Search found 100 matches

by Nicholas Chin 1G
Sat Mar 14, 2020 12:56 pm
Forum: Zero Order Reactions
Topic: Composition vs Decomposition
Replies: 3
Views: 19

Re: Composition vs Decomposition

Nope, it's the same rate equation.
by Nicholas Chin 1G
Sat Mar 14, 2020 12:53 pm
Forum: Zero Order Reactions
Topic: kind of reaction
Replies: 2
Views: 18

Re: kind of reaction

It's a reaction that does not depend on the amount of the reactant. For example, a saturated catalyst reaction, where the rate is limited by the number of open catalysts, is a zero order reaction because increasing the reactant won't do anything.
by Nicholas Chin 1G
Sat Mar 14, 2020 12:52 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Delta S
Replies: 8
Views: 26

Re: Delta S

The delta S total is the delta S of the system plus surroundings.
by Nicholas Chin 1G
Sat Mar 14, 2020 12:50 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: E vs Eo
Replies: 6
Views: 33

Re: E vs Eo

In some cases, standard E will be zero, so this equation can be used to find Ecell in concentration cells.
by Nicholas Chin 1G
Fri Mar 13, 2020 4:18 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Why is Q the concentration of anode/cathode?
Replies: 3
Views: 3506

Re: Why is Q the concentration of anode/cathode?

I believe it's because the anode proceeds backwards from the standard form of half reactions (i.e. Fe2+ +2 e- -> Fe(s)).
by Nicholas Chin 1G
Fri Mar 13, 2020 4:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 275
Views: 108549

Re: Saying Thank You to Dr. Lavelle

THANK YOU DR. LAVELLE!!!

Dr. Lavelle is genuinely one of the most entertaining and funny professors I've had in a while. I really like how pleased he looks whenever he turns into DJ Lavelle and bops to the music.
by Nicholas Chin 1G
Fri Mar 13, 2020 4:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 11
Views: 77

Re: Final

It should be released by Sunday, and it's timed for the same 3 hours that we would've been given. I'm sure he'll release more details tomorrow regarding the specific details.
by Nicholas Chin 1G
Thu Mar 12, 2020 3:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Format
Replies: 2
Views: 63

Re: Final Format

I'm guessing it's still going to be 180 just because that would mess up his scaling if he made it worth that little points.
by Nicholas Chin 1G
Thu Mar 12, 2020 3:47 pm
Forum: Balancing Redox Reactions
Topic: Test 2 Return
Replies: 20
Views: 131

Re: Test 2 Return

At least for Ben, he left his in his mailbox in Young Hall.
by Nicholas Chin 1G
Wed Mar 11, 2020 2:44 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: same equation?
Replies: 5
Views: 26

Re: same equation?

The one with ln has been rearranged so that you can create a graph of certain values that will result in a straight line, something that can't be done with the previous equation.
by Nicholas Chin 1G
Wed Mar 11, 2020 2:42 pm
Forum: Balancing Redox Reactions
Topic: Ecell values
Replies: 12
Views: 47

Re: Ecell values

You can use the appendix to look at the E values for the two half reactions. Since the equation for Ecell is E(c) = E(cath) - E(anode), then you can determine which reaction is cathode and which one is anode.
by Nicholas Chin 1G
Wed Mar 11, 2020 2:40 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: rate constant
Replies: 5
Views: 22

Re: rate constant

Catalysts lower the activation energy, meaning particles that are involved in collisions don't need as much energy to make the reaction go forward, increasing k.
by Nicholas Chin 1G
Wed Mar 11, 2020 2:39 pm
Forum: Zero Order Reactions
Topic: straight line to fit data
Replies: 5
Views: 21

Re: straight line to fit data

The slope will also give you a different constant value depending on the order of the reaction.
by Nicholas Chin 1G
Wed Mar 11, 2020 2:38 pm
Forum: General Science Questions
Topic: Chemistry Final
Replies: 16
Views: 151

Re: Chemistry Final

I think it's safe to assume it might just be free response, just like normal.
by Nicholas Chin 1G
Wed Mar 11, 2020 2:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 5
Views: 93

Re: Final

You can probably just scan it and send it to him, it sounds like this is all gonna be pretty informal.
by Nicholas Chin 1G
Tue Mar 10, 2020 12:54 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: Boltzmann Equation
Replies: 2
Views: 10

Re: Boltzmann Equation

R = Nk, where N is avogadro's constant and k is boltzmann's constant.
by Nicholas Chin 1G
Tue Mar 10, 2020 12:53 pm
Forum: General Rate Laws
Topic: pseudo rate laws
Replies: 5
Views: 24

Re: pseudo rate laws

I think it's just to note that it's not the original k that you're dealing with: it includes other constants.
by Nicholas Chin 1G
Tue Mar 10, 2020 12:51 pm
Forum: Balancing Redox Reactions
Topic: Half Reactions
Replies: 15
Views: 53

Re: Half Reactions

You first balance the oxygens by adding H2O on whatever side needs oxygen. Then you balance the extra hydrogens by adding H+ on the other side. If the reaction occurs in a basic solution, then you add to both sides the same amount of OH- as H+ you added.
by Nicholas Chin 1G
Sun Mar 08, 2020 8:55 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Exothermic vs. Endothermic
Replies: 14
Views: 37

Re: Exothermic vs. Endothermic

Generally, if the reactant energy is higher than the product energy, the reaction is exothermic, and vice versa for endothermic.
by Nicholas Chin 1G
Sun Mar 01, 2020 7:04 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Dissolved Metal
Replies: 3
Views: 36

Re: Dissolved Metal

I believe that in the context of electrolytic reactions, the anode is always the one that corrodes.
by Nicholas Chin 1G
Sun Mar 01, 2020 5:44 pm
Forum: Balancing Redox Reactions
Topic: Anode and Cathode
Replies: 9
Views: 67

Re: Anode and Cathode

I believe it's based on the E value for the half reactions. The more negative half reaction is the anode and the more positive half reaction is the cathode.
by Nicholas Chin 1G
Sun Mar 01, 2020 5:42 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 3
Views: 35

Re: Salt Bridge

I think if there isn't a salt bridge, there needs to be a porous membrane for ions to diffuse through in order to maintain the charge balance.
by Nicholas Chin 1G
Sun Mar 01, 2020 5:41 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Free energy
Replies: 3
Views: 41

Re: Free energy

Probably negative free energy means positive E(cell) potential. There's also an equation I believe that you should know, it's on the equation sheet.
by Nicholas Chin 1G
Sun Mar 01, 2020 5:40 pm
Forum: Balancing Redox Reactions
Topic: anode/cathod reversible
Replies: 4
Views: 35

Re: anode/cathod reversible

I think because electrochemistry reactions generally only go forward, since they have a positive E(cell) value.
by Nicholas Chin 1G
Sun Mar 01, 2020 5:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt bridge
Replies: 2
Views: 22

Re: Salt bridge

It's to maintain the charge balance between the anode and the cathode. As electrons move, the ions in solution have to move the opposite direction to counterbalance the difference in charge.
by Nicholas Chin 1G
Sun Feb 09, 2020 11:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q and K
Replies: 3
Views: 21

Re: Q and K

K is a constant for a reaction that tells you the concentrations of products and reactants needed for the reaction to be at equilibrium. Q is not a constant, and can be calculated (and is different) at any point in a reaction. The value of Q compared to K tells you which way the reaction is going at...
by Nicholas Chin 1G
Sun Feb 09, 2020 11:43 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: fractions
Replies: 3
Views: 26

Re: fractions

These are the fractions that you put in front of the ideal gas constant to get a Cp and Cv value, which are used for constant pressure and constant volume respectively. You can use this to calculate the heat put into a gas and its corresponding temperature change.
by Nicholas Chin 1G
Sun Feb 09, 2020 11:42 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: DeltaH
Replies: 2
Views: 18

Re: DeltaH

Delta H is enthalpy, which is the total heat change in a system. At constant pressures, it can be used interchangeably with q.
by Nicholas Chin 1G
Sun Feb 09, 2020 11:41 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: extensive vs intensive
Replies: 4
Views: 26

Re: extensive vs intensive

An extensive property depends on the amount (i.e. mass, volume). An intensive property is the same regardless how much you have (i.e. density, specific heat capacity).
by Nicholas Chin 1G
Sun Feb 09, 2020 11:40 pm
Forum: Calculating Work of Expansion
Topic: q=C delta T
Replies: 5
Views: 33

Re: q=C delta T

The c in q = C * delta T is the heat capacity, measured in Joules per Kelvin. The C in q = m * c* delta T is specific heat capacity, which is measured in Joules per Kelvin gram. The difference is that the first c has different values depending on the amount of some material you have, while the secon...
by Nicholas Chin 1G
Sun Feb 02, 2020 11:16 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Second Law and Biological Examples
Replies: 1
Views: 18

Re: Second Law and Biological Examples

Essentially, the second law of thermodynamics says that the entropy of the universe always increases. Thus, in biology, when there's a reaction that lowers the entropy of the universe (like anabolic metabolism), it must be accompanied or powered by something that increases the entropy more than the ...
by Nicholas Chin 1G
Sun Feb 02, 2020 11:14 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Biological reactions
Replies: 1
Views: 24

Re: Biological reactions

Because humans are open systems, so air and other things can freely leave our bodies, making the pressure in our bodies equal to the pressure outside.
by Nicholas Chin 1G
Sun Feb 02, 2020 11:13 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: degeneracy
Replies: 7
Views: 38

Re: degeneracy

Degeneracy is used to help calculate the entropy of a system, which can be used to calculate the Gibbs free energy of a reaction or system.
by Nicholas Chin 1G
Sun Feb 02, 2020 11:12 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: Boltzmann Equation
Replies: 3
Views: 23

Re: Boltzmann Equation

It's basically a way to determine the positional entropy (disorder) of a system, which does not take into account the temperature.
by Nicholas Chin 1G
Sun Feb 02, 2020 11:11 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Combustion
Replies: 5
Views: 31

Re: Combustion

I believe the water that is produced is water vapor, since for combustion to occur the temperature would have to be most likely above 100 C.
by Nicholas Chin 1G
Sun Jan 26, 2020 11:26 pm
Forum: Phase Changes & Related Calculations
Topic: ∆H
Replies: 17
Views: 88

Re: ∆H

I'm not sure it's the only way, but it's probably the most reliable way.
by Nicholas Chin 1G
Sun Jan 26, 2020 11:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: autoprotolysis
Replies: 7
Views: 51

Re: autoprotolysis

Autoprotolysis is not just the transfer of a H+ ion between an acid and a base, it's the transfer of an H+ between two identical molecules, one that can act as an acid and a base (like H2O). If you then take the equilibrium constant of the equation 2 H2O -> OH- + H30+, you'll get Kw = [OH-][H30+].
by Nicholas Chin 1G
Sun Jan 26, 2020 11:24 pm
Forum: Phase Changes & Related Calculations
Topic: Temp. of sample
Replies: 4
Views: 18

Re: Temp. of sample

Yes, that is what he meant. If you heat an ice cube very slowly while taking its temperature, you'll notice that when the ice cube transitions to a liquid, the temperature of the sample is staying around 0 degrees, not increasing.
by Nicholas Chin 1G
Sun Jan 26, 2020 11:22 pm
Forum: Phase Changes & Related Calculations
Topic: Differentiating (q) and (w)
Replies: 4
Views: 20

Re: Differentiating (q) and (w)

Work is a way of transferring energy, while heat is a form of energy.
by Nicholas Chin 1G
Sun Jan 26, 2020 11:21 pm
Forum: Calculating Work of Expansion
Topic: equipartition theorem
Replies: 2
Views: 23

Re: equipartition theorem

Probably just wait and see if he talks about it.
by Nicholas Chin 1G
Sun Jan 19, 2020 9:35 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5% rule
Replies: 4
Views: 35

Re: 5% rule

This rule is also only applied if K is a small value (<10^-3).
by Nicholas Chin 1G
Sun Jan 19, 2020 9:34 pm
Forum: Ideal Gases
Topic: R Constant
Replies: 18
Views: 135

Re: R Constant

The R constant is the universal gas constant, and the reason there are different values for it is because the units can vary, from atmospheres to barrs.
by Nicholas Chin 1G
Sun Jan 19, 2020 9:32 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Henderson Hasselbalch Equation
Replies: 3
Views: 24

Re: Henderson Hasselbalch Equation

The Henderson Hasselbalch Equation is an equation that uses the pKa and concentration of weak acid & conjugate base to quickly determine the pH, without having to go through the ICE table and quadratics.
by Nicholas Chin 1G
Sun Jan 19, 2020 9:29 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: temperature
Replies: 10
Views: 57

Re: temperature

Temperature changes the equilibrium constant, so make sure you have the right K constant if looking at a chart that gives you multiple.
by Nicholas Chin 1G
Sun Jan 19, 2020 9:29 pm
Forum: Identifying Acidic & Basic Salts
Topic: Strong Acids & Bases Ions
Replies: 3
Views: 36

Re: Strong Acids & Bases Ions

Strong acids and bases are just things you're going to have to memorize. Generally, strong bases are group 1 and group 2 metals with an OH group, meaning their conjugate ions are the metals. Strong acids are HBr, HCl, HI, HNO3, HClO4, HSO4, and their conjugate ions would just be those without the H.
by Nicholas Chin 1G
Sun Jan 12, 2020 9:09 pm
Forum: Ideal Gases
Topic: The Laws
Replies: 7
Views: 50

Re: The Laws

We get to gases later on so you don't really need to worry about it right now.
by Nicholas Chin 1G
Sun Jan 12, 2020 9:08 pm
Forum: Ideal Gases
Topic: P=(n/v)RT
Replies: 12
Views: 67

Re: P=(n/v)RT

Ruby Richter 2L wrote:So basically you're just multiplying the molarity times RT which gives you P?


Yea that's all you're doing.
by Nicholas Chin 1G
Sun Jan 12, 2020 9:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reaction Direction
Replies: 14
Views: 83

Re: Reaction Direction

You determine it by comparing the equilibrium constant (K) with the reaction quotient (Q). If Q is less than K, then there are less products so the reaction is going to the right. If Q is greater than K, then there are more products so the reaction is going to the left. In this case, it doesn't matt...
by Nicholas Chin 1G
Sun Jan 12, 2020 9:05 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Calculating Q
Replies: 16
Views: 69

Re: Calculating Q

Calculating Q is the same as calculating for K, which means you include all aqueous solutions and gases, and disregard liquids/solids.
by Nicholas Chin 1G
Wed Jan 08, 2020 11:47 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: N2O4 <--> 2NO2, color?
Replies: 3
Views: 42

Re: N2O4 <--> 2NO2, color?

Thank you! I was looking for this answer!
by Nicholas Chin 1G
Sat Dec 07, 2019 4:20 pm
Forum: Polyprotic Acids & Bases
Topic: Ions
Replies: 3
Views: 46

Re: Ions

The polyatomic ones.
by Nicholas Chin 1G
Sat Dec 07, 2019 4:19 pm
Forum: Identifying Acidic & Basic Salts
Topic: Spectator Ions?
Replies: 2
Views: 41

Re: Spectator Ions?

Spectator ions are generally just group 1 cations or halogens. Since they are stable, they don't want to react.
by Nicholas Chin 1G
Sat Dec 07, 2019 4:18 pm
Forum: Identifying Acidic & Basic Salts
Topic: weak bases produce acidic solutions?
Replies: 3
Views: 48

Re: weak bases produce acidic solutions?

Salts of weak bases and STRONG acids produce acidic solutions because the conjugate base of the acid is a very weak base while the conjugate acid of the weak base is relatively stronger, so it makes the solution its in acidic.
by Nicholas Chin 1G
Sat Dec 07, 2019 4:16 pm
Forum: Air Pollution & Acid Rain
Topic: acid rain
Replies: 1
Views: 55

Re: acid rain

It's just a real life example of an acidic reaction that he went over in class, and may show up on the test. He just went over the reactions involved.
by Nicholas Chin 1G
Sat Dec 07, 2019 4:11 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: weak acids have higher pH values?
Replies: 1
Views: 18

Re: weak acids have higher pH values?

Yes, it's just because strong acids dissociate more, so there will be more H+ present in a strong acid solution than a weak acid one even if they have the same concentration.
by Nicholas Chin 1G
Sun Dec 01, 2019 6:44 pm
Forum: Biological Examples
Topic: Polydentate
Replies: 4
Views: 42

Re: Polydentate

Polydentate refers to ligands that have multiple donor atoms and therefore can bind to a metal at multiple sites. Its significance can be seen in its biological aspects such as heme complexes and other things like that.
by Nicholas Chin 1G
Sun Dec 01, 2019 6:17 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: drawing a chelate
Replies: 2
Views: 43

Re: drawing a chelate

I think if you are given a chemical formula, it will have the bracket notation, so you will know it's a chelate complex. As for drawing the right structure, I guess you just follow the lewis structure rules and hope you get it right.
by Nicholas Chin 1G
Sun Dec 01, 2019 6:14 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Difference between weak acids/bases and strong acids/bases
Replies: 6
Views: 55

Re: Difference between weak acids/bases and strong acids/bases

Weak acids and bases will not fully dissociate when in an aqueous solution, strong acids and bases will.
by Nicholas Chin 1G
Sun Dec 01, 2019 6:11 pm
Forum: Student Social/Study Group
Topic: Study Strategies
Replies: 6
Views: 60

Re: Study Strategies

Probably just go to review sessions because those usually have the same concepts as what appear on the exam.
by Nicholas Chin 1G
Sun Dec 01, 2019 6:10 pm
Forum: Conjugate Acids & Bases
Topic: Acids and Bases
Replies: 3
Views: 32

Re: Acids and Bases

They're basically all referring to the same thing, but just approach it differently. Lewis acids are molecules that accept an electron pair, while lewis bases donate an electron pair. Bronsted acids donate a proton, while Bronsted bases accept a proton. Conjugate acids and bases are a little differe...
by Nicholas Chin 1G
Sun Nov 24, 2019 3:28 pm
Forum: Naming
Topic: #9C3 d
Replies: 2
Views: 60

Re: #9C3 d

I think it has to do with the fact water is less relevant than bisoxalato.
by Nicholas Chin 1G
Sun Nov 24, 2019 3:24 pm
Forum: Sigma & Pi Bonds
Topic: Sigma & Pi Bonds
Replies: 9
Views: 58

Re: Sigma & Pi Bonds

Sigma bonds have better overlap because their tips touch. Pi bonds are side to side interactions so there is less overlap.
by Nicholas Chin 1G
Sun Nov 24, 2019 3:16 pm
Forum: Hybridization
Topic: Single Electron Orbitals
Replies: 2
Views: 43

Re: Single Electron Orbitals

Hybridization occurs to stabilize the energy of bonding orbitals. Single electrons can still form a bond, so they don't need to be hybridized.
by Nicholas Chin 1G
Sun Nov 24, 2019 3:14 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Tetrahedral and Square Planar
Replies: 3
Views: 47

Re: Tetrahedral and Square Planar

Cisplatin, the drug used to stop DNA replication, is a square planar.
by Nicholas Chin 1G
Sun Nov 24, 2019 3:06 pm
Forum: Lewis Acids & Bases
Topic: Strong Acids
Replies: 8
Views: 61

Re: Strong Acids

No, you need to know all of them I'm pretty sure.
by Nicholas Chin 1G
Sun Nov 17, 2019 5:44 pm
Forum: Student Social/Study Group
Topic: test 2
Replies: 8
Views: 72

Re: test 2

Probably roughly the same amount as test 1.
by Nicholas Chin 1G
Sun Nov 17, 2019 5:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 2
Replies: 19
Views: 157

Re: Test 2

He said that we will never be graded on drawing Lewis structures according to VSEPR model. All you have to do is write out the bond angle and shape and stuff.
by Nicholas Chin 1G
Sun Nov 17, 2019 5:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar molecules
Replies: 2
Views: 26

Re: Polar molecules

Electrostatic potential is just a fancy way of saying an electric field. Polar molecules are one's that have a more negative end and positive end. So polar molecules, with their negative and positive ends, "interact" with an electric field. That is to say that the presence of an electric f...
by Nicholas Chin 1G
Sun Nov 17, 2019 5:35 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: 3F.3
Replies: 1
Views: 23

Re: 3F.3

For this problem, you basically have to determine which molecules are polar and which aren't. So looking at the four molecules, the molecules that aren't symmetric are going to be the polar molecules, and thus have "important" dipole-dipole interactions. In this case, it would be (b) and (...
by Nicholas Chin 1G
Sun Nov 17, 2019 5:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.15B
Replies: 1
Views: 28

Re: 2E.15B

We know that the bond angles are going to be distorted to slightly less than 120 and 90 degrees, but since we can't actually know how much, we usually say that there the bond angles are 90 and 120. In my discussion session, my TA said there would then be a followup question that asks if there is ang...
by Nicholas Chin 1G
Mon Nov 11, 2019 4:39 pm
Forum: Dipole Moments
Topic: Textbook question 3F.19 part b
Replies: 2
Views: 22

Re: Textbook question 3F.19 part b

Vapor pressure is lower with molecules with strong intermolecular forces. Since H2O has hydrogen bonding, it will have a lower vapor pressure than the other molecule.
by Nicholas Chin 1G
Mon Nov 11, 2019 4:35 pm
Forum: Dipole Moments
Topic: Textbook question 3F.1
Replies: 5
Views: 55

Re: Textbook question 3F.1

I'm not too sure but I think you just look at whether the molecule is polar (aka does it have dipoles that are not cancelled), whether the molecule can form hydrogen bonds, and other type of interactions that he went over in class.
by Nicholas Chin 1G
Mon Nov 11, 2019 4:32 pm
Forum: Administrative Questions and Class Announcements
Topic: 14BL
Replies: 5
Views: 72

Re: 14BL

Yea I think for the most part people take it in separate quarters just because it's easier that way.
by Nicholas Chin 1G
Mon Nov 11, 2019 4:29 pm
Forum: Dipole Moments
Topic: Textbook question 3F.19 part c
Replies: 1
Views: 24

Re: Textbook question 3F.19 part c

These two molecules are actually ones that he went over in class the other day. Because CH3(CH2)3CH3 is going to be more rectangular/spread out than the spherical shape of C(CH3)4, the dipole moments for the first molecule will be stronger because separate molecules will be able to get closer to eac...
by Nicholas Chin 1G
Mon Nov 11, 2019 4:08 pm
Forum: Trends in The Periodic Table
Topic: Ionization energy
Replies: 6
Views: 83

Re: Ionization energy

Because nitrogen has 3 parallel spin electrons in separate orbitals in the 2p subshell, while Oxygen has 3 parallel spin electrons and one antiparallel electron in the same orbital. Because of electron-electron repulsion and the fact that having a half-full 2p subshell is more stable, it is easier (...
by Nicholas Chin 1G
Sat Nov 02, 2019 5:31 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Ionic Character in Covalent Molecules and Vice-Versa
Replies: 2
Views: 32

Re: Ionic Character in Covalent Molecules and Vice-Versa

It becomes less confusing if you think of bonds as being on a spectrum rather than just either ionic or covalent. Bonds that are considered "covalent" still have ionic characteristics, which is why we talk about how electrons are not equally shared in covalent bonds. Bonds that are conside...
by Nicholas Chin 1G
Sat Nov 02, 2019 5:27 pm
Forum: Octet Exceptions
Topic: Covalent Bond
Replies: 4
Views: 38

Re: Covalent Bond

It's a covalent bond where one atom brings both electrons and one atom accepts both.
by Nicholas Chin 1G
Sat Nov 02, 2019 5:26 pm
Forum: Properties of Electrons
Topic: Lewis acids and bases
Replies: 3
Views: 73

Re: Lewis acids and bases

Coordinate covalent bonds are covalent bonds where one atom brings both electrons and one accepts electrons. Lewis acids (H+) accept two electrons to form a bond, while lewis bases donates both.
by Nicholas Chin 1G
Sat Nov 02, 2019 5:21 pm
Forum: Electronegativity
Topic: Definition
Replies: 2
Views: 27

Re: Definition

Electronegativity is a measure of the tendency of an atom to attract electrons. It has the same trend on the periodic table as atomic radius.
by Nicholas Chin 1G
Sat Nov 02, 2019 5:20 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 2A.1
Replies: 1
Views: 23

Re: 2A.1

a) 5, b) 4 c) 7 d) 3
by Nicholas Chin 1G
Sun Oct 27, 2019 11:05 pm
Forum: Ionic & Covalent Bonds
Topic: using the octet rule
Replies: 2
Views: 35

Re: using the octet rule

Assume that you always apply the octet for any bond except for the exceptions (P, S, Cl)
by Nicholas Chin 1G
Sun Oct 27, 2019 10:12 pm
Forum: Ionic & Covalent Bonds
Topic: electron configuration order
Replies: 6
Views: 80

Re: electron configuration order

So just like the d-orbital and s-orbital, the 5s comes first, but after 2 electrons are in the 5s the 4f is actually placed before when you're writing out the electron configuration. You don't really need to worry about it because he said we wouldn't be tested on it.
by Nicholas Chin 1G
Sun Oct 27, 2019 10:09 pm
Forum: Ionic & Covalent Bonds
Topic: electron configuration
Replies: 5
Views: 54

Re: electron configuration

It's because having 10 electrons in the d orbital and 1 in the s orbital is actually more stable than 9 electrons in the d orbital and 2 in the s orbital. This also applies for 5 electrons in the d orbital.
by Nicholas Chin 1G
Sun Oct 27, 2019 9:40 pm
Forum: Octet Exceptions
Topic: octet exceptions
Replies: 5
Views: 45

Re: octet exceptions

You can also use formal charge to see if the atom would be more stable with an expanded octet.
by Nicholas Chin 1G
Sun Oct 27, 2019 9:36 pm
Forum: Resonance Structures
Topic: Drawing Resonance Structures
Replies: 3
Views: 46

Re: Drawing Resonance Structures

It should be the arrows indicated between the various structures because we haven't really learned orgo yet.
by Nicholas Chin 1G
Mon Oct 21, 2019 10:52 am
Forum: *Shrodinger Equation
Topic: Hamiltonian
Replies: 6
Views: 50

Re: Hamiltonian

Yea, he specifically said in lecture that we will never be tested on this.
by Nicholas Chin 1G
Mon Oct 21, 2019 10:48 am
Forum: Einstein Equation
Topic: Alternative unit for J
Replies: 4
Views: 48

Re: Alternative unit for J

In what types of circumstances would it be necessary for us to convert J into these units? Can someone give a sample problem or example? I don't think there's any instance in chemistry where you would have to break down these units and use them, but in physics it can be useful to know these units t...
by Nicholas Chin 1G
Mon Oct 21, 2019 10:47 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: How to use it
Replies: 5
Views: 58

Re: How to use it

In addition to Brianna Becerra 1F, you would typically use this equation when being asked for the minimum uncertainty in speed/velocity when given the physical constraints or vice versa. Is minimum uncertainty something different or when we solve this equation we get minimum uncertainty? Minimum un...
by Nicholas Chin 1G
Mon Oct 21, 2019 10:45 am
Forum: Quantum Numbers and The H-Atom
Topic: Z
Replies: 5
Views: 61

Re: Quantum Number Z

We have not learned about a quantum number Z, but the letter Z can represent the nuclear charge of an atom.
by Nicholas Chin 1G
Mon Oct 21, 2019 10:43 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: S and P orbital
Replies: 3
Views: 32

Re: S and P orbital

Because in the case of the s and p orbitals, the difference between the energy of the orbitals are too great to make a difference when you have a full p orbital vs a full s orbital. In the 3d orbital vs the 4s orbital, the energies are very similar, so the fullness of the subshell makes a difference.
by Nicholas Chin 1G
Sun Oct 13, 2019 11:32 am
Forum: Properties of Light
Topic: Rydberg constant
Replies: 7
Views: 71

Re: Rydberg constant

The formula was derived empirically, meaning they looked at the data they collected from performing a spectroscopic experiment with hydrogen and developed a formula that fit the data they had. This means that it's only applicable to hydrogen.
by Nicholas Chin 1G
Sun Oct 13, 2019 11:30 am
Forum: Empirical & Molecular Formulas
Topic: Nomenclature
Replies: 11
Views: 203

Re: Nomenclature

Pretty sure we have to know how to do it at some point, but we're not expected to do it right now.
by Nicholas Chin 1G
Sun Oct 13, 2019 11:29 am
Forum: Balancing Chemical Reactions
Topic: F.3
Replies: 5
Views: 88

Re: F.3

When I asked my TA they said that we are expected to memorize the names of cations and anions, but I'm not sure if we have to memorize the acids yet since that's something we will cover later.
by Nicholas Chin 1G
Sat Oct 12, 2019 7:02 pm
Forum: SI Units, Unit Conversions
Topic: Weekly Posts
Replies: 7
Views: 81

Re: Weekly Posts

Pretty sure it's before 11:59 pm on Sunday
by Nicholas Chin 1G
Sat Oct 12, 2019 7:01 pm
Forum: Significant Figures
Topic: Sig Figs in Answer
Replies: 8
Views: 116

Re: Sig Figs in Answer

Although it's usually good practice to go to 4 for mass percentage composition, it actually depends on how many sig figs you have for the mass of elements you use. For example, if you use 12.01 for Carbon, you have 4. But if you use 12.0107, you have 6.
by Nicholas Chin 1G
Thu Oct 03, 2019 11:46 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity Equation
Replies: 2
Views: 24

Re: Molarity Equation

Molarity does not have the units of moles. It has the units mol/L, which is denoted as M in some cases.
by Nicholas Chin 1G
Wed Oct 02, 2019 12:08 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical and Molecular Formula Masses
Replies: 5
Views: 90

Re: Empirical and Molecular Formula Masses

If the given mass of the molecular formula is the g/mol, yes the empirical formula is wrong.
by Nicholas Chin 1G
Tue Oct 01, 2019 3:58 pm
Forum: Significant Figures
Topic: Question about significant figures and rounding a number
Replies: 4
Views: 82

Re: Question about significant figures and rounding a number

In regards to rounding for significant figures, you count out how many figures your answer should have first. So if your sig figs were 1, and your answer was 5.454545, you would only take the 5 in the ones place. Next, you would look one number to the right. You then apply the golden rule of roundin...
by Nicholas Chin 1G
Tue Oct 01, 2019 3:51 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: G.25 Dilution
Replies: 4
Views: 77

Re: G.25 Dilution

So if the wording is "double the volume 90 times," that means you have to multiply 10 mL by 2 90 times. An easy way to do this is just 10 mL * 2^90, which effectively "doubles the volume 90 times" since you multiply by 2 90 times. Now you have a volume initial (10 mL), a molarity...
by Nicholas Chin 1G
Mon Sep 30, 2019 4:24 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Fundamental E Problem 1
Replies: 3
Views: 51

Re: Fundamental E Problem 1

It's not really a formula, but you would use Avogadro's number multiplied by the diameter of an Ag atom, since 1 mol of Ag is 6.022 x 10^23 atoms. This would give you the length of the fiber assuming that it is only one atom thick and all the atoms are lined up perfectly.

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