Search found 50 matches

by Vincent Kim 2I
Fri Mar 16, 2018 3:45 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.65
Replies: 1
Views: 106

Re: 15.65

it increases the rate constant of both reactions, but more substantially for the one with the higher activation energy
by Vincent Kim 2I
Fri Mar 16, 2018 3:27 pm
Forum: *Ketones
Topic: Carbonyls
Replies: 2
Views: 377

Re: Carbonyls

carbonyls are C=O, and both ketones and aldehydes have a C=O bond
by Vincent Kim 2I
Fri Mar 16, 2018 3:15 pm
Forum: Balancing Redox Reactions
Topic: Basic conditions with OH
Replies: 3
Views: 141

Re: Basic conditions with OH

pH + pOH = 14
by Vincent Kim 2I
Fri Mar 16, 2018 3:14 pm
Forum: *Alkanes
Topic: The symbol R
Replies: 4
Views: 463

Re: The symbol R

R represents a carbon chain of any length
by Vincent Kim 2I
Thu Mar 15, 2018 10:02 pm
Forum: *Electrophiles
Topic: what is going to be on the final? [ENDORSED]
Replies: 12
Views: 855

Re: what is going to be on the final? [ENDORSED]

Lavelle distributes the range of questions relatively evenly, but since we learned some new material after the last test, I'd watch out for those
by Vincent Kim 2I
Thu Mar 15, 2018 9:55 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Fast or Slow
Replies: 8
Views: 333

Re: Fast or Slow

I'm pretty sure this fact will be given in a problem
by Vincent Kim 2I
Thu Mar 15, 2018 9:51 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Please explain k'
Replies: 3
Views: 170

Re: Please explain k'

k' is the reverse rate constant of the reaction
by Vincent Kim 2I
Thu Mar 15, 2018 9:42 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.97
Replies: 1
Views: 114

Re: 14.97

I may be wrong but I think it's because there's a coefficient of 2 in front of H+
by Vincent Kim 2I
Thu Mar 15, 2018 9:38 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: The Effect of Temperature
Replies: 3
Views: 130

Re: The Effect of Temperature

Raising the temperature increases the speed of the reaction, essentially increasing the rate constant
by Vincent Kim 2I
Thu Mar 15, 2018 9:36 pm
Forum: *Ethers
Topic: Nucleophile
Replies: 3
Views: 699

Re: Nucleophile

Nucleophiles donate electrons just like a Lewis Base
by Vincent Kim 2I
Thu Mar 15, 2018 3:21 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb calorimeter
Replies: 2
Views: 221

Re: Bomb calorimeter

I think the constant volume refers to the entire container, as it doesn't change as the pressure increases or decreases inside, as it is a isolated system
by Vincent Kim 2I
Thu Mar 15, 2018 2:34 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.29
Replies: 2
Views: 158

Re: 14.29

All the states should be given in a standard reduction potential chart
by Vincent Kim 2I
Thu Mar 15, 2018 2:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Questions in the second test
Replies: 2
Views: 129

Re: Questions in the second test

The same goes for the other way around, the lower a substance's reduction potential, the better of a reducing agent it is
by Vincent Kim 2I
Thu Mar 15, 2018 2:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.13 b
Replies: 4
Views: 200

Re: 14.13 b

I'm pretty sure you're correct, it shouldn't need to be written on the left side
by Vincent Kim 2I
Thu Mar 15, 2018 2:22 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Coefficients when writing cell diagrams
Replies: 3
Views: 159

Re: Coefficients when writing cell diagrams

Coefficients are not in the cell diagram, only the chemical equation
by Vincent Kim 2I
Mon Mar 12, 2018 2:02 am
Forum: Zero Order Reactions
Topic: Half life
Replies: 7
Views: 591

Re: Half life

Yes, first order half lives apply to radioactive decay. Zero order and Second order half lives exist in real life with other processes
by Vincent Kim 2I
Mon Mar 12, 2018 1:59 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 65.b
Replies: 2
Views: 132

Re: 65.b

Yes you can determine that the reaction is endothermic because the formation of one product is favored over that one product being broken up into two different molecules
by Vincent Kim 2I
Sun Mar 04, 2018 11:22 pm
Forum: General Rate Laws
Topic: zero order in rate laws
Replies: 8
Views: 286

Re: zero order in rate laws

Unless the problem wants you to write it out specifically, probably not
by Vincent Kim 2I
Tue Feb 13, 2018 5:48 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: "Ideal"
Replies: 6
Views: 255

Re: "Ideal"

Usually on these tests, we are given the fact that the gases are ideal
by Vincent Kim 2I
Sun Feb 11, 2018 11:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: delta H vs delta H naught
Replies: 2
Views: 437

Re: delta H vs delta H naught

yes, this way delta H naught can be used for any amount of compound given, instead of the specific value that is produced when solving for simply delta H
by Vincent Kim 2I
Sun Feb 11, 2018 11:24 pm
Forum: Phase Changes & Related Calculations
Topic: calculating a phase change in a reaction
Replies: 5
Views: 254

Re: calculating a phase change in a reaction

I think as a general rule if you're calculating heat you need to account for phase changes, but on the midterm things should be a little clearer.
by Vincent Kim 2I
Sat Feb 10, 2018 9:21 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy
Replies: 3
Views: 138

Re: Entropy

all variations of delta S = nRln(V2/V1), S = kBlnW, the gibb's free energy equation, delta S = qrev/T

these are just some I could think of right now, but there's probably more
by Vincent Kim 2I
Sat Feb 10, 2018 9:02 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Derivations of Equations
Replies: 5
Views: 217

Re: Derivations of Equations

The derivations are just nice to know in order to understand the relationships of each term with another, but it's not necessary for the midterm.
by Vincent Kim 2I
Sat Feb 10, 2018 7:54 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.101 (b) [ENDORSED]
Replies: 4
Views: 535

Re: 9.101 (b) [ENDORSED]

Just further developing on the previous reply, since delta S is q/T, the greater T is, the smaller delta S is. It's simply an inverse relationship
by Vincent Kim 2I
Mon Jan 22, 2018 5:16 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hesss Law
Replies: 6
Views: 237

Re: Hesss Law

It's also in the textbook on chapter 8, section 16 for a quick reference
by Vincent Kim 2I
Mon Jan 22, 2018 5:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Units of Standard Enthalpies of Formation
Replies: 2
Views: 121

Re: Units of Standard Enthalpies of Formation

Essentially, it doesn't really matter whether it's kj or kj/mol, just use whatever you end up with as you work through the problem.
by Vincent Kim 2I
Mon Jan 22, 2018 5:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Concepts for Chapter 8 [ENDORSED]
Replies: 5
Views: 263

Re: Concepts for Chapter 8 [ENDORSED]

It helps to work through all of the homework questions he assigns if you haven't done that already.
by Vincent Kim 2I
Sun Jan 14, 2018 3:25 pm
Forum: Phase Changes & Related Calculations
Topic: Heat Capacity vs. Specific Heat Capacity
Replies: 3
Views: 277

Re: Heat Capacity vs. Specific Heat Capacity

Heat capacity isn't specific to a certain value and is fluid depending on the amount of substance there is. Specific heat capacity only refers to the amount of energy needed to raise the temperature of 1 gram of a substance by 1 C. No matter how much substance there is, the specific heat capacity wi...
by Vincent Kim 2I
Sun Jan 14, 2018 3:15 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 3
Views: 163

Re: Bond Enthalpies

Resonance shouldn't necessarily affect bond enthalpy, as you can still use the values given to you to determine what you are looking for. For example a single bond between CO has bond enthalpy of 358 kj/mol, while a double bond between CO has bond enthalpy of 799 kj/mol. Either way, you're adding th...
by Vincent Kim 2I
Sun Jan 14, 2018 3:07 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Infinite Forms of Hess's Law
Replies: 5
Views: 137

Re: Infinite Forms of Hess's Law

There can be much more than 2-4 reactions involved with the use of Hess's Law, but it's not necessary to use all of them because it's possible to represent the steps of a chemical reaction with fewer steps.
by Vincent Kim 2I
Sat Dec 09, 2017 8:14 pm
Forum: Naming
Topic: Test 4
Replies: 4
Views: 372

Re: Test 4

Yes, the oxidation number of Hg would be (III) instead of (I), as the two Fluoride ions make the overall charge -2, which requires a +3 oxidation state from the Hg to make the compound +1.
by Vincent Kim 2I
Sat Dec 09, 2017 8:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ice box question
Replies: 2
Views: 324

Re: ice box question

It's not that the equation flips from products becoming the reactants, but more that we are trying to calculate at which concentrations the reaction reaches equilibrium. If you just flip the equilibrium constant to 1/K, you're not changing anything about the concentrations.
by Vincent Kim 2I
Sat Dec 09, 2017 8:05 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Change in Equilibrium Constant
Replies: 2
Views: 245

Re: Change in Equilibrium Constant

The equilibrium constant K only changes when the concentrations of the reactants and products are changed, not when their stoichiometric constants are.
by Vincent Kim 2I
Thu Dec 07, 2017 11:19 pm
Forum: Lewis Acids & Bases
Topic: Identifying Lewis Acid
Replies: 3
Views: 213

Re: Identifying Lewis Acid

A simple Pt could be confusing to a reader, and it just makes it easier for everybody if you take the extra measure to write the oxidation number.
by Vincent Kim 2I
Thu Dec 07, 2017 10:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Pi bond
Replies: 3
Views: 217

Re: Pi bond

Essentially if it doesn't matter which atom specifically needs the double bond in the lewis structure, then there is delocalization. For example, benzene, a 6 Carbon ring with three double bonds has delocalized pi bonds because there it doesn't matter which 3 Carbons are double bonded together, so l...
by Vincent Kim 2I
Thu Dec 07, 2017 10:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE table
Replies: 7
Views: 465

Re: ICE table

Basically when the Q and K values in the problem are very close, then the changes in concentration (x) will be extremely small, even negligible in most cases.
by Vincent Kim 2I
Thu Dec 07, 2017 9:17 pm
Forum: Amphoteric Compounds
Topic: Is water both amphoteric and amphiprotic? [ENDORSED]
Replies: 2
Views: 466

Re: Is water both amphoteric and amphiprotic? [ENDORSED]

Also I believe any amphiprotic molecule is also amphoteric, but not any amphoteric molecule is amphiprotic.
by Vincent Kim 2I
Sun Nov 12, 2017 3:53 pm
Forum: Resonance Structures
Topic: Understanding Resonance Structures
Replies: 6
Views: 395

Re: Understanding Resonance Structures

Resonance is just a term to describe when a molecule has a double bond that can be placed in multiple locations without changing the actual structure of the molecule. A molecule with resonance will always have the same formal charge, that doesn't change. Naturally, the real structure of the molecule...
by Vincent Kim 2I
Sun Nov 12, 2017 3:06 pm
Forum: Ionic & Covalent Bonds
Topic: Bond types
Replies: 2
Views: 144

Re: Bond types

Also, a general rule of thumb:
Metals typically make ionic bonds with nonmetals, as their electronegativity difference is high
Nonmetals typically make covalent bonds with nonmetals, as their electronegativity difference is low
by Vincent Kim 2I
Sun Nov 05, 2017 5:24 pm
Forum: Ionic & Covalent Bonds
Topic: How to easily tell between Ionic and Covalent bonds?
Replies: 8
Views: 473

Re: How to easily tell between Ionic and Covalent bonds?

I really doubt he expects us to memorize all values of electronegativity, so they'll probably be given to us.
by Vincent Kim 2I
Sun Nov 05, 2017 5:19 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Lower in Energy? [ENDORSED]
Replies: 6
Views: 295

Re: Lower in Energy? [ENDORSED]

Typically we look at the principal quantum number to determine which orbital is lower in energy, but in the case of 3d and 4s, 4s is lower.
by Vincent Kim 2I
Sat Oct 28, 2017 4:58 pm
Forum: Lewis Structures
Topic: S and P blocks and Lewis structures [ENDORSED]
Replies: 4
Views: 220

Re: S and P blocks and Lewis structures [ENDORSED]

You know whether a molecule uses a double or triple bond if you use all the available electrons in the covalent bond. For example, Carbonate (CO 3 2- ) has 24 valence electrons in total (4 from Carbon, 18 from three Oxygens, 2 from the 2- charge). The Carbon atom needs to double bond to one of the O...
by Vincent Kim 2I
Sat Oct 28, 2017 4:01 pm
Forum: Hybridization
Topic: Principle Quantum Number in D-Block [ENDORSED]
Replies: 4
Views: 301

Re: Principle Quantum Number in D-Block [ENDORSED]

You start filling the 3d orbital after 4s because the 4s orbital generally has lower energy than the 3d orbital.
by Vincent Kim 2I
Sun Oct 22, 2017 9:18 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Quantum Number l exception [ENDORSED]
Replies: 4
Views: 284

Re: Quantum Number l exception [ENDORSED]

The value of l is also not just (n-1), but can also include the negatives numbers too. For s: l can only be 0, while for p: l can be -1, 0, and 1.
by Vincent Kim 2I
Sun Oct 22, 2017 8:58 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: XYZ [ENDORSED]
Replies: 4
Views: 278

Re: XYZ [ENDORSED]

You don't necessarily have to think of the p-orbital as XYZ, it's just a label for each of the three orbital subsets. You can simply call them subset 1, subset 2, and subset 3 if you want. It's the same as you learned in high school.
by Vincent Kim 2I
Sat Oct 14, 2017 4:28 pm
Forum: Properties of Electrons
Topic: 1.3 Atomic Spectra [ENDORSED]
Replies: 1
Views: 159

Re: 1.3 Atomic Spectra [ENDORSED]

The energy levels don't have to have a specific interval of change. The Balmer series just refers to whenever electrons transition to the principal quantum number 2. It can be from both n=3 to n=2 and n=4 to n=2.
by Vincent Kim 2I
Sat Oct 14, 2017 4:21 pm
Forum: Properties of Light
Topic: Photoelectric Experiments:Light [ENDORSED]
Replies: 4
Views: 273

Re: Photoelectric Experiments:Light [ENDORSED]

I'm pretty sure ultraviolet light is typically used for photoelectric experiments.
by Vincent Kim 2I
Sat Oct 14, 2017 4:16 pm
Forum: Photoelectric Effect
Topic: Post-Module Question #29 [ENDORSED]
Replies: 1
Views: 152

Re: Post-Module Question #29 [ENDORSED]

You're right to be using the work function, but the units are wrong. The question asks for how much energy is required to remove an electron from one sodium atom.

This means that you need to divide 1.506 x 10^5 J.mol-1 by avogadro's number (6.022 x 10^23).

It should give you 2.501 x 10^-19 J.
by Vincent Kim 2I
Sat Oct 14, 2017 2:53 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Doubt [ENDORSED]
Replies: 4
Views: 233

Re: Photoelectric Effect Doubt [ENDORSED]

Is it the number of photons or the energy of the photons that causes electrons to be ejected from the metal?

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