Search found 101 matches
- Wed Mar 10, 2021 7:07 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode always on left in cell diagram?
- Replies: 6
- Views: 501
Re: Anode always on left in cell diagram?
yes anode is always on the left to avoid confusion. this is a typo
- Wed Mar 10, 2021 7:06 pm
- Forum: General Rate Laws
- Topic: Intermediate
- Replies: 59
- Views: 4012
Re: Intermediate
an intermediate is a product in one step, then consumed as a reactant in the next step. since it goes from being a product to a reactant, it cancels out and is not included in the overall reaction equation
- Wed Mar 10, 2021 7:05 pm
- Forum: Balancing Redox Reactions
- Topic: Balacing redox reactions
- Replies: 6
- Views: 419
Re: Balacing redox reactions
1. balance elements other than hydrogen and oxygen with stoichiometric coefficients
2. balance oxygen with H2O molecules
3. balance hydrogen with H+
4. balance charge by adding electrons wherever necessary
2. balance oxygen with H2O molecules
3. balance hydrogen with H+
4. balance charge by adding electrons wherever necessary
- Wed Mar 10, 2021 7:03 pm
- Forum: General Rate Laws
- Topic: slow step
- Replies: 7
- Views: 376
Re: slow step
i don't think we can determine that without that doing experiments and calculations. i'm pretty sure they would tell us which is the slow step in a problem
- Wed Mar 10, 2021 7:01 pm
- Forum: Zero Order Reactions
- Topic: zero order
- Replies: 47
- Views: 1999
Re: zero order
it means that the rate of the reaction is not dependent of the concentration of the reactants. the rate depends on k
- Sat Mar 06, 2021 11:44 am
- Forum: Zero Order Reactions
- Topic: When to use each order
- Replies: 19
- Views: 1177
Re: When to use each order
i think it's easiest to look at it graphically. if you graph ln [A] vs time and you get a straight line with a negative slope, this is first order. If you graph 1/[A] vs time and you get a straight line with positive slope, this is second order. if you graph [A] vs time and you get a straight line w...
- Sat Mar 06, 2021 11:39 am
- Forum: Balancing Redox Reactions
- Topic: How to Determine if a Reaction is in Basic or Acidic Solution?
- Replies: 53
- Views: 3479
Re: How to Determine if a Reaction is in Basic or Acidic Solution?
the problem will have to specify whether it is in acidic or basic solution
- Sat Mar 06, 2021 11:37 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: what is slow? fast?
- Replies: 11
- Views: 1636
Re: what is slow? fast?
if a reaction has two steps, the slower reaction will determine the rate of the reaction because the reaction will be limited to how fast the slowest step occurs
- Sat Mar 06, 2021 11:35 am
- Forum: Student Social/Study Group
- Topic: 14B Final
- Replies: 22
- Views: 1110
Re: 14B Final
i think professor lavelle is going to divide the final based on how long we spent on each section. The longer we spent on a section, the larger its portion on the final will be.
- Sat Mar 06, 2021 11:34 am
- Forum: Student Social/Study Group
- Topic: From pKa to pH
- Replies: 6
- Views: 461
Re: From pKa to pH
pKa + pKb= PKw
pH+pOH=14
Ka*Kb=Kw= 1x10^-14
[OH-]*[H+]=1x10^-14
pH+pOH=14
Ka*Kb=Kw= 1x10^-14
[OH-]*[H+]=1x10^-14
- Sun Feb 28, 2021 4:57 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: What is Potential?
- Replies: 14
- Views: 657
Re: What is Potential?
this means that the cathode has a greater electron pulling ability. aka the cathode has a greater likelihood of being reduced, which means it is gaining electrons
- Sun Feb 28, 2021 4:54 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Moles in ΔG = -nFE
- Replies: 45
- Views: 4267
Re: Moles in ΔG = -nFE
n is the number of electrons transferred. to find this you have to find the balanced half reactions (including the electrons) and from there you can see how many electrons were transferred. that would be your value for n in ΔG=-nFE
- Sun Feb 28, 2021 4:52 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: sapling week 7/8 #12
- Replies: 6
- Views: 3406
Re: sapling week 7/8 #12
first fin E°cell using the standard reduction potentials given. then use the equation ΔG°=-nFE°
- Sun Feb 28, 2021 4:49 pm
- Forum: Balancing Redox Reactions
- Topic: adding water in the reaction
- Replies: 13
- Views: 729
Re: adding water in the reaction
if the oxygen atoms are not balanced we add water molecules to balance it out.
- Sun Feb 28, 2021 4:48 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Adding Pt(s) to the cell diagram
- Replies: 13
- Views: 590
Re: Adding Pt(s) to the cell diagram
if there isn't a metal conductor we need to add Pt(s)
- Sun Feb 21, 2021 4:18 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Q and K
- Replies: 40
- Views: 2991
Re: Q and K
If Q<K, the reaction will favor the products. If Q>K, the reaction will favor the reactants
- Sat Feb 20, 2021 6:51 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: anode and cathode L/R
- Replies: 14
- Views: 706
Re: anode and cathode L/R
they can be on either side but when we represent them on paper with cell diagrams the anode goes on the left and the cathode goes on the right
- Sat Feb 20, 2021 6:48 pm
- Forum: Balancing Redox Reactions
- Topic: Salt Bridges
- Replies: 21
- Views: 891
Re: Salt Bridges
we must include a salt bridge in order to keep both solutions neutral. as the anode loses electrons, cations form. the salt bridge provides anions to keep the solution neutral.
- Sat Feb 20, 2021 6:46 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta G and G naught
- Replies: 46
- Views: 4750
Re: Delta G and G naught
Delta G is at standard conditions. standard conditions are 1 atm and 298 K (room temp, 25 degree Celsius)
- Tue Feb 16, 2021 9:33 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy and Temperature
- Replies: 4
- Views: 531
Entropy and Temperature
Why does delta S decrease when temperature increases? I understand it in terms of the equation of delta S because temperature is on the denominator, I just don't understand it conceptually. Can someone please explain this?
- Sat Feb 13, 2021 9:09 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Temperature and Volume
- Replies: 10
- Views: 575
Re: Temperature and Volume
an increase in both volume and temperature results in an entropy increase.
- Sat Feb 13, 2021 9:06 pm
- Forum: Calculating Work of Expansion
- Topic: Positive vs. Negative Work
- Replies: 22
- Views: 946
Re: Positive vs. Negative Work
positive work means that work is being done to the system while negative work means the system is doing work. the negative value represents the system losing energy
- Sat Feb 13, 2021 9:05 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Low temp making DeltaG negative?
- Replies: 8
- Views: 439
Re: Low temp making DeltaG negative?
this would not be possible because the negative delta S value would make t*delta S positive. therefore, delta G would always be negative
- Sat Feb 13, 2021 4:28 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Sapling Week 5/6 #20
- Replies: 4
- Views: 266
Re: Sapling Week 5/6 #20
yes I had trouble figuring this out until I realized that the right side of the curve was pointing toward equilibrium (delta G is decreasing) so both sides are spontaneous!
- Fri Feb 12, 2021 9:20 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Delta U, Delta S, q, and w for isobaric conditions
- Replies: 2
- Views: 894
Re: Delta U, Delta S, q, and w for isobaric conditions
work would not be 0 because the equation is w= -P* (delta V). The equation does not include delta P so P would just be the constant pressure and delta V would be the change in volume.
- Sat Feb 06, 2021 10:59 pm
- Forum: Ideal Gases
- Topic: Kc vs. Kp
- Replies: 71
- Views: 2898
Re: Kc vs. Kp
yes we solve for kc the same way we solve for kp! :)
- Sat Feb 06, 2021 10:57 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: specific vs molar heat capacity
- Replies: 16
- Views: 964
Re: specific vs molar heat capacity
specific heat capacity is the heat capacity in terms of grams present. molar heat capacity is the heat capacity in terms of moles present. it really just depends on what information is given in the problem
- Sat Feb 06, 2021 10:54 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: deltaU
- Replies: 29
- Views: 956
Re: deltaU
delta U is change in internal energy. delta U= q+w
- Sat Feb 06, 2021 10:52 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Key points of First Law
- Replies: 8
- Views: 258
Re: Key points of First Law
as everyone said before, the first law of thermodynamics basically states the conservation of energy
- Mon Feb 01, 2021 5:45 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: delta U versus delta H
- Replies: 5
- Views: 196
delta U versus delta H
what is the difference between delta U and delta H?
- Sat Jan 30, 2021 5:16 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Molar and Specific Heat Capacity
- Replies: 6
- Views: 291
Re: Molar and Specific Heat Capacity
they are not interchangeable. it depends on what information you're given. if you have moles, then you would use molar heat capacity. if you have grams you would use specific heat capacity.
- Sat Jan 30, 2021 5:15 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: change in celsius = change in kelvin
- Replies: 22
- Views: 8076
Re: change in celsius = change in kelvin
a change of 1 degree Celsius is the same as a change of 1 degree in kelvin. the only difference is that kelvin starts at 0 while Celsius starts at -273. so to convert from Celsius to kelvin all you have to do is add 273 to Celsius.
- Fri Jan 29, 2021 9:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ka and Kb
- Replies: 9
- Views: 450
Re: Ka and Kb
you have to check whether the anion or the cation of the salt will the affect the ph. from there you can determine if it's a conjugate base or acid. if it is a base you use kb, and if it is an acid use ka
- Fri Jan 29, 2021 9:19 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: R Constant
- Replies: 91
- Views: 7526
Re: R Constant
there are several values of R and the only way we know which one to pick is by looking at the units. match the units of the info they give to the units in R
- Fri Jan 29, 2021 9:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: endothermic/exothermic
- Replies: 43
- Views: 4883
Re: endothermic/exothermic
when you need to break bonds for the phase change it is endothermic. for example going from a solid to a liquid is endothermic because some bonds have to be broken in order for it to become a liquid. if bonds need to form it will be exothermic.
- Fri Jan 22, 2021 10:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ordering from weakest to strongest Acd/base
- Replies: 11
- Views: 597
Re: Ordering from weakest to strongest Acd/base
a strong acid has a low pKa value and a large Ka value. a strong base has a low pKb value and a large Kb value
- Fri Jan 22, 2021 10:37 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Concentration X
- Replies: 4
- Views: 318
Re: Concentration X
if you have x^3 in your equation you can just approximate and say that the value of x is negligible in the denominator. having x^3 prevents you from using the quadratic equation so to solve we have to approximate. I believe our K value has to be less than 10^-4 to approximate but i could be wrong
- Thu Jan 21, 2021 8:47 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heat and temperature change
- Replies: 6
- Views: 223
Re: Heat and temperature change
the temperature doesn't rise during a phase change because the energy goes towards altering the molecules and changing the phase. once the phase changes the temperature increases until the substance changes phases again.
- Thu Jan 21, 2021 8:45 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong acids & bases
- Replies: 4
- Views: 252
Re: Strong acids & bases
their equilibrium constants are just very large because the acid/base almost completely dissociates
- Thu Jan 21, 2021 8:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Buffers?
- Replies: 3
- Views: 153
Re: Buffers?
I would wait for professor lavelle to mention it lecture
- Sat Jan 16, 2021 6:45 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kw constant
- Replies: 25
- Views: 918
Re: Kw constant
H2O is in excess so the change in concentration would be negligible. if we were to add it into Kw it would be in the numerator and denominator, and therefore would cancel out.
- Sat Jan 16, 2021 6:43 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle
- Replies: 19
- Views: 1518
Re: Le Chatelier's Principle
basically it says that if there is a change in the system the chemical reaction will "shift" to go back to equilibrium and minimize the effects of that change
- Sat Jan 16, 2021 6:42 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Using the ICE table
- Replies: 36
- Views: 1517
Re: Using the ICE table
yes! an ICE table can be used for both partial pressures and concentrations.
- Fri Jan 15, 2021 2:33 pm
- Forum: General Science Questions
- Topic: Calculating Ka from pKa
- Replies: 7
- Views: 1504
Re: Calculating Ka from pKa
to find Ka from pKa you would do 10^(-pKa)
- Fri Jan 15, 2021 2:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Finding pH for salts
- Replies: 2
- Views: 120
Finding pH for salts
How would we find the pH of a salt if both the cation and anion affect the pH of the solution?
- Tue Jan 12, 2021 5:50 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Quotient
- Replies: 10
- Views: 1019
Re: Reaction Quotient
Q uses the concentration values we currently have, but K uses the equilibrium concentrations
- Tue Jan 12, 2021 5:48 pm
- Forum: Administrative Questions and Class Announcements
- Topic: UA Workshops
- Replies: 6
- Views: 281
Re: UA Workshops
all the worksheets are different for every UA. go to as many as you can they are so so so helpful!!
- Tue Jan 12, 2021 5:46 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kw= 1.0 x 10^-14
- Replies: 11
- Views: 1739
Re: Kw= 1.0 x 10^-14
as everyone said above Kw was experimentally determined
- Tue Jan 12, 2021 5:43 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Bars
- Replies: 8
- Views: 349
Re: Bars
yes 1 bar is approximately 1 atm so we say that 1atm=1bar
- Thu Jan 07, 2021 5:37 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE tables
- Replies: 11
- Views: 576
Re: ICE tables
I is initial concentrations, C is change in concentrations, and E is concentrations at equilibrium. Depending on what information we're given, we can use ICE tables to find the K value, or concentrations at equilibrium (if we already know the K value).
- Thu Jan 07, 2021 5:32 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: change in pressure
- Replies: 8
- Views: 427
Re: change in pressure
if both sides of the equation have the same number of moles, a change in pressure will not affect equilibrium
- Thu Jan 07, 2021 5:31 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling #4
- Replies: 5
- Views: 203
Sapling #4
Problem 4 says: At a certain temperature, the given reaction has an equilibrium constant of Kp=341
PCl3(g)+Cl2(g)↽−−⇀PCl5(g)
PCl5 is placed in a sealed container at an initial pressure of 0.0220 bar. What is the total pressure at equilibrium?
Can someone explain how to solve this?
PCl3(g)+Cl2(g)↽−−⇀PCl5(g)
PCl5 is placed in a sealed container at an initial pressure of 0.0220 bar. What is the total pressure at equilibrium?
Can someone explain how to solve this?
- Thu Jan 07, 2021 4:53 pm
- Forum: Ideal Gases
- Topic: Reaction Quotient(Q) vs. Equilibrium Constant(K)
- Replies: 9
- Views: 1215
Re: Reaction Quotient(Q) vs. Equilibrium Constant(K)
Q is at any point in the reaction but K is at equilibrium. comparing Q and K can tell you that the reaction is at equilibrium, or whether the reaction will shift to the right or the left to reach equilibrium
- Thu Jan 07, 2021 4:52 pm
- Forum: General Science Questions
- Topic: mole vs. M
- Replies: 16
- Views: 3217
Re: mole vs. M
M is concentration in mol/L. moles will be expressed as mol or mole
- Tue Dec 15, 2020 7:36 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric vs Amphiprotic
- Replies: 7
- Views: 531
Amphoteric vs Amphiprotic
What's the difference between amphoteric and amphiprotic?
- Sun Dec 06, 2020 5:49 pm
- Forum: Hybridization
- Topic: Good video about hybridization
- Replies: 7
- Views: 520
Re: Good video about hybridization
omg thank you! this is so so so helpful <3
- Sun Dec 06, 2020 5:09 pm
- Forum: Amphoteric Compounds
- Topic: Sapling HW #2 [ENDORSED]
- Replies: 4
- Views: 691
Sapling HW #2 [ENDORSED]
Can someone explain how to determine which substance is amphoteric? Here's the question:
Which of these substances is amphoteric, that is, it can act as a Brønsted acid and a Brønsted base?
BrO2^-
H3PO4
HBrO2
PO4^3-
H2PO4^-
Which of these substances is amphoteric, that is, it can act as a Brønsted acid and a Brønsted base?
BrO2^-
H3PO4
HBrO2
PO4^3-
H2PO4^-
- Sun Dec 06, 2020 11:40 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Flashcards
- Replies: 8
- Views: 338
Re: Flashcards
flashcards are super super helpful when trying to memorize names, or just learning the concepts. i would definitely say use flashcards for learning the different shapes of compounds, and naming compounds.
- Sun Dec 06, 2020 11:39 am
- Forum: Naming
- Topic: Naming Coordination Compounds
- Replies: 9
- Views: 567
Naming Coordination Compounds
When do we add -ate to the end of the metal name?
- Sun Dec 06, 2020 11:37 am
- Forum: Lewis Acids & Bases
- Topic: Acids question
- Replies: 4
- Views: 237
Acids question
When would we use the equation Ka= [A-][H+]/[AH]?
- Sun Nov 29, 2020 5:51 pm
- Forum: Lewis Structures
- Topic: Sapling Week 7/8 #12
- Replies: 8
- Views: 396
Re: Sapling Week 7/8 #12
hi so you would use the mass percentages and assuming that you have a 100 gram sample we would have 37.5 g C, 12.6 g H, and 49.9 g O. Convert these to moles and find the molecular formula. This will be the formula used to draw the lewis structure and determine the hybridization
- Sun Nov 29, 2020 5:47 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelates General Question
- Replies: 2
- Views: 105
Re: Chelates General Question
from my understanding a chelate contains a ligand that forms a ring of atoms that includes a central metal atom. i'm not completely sure why chelates form so if you know please let us know lol :)
- Sun Nov 29, 2020 5:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: #13 Sapling Week 8
- Replies: 18
- Views: 718
Re: #13 Sapling Week 8
since each carbon atom has 4 regions of electron density (4 bonds) the shape is tetrahedral
- Sun Nov 29, 2020 5:36 pm
- Forum: Limiting Reactant Calculations
- Topic: Cl vs Cl2
- Replies: 9
- Views: 7407
Re: Cl vs Cl2
Yes! chlorine gas is a diatomic molecule and therefore chlorine gas is Cl2
- Sat Nov 28, 2020 4:52 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Delocalized Pi Bond
- Replies: 5
- Views: 190
Delocalized Pi Bond
What is a delocalized pi bond?
- Sun Nov 22, 2020 7:12 pm
- Forum: Lewis Structures
- Topic: Central Atom Question
- Replies: 20
- Views: 1263
Re: Central Atom Question
As Dr. Lavelle has mentioned in lecture, H can never be the central atom because it can only have 1 bond
- Sun Nov 22, 2020 7:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Question About Seesaw Molecular Geometry
- Replies: 3
- Views: 267
Re: Question About Seesaw Molecular Geometry
having the lone pair in the equatorial plane is more favorable because it only interacts with 2 bonds at 90 degrees. if it was on the axial plane it would interact w/ three atoms.
- Sun Nov 22, 2020 7:06 pm
- Forum: Lewis Structures
- Topic: Focus 2 Exercise 7
- Replies: 3
- Views: 168
Re: Focus 2 Exercise 7
For a structure like this it's more trying different things and seeing which works. I had some trouble on this too but you just have to take different approaches and see which gives you the most stable and correct structure. there are multiple ways to do it
- Sun Nov 22, 2020 7:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Shape of XeF2
- Replies: 2
- Views: 113
Shape of XeF2
How does XeF2 have a linear shape if it has 3 lone pairs?
- Sun Nov 22, 2020 6:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling HW #3
- Replies: 3
- Views: 280
Sapling HW #3
Question 3 says: A Lewis structure is a two-dimensional representation of a molecule that does not necessarily show what shape that molecule would take in three dimensions. Based on the Lewis structure and your knowledge of VSEPR theory, approximate the smallest bond angle in this molecule. I'm not ...
- Sun Nov 15, 2020 6:27 pm
- Forum: Ionic & Covalent Bonds
- Topic: Hydrogen Bonding
- Replies: 13
- Views: 462
Hydrogen Bonding
What specific characteristic do N, O, and F have that allow them to hydrogen bond with H? Is it just because they are highly electronegative?
- Sun Nov 15, 2020 6:23 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Electronegativity chart for Midterm
- Replies: 7
- Views: 405
Re: Electronegativity chart for Midterm
Hmmmm I'm not 100% sure but I think if we had to use electronegativity values, they would be given in the problem. To my understanding there isn't a chart we should print out but if I'm wrong pls correct me :)
- Sun Nov 15, 2020 6:21 pm
- Forum: Ionic & Covalent Bonds
- Topic: Difference on how atomic size affects covalent and dipole interactions
- Replies: 9
- Views: 2102
Re: Difference on how atomic size affects covalent and dipole interactions
yes, a greater atomic radius in LDF makes it more polarizable. In terms of ionic bonds, this means that the bigger the radius of the anion, the easier it is for it to be distorted, which gives it some covalent characteristics
- Sun Nov 15, 2020 6:09 pm
- Forum: Bond Lengths & Energies
- Topic: Textbook question
- Replies: 3
- Views: 297
Re: Textbook question
Since AsF3 is polar, the bonds are stronger meaning it would require more energy to break the bonds. Therefore it would require a greater melting point compared to a non polar molecule like AsF5
- Thu Nov 12, 2020 9:22 pm
- Forum: Ionic & Covalent Bonds
- Topic: Sapling HW Question 13
- Replies: 3
- Views: 250
Sapling HW Question 13
Hi can someone explain how to do this problem? I can't seem to get the correct answer. Urea is an organic compound widely used as a fertilizer. Its solubility in water allows it to be made into aqueous fertilizer solutions and applied to crops in a spray. What is the maximum theoretical number of wa...
- Sun Nov 08, 2020 2:38 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge and Lewis Structures
- Replies: 10
- Views: 551
Re: Formal Charge and Lewis Structures
I think finding the formal charges will make it easier to determine if your structure is the most stable form.
- Sat Nov 07, 2020 7:58 pm
- Forum: Naming
- Topic: Formulas based on names
- Replies: 8
- Views: 1431
Re: Formulas based on names
yeah I would say to just learn the rules for naming the really common formulas. that would really help you during exams and practice problems
- Thu Nov 05, 2020 5:21 pm
- Forum: Lewis Structures
- Topic: Formal Charge
- Replies: 5
- Views: 177
Formal Charge
Is the structure more stable when the formal charges add up to 0, or if they add up to the net charge?
- Thu Nov 05, 2020 5:14 pm
- Forum: Lewis Structures
- Topic: Sapling Homework Problem
- Replies: 5
- Views: 225
Re: Sapling Homework Problem
lewis acids accept electrons while lewis bases donate electrons
- Thu Nov 05, 2020 11:58 am
- Forum: Lewis Structures
- Topic: Sapling HW Question 3
- Replies: 5
- Views: 224
Sapling HW Question 3
Hi could someone explain how to draw the lewis structure for the phosphite ion? I keep getting it wrong and I'm not sure why
- Sun Nov 01, 2020 12:46 pm
- Forum: Photoelectric Effect
- Topic: Sampling Hw #19
- Replies: 2
- Views: 219
Re: Sampling Hw #19
Hi so the only equation you would need is lambda= h/m x v. For each of the particles given all the values stay the same except their masses. So to find velocity I would reorganize the equation to equal v, v=h/m x lambda. Then the only value that would change based on the particle is the mass, and th...
- Sun Nov 01, 2020 12:39 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: when n=5 and l=4
- Replies: 16
- Views: 4626
Re: when n=5 and l=4
If n=5, then l can theoretically equal 0,1,2,...,n-1
- Sun Nov 01, 2020 12:36 pm
- Forum: DeBroglie Equation
- Topic: Sapling HW Question 25
- Replies: 8
- Views: 609
Sapling HW Question 25
Hi I can't figure out how to solve the second part to this problem. The problem says: The E. coli bacterium is about 1.7 μm long. Suppose you want to study it using photons of that wavelength or electrons having that de Broglie wavelength. What is the energy E photon of the photon? What is the energ...
- Sun Nov 01, 2020 12:09 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: ml in quantum numbers
- Replies: 3
- Views: 163
Re: ml in quantum numbers
Hi ml is referring to the orientation of the angular momentum, (like px, py, pz). Each orientation also refers to an orbital in a subshell. For example, px may refer to the first orbital of the p block. This relates to the spin of an electron because since there are two electrons in each orbital, ea...
- Sun Nov 01, 2020 11:58 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: N levels for electron configurations
- Replies: 6
- Views: 377
Re: N levels for electron configurations
Yes as everyone said above l correlates to the subshell. if l=1, then we are in the p subshell
- Sun Oct 25, 2020 8:54 pm
- Forum: Properties of Light
- Topic: Amplitude
- Replies: 9
- Views: 553
Re: Amplitude
yes amplitude is only used in the wave model. when light acts like a photon amplitude does not increase the energy. the only way to increase energy would be to increase frequency.
- Sun Oct 25, 2020 5:17 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: E.23 Part A and C
- Replies: 4
- Views: 362
Re: E.23 Part A and C
I'm pretty sure part A is CuBr2, but either way Megan's steps are correct. If you follow the same steps for part c, (make sure to convert kg of UF6 to g), you should get 430. mol F^- as your answer
- Sun Oct 25, 2020 4:57 pm
- Forum: Properties of Light
- Topic: Balmer or Lyman Series
- Replies: 9
- Views: 344
Re: Balmer or Lyman Series
The Lyman Series ends in n=1 and the Balmer Series ends in n=2. Also, the Lyman Series emits UV light because the gap between n=2 and n=1 is really big. Balmer series emit visible light. So if the problem says that UV light is emitted, you know that it's a Lyman series and that n final= 1. Hope that...
- Sat Oct 24, 2020 9:47 pm
- Forum: DeBroglie Equation
- Topic: Advice for Correct Units for Midterm
- Replies: 8
- Views: 400
Re: Advice for Correct Units for Midterm
yes!! i've noticed that i always make mistakes when i don't write my units throughout the problem. i always make sure to write my units even if it takes a little longer to solve the problem :)
- Sat Oct 24, 2020 9:42 pm
- Forum: Student Social/Study Group
- Topic: Midterm Question
- Replies: 9
- Views: 559
Re: Midterm Question
Yes we will be given constants, equations, and the periodic table. There are two links Professor Lavelle's website with equations and the periodic table. I would highly recommend printing those out! For studying I would just focus on understanding the constants and equations and when to apply them.
- Sun Oct 18, 2020 8:25 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Bohr frequency condition
- Replies: 5
- Views: 211
Re: Bohr frequency condition
yes everyone above is correct. it's basically saying the delta E can be applied to the E=hv equation to solve for frequency.
- Sun Oct 18, 2020 8:07 pm
- Forum: Properties of Light
- Topic: Work Function
- Replies: 3
- Views: 222
Re: Work Function
yes the work function is the threshold energy. to find the work function (if they don't already provide it) you would use the equation Ephoton - work function= kinetic energy
- Fri Oct 16, 2020 2:22 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Lecture 7 Question [ENDORSED]
- Replies: 4
- Views: 282
Re: Lecture 7 Question [ENDORSED]
yes the analogy is a perfect example. the negative sign is to show that the electron is losing energy, but we change it to a positive to calculate for wavelength and frequency, etc. basically to prove the conservation of energy.
- Wed Oct 14, 2020 9:25 pm
- Forum: General Science Questions
- Topic: Balancing equations
- Replies: 19
- Views: 2747
Re: Balancing equations
yes i take similar approaches to everyone above. no matter which approach you take you should get the same answer. a chemical equation only has one correct balanced equation.
- Wed Oct 14, 2020 9:21 pm
- Forum: *Black Body Radiation
- Topic: What is Black Body?
- Replies: 53
- Views: 2530
Re: What is Black Body?
a black body is an object that emits/absorbs all frequencies of light. however, this is a theoretical concept because no such object exists.
- Fri Oct 09, 2020 8:18 pm
- Forum: Properties of Light
- Topic: photoelectric effect
- Replies: 5
- Views: 255
Re: photoelectric effect
That is a great question. In the photoelectric experiment they observed that increasing the intensity of the light did not eject electrons and they concluded that light was not acting like a wave. Instead it was acting like it was made of individual photons, where the individual photon's energy mus...
- Thu Oct 08, 2020 10:02 pm
- Forum: SI Units, Unit Conversions
- Topic: Mole ratios: Don't forget them; how to convert g of one compound to g to an another compound/element.
- Replies: 4
- Views: 293
Re: Mole ratios: Don't forget them; how to convert g of one compound to g to an another compound/element.
Yes! This is a super important concept to understand when trying to find the amount of product produced. This is why knowing how to balance an equation and converting between mols and grams is a key concept. Thanks for this great explanation.
- Thu Oct 08, 2020 9:56 pm
- Forum: SI Units, Unit Conversions
- Topic: Acronym for prefixes
- Replies: 7
- Views: 524
Re: Acronym for prefixes
Thank you for these great acronyms! This will be super helpful when working with prefixes. :)
- Thu Oct 08, 2020 9:19 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: #25 on Molarity and Dilution of a Solution Post Assessment
- Replies: 6
- Views: 344
Re: #25 on Molarity and Dilution of a Solution Post Assessment
I did this post assessment module a few days ago but if I remember correctly I got it right using these steps: Convert the 5.00 g KMnO4 to mols using its molar mass (158.04g/mol) and you'll get 0.0316 mol. Then using the volume you're given, find the molarity of the solution. Make sure to change th...
- Tue Oct 06, 2020 11:33 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: #25 on Molarity and Dilution of a Solution Post Assessment
- Replies: 6
- Views: 344
Re: #25 on Molarity and Dilution of a Solution Post Assessment
I did this post assessment module a few days ago but if I remember correctly I got it right using these steps: Convert the 5.00 g KMnO4 to mols using its molar mass (158.04g/mol) and you'll get 0.0316 mol. Then using the volume you're given, find the molarity of the solution. Make sure to change the...