Search found 101 matches

by Daniel Chen 2L
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: 8
Views: 24

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?
by Daniel Chen 2L
Mon Mar 16, 2020 1:46 pm
Forum: *Enzyme Kinetics
Topic: Catalysts and enthalpy
Replies: 4
Views: 23

Re: Catalysts and enthalpy

One of the main things that a catalyst does is change the amount of work that a system does.
by Daniel Chen 2L
Mon Mar 16, 2020 12:11 pm
Forum: *Enzyme Kinetics
Topic: catalysts
Replies: 4
Views: 20

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.
by Daniel Chen 2L
Mon Mar 16, 2020 12:10 pm
Forum: *Enzyme Kinetics
Topic: Lecture 3/6
Replies: 2
Views: 15

Re: Lecture 3/6

We also discussed how to approach proposed reaction mechanisms with multiple steps.
by Daniel Chen 2L
Mon Mar 16, 2020 11:49 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Exothermic reactions
Replies: 3
Views: 26

Re: Exothermic reactions

So basically what you are saying is that a decrease in temperature will decrease the rate of an exothermic reaction?
by Daniel Chen 2L
Sun Mar 08, 2020 4:59 pm
Forum: First Order Reactions
Topic: preferred form of rates
Replies: 2
Views: 32

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"
by Daniel Chen 2L
Sun Mar 08, 2020 4:43 pm
Forum: General Rate Laws
Topic: affect of temperature on K
Replies: 4
Views: 45

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?
by Daniel Chen 2L
Sun Mar 08, 2020 4:37 pm
Forum: General Rate Laws
Topic: the variable A
Replies: 4
Views: 16

Re: the variable A

The variable A is the frequency or the pre-exponential factor.
by Daniel Chen 2L
Sun Mar 08, 2020 4:35 pm
Forum: General Rate Laws
Topic: Ammonia rate of consumption
Replies: 1
Views: 7

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.
by Daniel Chen 2L
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: 36

Re: Calculating Q

I get that Q is [products]/[reactants] but why, for galvanic cells, is it anode/cathode?
by Daniel Chen 2L
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: 37

Re: Corrosion

I don't remember learning this in class? Is this in any of the textbook sections that we have for homework?
by Daniel Chen 2L
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: 32

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?
by Daniel Chen 2L
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: 21

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.
by Daniel Chen 2L
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: 30

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?
by Daniel Chen 2L
Sun Feb 23, 2020 9:56 pm
Forum: Balancing Redox Reactions
Topic: Test 2
Replies: 9
Views: 55

Re: Test 2

Is the general topic of Test 2 going to be Gibb's Free Energy and Electrochemistry?
by Daniel Chen 2L
Sun Feb 23, 2020 9:54 pm
Forum: Balancing Redox Reactions
Topic: Gas Rxns
Replies: 2
Views: 48

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?
by Daniel Chen 2L
Sun Feb 23, 2020 9:51 pm
Forum: Balancing Redox Reactions
Topic: Reduction?
Replies: 13
Views: 74

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).
by Daniel Chen 2L
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: 36

Re: Cell Diagram, what to include

There can also be acidic and basic redox reactions. So that's why there may be H+ ions?
by Daniel Chen 2L
Sun Feb 23, 2020 9:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Potentials
Replies: 2
Views: 13

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?
by Daniel Chen 2L
Sun Feb 16, 2020 10:16 pm
Forum: Balancing Redox Reactions
Topic: Charge of permanganate
Replies: 5
Views: 25

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.
by Daniel Chen 2L
Sun Feb 16, 2020 10:14 pm
Forum: Balancing Redox Reactions
Topic: easier to split?
Replies: 6
Views: 33

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.
by Daniel Chen 2L
Sun Feb 16, 2020 10:13 pm
Forum: Balancing Redox Reactions
Topic: Oxygen and Hydrogen
Replies: 4
Views: 24

Re: Oxygen and Hydrogen

Free elements have an oxidation number of 0 though, right?
by Daniel Chen 2L
Sun Feb 16, 2020 10:11 pm
Forum: Balancing Redox Reactions
Topic: Oxygen
Replies: 9
Views: 42

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?
by Daniel Chen 2L
Sun Feb 16, 2020 10:09 pm
Forum: Balancing Redox Reactions
Topic: In Class Example
Replies: 4
Views: 24

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.
by Daniel Chen 2L
Sat Feb 08, 2020 6:20 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeter
Replies: 5
Views: 32

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.
by Daniel Chen 2L
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: 37

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?
by Daniel Chen 2L
Sat Feb 08, 2020 6:14 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: degeneracy
Replies: 7
Views: 38

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.
by Daniel Chen 2L
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: 207

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...
by Daniel Chen 2L
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: 35

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...
by Daniel Chen 2L
Sat Feb 01, 2020 5:58 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: isolated system
Replies: 13
Views: 48

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.
by Daniel Chen 2L
Sat Feb 01, 2020 5:56 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Reversible vs Irreversible formula
Replies: 4
Views: 68

Re: Reversible vs Irreversible formula

So if the pressure of the system is not constant, then the formula is reversible?
by Daniel Chen 2L
Sat Feb 01, 2020 5:54 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed Systems
Replies: 8
Views: 35

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...
by Daniel Chen 2L
Sat Feb 01, 2020 5:51 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Pressure in an open beaker
Replies: 12
Views: 59

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?
by Daniel Chen 2L
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: 26

Re: Standard Reaction Enthalpies

So are you saying that the standard reaction enthalpy is 0 when a reaction does not occur under standard conditions?
by Daniel Chen 2L
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: 44

Re: Help

Is this a homework problem that we have to do?
by Daniel Chen 2L
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: 10

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.
by Daniel Chen 2L
Sat Jan 25, 2020 4:01 pm
Forum: Phase Changes & Related Calculations
Topic: Steam v. liquid
Replies: 7
Views: 53

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.
by Daniel Chen 2L
Sat Jan 25, 2020 4:00 pm
Forum: Phase Changes & Related Calculations
Topic: Constant pressure and constant volume
Replies: 3
Views: 41

Re: Constant pressure and constant volume

Have we learned about how heat, work, and internal energies respond to these yet?
by Daniel Chen 2L
Sat Jan 25, 2020 3:58 pm
Forum: Phase Changes & Related Calculations
Topic: Proton transfer in water
Replies: 3
Views: 22

Re: Proton transfer in water

Isn't the Ka for water is 1.0 * 10^-7 at 25 degrees Celsius?
by Daniel Chen 2L
Sat Jan 18, 2020 5:57 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5I.11 units
Replies: 5
Views: 43

Re: 5I.11 units

Could you not just convert the mmol values to mol so you can calculate the concentrations that way?
by Daniel Chen 2L
Sat Jan 18, 2020 5:56 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: K comparison
Replies: 4
Views: 39

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?
by Daniel Chen 2L
Sat Jan 18, 2020 5:53 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ice table/quadratic
Replies: 6
Views: 47

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...
by Daniel Chen 2L
Sat Jan 18, 2020 5:49 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE Tables
Replies: 3
Views: 39

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.
by Daniel Chen 2L
Sat Jan 18, 2020 5:11 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q < K
Replies: 16
Views: 70

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.
by Daniel Chen 2L
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: 33

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.
by Daniel Chen 2L
Sat Jan 11, 2020 4:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Assuming +/- x is Negligible
Replies: 4
Views: 43

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?
by Daniel Chen 2L
Sat Jan 11, 2020 4:14 pm
Forum: Ideal Gases
Topic: Law of Effusion, Kinetic Model, and Maxwell Distribution
Replies: 3
Views: 39

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.
by Daniel Chen 2L
Sat Jan 11, 2020 4:13 pm
Forum: Ideal Gases
Topic: The Difference between Q and Kc [ENDORSED]
Replies: 18
Views: 1116

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.
by Daniel Chen 2L
Sat Jan 11, 2020 4:11 pm
Forum: Ideal Gases
Topic: Ideal Gas Law
Replies: 6
Views: 40

Re: Ideal Gas Law

So is the Ideal Gas Law used for reactions with gasses only, or is it more specific than that?
by Daniel Chen 2L
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: 49

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.
by Daniel Chen 2L
Sat Dec 07, 2019 7:04 pm
Forum: Naming
Topic: Molecular formula for long ligands
Replies: 2
Views: 27

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.
by Daniel Chen 2L
Sat Dec 07, 2019 7:02 pm
Forum: Naming
Topic: cisplatin
Replies: 4
Views: 37

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.
by Daniel Chen 2L
Sat Dec 07, 2019 7:00 pm
Forum: Naming
Topic: bis-,tris-,tetrakis-
Replies: 2
Views: 20

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.
by Daniel Chen 2L
Sat Dec 07, 2019 6:52 pm
Forum: Naming
Topic: Latin Names
Replies: 3
Views: 33

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.
by Daniel Chen 2L
Thu Nov 28, 2019 4:37 pm
Forum: Amphoteric Compounds
Topic: Amphoteric
Replies: 8
Views: 67

Re: Amphoteric

Don't amphoteric compounds include those atoms from the periodic table that are just left of the metalloid diagonal line?
by Daniel Chen 2L
Thu Nov 28, 2019 4:09 pm
Forum: Naming
Topic: Organometallic complex
Replies: 2
Views: 20

Re: Organometallic complex

I think organometallic complexes are just coordination complexes with carbon in them? I'm not too sure about this.
by Daniel Chen 2L
Thu Nov 28, 2019 3:52 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydente - CO3 2-
Replies: 1
Views: 34

Re: Polydente - CO3 2-

Apparently carbonate is normally monodentate, but it can also bind to two different metals?
by Daniel Chen 2L
Thu Nov 28, 2019 3:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination number of [Co(Ox)3]3-
Replies: 2
Views: 20

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.
by Daniel Chen 2L
Thu Nov 28, 2019 3:45 pm
Forum: Biological Examples
Topic: vitamin b12
Replies: 3
Views: 41

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.
by Daniel Chen 2L
Sun Nov 24, 2019 8:29 pm
Forum: Naming
Topic: atoms outside of the coordination complex
Replies: 2
Views: 25

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?
by Daniel Chen 2L
Sun Nov 24, 2019 8:27 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Fac and Mer isomers
Replies: 2
Views: 17

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.
by Daniel Chen 2L
Sun Nov 24, 2019 8:26 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Organometallic complex
Replies: 1
Views: 13

Re: Organometallic complex

I think that for an organometallic complex to be organic it has to have a Carbon in it.
by Daniel Chen 2L
Sun Nov 24, 2019 8:25 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Negative coordination compound
Replies: 1
Views: 21

Re: Negative coordination compound

I didn't realize that it was uncommon for coordination compounds to be negative. Are they not typically negative?
by Daniel Chen 2L
Sun Nov 24, 2019 8:23 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Drawing Structures
Replies: 4
Views: 49

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.
by Daniel Chen 2L
Sun Nov 17, 2019 10:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs on VSEPR Model
Replies: 2
Views: 20

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.
by Daniel Chen 2L
Sun Nov 17, 2019 9:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shapes
Replies: 5
Views: 39

Re: Shapes

I think you're supposed to look into the specific shape of the different central atoms and their surrounding atoms?
by Daniel Chen 2L
Sun Nov 17, 2019 9:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: equatorial v. axial
Replies: 4
Views: 31

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.
by Daniel Chen 2L
Sun Nov 17, 2019 9:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 4
Views: 36

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?
by Daniel Chen 2L
Sun Nov 17, 2019 9:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: vsepr angles
Replies: 10
Views: 56

Re: vsepr angles

Yes.
by Daniel Chen 2L
Sun Nov 10, 2019 8:46 pm
Forum: Bond Lengths & Energies
Topic: Dissociation Energy
Replies: 9
Views: 48

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???
by Daniel Chen 2L
Sun Nov 10, 2019 8:42 pm
Forum: Bond Lengths & Energies
Topic: Ionic/covalent Character
Replies: 3
Views: 29

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.
by Daniel Chen 2L
Sun Nov 10, 2019 8:39 pm
Forum: Bond Lengths & Energies
Topic: Resonance Bond Lengths
Replies: 3
Views: 25

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.
by Daniel Chen 2L
Sun Nov 10, 2019 8:37 pm
Forum: Bond Lengths & Energies
Topic: Week 7 Homework
Replies: 15
Views: 174

Re: Week 7 Homework

But are we able to turn in homework from the Topic 2 section still?
by Daniel Chen 2L
Sun Nov 10, 2019 8:36 pm
Forum: Bond Lengths & Energies
Topic: Hydrogen bonding
Replies: 2
Views: 28

Re: Hydrogen bonding

I'm pretty sure there is a range of Hydrogen bonds attractive force, but it isn't always -20 kJ/mol.
by Daniel Chen 2L
Sun Nov 03, 2019 8:49 pm
Forum: Electronegativity
Topic: memorizing tables
Replies: 9
Views: 54

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...
by Daniel Chen 2L
Sun Nov 03, 2019 8:46 pm
Forum: Electronegativity
Topic: Electronegativity and ionic/covalent bond
Replies: 2
Views: 21

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 ...
by Daniel Chen 2L
Sun Nov 03, 2019 8:43 pm
Forum: Formal Charge and Oxidation Numbers
Topic: En
Replies: 3
Views: 32

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.
by Daniel Chen 2L
Sun Nov 03, 2019 8:31 pm
Forum: Octet Exceptions
Topic: Valence Electrons for Transition Metals
Replies: 4
Views: 55

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-).
by Daniel Chen 2L
Sun Nov 03, 2019 7:47 pm
Forum: Coordinate Covalent Bonds
Topic: bond question
Replies: 5
Views: 96

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.
by Daniel Chen 2L
Sat Oct 26, 2019 5:19 pm
Forum: Ionic & Covalent Bonds
Topic: Effective charge
Replies: 3
Views: 40

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.
by Daniel Chen 2L
Sat Oct 26, 2019 5:01 pm
Forum: Lewis Structures
Topic: Magnetic Spin Quantum Number
Replies: 3
Views: 29

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.
by Daniel Chen 2L
Sat Oct 26, 2019 4:53 pm
Forum: Lewis Structures
Topic: Video Modules
Replies: 11
Views: 104

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...
by Daniel Chen 2L
Sat Oct 26, 2019 4:44 pm
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 5
Views: 53

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.
by Daniel Chen 2L
Sat Oct 26, 2019 4:31 pm
Forum: Sigma & Pi Bonds
Topic: orbitals
Replies: 3
Views: 269

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?
by Daniel Chen 2L
Sun Oct 20, 2019 10:29 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: how to prepare
Replies: 22
Views: 173

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...
by Daniel Chen 2L
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: 24

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?
by Daniel Chen 2L
Sun Oct 20, 2019 10:19 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: multiple planes in orbitals
Replies: 2
Views: 21

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.
by Daniel Chen 2L
Sun Oct 20, 2019 10:17 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Planes
Replies: 3
Views: 29

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.
by Daniel Chen 2L
Sun Oct 20, 2019 10:15 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Exceptions
Replies: 2
Views: 18

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?
by Daniel Chen 2L
Sun Oct 13, 2019 10:04 am
Forum: Student Social/Study Group
Topic: Atomic Spectra: Energy Levels
Replies: 3
Views: 51

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.
by Daniel Chen 2L
Sun Oct 13, 2019 10:01 am
Forum: Properties of Light
Topic: Quantum Levels
Replies: 9
Views: 80

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.
by Daniel Chen 2L
Sun Oct 13, 2019 9:56 am
Forum: Properties of Light
Topic: Photoelectric Effect
Replies: 3
Views: 64

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...
by Daniel Chen 2L
Sun Oct 13, 2019 9:50 am
Forum: Properties of Light
Topic: Large Objects
Replies: 7
Views: 74

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.
by Daniel Chen 2L
Sun Oct 13, 2019 9:41 am
Forum: Properties of Light
Topic: Question of the Hypothetical Variety (nah not really)
Replies: 2
Views: 19

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.
by Daniel Chen 2L
Sat Oct 05, 2019 4:15 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Moles
Replies: 3
Views: 59

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...
by Daniel Chen 2L
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: 53

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.
by Daniel Chen 2L
Sat Oct 05, 2019 4:04 pm
Forum: SI Units, Unit Conversions
Topic: Rounding
Replies: 6
Views: 89

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 ...
by Daniel Chen 2L
Sat Oct 05, 2019 4:00 pm
Forum: SI Units, Unit Conversions
Topic: E.23 Part B
Replies: 2
Views: 33

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 * ...

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