Search found 101 matches
- Mon Mar 16, 2020 1:48 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration Cells
- Replies: 9
- Views: 671
Re: Concentration Cells
But doesn't the concentrations of the reactants and products in a concentration cell have to be different in order to generate voltage?
- Mon Mar 16, 2020 1:46 pm
- Forum: *Enzyme Kinetics
- Topic: Catalysts and enthalpy
- Replies: 6
- Views: 2416
Re: Catalysts and enthalpy
One of the main things that a catalyst does is change the amount of work that a system does.
- Mon Mar 16, 2020 12:11 pm
- Forum: *Enzyme Kinetics
- Topic: catalysts
- Replies: 4
- Views: 443
Re: catalysts
I think it's that a catalyst directly affects one step of a reaction, but has an effect on the entire reaction as a whole.
- Mon Mar 16, 2020 12:10 pm
- Forum: *Enzyme Kinetics
- Topic: Lecture 3/6
- Replies: 2
- Views: 339
Re: Lecture 3/6
We also discussed how to approach proposed reaction mechanisms with multiple steps.
- Mon Mar 16, 2020 11:49 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Exothermic reactions
- Replies: 5
- Views: 414
Re: Exothermic reactions
So basically what you are saying is that a decrease in temperature will decrease the rate of an exothermic reaction?
- Sun Mar 08, 2020 4:59 pm
- Forum: First Order Reactions
- Topic: preferred form of rates
- Replies: 2
- Views: 218
Re: preferred form of rates
They are both correct, but it's a lot more preferred to have it written out in the provided formula that's given "-1/a d[A]/dt = 1/b d[B]dt = 1/c d[C]/dt"
- Sun Mar 08, 2020 4:46 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Reaction Mechanism and Method of Initial Rates
- Replies: 2
- Views: 213
Re: Reaction Mechanism and Method of Initial Rates
I think that he said that we could?
- Sun Mar 08, 2020 4:43 pm
- Forum: General Rate Laws
- Topic: affect of temperature on K
- Replies: 4
- Views: 319
Re: affect of temperature on K
If the reverse reaction is favored and k' is the constant for the reverse reaction, shouldn't that one increase as well? I mean, I know it's a constant, but since the temperature has an effect on k then it should change right?
- Sun Mar 08, 2020 4:37 pm
- Forum: General Rate Laws
- Topic: the variable A
- Replies: 4
- Views: 322
Re: the variable A
The variable A is the frequency or the pre-exponential factor.
- Sun Mar 08, 2020 4:35 pm
- Forum: General Rate Laws
- Topic: Ammonia rate of consumption
- Replies: 1
- Views: 165
Re: Ammonia rate of consumption
I like to think that the rate of consumption has to do with the rate of the slowest step of the reaction rather than the concentration of ammonia.
- Sun Mar 01, 2020 5:28 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Calculating Q
- Replies: 3
- Views: 303
Re: Calculating Q
I get that Q is [products]/[reactants] but why, for galvanic cells, is it anode/cathode?
- Sun Mar 01, 2020 5:25 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Corrosion
- Replies: 5
- Views: 389
Re: Corrosion
I don't remember learning this in class? Is this in any of the textbook sections that we have for homework?
- Sun Mar 01, 2020 4:51 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Deriving the Nernst Equation
- Replies: 3
- Views: 331
Re: Deriving the Nernst Equation
If it has the naught then that means it is at standard conditions. I think you can use the equation just fine not at standard conditions, you just have to do it without the naught?
- Sun Mar 01, 2020 4:49 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: When to use units of mole?
- Replies: 2
- Views: 215
Re: When to use units of mole?
Would it not be better to just include the unit in your calculations? I'm not too sure if you can just leave it out or not.
- Sun Mar 01, 2020 4:47 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration Cells
- Replies: 4
- Views: 311
Concentration Cells
Can someone explain to me how concentration cells are different from the regular galvanic cells we learned about in class? Also, why is the standard cell potential 0 in these types of cells?
- Sun Feb 23, 2020 9:56 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 9
- Views: 510
Re: Test 2
Is the general topic of Test 2 going to be Gibb's Free Energy and Electrochemistry?
- Sun Feb 23, 2020 9:54 pm
- Forum: Balancing Redox Reactions
- Topic: Gas Rxns
- Replies: 2
- Views: 237
Re: Gas Rxns
Can redox reactions happen with the reactants and products in their gaseous states, and can water still be used to balance the reaction?
- Sun Feb 23, 2020 9:51 pm
- Forum: Balancing Redox Reactions
- Topic: Reduction?
- Replies: 13
- Views: 620
Re: Reduction?
The part of the redox reaction that is the reduction half-reaction is the one that gains the electron. If you remember the term OILRIG, then you'll be alright (Oxidation is Lose, Reduction is Gain).
- Sun Feb 23, 2020 9:44 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram, what to include
- Replies: 3
- Views: 244
Re: Cell Diagram, what to include
There can also be acidic and basic redox reactions. So that's why there may be H+ ions?
- Sun Feb 23, 2020 9:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Potentials
- Replies: 2
- Views: 189
Re: Cell Potentials
In class we learned about two different equations, that kinda gave the same answer for some of the cell potential questions. But they aren't different methods for the same thing, are they? Aren't they equations for different things?
- Sun Feb 16, 2020 10:16 pm
- Forum: Balancing Redox Reactions
- Topic: Charge of permanganate
- Replies: 5
- Views: 331
Re: Charge of permanganate
In general, you just add the charges up of all the elements in the compound and you should get the total charge.
- Sun Feb 16, 2020 10:14 pm
- Forum: Balancing Redox Reactions
- Topic: easier to split?
- Replies: 6
- Views: 410
Re: easier to split?
By the way, it's not meant literally, but figuratively. He separates the reaction equation into parts so that it would be easier to understand.
- Sun Feb 16, 2020 10:13 pm
- Forum: Balancing Redox Reactions
- Topic: Oxygen and Hydrogen
- Replies: 4
- Views: 221
Re: Oxygen and Hydrogen
Free elements have an oxidation number of 0 though, right?
- Sun Feb 16, 2020 10:11 pm
- Forum: Balancing Redox Reactions
- Topic: Oxygen
- Replies: 9
- Views: 415
Re: Oxygen
Is "oxidation number" the number that is assigned to an element because it's missing a certain amount of electrons to reach an octet, or is it only used for when elements are oxidized in redox reactions?
- Sun Feb 16, 2020 10:09 pm
- Forum: Balancing Redox Reactions
- Topic: In Class Example
- Replies: 4
- Views: 282
Re: In Class Example
I don't think you have to do it this way, but it makes things a lot easier to see and understand.
- Sat Feb 08, 2020 6:20 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calorimeter
- Replies: 5
- Views: 373
Re: Calorimeter
Usually, the heat capacity of a Calorimeter is already known, so that way scientists can use them to find the heat capacities or other factors of the materials placed in them.
- Sat Feb 08, 2020 6:16 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: Error in Boltzmann Equation
- Replies: 4
- Views: 257
Re: Error in Boltzmann Equation
Does this mean that making a large error in W, will make a small error in S? How do they correlate with each other?
- Sat Feb 08, 2020 6:14 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: degeneracy
- Replies: 17
- Views: 598
Re: degeneracy
Degeneracy was talked about in the lecture. I think it was the lecture about the number of possible positions for a molecule or something like that.
- Sat Feb 08, 2020 6:12 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Difference between Molar Entropy and Standard Residual Entropy
- Replies: 3
- Views: 529
Re: Difference between Molar Entropy and Standard Residual Entropy
The denotation from Standard Residual Entropy is W, right?
- Sat Feb 08, 2020 6:10 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Delta S=0 for elemental molecules?
- Replies: 2
- Views: 517
Re: Delta S=0 for elemental molecules?
The Delta S for formation is 0 because they are already in their standard states. That's how they are found in nature. Trying to find the change in entropy for the formation of standard states from their standard states, is like trying to change something into the thing they already are, like trying...
- Sat Feb 01, 2020 6:02 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Elements
- Replies: 8
- Views: 135
Re: Elements
I'm not really sure I can explain this all that well, but it's something along the line of this: You're trying to form the standard state of something from something, yes? So the energy from that is the standard enthalpy of formation. For a substance like O2 gas, which is the standard state of its e...
- Sat Feb 01, 2020 5:58 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: isolated system
- Replies: 13
- Views: 606
Re: isolated system
Another silly example, that I had once done in high school I think, was a double-layered foam cup. It was very crude, but it got the job done.
- Sat Feb 01, 2020 5:56 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Reversible vs Irreversible formula
- Replies: 4
- Views: 166
Re: Reversible vs Irreversible formula
So if the pressure of the system is not constant, then the formula is reversible?
- Sat Feb 01, 2020 5:54 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Closed Systems
- Replies: 8
- Views: 389
Re: Closed Systems
An example that Dr. Lavelle gave us in class between the difference between the closed and isolated systems is that typically the isolated system is insulated. This way, since the system is insolated, it can't transfer energy with its surroundings. A closed system is, however, not insulated. That me...
- Sat Feb 01, 2020 5:51 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Pressure in an open beaker
- Replies: 12
- Views: 735
Re: Pressure in an open beaker
Since the beaker is an open system, you can assume that the pressure is whatever the atmospheric pressure is. Unless you are somehow constantly changing in elevations or something else, I think you can otherwise assume that the pressure is constant?
- Sat Jan 25, 2020 4:06 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard Reaction Enthalpies
- Replies: 2
- Views: 49
Re: Standard Reaction Enthalpies
So are you saying that the standard reaction enthalpy is 0 when a reaction does not occur under standard conditions?
- Sat Jan 25, 2020 4:04 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Help
- Replies: 1
- Views: 86
Re: Help
Is this a homework problem that we have to do?
- Sat Jan 25, 2020 4:03 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: standard enthalpy
- Replies: 2
- Views: 41
Re: standard enthalpy
I kind of just think about it as the standard enthalpy is when the system is in standard conditions or something. Like when everything is kept constant and is managed. That's what we learned in LS 7A at least.
- Sat Jan 25, 2020 4:01 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam v. liquid
- Replies: 7
- Views: 257
Re: Steam v. liquid
The release of energy on the skin is largely different and that's what causes the burns since it's so much larger for steam.
- Sat Jan 25, 2020 4:00 pm
- Forum: Phase Changes & Related Calculations
- Topic: Constant pressure and constant volume
- Replies: 3
- Views: 148
Re: Constant pressure and constant volume
Have we learned about how heat, work, and internal energies respond to these yet?
- Sat Jan 25, 2020 3:58 pm
- Forum: Phase Changes & Related Calculations
- Topic: Proton transfer in water
- Replies: 3
- Views: 156
Re: Proton transfer in water
Isn't the Ka for water is 1.0 * 10^-7 at 25 degrees Celsius?
- Sat Jan 18, 2020 5:57 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: 5I.11 units
- Replies: 5
- Views: 329
Re: 5I.11 units
Could you not just convert the mmol values to mol so you can calculate the concentrations that way?
- Sat Jan 18, 2020 5:56 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: K comparison
- Replies: 4
- Views: 192
Re: K comparison
Is this also the situation in which you can approximate the calculation in the ICE table if the K value is less than 10^-3 or am I thinking about something else?
- Sat Jan 18, 2020 5:53 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ice table/quadratic
- Replies: 6
- Views: 256
Re: ice table/quadratic
It's definitely possible for this to happen! One of the practice problems that I had been doing in my discussion had a problem like this. In this case, you should check whether the values you got are possible. For example, for the problem that I did, of the equilibrium molarity values that I receive...
- Sat Jan 18, 2020 5:49 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE Tables
- Replies: 3
- Views: 186
Re: ICE Tables
It's also possible that there will be problems that ask for certain initial concentrations or pressures and you're given the equilibrium concentrations and pressures. You can use an ICE table to solve for those as well.
- Sat Jan 18, 2020 5:11 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q < K
- Replies: 16
- Views: 796
Re: Q < K
When Q is less than K it means that the reaction hasn't gone all the way through yet, and is not at equilibrium. It is more shifted to the right side.
- Sat Jan 11, 2020 4:20 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Changes in Pressure
- Replies: 3
- Views: 153
Re: Changes in Pressure
I think it's the fact that it isn't just a change of pressure will change whether a reaction will be forward of in reverse, it's more of how has the pressure changed and if there are any other modified factors.
- Sat Jan 11, 2020 4:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Assuming +/- x is Negligible
- Replies: 4
- Views: 164
Re: Assuming +/- x is Negligible
Will we be expected to sometimes use the approximations, or will we be able to just to use the quadratic formula instead?
- Sat Jan 11, 2020 4:14 pm
- Forum: Ideal Gases
- Topic: Law of Effusion, Kinetic Model, and Maxwell Distribution
- Replies: 3
- Views: 140
Re: Law of Effusion, Kinetic Model, and Maxwell Distribution
I think these topics will be touched upon later on when Dr. Lavelle decides to lecture about Kinetics. Not too sure though.
- Sat Jan 11, 2020 4:13 pm
- Forum: Ideal Gases
- Topic: The Difference between Q and Kc [ENDORSED]
- Replies: 18
- Views: 8577
Re: The Difference between Q and Kc [ENDORSED]
If you later find that you're wondering about the difference between Q and Kp (pressure, rather than Kc, which is concentration), then you can just come back here because it's pretty much similar, I think.
- Sat Jan 11, 2020 4:11 pm
- Forum: Ideal Gases
- Topic: Ideal Gas Law
- Replies: 6
- Views: 170
Re: Ideal Gas Law
So is the Ideal Gas Law used for reactions with gasses only, or is it more specific than that?
- Sat Dec 07, 2019 7:21 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: acid & bases to memorize
- Replies: 3
- Views: 291
Re: acid & bases to memorize
Yes, basically you just need to memorize the list of strong acids and bases. The UAs said that if an acid or base isn't a strong one, just immediately assume that it is a weak acid or base.
- Sat Dec 07, 2019 7:04 pm
- Forum: Naming
- Topic: Molecular formula for long ligands
- Replies: 2
- Views: 218
Re: Molecular formula for long ligands
Yes, you can write the abbreviations for the compounds. As for what Dr. Lavelle prefers, I'm sure he's okay with using the abbreviations if he allows it for the test.
Re: cisplatin
It's formed with a platinum atom as the central atom and two chlorines on the same side and then two ammonia molecules on the other side.
- Sat Dec 07, 2019 7:00 pm
- Forum: Naming
- Topic: bis-,tris-,tetrakis-
- Replies: 2
- Views: 188
Re: bis-,tris-,tetrakis-
You change it to bis-, tris-, and tetrakis- for polydentate so that it's emphasized that it is a polydentate complex.
- Sat Dec 07, 2019 6:52 pm
- Forum: Naming
- Topic: Latin Names
- Replies: 3
- Views: 143
Re: Latin Names
I'm not too sure, but I'm just assuming that that's just something you have to memorize. You don't have to currently know too much though.
- Thu Nov 28, 2019 4:37 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric
- Replies: 8
- Views: 377
Re: Amphoteric
Don't amphoteric compounds include those atoms from the periodic table that are just left of the metalloid diagonal line?
- Thu Nov 28, 2019 4:09 pm
- Forum: Naming
- Topic: Organometallic complex
- Replies: 2
- Views: 124
Re: Organometallic complex
I think organometallic complexes are just coordination complexes with carbon in them? I'm not too sure about this.
- Thu Nov 28, 2019 3:52 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydente - CO3 2-
- Replies: 1
- Views: 160
Re: Polydente - CO3 2-
Apparently carbonate is normally monodentate, but it can also bind to two different metals?
- Thu Nov 28, 2019 3:49 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination number of [Co(Ox)3]3-
- Replies: 2
- Views: 887
Re: Coordination number of [Co(Ox)3]3-
I'm pretty sure "Ox" is not EDTA. I think it was the abbreviation for an oxalate ion.
- Thu Nov 28, 2019 3:45 pm
- Forum: Biological Examples
- Topic: vitamin b12
- Replies: 3
- Views: 224
Re: vitamin b12
I think vitamin b12 was just a biological example that he was giving. I don't think we have to specifically know too much about it.
- Sun Nov 24, 2019 8:29 pm
- Forum: Naming
- Topic: atoms outside of the coordination complex
- Replies: 2
- Views: 68
Re: atoms outside of the coordination complex
I don't think we need to factor the prefixes for the atoms in the alphabetization of the naming, do we?
- Sun Nov 24, 2019 8:27 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Fac and Mer isomers
- Replies: 2
- Views: 142
Re: Fac and Mer isomers
I don't think we have gone over this in class yet, so maybe we can wait and see? He might go over it in lecture, not too sure.
- Sun Nov 24, 2019 8:26 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Organometallic complex
- Replies: 1
- Views: 84
Re: Organometallic complex
I think that for an organometallic complex to be organic it has to have a Carbon in it.
- Sun Nov 24, 2019 8:25 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Negative coordination compound
- Replies: 1
- Views: 146
Re: Negative coordination compound
I didn't realize that it was uncommon for coordination compounds to be negative. Are they not typically negative?
- Sun Nov 24, 2019 8:23 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Drawing Structures
- Replies: 4
- Views: 254
Re: Drawing Structures
Are you talking about when drawing the Lewis Structures? I think you can just draw the Lewis Structures how you would normally.
- Sun Nov 17, 2019 10:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs on VSEPR Model
- Replies: 2
- Views: 126
Re: Lone Pairs on VSEPR Model
Lone pairs are only supposed to be on the equatorial positions because those are the most stable I think.
- Sun Nov 17, 2019 9:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Shapes
- Replies: 5
- Views: 267
Re: Shapes
I think you're supposed to look into the specific shape of the different central atoms and their surrounding atoms?
- Sun Nov 17, 2019 9:57 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: equatorial v. axial
- Replies: 4
- Views: 257
Re: equatorial v. axial
The repulsion forces and bond angles are different for equatorial and axial. Axial has two repulsion forces since it's two ends of an axis. Equatorial may have 3 or more repulsion forces.
- Sun Nov 17, 2019 9:53 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 4
- Views: 231
Re: Bond Angles
It's pretty much memorization though. I mean, if you find the shape of the molecule, you can draw it out and then get the angle from there?
- Sun Nov 17, 2019 9:52 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: vsepr angles
- Replies: 10
- Views: 415
Re: vsepr angles
Yes.
- Sun Nov 10, 2019 8:46 pm
- Forum: Bond Lengths & Energies
- Topic: Dissociation Energy
- Replies: 9
- Views: 349
Re: Dissociation Energy
If breaking a bond requires energy then is energy gained to break the bond and the energy is released when the bond is broken???
- Sun Nov 10, 2019 8:42 pm
- Forum: Bond Lengths & Energies
- Topic: Ionic/covalent Character
- Replies: 3
- Views: 162
Re: Ionic/covalent Character
Water is able to dissolve those ionic molecules because the attraction between the positive and negative parts of the water and the other molecule is able to separate the separate atoms of the ionic molecule from each other.
- Sun Nov 10, 2019 8:39 pm
- Forum: Bond Lengths & Energies
- Topic: Resonance Bond Lengths
- Replies: 3
- Views: 143
Re: Resonance Bond Lengths
It isn't always between just a single bond and a double bond since there can also be triple bonds, but basically it's just an average length between all bonds.
- Sun Nov 10, 2019 8:37 pm
- Forum: Bond Lengths & Energies
- Topic: Week 7 Homework
- Replies: 15
- Views: 805
Re: Week 7 Homework
But are we able to turn in homework from the Topic 2 section still?
- Sun Nov 10, 2019 8:36 pm
- Forum: Bond Lengths & Energies
- Topic: Hydrogen bonding
- Replies: 2
- Views: 215
Re: Hydrogen bonding
I'm pretty sure there is a range of Hydrogen bonds attractive force, but it isn't always -20 kJ/mol.
- Sun Nov 03, 2019 8:49 pm
- Forum: Electronegativity
- Topic: memorizing tables
- Replies: 9
- Views: 303
Re: memorizing tables
You probably don't have to memorize the electronegativity of every single element on the periodic table, but you can remember that Fluroine (F) is the most electronegative (4) and Francium is the least electronegative (0.7). Reminder: electronegativity increases as you go across a period from left t...
- Sun Nov 03, 2019 8:46 pm
- Forum: Electronegativity
- Topic: Electronegativity and ionic/covalent bond
- Replies: 2
- Views: 238
Re: Electronegativity and ionic/covalent bond
If you can recall from the lecture, the difference in electronegativity between the two atoms that are bonded can usually tell you when the bond is covalent or ionic. When the difference in electronegativity is > 1.5, then the bond is covalent. When the difference in electronegativity is < 2.5 then ...
- Sun Nov 03, 2019 8:43 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: En
- Replies: 3
- Views: 213
Re: En
An example of when this formula would be used is when a question asks something like, an electron moves from n=3 down to n=1. You'd calculate that difference of energy with delta E (E final - E initial). To calculate this you use that formula and plug in the values of n, in this case 3 and 1.
- Sun Nov 03, 2019 8:31 pm
- Forum: Octet Exceptions
- Topic: Valence Electrons for Transition Metals
- Replies: 4
- Views: 490
Re: Valence Electrons for Transition Metals
I don't think the d-orbital counts as an orbital which has valence electrons? Typically valence electrons are in the s and p-orbitals, which is why the transitions metals will have their valence electrons in the s-orbitals (2 e-).
- Sun Nov 03, 2019 7:47 pm
- Forum: Coordinate Covalent Bonds
- Topic: bond question
- Replies: 5
- Views: 363
Re: bond question
Coordinate covalent bonds form when an atom gives a lone pair of electrons to a bond. I can't give an example of one forming in nature at the moment, but coordinate covalent bonds are as strong as other covalent bonds.
- Sat Oct 26, 2019 5:19 pm
- Forum: Ionic & Covalent Bonds
- Topic: Effective charge
- Replies: 3
- Views: 151
Re: Effective charge
In response to your second question, the electrons in the d-orbital actually shield poorly, so it would not increase electron shielding.
- Sat Oct 26, 2019 5:01 pm
- Forum: Lewis Structures
- Topic: Magnetic Spin Quantum Number
- Replies: 3
- Views: 129
Re: Magnetic Spin Quantum Number
So for example, in the p-orbital, the first 3 electrons are up spins and the last 3 are down spins. So the first 3 are +1/2 since they are up spins and the last 3 are -1/2 since they are down spins.
- Sat Oct 26, 2019 4:53 pm
- Forum: Lewis Structures
- Topic: Video Modules
- Replies: 11
- Views: 394
Re: Video Modules
It would be nice if there were more video modules for the other topics that we would be covering the future too. I like to use those for review and also watch them before the lecture for previews, so they really help. Honestly, there are times when I forget what is said in the lecture, or I just don...
- Sat Oct 26, 2019 4:44 pm
- Forum: Lewis Structures
- Topic: Lewis Structure
- Replies: 5
- Views: 209
Re: Lewis Structure
Yes, it is typically the least electronegative atom that goes in the middle. In addition, Hydrogen atoms are never in the center.
- Sat Oct 26, 2019 4:31 pm
- Forum: Sigma & Pi Bonds
- Topic: orbitals
- Replies: 3
- Views: 655
Re: orbitals
In Chemistry 14A, I think it was mentioned that we won't be going past the d orbital. I'm pretty sure we are only going up to the first line of the d-block?
- Sun Oct 20, 2019 10:29 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: how to prepare
- Replies: 22
- Views: 821
Re: how to prepare
Usually what I do to really make myself feel prepared is a series of specific steps. Professor Lavelle usually tells us what we are going to be covering in the next lecture so to prepare for that I usually first read the section in the textbook and look over and do the example problems. After that I...
- Sun Oct 20, 2019 10:23 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: More than one electron in an orbital
- Replies: 2
- Views: 93
Re: More than one electron in an orbital
Um, I think that this question is a lot more specified then what we covered so far in our lectures. We so far went up to Pauli Exclusion principle (which is what the previous comment was explaining), but maybe you can ask Professor Lavelle after a lecture?
- Sun Oct 20, 2019 10:19 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: multiple planes in orbitals
- Replies: 2
- Views: 98
Re: multiple planes in orbitals
I'm pretty sure that we don't need to mathematically determine the x, y, and z, but when writing electron figurations like the 2p orbital, it goes in the order of x, then y, then z.
- Sun Oct 20, 2019 10:17 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Planes
- Replies: 3
- Views: 89
Re: Planes
The different orbitals like p, d, and f have different planes and I think they are just different types of orientations of the electron.
- Sun Oct 20, 2019 10:15 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Exceptions
- Replies: 2
- Views: 103
Re: Exceptions
I think it might also have something to do with the positioning of the electrons and it being farther away (outer shell) making it easier to react with something else and stability?
- Sun Oct 13, 2019 10:04 am
- Forum: Student Social/Study Group
- Topic: Atomic Spectra: Energy Levels
- Replies: 3
- Views: 146
Re: Atomic Spectra: Energy Levels
If you read through the section of the textbook regarding atomic spectra, there are examples given walking you through how to do different problems regarding the topic. I'm sure the homework problems will be similar to something like those.
- Sun Oct 13, 2019 10:01 am
- Forum: Properties of Light
- Topic: Quantum Levels
- Replies: 9
- Views: 386
Re: Quantum Levels
I remember during the lecture Professor Lavelle did say that the electron could go infinitely away from the nucleus. The energy would, however, be zero. He did say that would be our reference point though. So I'm not exactly sure about a limit.
- Sun Oct 13, 2019 9:56 am
- Forum: Properties of Light
- Topic: Photoelectric Effect
- Replies: 3
- Views: 168
Re: Photoelectric Effect
Because photons are quantized, no matter how much you intensify the light of a low frequency, the amount of energy per photon will not increase. All you would be doing is emitting more and more photons. That's why even if you release low intensity but high-frequency light, electrons can be removed f...
- Sun Oct 13, 2019 9:50 am
- Forum: Properties of Light
- Topic: Large Objects
- Replies: 7
- Views: 1080
Re: Large Objects
And remember! As said during the lecture, anything beyond X * 10^-15 is the limit for what would be too small of a wavelength to be recognized. For example, a baseball had 10^-34 and a car had 10^-38, which is way too small to be measured.
- Sun Oct 13, 2019 9:41 am
- Forum: Properties of Light
- Topic: Question of the Hypothetical Variety (nah not really)
- Replies: 2
- Views: 89
Re: Question of the Hypothetical Variety (nah not really)
Yes. Basically all electromagnetic radiation travels at the speed of light, but only in a vacuum. If it were in different circumstances then it could be different since other molecules would interact with thee electromagnetic radiation.
- Sat Oct 05, 2019 4:15 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Moles
- Replies: 3
- Views: 241
Re: Moles
For the equation that you presented, it should be 2 moles of K to 1 mole of H2. Therefore if you're doing some sort of conversion with this it should be (2 mol K)/(1 mol H2). It depends on what you're trying to find though since H2 is different from H. Obviously H2 is a molecule of 2 Hydrogens put t...
- Sat Oct 05, 2019 4:07 pm
- Forum: Empirical & Molecular Formulas
- Topic: Is there an easier way to figure out which integer to multiply the number of atoms with to get a whole number?
- Replies: 4
- Views: 210
Re: Is there an easier way to figure out which integer to multiply the number of atoms with to get a whole number?
If it makes it easier for you, you can try to turn the decimal into a fraction and then multiply all the numbers by the denominator. For example if you had the decimal 1.33, the fraction of that should be 4/3 so just multiply all the numbers by 3.
- Sat Oct 05, 2019 4:04 pm
- Forum: SI Units, Unit Conversions
- Topic: Rounding
- Replies: 6
- Views: 379
Re: Rounding
Usually, when doing the calculations, I try to keep all of the numbers as exact as possible. It's when I get to the end of the problem I try to round it to the significant figures. The teaching fellow for my discussion said that we shouldn't have to worry about it too much right now though. As long ...
- Sat Oct 05, 2019 4:00 pm
- Forum: SI Units, Unit Conversions
- Topic: E.23 Part B
- Replies: 3
- Views: 180
Re: E.23 Part B
Scientific notation is basically a way of writing a number that's too big or too small in a more convenient form. For example, if you have a large number like 145,000,000, you can simplify this into 1.45 * 10^8. Or, if you have a small number like 0.000000145, then you can simplify this into 1.45 * ...