Search found 18 matches

by Katherine Ho 1E
Tue Mar 08, 2016 3:23 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Final 2012 Q8B
Replies: 1
Views: 289

Final 2012 Q8B

The question asks to draw the preferred conformation for 1-1-Bromochlorocyclohexane

My question is, why is it more stable to have Bromine in the equatorial down position and not chlorine?
by Katherine Ho 1E
Fri Mar 04, 2016 11:09 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7951
Views: 1213854

Re: Chemistry Jokes

What kind of fish is made of only two sodium atoms?

2 Na
by Katherine Ho 1E
Tue Feb 23, 2016 10:48 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Self Test 4.4A Delta G and Activation Energy
Replies: 1
Views: 333

Self Test 4.4A Delta G and Activation Energy

Self Test 4.4 has a diagram of a reaction plotted against the Standard Gibb's Free Energy, G on the y axis and shows a curve where the first hump is lower than the second It asks which step has the larger Delta G 0 and and which has a larger Ea From the answers, step 2 has a larger Delta G and step ...
by Katherine Ho 1E
Sat Feb 20, 2016 7:45 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Course Reader Example
Replies: 1
Views: 290

Re: Course Reader Example

I think you might be mistaken... In transition state 1, one bond connecting the carbons is broken AND the bond between H-Br is also broken. Since H-BR is broken, H then bonds to one of the carbons (that was previously broken from a double to a single bond) After T1, the intermediate forms and prompt...
by Katherine Ho 1E
Sat Feb 20, 2016 5:26 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Chemical Kinetics Concepts (HW: 15.79)
Replies: 1
Views: 337

Re: Chemical Kinetics Concepts (HW: 15.79)

Kinetic control predominates at low temperatures. Because if the reaction occurs under kinetic control, that means that the product is formed by the faster reaction and a faster reaction means that it has a lower activation energy and a larger rate constant due to that lower activation energy barrie...
by Katherine Ho 1E
Wed Feb 03, 2016 10:36 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Winter 2011 Midterm Practice Q 1A
Replies: 2
Views: 309

Winter 2011 Midterm Practice Q 1A

1A asks, given that the enthalpy of combustion of benzoic acid is -3227 kJ/mol and that 1.453 g of benzoic acid was burned in a calorimeter, the temperature increased by 2.265 degrees Celcius, what is the heat capacity of the calorimeter? I understand how to solve the problem, but I was wondering wh...
by Katherine Ho 1E
Mon Jan 25, 2016 10:11 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Finding Range of Temperatures and Delta G
Replies: 2
Views: 1192

Finding Range of Temperatures and Delta G

Regarding question 12 on Quiz 1 2014 The question asks, what is the rage of temperatures at which the reaction is spontaneous, at standard conditions? Once we find delta H and delta S to plug into the formula DG = DH -TDS to solve for T, why is it that delta G = 0? I somewhat understand that it's to...
by Katherine Ho 1E
Fri Jan 22, 2016 3:56 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard RXN Entropy/Enthalpy
Replies: 3
Views: 482

Re: Standard RXN Entropy/Enthalpy

You subtract when they ask you to find H rxn using mean bond enthalpies because what it's really asking for is delta H rxn = sum of mean bond enthalpies broken - sum of mean bond enthalpies formed Knowing whether you use products-reactants vs reactants-products (really bonds broken-bonds formed) dep...
by Katherine Ho 1E
Fri Jan 15, 2016 9:14 pm
Forum: Phase Changes & Related Calculations
Topic: Heating Curves vs. Cooling Curves
Replies: 1
Views: 3628

Re: Heating Curves vs. Cooling Curves

They're pretty much the same idea showing the different phases of something at certain temperatures over time. For example, let's take water/ice. We denote the temperature of water on the vertical axis and the amount of heat added over time on the horizontal axis. If we want to diagram the phases of...
by Katherine Ho 1E
Fri Jan 08, 2016 3:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Final Temperature
Replies: 1
Views: 198

Re: Calculating Final Temperature

If I interpreted your question right, I think this is because... Ice has an initial temperature of 0, but when you drop it into water (temperature > 0), the ice changes the temperature of the water so this temperature would be Tf To find the change, you are correct in saying that it's Tf-0 However, ...
by Katherine Ho 1E
Fri Nov 20, 2015 4:22 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE Table-Change in Concentration
Replies: 2
Views: 805

Re: ICE Table-Change in Concentration

Another tip that seems to help me a lot is to read or skim the textbook before a lecture. You'll have a general idea of what's going on, but if you're not completely sure, then the lecture will help explain it. Plus, lecture is much more interesting to me when I can make connections to what I read. ...
by Katherine Ho 1E
Fri Nov 13, 2015 11:22 pm
Forum: Naming
Topic: Naming and Biological Examples
Replies: 1
Views: 289

Re: Naming and Biological Examples

That should be under chapter 16 :)
by Katherine Ho 1E
Fri Nov 06, 2015 12:33 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: How important is the central atom? Hypothetical question
Replies: 2
Views: 450

How important is the central atom? Hypothetical question

This is far fetched, but it's interesting, so here goes. If hemoglobin contains an Fe atom at its center, and chlorophyll contains a Mg atom at its center where both structures are similar and perform similar functions in their respective purposes (transport oxygen/photosynthesis ► production of oxy...
by Katherine Ho 1E
Sat Oct 31, 2015 11:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Shape Chart
Replies: 1
Views: 415

Re: VSEPR Shape Chart

Yes, bent and angular are used interchangeably :)
by Katherine Ho 1E
Sun Oct 25, 2015 11:04 pm
Forum: Lewis Structures
Topic: Max number in expanded octet
Replies: 2
Views: 1059

Max number in expanded octet

What's the maximum number of bonds that an expanded octet can have? I've seen some that go up to 10 or 12 electrons via extra bonds but is there a limit to the number of bonds that can occur?
by Katherine Ho 1E
Sat Oct 17, 2015 2:34 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground State configurations
Replies: 1
Views: 341

Ground State configurations

How do we know if a given electron configuration is in the ground state or not?
by Katherine Ho 1E
Sat Oct 10, 2015 10:32 am
Forum: Quantum Numbers and The H-Atom
Topic: Determining the Spin of an Electron
Replies: 2
Views: 434

Re: Determining the Spin of an Electron

Given that each electron orbital can hold up to two electrons, remember that electrons tend to fill up the orbitals one at a time in each orbital before they begin pairing up. So if the first electron is spin up, usually in most cases, the other would spin down in the opposite direction. So for exam...
by Katherine Ho 1E
Thu Oct 01, 2015 11:49 pm
Forum: Photoelectric Effect
Topic: Particle in a Box
Replies: 1
Views: 331

Particle in a Box

Can someone explain/go into detail/give another example of the particle in a box concept? To my understanding as the book describes with the guitar analogy/example, does it mean to say that a particle, confined between two walls, is moving and that the number of "half-waves" that can fit i...

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