2
- Views: 154
Re: Coordinate covalent bonds
in a coordinate covalent bond, the electrons involved in bonding comes from one of the atoms, while in normal covalent bonds both atoms will contribute electrons
- Sat Nov 23, 2019 9:53 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted Acids vs Lewis acids
- Replies: 4
- Views: 165
Re: Bronsted Acids vs Lewis acids
a bronsted acid describes acids as proton donors, as in they lose an H+. the lewis definition of an acid is that they are electron acceptors, so they gain electrons.
- Sat Nov 23, 2019 9:51 pm
- Forum: Sigma & Pi Bonds
- Topic: How to Find Sigma Bonds and Pi Bonds
- Replies: 15
- Views: 1220
Re: How to Find Sigma Bonds and Pi Bonds
draw the lewis structure. a single bond is one sigma bond, a double bond is one sigma bond and one pi bond, and a triple bond is one sigma bond and two pi bonds.
- Sat Nov 16, 2019 4:35 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent or Angular
- Replies: 13
- Views: 1131
Re: Bent or Angular
i don't believe there's a difference? the textbook may say angular but lavelle referred to it as "bent"
- Sat Nov 16, 2019 4:22 pm
- Forum: Bond Lengths & Energies
- Topic: Dissociation Energy
- Replies: 9
- Views: 409
Re: Dissociation Energy
dissociation energy is the energy required to break a bond, and since breaking bonds requires energy, the dissociation energy will be positive
- Sat Nov 16, 2019 4:17 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 Points
- Replies: 9
- Views: 615
Re: Boiling Points
the stronger the intermolecular force, the higher the boiling point. for example, the boiling point of water is 100 C, while the boiling point of methane (CH4) is like -260 C. water molecules are polar, which means there will be dipole-dipole forces as well as LDF (LDF are present in all molecules i...
- Sat Nov 16, 2019 4:06 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: Does dipole-dipole force only exist among polar molecules?
- Replies: 9
- Views: 1320
Re: Does dipole-dipole force only exist among polar molecules?
yes, because of the partial charges
- Sat Nov 16, 2019 3:59 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: polar vs nonpolar
- Replies: 6
- Views: 320
Re: polar vs nonpolar
i prefer to draw the lewis structure; then you can see if the structure is symmetrical or not.
- Fri Nov 08, 2019 7:29 pm
- Forum: Dipole Moments
- Topic: Dipole Moments
- Replies: 5
- Views: 464
Re: Dipole Moments
dipole moments are the result of differences in electronegativity, and the atoms share electrons unequally. this creates a partial charge of +/-.
- Fri Nov 08, 2019 7:27 pm
- Forum: Electronegativity
- Topic: memorizing tables
- Replies: 9
- Views: 344
Re: memorizing tables
i don't think you need to memorize the actual numbers, but you can at least have a general, relative estimate of the values maybe
- Fri Nov 08, 2019 7:26 pm
- Forum: Dipole Moments
- Topic: Dipole - Dipole vs. Hydrogen Bonding
- Replies: 7
- Views: 1709
Re: Dipole - Dipole vs. Hydrogen Bonding
h bonding is an intermolecular force, so attraction between molecules. it is the stronger than dipole-dipole, which is also an intermolecular force. h bonding is weaker than covalent or ionic bonds though.
- Fri Nov 08, 2019 7:22 pm
- Forum: Lewis Structures
- Topic: Formal Charges
- Replies: 15
- Views: 984
Re: Formal Charges
the charge isn't necessarily for the central atom. the most electronegative atom should have the negative charge
- Fri Nov 08, 2019 7:21 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: Shape of Molecule
- Replies: 5
- Views: 309
Re: Shape of Molecule
yes; shape can determine how close molecules are able to get to each other.
- Sun Nov 03, 2019 4:23 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: polarizing power
- Replies: 3
- Views: 173
Re: polarizing power
ions with high polarizing power cause large distortions in another atom's electron cloud. to determine polarizing power, you'll have to take into consideration the atomic radius and charge; small cations that are highly charged have the most polarizing power. due to the small size, the nucleus of th...
- Sun Nov 03, 2019 4:13 pm
- Forum: Bond Lengths & Energies
- Topic: Resonance bond length
- Replies: 4
- Views: 269
Re: Resonance bond length
kind of yeah? i see it more as resonance describing the delocalization of electrons. but yes the bond length is the average
- Sun Nov 03, 2019 2:49 pm
- Forum: Octet Exceptions
- Topic: What are radicals
- Replies: 7
- Views: 288
Re: What are radicals
radicals are compounds that have a lone electron. this makes them very reactive, and they're significant because they can damage DNA and cause mutations.
- Sun Nov 03, 2019 2:45 pm
- Forum: Dipole Moments
- Topic: Dipole moments
- Replies: 5
- Views: 322
Re: Dipole moments
a dipole moment occurs when atoms in a molecule share electrons unequally. this means there's a difference in electronegativity, and this creates partially negative and positive regions which gives the molecule ionic character
- Sun Nov 03, 2019 2:28 pm
- Forum: Dipole Moments
- Topic: Hydrogen Bond
- Replies: 7
- Views: 413
Re: Hydrogen Bond
a hydrogen bond is a type of dipole-dipole interaction, but it's specifically between hydrogen and N, O, or F. it's the stronger than dipole-dipole because of the partially positive hydrogen atom and partially negative N O or F
- Sun Oct 27, 2019 9:18 am
- Forum: Lewis Structures
- Topic: Drawing Lewis Structure
- Replies: 6
- Views: 211
Re: Drawing Lewis Structure
i would assume we have to draw the lone pairs since we haven't been told otherwise. just draw them to be safe
- Sat Oct 26, 2019 10:30 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Ms and ML
- Replies: 6
- Views: 2062
Re: Ms and ML
ml is actually the quantum number that is from -l to +l. it means that ml can take on integer values from -l to +l; for example, if l was 2, then ml can be -2, -1, 0, 1, or 2. and ms is either -1/2 or +1/2
- Sat Oct 26, 2019 2:48 pm
- Forum: Trends in The Periodic Table
- Topic: Electronegativity vs Electron Affinity
- Replies: 6
- Views: 298
Re: Electronegativity vs Electron Affinity
electronegativity is how well an atom can attract electrons, or basically an atom's ability to attract electrons. electron affinity is the amount of energy released when an electron is added to a neutral and gaseous atom
- Sat Oct 26, 2019 10:08 am
- Forum: Trends in The Periodic Table
- Topic: atomic radius
- Replies: 3
- Views: 191
Re: atomic radius
atomic radius is the distance from the nucleus to the outmost shell. i don't think we need to calculate it; i would assume the atomic radius would be either given to us in a problem, or we can solve for it with basic math (correct me if i'm wrong though).
- Sat Oct 26, 2019 8:59 am
- Forum: Resonance Structures
- Topic: Bond Lengths
- Replies: 5
- Views: 636
Re: Bond Lengths
the electrons in resonance structures are delocalized, and this spreads multiple-bond character over the whole molecule. the resonance structures don't depict how the molecule actually looks like, so the bond lengths are the average between the single and double bonds
- Sat Oct 26, 2019 8:54 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: ml alue (i.e., ...-1,0,1,....)
- Replies: 2
- Views: 167
Re: ml alue (i.e., ...-1,0,1,....)
the l value is determined by the n value, and ml is determined by l. ml can be any whole number from -l to +l; for example, if l=1, then ml can be -1, 0, and +1
- Sat Oct 19, 2019 9:59 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Inner e- and Outer e-
- Replies: 14
- Views: 505
Re: Inner e- and Outer e-
the inner electrons "shield" the outer electrons from the electrostatic pull of the nucleus. this reduced electrostatic attraction is the "effective nuclear charge". this becomes important later when it comes to ionization and bonding
- Sat Oct 19, 2019 12:04 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals vs. Shells
- Replies: 5
- Views: 196
Re: Orbitals vs. Shells
a shell is the energy level, which is n. orbitals are denoted by ml, and are the shapes that can hold up to 2 electrons. i'll attempt to give an example: n=2, l=1, so we have 2p. there can be 3 values for ml, so we have px, py, and pz. if you remember high school chemistry and electron configuration...
- Sat Oct 19, 2019 11:57 am
- Forum: *Shrodinger Equation
- Topic: Concepts of Schrodinger equation
- Replies: 3
- Views: 161
Re: Concepts of Schrodinger equation
schrodinger's equation solves for a wave function (treating electrons as matter waves) and it can be used to find the relative location of an electron and the probability of finding an electrons in a location.
- Thu Oct 17, 2019 4:57 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes
- Replies: 7
- Views: 397
Re: Nodal Planes
nodal planes are where the probability of finding electrons is zero. they're derived from schrodinger's equation
- Thu Oct 17, 2019 4:47 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty application
- Replies: 3
- Views: 165
Re: Uncertainty application
in order to use the uncertainty equation, you need to have some value for mass. because photons have no mass, you cannot use the momentum equation p=mv and thus, you cannot calculate the uncertainty
- Sat Oct 12, 2019 7:46 pm
- Forum: Properties of Electrons
- Topic: Electron Excitation
- Replies: 6
- Views: 332
Re: Electron Excitation
when an electron is excited, it means that it has absorbed energy and has jumped to a higher energy level.
- Sat Oct 12, 2019 7:38 pm
- Forum: Properties of Light
- Topic: Speed of Light
- Replies: 41
- Views: 2850
Re: Speed of Light
the speed of light changes depending on the medium it is traveling through; however, the constant 3.00x10^8 m/s is used when assuming the light is traveling through a vacuum. therefore, in our case, the speed of light is constant.
- Fri Oct 11, 2019 9:43 am
- Forum: Balancing Chemical Reactions
- Topic: Balancing Chemical Reactions
- Replies: 20
- Views: 1175
Re: Balancing Chemical Reactions
i try to balance the coefficient one by one by making a list, but when i get an odd number, I double the coefficients and that usually works out in the end
- Fri Oct 11, 2019 9:41 am
- Forum: Properties of Light
- Topic: Speed of light
- Replies: 9
- Views: 314
Re: Speed of light
we use the constant c when we are assuming the situation is in a vacuum. however, it is true that light travels different under different mediums.
- Fri Oct 11, 2019 9:37 am
- Forum: Properties of Light
- Topic: Converting units
- Replies: 8
- Views: 229
Re: Converting units
To convert from nanometers to angstroms, you multiply by 10.