Search found 102 matches
- Tue Mar 17, 2020 8:09 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Endgame 5d
- Replies: 3
- Views: 470
Re: Endgame 5d
The original equation has 2e- but since every molecule has a stoichiometric coefficient of 2 you can divide the equation by 2, so n=1 instead of 2
- Sat Mar 14, 2020 9:39 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalyst's effect on overall reaction
- Replies: 7
- Views: 448
Re: Catalyst's effect on overall reaction
One way to think of it is remembering the saying "a chain is only as strong as its weakest link". So, if you make the fast step faster, it won't change the fact that the slow step is still slow, which makes the reaction slow, or the "chain weak". In order to make the reaction fas...
- Sat Mar 14, 2020 9:34 am
- Forum: Second Order Reactions
- Topic: Third Order Reactions [ENDORSED]
- Replies: 9
- Views: 702
Third Order Reactions [ENDORSED]
Will we be asked to assess third order reactions on the final? There are a few assigned homework problems which involve them. I think I remember Dr. Lavelle saying we wouldn't address them in this class, but there are assigned problems involved third order reactions
- Sat Mar 14, 2020 9:29 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: when doesn't a solid's temp change?
- Replies: 3
- Views: 368
Re: when doesn't a solid's temp change?
I'm sure it does change but for the purposes of this question I don't think it matters. That may be a topic addressed in more advanced classes but this class seems to simplify thermodynamics to a certain extent, because it is a really complicated topic
- Sat Mar 14, 2020 9:26 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: 7B.1
- Replies: 3
- Views: 293
Re: 7B.1
I think if you're only given one thing (like mass) then you have to plug it in and it will work as long as you are using like values
- Sat Mar 14, 2020 9:24 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Substituing in the rate law
- Replies: 1
- Views: 148
Substituing in the rate law
How do you know when you need to substitute in the rate law? I.e. like the last example in Dr. Lavelle's review slides
- Wed Mar 04, 2020 3:49 pm
- Forum: Van't Hoff Equation
- Topic: 5J.15
- Replies: 3
- Views: 428
Re: 5J.15
There are multiple ways to get the answer, Van't Hoff's equation is one, but you can use △G=-RTlnK and just change the T value when solving for K which would give you K at that temperature
- Wed Mar 04, 2020 3:46 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Liquids in cell diagrams
- Replies: 2
- Views: 146
Re: Liquids in cell diagrams
Yeah, as the previous poster said you dont need to include H2O because it is assumed to be in the equation. But, if there is another liquid, you do have to include it. Additionally, if the two reactions occur in the same solution, then you have to add Platinum (Pt)
- Wed Mar 04, 2020 3:43 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6N.3 part c
- Replies: 2
- Views: 258
Re: 6N.3 part c
Yes, you need to convert Torr into atm. The conversion is 1atm=760 Torr
- Wed Mar 04, 2020 3:41 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Calculating Gibbs Free Energy
- Replies: 6
- Views: 419
Re: Calculating Gibbs Free Energy
G=H-TS
Enthalpy (H) and entropy (S) take into account stoichiometric coefficients, so I guess you could say that G requires you take into account stoichiometric coefficients. However, when calculating G in regards to electrochemistry, you do not take them into account.
Enthalpy (H) and entropy (S) take into account stoichiometric coefficients, so I guess you could say that G requires you take into account stoichiometric coefficients. However, when calculating G in regards to electrochemistry, you do not take them into account.
- Mon Mar 02, 2020 4:36 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Electrolysis
- Replies: 2
- Views: 219
Electrolysis
What is electrolysis and how does it apply to what we've learned about redox reactions, etc?
- Fri Feb 28, 2020 2:48 pm
- Forum: Balancing Redox Reactions
- Topic: 6K.1 part b
- Replies: 1
- Views: 106
Re: 6K.1 part b
You add electrons to balance the charges of either side of the reaction. Also, you have to multiply an equation by a number sometimes in order to get the electrons in both half reactions to cancel out
- Fri Feb 28, 2020 2:40 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Corrosion Causes
- Replies: 1
- Views: 114
Corrosion Causes
What causes corrosion and how is it an example of a redox reaction?
- Fri Feb 28, 2020 2:37 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: finding top of your series
- Replies: 3
- Views: 285
Re: finding top of your series
I think the strongest oxidizing agent is the one that has the most positive E value. So, for example Ag+ + e- -> Ag (E=.80V) and AgBr + e- -> Ag + Br-(E= .07V). In this case, the first reaction is the better oxidizing agent
- Fri Feb 28, 2020 2:29 pm
- Forum: Balancing Redox Reactions
- Topic: Writing half reactions
- Replies: 9
- Views: 632
Re: Writing half reactions
I think it's best to keep oxidized molecules on the left and reduced on the right because this is how you write out cell diagrams (oxidized II reduced)
- Fri Feb 28, 2020 2:26 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 5g. 13)
- Replies: 3
- Views: 254
Re: 5g. 13)
The solution is simply substituting variables; standard delta G = -RTlnK to give the equation Delta G= -RTlnK + RTlnQ. I don't believe it has anything to do with equilibrium
- Wed Feb 19, 2020 7:33 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox
- Replies: 5
- Views: 361
Re: Balancing Redox
What about for the transition metals? How do you determine the charges of those?
- Wed Feb 19, 2020 7:31 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: E as intensive property
- Replies: 5
- Views: 357
E as intensive property
In class it was said that E was an intensive property. What does that mean and what are the implications for our use of E and calculating it?
- Wed Feb 19, 2020 7:28 pm
- Forum: Van't Hoff Equation
- Topic: 5G.21
- Replies: 4
- Views: 507
Re: 5G.21
You’d use the equation G=-RTlnK. You want to solve for K so you’d rearrange the equation to be -G/RT=lnK. You have all the values needed besides G which you can get from appendix 2A, and then you solve for K!
- Wed Feb 19, 2020 7:25 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 5G.3 Reading in Outline 4
- Replies: 1
- Views: 121
Re: 5G.3 Reading in Outline 4
I would assume not if it’s not in the outlines on the class website. There’s a lot of topics in the book that aren’t taught so just look at the syllabus for clarification
- Wed Feb 19, 2020 5:56 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: converting T to kelvin
- Replies: 46
- Views: 3318
Re: converting T to kelvin
I think it's important to convert C to K just to be safe; a lot of times using K will make it so the units cancel, so I just always convert C to K to be safe
- Tue Feb 11, 2020 9:18 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Partial Pressure equilibrium problems
- Replies: 2
- Views: 185
Partial Pressure equilibrium problems
How do you go about solving problems asking for the partial pressure of the reactants/products? Would you solve for the partial pressure first and then complete the ICE table or...?
- Tue Feb 11, 2020 9:16 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: U(total)=(3/2)nrt
- Replies: 2
- Views: 190
Re: U(total)=(3/2)nrt
using 3/2R is for if there is constant volume in the process
- Tue Feb 11, 2020 9:14 am
- 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: 4G.5 Trans Isomer
- Replies: 1
- Views: 62
Re: 4G.5 Trans Isomer
The two red molecules only have to be opposite of each other; so, they can be in the orientation shown in the diagram, or they could be on the horizontal plane, across from each other in two different ways
- Tue Feb 11, 2020 9:11 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 4F.3 Reversible Process
- Replies: 2
- Views: 98
Re: 4F.3 Reversible Process
Maybe it's because the heat can be given off from the copper block?
- Tue Feb 11, 2020 9:09 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Delta S(total)
- Replies: 3
- Views: 81
Re: Delta S(total)
Since entropy is a state function, Delta S could be equal to zero if you return to your "starting point". So, if you increase the volume of a container containing gas and then compress it to its original volume, delta S would be zero
- Wed Feb 05, 2020 2:57 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: q/T=H/T
- Replies: 1
- Views: 126
q/T=H/T
Today in lecture, Dr Lavelle had a slide going over entropy in phase changes and one equation on that page said q(rev)/T=deltaH/T. Can someone please explain this concept?
- Wed Feb 05, 2020 2:55 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: heat given off by rxn = - heat absorbed by solution
- Replies: 6
- Views: 289
Re: heat given off by rxn = - heat absorbed by solution
Yeah, whenever a system loses energy in whatever form, that value will be negative. But, that energy must go somewhere else so the energy will be absorbed by another system, so it will be positive for that system
- Wed Feb 05, 2020 2:53 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: 130
3rd Law
Can someone please explain what the 3rd law of thermo says? I wasn't quite clear on it when Lavelle explained it, I felt like it was very brief. Thanks!
- Wed Feb 05, 2020 2:51 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: internal energy of an ideal gas
- Replies: 2
- Views: 161
Re: internal energy of an ideal gas
In addition to the previous poster, since the reaction is isothermal, the temperature is constant, so the heat can slowly enter the system and offset the energy lost by work. It's important to note that this happens when the reaction is isothermal
- Wed Feb 05, 2020 2:48 pm
- Forum: Calculating Work of Expansion
- Topic: Understanding equation for work at constant pressure
- Replies: 3
- Views: 134
Re: Understanding equation for work at constant pressure
Do you mean w= -nRTln(V2/V1)? This equation comes from taking the integral of (nRT)(dV)/V. You can pull the constants out in front of the integral sign so you have -nRT multiplied by the integral of dv/V from V1 to V2, which is ln(V2/V1)
- Fri Jan 31, 2020 7:10 pm
- Forum: Calculating Work of Expansion
- Topic: Difference between irreversible/reversible reaction?
- Replies: 2
- Views: 158
Difference between irreversible/reversible reaction?
What is the difference between irreversible/reversible reactions? Can someone please give an example?
- Fri Jan 31, 2020 7:08 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: When to leave out reactants/products from enthalpy calculations
- Replies: 4
- Views: 146
When to leave out reactants/products from enthalpy calculations
How do you know when a compound is in its purest form, aka when it won't impact enthalpy change?
- Fri Jan 31, 2020 7:04 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes
- Replies: 17
- Views: 704
Re: Phase Changes
The temperature must be high enough to cause the phase change but not high enough to cause the system to change temperature
- Fri Jan 31, 2020 7:02 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q=nCT
- Replies: 2
- Views: 1525
q=nCT
For this equation, will n always be in moles? In the book solutions, I've seen both moles and grams used and am not sure when to use which
- Fri Jan 31, 2020 6:50 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4A.13
- Replies: 4
- Views: 119
4A.13
In the solution, it shows q(reaction) equal to -q(calorimeter). Why is this? And how do you know when to use this method?
- Thu Jan 23, 2020 12:58 pm
- Forum: Ideal Gases
- Topic: Equilibrium Constant
- Replies: 7
- Views: 236
Re: Equilibrium Constant
K is represented by the products/reactants. So, if K is really small (less than 10^-3) then there are more reactants than products
- Thu Jan 23, 2020 12:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Buffers
- Replies: 3
- Views: 119
Buffers
How do you know when it's appropriate to make a buffer? As in, what in a question tells you you need to make a buffer?
- Thu Jan 23, 2020 12:25 pm
- Forum: Phase Changes & Related Calculations
- Topic: State Property
- Replies: 6
- Views: 361
Re: State Property
A state property does not depend on the path taken to obtain that state. Some examples are energy, pressure, volume, and temperature
- Thu Jan 23, 2020 12:22 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heating curve
- Replies: 2
- Views: 229
Re: Heating curve
https://s3-us-west-2.amazonaws.com/courses-images/wp-content/uploads/sites/752/2016/09/26195026/ating-20curve-20of-20water.jpeg maybe this picture of the heating curve for water will help. As the previous poster said, it requires a lot of energy to turn water into a vapor which is why steam can cau...
- Thu Jan 23, 2020 12:12 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Buffers
- Replies: 3
- Views: 99
Re: Buffers
Lavelle gave an example of creating a buffer in class so I would think it's possible for it to be on the test, or even the midterm and final
- Thu Jan 16, 2020 4:01 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in pressure effect on reactions
- Replies: 3
- Views: 78
Change in pressure effect on reactions
How does a reaction respond in response to pressure? I was confused when Lavelle was explaining this in class
- Thu Jan 16, 2020 3:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When to find pressure for equilibrium problems
- Replies: 3
- Views: 127
When to find pressure for equilibrium problems
When do we have to find the partial pressure for the gases involved in an equilibrium problem? There are gases in essentially every equilibrium problem but their partial pressures are not always calculated.
- Thu Jan 16, 2020 3:54 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q and K
- Replies: 4
- Views: 116
Q and K
What does it mean in terms of which way the reaction will proceed if Q is less than K? Greater than K?
- Thu Jan 16, 2020 3:53 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: percentage reacted
- Replies: 3
- Views: 120
Re: percentage reacted
To find x, you would set .133-x (the statement for the final H2 concentration) equal to .40 x .133mol/L because 60% of the H2 was used, so 40% remains
- Thu Jan 16, 2020 3:47 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Inert Gas
- Replies: 7
- Views: 299
Inert Gas
How do you tell if a gas is an inert gas?
- Sat Jan 11, 2020 7:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: States of matter [ENDORSED]
- Replies: 4
- Views: 156
Re: States of matter [ENDORSED]
solids/liquids aren't included in the equilibrium constant because their concentrations don't change enough to affect K
- Tue Jan 07, 2020 3:16 pm
- Forum: Ideal Gases
- Topic: ICE Table Variables
- Replies: 6
- Views: 275
Re: ICE Table Variables
Using "x" in the ICE tables would definitely be helpful if the problem is complicated enough, but if it's simple and you can figure out the change without variables, that might be easier
- Tue Jan 07, 2020 3:10 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: How to make ICE box
- Replies: 17
- Views: 1231
How to make ICE box
I understand the initial and equilibrium rows in the ICE box but how do you figure out the change row? That is, how do you figure out what the change in concentration will be?
- Tue Jan 07, 2020 3:06 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: HW 5I.5
- Replies: 3
- Views: 160
HW 5I.5
What does the unit bar stand for in problem I5? Is it just another unit for pressure?
- Tue Jan 07, 2020 3:03 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc vs Kp
- Replies: 2
- Views: 130
Kc vs Kp
when do you write the equilibrium constant as Kc as opposed to Kp?
- Mon Dec 02, 2019 1:56 pm
- Forum: Octet Exceptions
- Topic: 2.27
- Replies: 7
- Views: 660
Re: 2.27
Yes, only species with odd numbers of electrons are radicals (ex CH3 has 7 valence electrons so it is a radical)
- Mon Dec 02, 2019 1:51 pm
- Forum: Lewis Acids & Bases
- Topic: Relationship between Bronsted and Lewis Acids and Bases
- Replies: 2
- Views: 86
Relationship between Bronsted and Lewis Acids and Bases
What is the relationship between Bronsted and Lewis acids and bases? Can a molecule be both?
- Mon Dec 02, 2019 1:44 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: Stronger london forces
- Replies: 1
- Views: 149
Stronger london forces
what can make london forces stronger?
- Mon Dec 02, 2019 1:38 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelating complexes
- Replies: 6
- Views: 367
Chelating complexes
What makes it possible for a chelate to form and how could you tell if it was possible?
- Mon Dec 02, 2019 1:33 pm
- Forum: Biological Examples
- Topic: Chromium, Iron, Cobalt functioms
- Replies: 1
- Views: 116
Chromium, Iron, Cobalt functioms
What are the functions of Cr, Fe, and Co in biological systems? And how deeply will we be expected to know how they perform their function?
- Mon Dec 02, 2019 1:25 pm
- Forum: Hybridization
- Topic: Textbook Focus
- Replies: 2
- Views: 223
Re: Textbook Focus
I don't think there's any specific reason why sp3 is focused on. It is very common but there isn't anything special about it as far as I know.
- Mon Dec 02, 2019 1:24 pm
- Forum: Conjugate Acids & Bases
- Topic: Conjugate vs Bronsted acids/bases
- Replies: 4
- Views: 242
Re: Conjugate vs Bronsted acids/bases
Bronsted acid: a species that donates a proton Bronsted base: a species that accepts a proton Conjugate base: what is left over after an acid donates a proton Conjugate acid: what is formed when a base accepts a proton Bronsted acids have conjugate bases and Bronsted bases have conjugate acids. In t...
- Mon Dec 02, 2019 1:18 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: seesaw
- Replies: 4
- Views: 247
Re: seesaw
KA x KB= KW
So, as KA increases, KB will decrease. As KB increases, KA will decrease. The two values must always equal KW so they will change in accordance with the concentration of one another.
So, as KA increases, KB will decrease. As KB increases, KA will decrease. The two values must always equal KW so they will change in accordance with the concentration of one another.
- Mon Dec 02, 2019 1:16 pm
- Forum: Amphoteric Compounds
- Topic: 6A17
- Replies: 2
- Views: 116
Re: 6A17
For me, I had trouble with knowing how c and d were amphoteric. Metalloids are amphoteric and they are marked on the periodic table as the elements that are between the metals and nonmetals; they follow a diagonal band.
- Mon Dec 02, 2019 1:13 pm
- Forum: Bronsted Acids & Bases
- Topic: Lecture 12/2
- Replies: 3
- Views: 220
Lecture 12/2
At the end of class Lavelle said that something about weak acids and bases affecting pH... did he say that weak acids and bases DO affect pH or do NOT affect pH? I didn't catch it. Thanks!
- Sat Nov 23, 2019 10:25 pm
- Forum: Naming
- Topic: English v Latin names
- Replies: 2
- Views: 142
English v Latin names
When is it appropriate to use the English and latin name of an element when naming a coordination compound?
- Sat Nov 23, 2019 10:24 pm
- Forum: Resonance Structures
- Topic: Bond Length/Delocalized Electrons
- Replies: 2
- Views: 288
Re: Bond Length/Delocalized Electrons
Resonance structures cause the length of a bond to change slightly. Although there are multiple lewis structures for resonance structures, the true structure of the molecule is a blend of the resonance structures. This means the bond lengths are a blend between single, double bonds, causing the bond...
- Sat Nov 23, 2019 10:21 pm
- Forum: Sigma & Pi Bonds
- Topic: HW 2F.3.
- Replies: 5
- Views: 917
Re: HW 2F.3.
Yes, the most important thing is to draw the Lewis structure correctly and then from there it should be simple using the rules the previous poster stated to count the sigma and pi bonds
- Sat Nov 23, 2019 10:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T-shaped v. Trigonal pyramid
- Replies: 9
- Views: 523
Re: T-shaped v. Trigonal pyramid
T- shaped has a trigonal bipyramidal arrangement, but has 2 lone pairs and 3 bonds (AX3E2). Trigonal pyramid has a tetrahedral arrangement but has one lone pair and 3 bonding pairs (AX3E)
- Thu Nov 21, 2019 4:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angles for trigonal bipyramidal and octahedral
- Replies: 2
- Views: 116
Bond angles for trigonal bipyramidal and octahedral
What are the bond angles for Trigonal Bipyramidal and octahedral arrangements when they have one and two lone pairs? i.e. bond angles for seesaw, t shaped, square pyramidal and square planar?
- Sat Nov 16, 2019 4:32 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: strongest intermolecular forces
- Replies: 7
- Views: 703
strongest intermolecular forces
What are the strongest intermolecular forces in order? I know induced dipole-induced dipole is the weakest but where do the other forces fall into the ranking of strongest intermolecular forces?
- Sat Nov 16, 2019 4:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Octahedral with lone pair(s) shape
- Replies: 1
- Views: 115
Octahedral with lone pair(s) shape
What shape would you get if a molecule with an octahedral arrangement has one lone pair? Two lone pairs?
- Sat Nov 16, 2019 4:15 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: Types of Forces
- Replies: 2
- Views: 150
Re: Types of Forces
All molecules can have induced dipole-induced dipole bonding, even polar ones. Problem 3f.1 in the book is an example of this. Part (a) and (d) are listed as being able to have induced dipole-induced dipole interactions along with dipole-dipole interactions
- Sat Nov 16, 2019 4:12 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Dipole-dipole in H2SeO4
- Replies: 3
- Views: 408
Re: Dipole-dipole in H2SeO4
The structure of this molecule would have Se at the center and 4 oxygen's around it, then hydrogens bonded to the oxygens. This causes the molecule to be polar because O and H have a significant enough electronegativity difference to cause a polar bond. Therefore this molecule can have dipole-dipole...
- Sat Nov 16, 2019 4:09 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: 576
Boiling Points
What intermolecular forces cause higher boiling points? Lower boiling points? And what are some examples?
- Sat Nov 09, 2019 6:29 pm
- Forum: Dipole Moments
- Topic: Dipole-Dipole Interactions / H-bonding
- Replies: 2
- Views: 169
Re: Dipole-Dipole Interactions / H-bonding
Yes, hydrogen bonding is a type of dipole-dipole interaction. It is not as strong as covalent or ionic bond
- Sat Nov 09, 2019 6:25 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarisability
- Replies: 3
- Views: 219
Re: Polarisability
Larger molecules are more polarizable because the electrons in the outer shell are easier to take away. This is because they are "shielded" from the nucleus by the other electrons so they can be taken away from the atom easier.
- Sat Nov 09, 2019 6:18 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polairzability characteristics
- Replies: 3
- Views: 217
Polairzability characteristics
In lecture on Friday, Lavelle said that if an atom is highly polarizable, it is solid at room temperature. Why is this?
- Sat Nov 09, 2019 6:14 pm
- Forum: Bond Lengths & Energies
- Topic: Hydrogen Bonding melting point
- Replies: 3
- Views: 114
Hydrogen Bonding melting point
Why does hydrogen bonding explain higher melting points? I missed Lavelle's explanation on why this was the case
- Sat Nov 09, 2019 6:06 pm
- Forum: Electronegativity
- Topic: Periodic Trend
- Replies: 13
- Views: 748
Re: Periodic Trend
Electronegativity increases up a column and left to right across a period. The noble gasses are exceptions because they have a full octet so they are not trying to take any electrons. One way to think of electronegativity is how bad an atom wants an electron.
- Sat Nov 02, 2019 9:23 am
- Forum: Resonance Structures
- Topic: Tips for drawing resonance structures
- Replies: 3
- Views: 129
Tips for drawing resonance structures
Does anyone have any advice for figuring out the various resonance structures?
- Sat Nov 02, 2019 9:21 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron configuration rules
- Replies: 1
- Views: 556
Electron configuration rules
What do each of the rules for electron configurations ( pauli's, hund's, aufbau) mean and what would and electron configuration look like if you violated them?
- Sat Nov 02, 2019 9:19 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Electron configuration rules
- Replies: 1
- Views: 102
Electron configuration rules
What do each of the rules for electron configurations ( pauli's, hund's, aufbau) mean and what would and electron configuration look like if you violated them?
- Sat Nov 02, 2019 9:15 am
- Forum: Trends in The Periodic Table
- Topic: Electronegativity trend exception
- Replies: 3
- Views: 2230
Electronegativity trend exception
Last night in the review session with Lyndon, it was said that Nitrogen has a higher electronegativity than oxygen. Can someone explain why this is?
- Sat Nov 02, 2019 9:13 am
- Forum: Properties of Light
- Topic: Wavelengths
- Replies: 2
- Views: 133
Re: Wavelengths
yeah, I don't think we need to know exact cutoffs but it is important to know in what range visible light is and the ranges for infrared and ultraviolet. ultraviolet light is less than 400nm and infrared is more than 700nm. You don't have to state any info about the light type or if its visible unle...
- Sat Nov 02, 2019 9:06 am
- Forum: Octet Exceptions
- Topic: Octet Exception
- Replies: 5
- Views: 252
Re: Octet Exception
The elements in period three and the subsequent periods along with the column 13 elements are exceptions to the octet rule
- Fri Oct 25, 2019 4:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: ground-state configuration of ions
- Replies: 4
- Views: 147
Re: ground-state configuration of ions
Yes, it is [Ar] 3d^10 because Cu+ loses an electron. When this type of situation comes up, you always remove or add an electron from the outer shell
- Fri Oct 25, 2019 4:13 pm
- Forum: Octet Exceptions
- Topic: Determining Exceptions
- Replies: 3
- Views: 245
Re: Determining Exceptions
So far the only exception to the octet rule that we've learned is that atoms in period 3 and higher can have more than 8 electrons in their outer shell due to the possibility of having a d orbital (as l can equal 0,1, and 2 when n=3)
- Fri Oct 25, 2019 4:09 pm
- Forum: Trends in The Periodic Table
- Topic: Stable Structures
- Replies: 5
- Views: 351
Re: Stable Structures
Yes, you use FC = V - (L + S/2). Not all structures will have a formal charge equal to 0 but you want to find the structure that is closest to that value. Also, remember you have to find the formal charge for each atom
- Fri Oct 25, 2019 4:04 pm
- Forum: Resonance Structures
- Topic: Delocalization
- Replies: 2
- Views: 124
Re: Delocalization
Like the previous poster said, delocalization is when there is resonance in the structure of the molecule. You know an electron is delocalized when it is possible for structures to have multiple bonds in different locations (ex. NO3 example from class; the double bond with nitrogen and oxygen can be...
- Fri Oct 25, 2019 3:59 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 6
- Views: 845
Re: Formal Charge
The formal charge is the charge on each atom and it is calculated after a Lewis structure is made. They are useful to calculate so you know "good" you structure is; the closer the formal charge is to zero, the better the model
- Thu Oct 17, 2019 10:13 am
- Forum: Properties of Electrons
- Topic: 1B. 15C [ENDORSED]
- Replies: 4
- Views: 265
Re: 1B. 15C [ENDORSED]
The energy required to remove the electron is added to the electron's kinetic energy because you need the total energy that caused the electron not only to be ejected but to be ejected at 3.63 x 10^3 km/s. So, because the electron was ejected at that speed, the energy required to eject it is added t...
- Thu Oct 17, 2019 10:08 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbital shapes
- Replies: 3
- Views: 118
Orbital shapes
Is there a trick to remembering what all the orbital shapes look like? As in, is there a method to remembering what dxy, dy2, d2x,dx2y2, etc all look like?
- Thu Oct 17, 2019 10:02 am
- Forum: Properties of Light
- Topic: Vacuum
- Replies: 3
- Views: 134
Re: Vacuum
I agree with the previous post, but to simplify it, being in a vacuum means there are no outside forces working on a given thing.
- Thu Oct 17, 2019 10:00 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: HW D13
- Replies: 3
- Views: 150
HW D13
For part c and d, how would you go about determining the values asked for from the given state of the electron? I guess my bigger question is how would you figure out values of n,l, and ml from a given 6d subshell, or something like that?
- Thu Oct 17, 2019 9:57 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Spin State
- Replies: 17
- Views: 378
Spin State
What do the +1/2 and -1/2 mean with regards to spin state? Is it the direction in which the electron spins? And how would the spin state be determined?
- Sat Oct 12, 2019 3:16 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Textbook 1B.25
- Replies: 1
- Views: 82
Re: Textbook 1B.25
The equation for the uncertainty equation is (delta p)(delta x)>(h)/(4pi), where h is planck's constant of 6.63x10^-34, delta p is the spread in values of momentum, and delta x is the spread in values of distance.
Hopefully that helps with the mathematical representation.
Hopefully that helps with the mathematical representation.
- Sat Oct 12, 2019 3:07 pm
- Forum: Photoelectric Effect
- Topic: Molecular Spectroscopy
- Replies: 3
- Views: 148
Re: Molecular Spectroscopy
It can be, as, just like various atoms, various molecules absorb different types of light, just like atoms.
- Sat Oct 12, 2019 2:59 pm
- Forum: Properties of Electrons
- Topic: Wavelike properties of electrons
- Replies: 3
- Views: 149
Re: Wavelike properties of electrons
Wavelike properties can be seen in very small things (like an electron) with a high velocity. This why wavelike properties are noticed in electrons, and not other objects like a car. All things have wavelike properties but they are not detectable. In the car example, it is too large for its waveleng...
- Sat Oct 12, 2019 2:52 pm
- Forum: Properties of Light
- Topic: Equations
- Replies: 4
- Views: 127
Re: Equations
Most of the equations we've learned to apply to EMR, but as others have said, not the De Broglie Equation. Something that may help you remember this is that most of the equations we've learned have similar or related variables and the De Broglie equation involves mass and velocity (momentum) so they...
- Sat Oct 12, 2019 2:45 pm
- Forum: Limiting Reactant Calculations
- Topic: percent yield
- Replies: 10
- Views: 803
Re: percent yield
I believe you only find the percent yield if it is asked in the question, but there may be some scenarios where you need it for a step in the problem. Also, questions don't always explicitly ask what they want you to find so be aware of that
- Thu Oct 03, 2019 3:07 pm
- Forum: Limiting Reactant Calculations
- Topic: Fundamentals M15
- Replies: 3
- Views: 186
Fundamentals M15
For problem M15, how would I go about this problem? Not really sure where to start
- Thu Oct 03, 2019 3:02 pm
- Forum: Balancing Chemical Reactions
- Topic: Fundamentals H21
- Replies: 2
- Views: 234
Fundamentals H21
For this problem, how would you write its chemical formula? I understand the corresponding compounds for carbon dioxide, oxygen, and water, but I'm not sure about the aqueous solution part of the products.
- Thu Oct 03, 2019 2:51 pm
- Forum: Balancing Chemical Reactions
- Topic: Fundamentals L39
- Replies: 2
- Views: 133
Fundamentals L39
I'm a bit confused on how to go about this problem. Does anybody have any hints or ideas? How would we know what the oxide is?