Search found 33 matches

by Hee Sang Kim 3L
Sat Mar 12, 2016 8:04 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Rate constant and Ea
Replies: 1
Views: 381

Rate constant and Ea

Why does change in rate constant have no effect on activation energy? In the course reader, it says that catalyst speeds up the reaction (K) by lowering the Ea.
by Hee Sang Kim 3L
Sun Mar 06, 2016 11:33 pm
Forum: *Alkenes
Topic: Vinyl substituent
Replies: 2
Views: 520

Vinyl substituent

We learned how to draw vinyl as a parent chain but how is it supposed to look like as a substituent?
by Hee Sang Kim 3L
Sun Feb 28, 2016 8:43 pm
Forum: *Alkanes
Topic: 4-ethyl-2,2-dimethyl-hexane
Replies: 1
Views: 390

4-ethyl-2,2-dimethyl-hexane

In the course reader, why is it 4-ethyl-2,2-dimethyl-hexane instead of 3-ethyl-5,5-dimethyl-hexane? why does it not follow the "1st named group gets lower number" rule? I know the course reader says "#chain to give lowest # to substituents". Does that mean since theres 2 methyl b...
by Hee Sang Kim 3L
Sun Feb 28, 2016 2:33 pm
Forum: *Nucleophiles
Topic: Neutral element
Replies: 1
Views: 484

Neutral element

Are all elements (excluding noble gas) are electrophiles if they are not negatively charged? For example C is electrophile but Carbon ion is nucleophile?
by Hee Sang Kim 3L
Sat Feb 13, 2016 7:05 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Energetically favorable
Replies: 1
Views: 7986

Energetically favorable

What is energetically favorable and is it the same thing with being exothermic?
Does a energetically favorable reaction not be spontaneous?
by Hee Sang Kim 3L
Sat Feb 13, 2016 6:25 pm
Forum: Second Order Reactions
Topic: workbook quiz2 preparation winter 2014 question.
Replies: 2
Views: 504

workbook quiz2 preparation winter 2014 question.

I have 2 questions from workbook quiz2 preparation winter 2014. #10 from it asks what is the activation energy for the reaction based on the K value that we have. Are we supposed to know how to do that for quiz2? If we do, please teach me #12, it tells you to graph the data, find the slope and get t...
by Hee Sang Kim 3L
Sat Feb 13, 2016 4:14 pm
Forum: First Order Reactions
Topic: HW question 15.37
Replies: 1
Views: 412

HW question 15.37

Why does HW question 15.37 C) not require the volume in the calculation? Do we not have to calculate the molarity?
by Hee Sang Kim 3L
Fri Feb 12, 2016 7:11 pm
Forum: Second Order Reactions
Topic: Half life equations
Replies: 1
Views: 378

Half life equations

Are we supposed to know how to derive all these integrated rate law equations and half life equations?
by Hee Sang Kim 3L
Mon Feb 08, 2016 10:57 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: internal heat change of monotomic ideal gas
Replies: 2
Views: 496

internal heat change of monotomic ideal gas

does " ΔU=3/2RT" only apply to monotomic ideal gas?
by Hee Sang Kim 3L
Fri Feb 05, 2016 6:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt bridge
Replies: 1
Views: 325

Salt bridge

How exactly does the salt bridge prevent one side getting to postitive and another getting too negative? What is the detailed process?
by Hee Sang Kim 3L
Sun Jan 31, 2016 4:38 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Delta G
Replies: 1
Views: 351

Delta G

Why is delta G= W max at constant T and P?
by Hee Sang Kim 3L
Wed Jan 27, 2016 11:43 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Textbook question 9.35
Replies: 1
Views: 330

Textbook question 9.35

Container A is fi lled with 1.0 mol of the atoms of an ideal monatomic gas. Container B has 1.0 mol of atoms bound together as diatomic molecules that are not vibrationally active. Container C has 1.0 mol of atoms bound together as diatomic molecules that are vibrationally active. The containers all...
by Hee Sang Kim 3L
Tue Jan 26, 2016 7:17 pm
Forum: Calculating Work of Expansion
Topic: Textbook question clarification
Replies: 2
Views: 418

Textbook question clarification

There was a textbook question asking "Calculate the change in molar entropy of an ideal gas when it is compressed isothermally to one-third its initial volume. " Is ideal gas implaying that is 1 mol of gas? How do we know the mole of gas
by Hee Sang Kim 3L
Tue Jan 26, 2016 7:15 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook question
Replies: 3
Views: 550

Re: Textbook question

Water expands when it freezes. How much work does 100. g of water do when it freezes at 0.0 C and pushes back the metal wall of a pipe that exerts an opposing pressure of 1070 atm? The densities of water and ice at 0.0 C are 1.00 gcm3 and 0.92 gcm3, respectively. The textbook answer is -0.86KJ.
by Hee Sang Kim 3L
Tue Jan 26, 2016 12:49 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook question
Replies: 3
Views: 550

Textbook question

Is there something wrong with textbook question 8.1A Selftest on page264? Because I feel like the answer multiplied the mass by the density not dividing by the density
by Hee Sang Kim 3L
Sun Jan 17, 2016 4:24 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Reversible and irreversible
Replies: 2
Views: 507

Reversible and irreversible

What is the exact difference of reversible process and irreversible process and why does reversible process always has more work done?
by Hee Sang Kim 3L
Sat Jan 09, 2016 12:40 am
Forum: Phase Changes & Related Calculations
Topic: Heat
Replies: 1
Views: 327

Heat

Why is the heat equation always negative? Or is it only when it is releasing energy
by Hee Sang Kim 3L
Tue Dec 01, 2015 12:53 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Br2 2+
Replies: 1
Views: 521

Br2 2+

In one of the course reader practice final exam, it says Br2 2+ is diamagnetic. But it is supposed to be paramagnetic right?
by Hee Sang Kim 3L
Thu Nov 26, 2015 10:34 pm
Forum: Calculating the pH of Salt Solutions
Topic: Hw question 77
Replies: 1
Views: 386

Hw question 77

Do we have to know the calculation involved Ka1 and ka2?
by Hee Sang Kim 3L
Thu Nov 26, 2015 10:32 pm
Forum: Calculating the pH of Salt Solutions
Topic: AlCl3
Replies: 3
Views: 656

Re: AlCl3

Is it in the textbook?
by Hee Sang Kim 3L
Thu Nov 26, 2015 8:04 pm
Forum: Calculating the pH of Salt Solutions
Topic: AlCl3
Replies: 3
Views: 656

AlCl3

For question 69 b), where do you get the Ka of Al3+
by Hee Sang Kim 3L
Thu Nov 26, 2015 7:17 pm
Forum: Lewis Acids & Bases
Topic: SO2
Replies: 2
Views: 855

SO2

Why is SO2 a lewis acid. Apparently it can accept an electron pair, but why and how?
by Hee Sang Kim 3L
Mon Nov 23, 2015 11:29 pm
Forum: Identifying Acidic & Basic Salts
Topic: Exceptions of anions
Replies: 2
Views: 499

Exceptions of anions

Why were HSO4- and H2PO4- exceptions from anions making solution basic again?
by Hee Sang Kim 3L
Mon Nov 23, 2015 8:58 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength of acidity
Replies: 1
Views: 405

Strength of acidity

It is said that longer the A-H bond, more acidic it is. That means HI is more acidic than HCl due to the bigger size of Iodine that causese longer bond. However, second property was depedent on electronegativity, and examples were given so that CL-O-H is more acidic than I-O-H. Doesnt this contradic...
by Hee Sang Kim 3L
Wed Nov 18, 2015 4:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Significant figure
Replies: 1
Views: 310

Significant figure

Hi i was confused between how to apply sigfig rules Basically if we look at the textbook question 11.57, the solution manual uses the intermediate sigfig which means it rounds up for the addition part. However, thats not how i learned in highschool and i was really confused. Do we round up the sigfi...
by Hee Sang Kim 3L
Sun Nov 08, 2015 6:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: name of iron
Replies: 2
Views: 382

name of iron

I realized that some of the question use the name "iron" when naming coordinate compounds and some of others use "ferrate". How do we know when to use what
by Hee Sang Kim 3L
Thu Oct 29, 2015 12:30 pm
Forum: Resonance Structures
Topic: SO4 2-
Replies: 1
Views: 5792

SO4 2-

Sulfate ion has two ways of drawing its lewis structure. One is to follow the octet rule and having single bond for each oxygen each perfectly satisfies the octet rule. However, since sulfate can hold more than 8 electrons, it is better to draw the lewis structure with 2 double bond oxygens and 2 si...
by Hee Sang Kim 3L
Thu Oct 29, 2015 1:19 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: CO mo diagram
Replies: 1
Views: 239

CO mo diagram

Hi, in lecture, Dr. Lavelle said that 2p and 2s orbitals of Carbon is higher than those of oxygen. Why? I did not catch what he said.
by Hee Sang Kim 3L
Sun Oct 25, 2015 12:19 am
Forum: Dipole Moments
Topic: polarizability in ionic model
Replies: 1
Views: 353

polarizability in ionic model

It is said that highly distorted electron in atoms and ions are highly polarizable and that result in more covalent caracter. Why? isnt it supposed to be have more ionic ?
by Hee Sang Kim 3L
Fri Oct 16, 2015 8:26 pm
Forum: Octet Exceptions
Topic: Octet Exception (Course Reader)
Replies: 1
Views: 455

Re: Octet Exception (Course Reader)

Hi Nick. Beryllium chloride has a linear shape and beryllium is an octet exception because beryllium ion loses an electron when it forms bond, and that means it has the same electron configuration as Helium, which is a duplet instead of an octet.
by Hee Sang Kim 3L
Fri Oct 09, 2015 8:50 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Unpaired Electron
Replies: 2
Views: 1789

Re: Unpaired Electron

OMG sorry i was really dumb, this time i figured out. So basically u gotta write down the electron configuration and see. For example, if it is asking for unpaired electron of silicon, silicon's electron configuration is [Ne]3s2 3p2. According to Hund's rule, due to electron repulsion, electron in s...
by Hee Sang Kim 3L
Fri Oct 09, 2015 7:02 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Unpaired Electron
Replies: 2
Views: 1789

Re: Unpaired Electron

Hi, you look at the periodic table and see which group it belongs to. For example, if you look at Berylium, its on the group 2, so it has 2 out of 8 electron, which means 8-2=6. so 6 unpaired elctrons. If you look at Oxygen, it is technically in group 16, but you need to ignore the d block which is ...
by Hee Sang Kim 3L
Fri Oct 09, 2015 6:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configuration for Thorium
Replies: 1
Views: 1388

Electron configuration for Thorium

Apparently, electron configuration for Thorium is [Rn] 6d2 7s2. However, I thought it would be [Rn] 5f1 6d1 7s2 since its on the F block right after the first 6d element (Actinium). Help!

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