Search found 19 matches

by hpage204
Mon Mar 07, 2016 11:11 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Steric Strain
Replies: 1
Views: 312

Re: Steric Strain

Steric strain is caused by unfavorable "steric interactions" between atoms or substituents on a molecule. Steric interactions occur between atoms or molecules that are close to one another; their electron density causes them to repel one another. Basically, atoms don't want to be close to ...
by hpage204
Mon Mar 07, 2016 11:07 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Trans vs Cis stablity
Replies: 3
Views: 552

Re: Trans vs Cis stablity

Someone asked a really similar question in the 11:00 lecture today... I believe the answer was that trans is more stable in most cases, but depending on the size and number of the substituents, this isn't always the case. I think the best option is to picture the alignment of the molecule and try an...
by hpage204
Tue Mar 01, 2016 3:10 pm
Forum: *Cycloalkanes
Topic: Naming—alphabetical order
Replies: 1
Views: 406

Re: Naming—alphabetical order

I think this has to do with substituents. Because the substituent (1-methyl) is on the propyl substituent, the (1-Methylpropyl) part of the chemical name is relating to the substituent of a substituent. Substituents always get priority, so the substituent of the substituent goes before the 4-methyl ...
by hpage204
Thu Feb 25, 2016 2:18 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Question 8 From This Year's Midterm
Replies: 1
Views: 370

Question 8 From This Year's Midterm

This question asks for the redox reaction and maximum potential created by a cell with a 1.0M Ag+ solution in one electrode and a 1.0M Cd2+ solution in another electrode. I understand both half reactions and how to get the cell potential from these equations; however, because the reduction potential...
by hpage204
Tue Feb 16, 2016 2:43 pm
Forum: Second Order Reactions
Topic: reaction rate and rate constant
Replies: 1
Views: 319

Re: reaction rate and rate constant

The reaction rate is the rate at which a product is produced or a reactant is consumed. The rate constant is the calculated value, K, that is used to calculate the reaction rate. K varies for each reaction and must be calculated to determine a reaction's rate law. Also, the units for K vary dependin...
by hpage204
Tue Feb 09, 2016 12:20 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: Perfect Crystal
Replies: 1
Views: 2232

Re: Perfect Crystal

A perfect crystal is a "perfectly ordered substance". In other words, it is a sample of something in which all the molecules are lined up perfectly and there are no imperfections. I think it's easier to understand when you consider S=K_{b}lnW . Think about calculating degeneracy for a subs...
by hpage204
Tue Feb 09, 2016 11:44 am
Forum: Phase Changes & Related Calculations
Topic: ndeltaH(phase change) + MCdeltaT
Replies: 2
Views: 899

Re: ndeltaH(phase change) + MCdeltaT

Values of \Delta H of fusion and/or vaporization given in most problems and tables are written in terms of kJ/mol, so when you calculate the \Delta H of more than one mol, you must multiply it by the number of moles of the substance undergoing the phase change. Another way of thinking of this is tha...
by hpage204
Mon Feb 08, 2016 9:34 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Homework 14.97
Replies: 1
Views: 248

Homework 14.97

Problem 97 asks to calculate the Ka of HF given that 2(H+)(aq)+F2(g)+(2e-) \rightarrow 2HF(aq) has an E\circ =+3.03V. The solution manual uses the reverse equation and that of F2(g)+2e- \rightarrow 2F- to calculate Ecell and then the value of Ka. However, even though HF is used in the anode and the ...
by hpage204
Mon Jan 25, 2016 8:16 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: delta g = 0
Replies: 1
Views: 623

Re: delta g = 0

If you're referring to Gibbs Free Energy, is zero when the reaction is at equilibrium--this might be the boiling point I think.
by hpage204
Mon Jan 18, 2016 9:40 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Which Has Higher Entropy?
Replies: 1
Views: 3411

Re: Which Has Higher Entropy?

I think that the first thing to consider would be the state of the samples/compounds. This is the easiest thing to realize and is a major determinant of the sample's entropy. After that, if they're in the same state, I usually consider the size of the molecules and their polarities to try and get so...
by hpage204
Sun Jan 10, 2016 6:11 pm
Forum: Phase Changes & Related Calculations
Topic: Problem 8.41
Replies: 1
Views: 299

Problem 8.41

Hello, Problem 41 in chapter 8 involves 80g of ice at 0 degrees C being added to 400 g of water at 40C and asks what the final temperature is. I used the specific heat capacities of water and ice and the equation q=mCp(Tf-Ti) and set the qs equal to each other for the ice and the water, but I kept o...
by hpage204
Fri Dec 04, 2015 8:01 pm
Forum: *Titrations & Titration Calculations
Topic: Calculating pH at stoichiometric point for weak acids
Replies: 1
Views: 596

Calculating pH at stoichiometric point for weak acids

This question is based off of number 8f from the 2010 final in the course reader. The question involves the titration of 25.0mL of 0.10M acetic acid (CH3COOH) with .10M NaOH. Part F asks to calculate the pH at the stoichiometric point. In the solutions, it says that the pH is that of .050M NaCH3CO2....
by hpage204
Thu Dec 03, 2015 9:26 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acids and pH
Replies: 1
Views: 359

Lewis Acids and pH

If Lewis acids are defined by their tendency to accept electron pairs, do they still lower a solutions's pH? How does the accepting of electrons increase the concentration of hydronium?
by hpage204
Tue Dec 01, 2015 11:56 pm
Forum: Polyprotic Acids & Bases
Topic: What makes an acid strong?
Replies: 1
Views: 760

What makes an acid strong?

Table J.1 in the Fundamentals section of the textbook lists common strong acids and bases. HCl, HClO3, and HClO4 are all listed as strong acids. Just out of curiosity, can Chlorine Dioxide form an acid? If so, why isn't HClO2 a strong acid like the other chlorates' acids are? Why does the number of ...
by hpage204
Wed Nov 11, 2015 2:44 pm
Forum: Naming
Topic: Writing Formulas from names
Replies: 1
Views: 386

Writing Formulas from names

Number 17.31a asks for the formula of potassium hexacyanidochromate(III). From my understanding, the roman numerals at the end of the name implied that the chromate ion had an oxidation state of 3+. This would mean that the [Cr(CN)6] part of the compound would have a net positive charge, and if it w...
by hpage204
Mon Nov 02, 2015 12:33 am
Forum: Octet Exceptions
Topic: Octet Exception
Replies: 2
Views: 525

Re: Octet Exception

The first thing you need to consider is whether or not an octet exception is an option. In order to have more than an octet, the central atom needs to be a nonmetal in period three or later so that it has the empty d orbitals needed to expand its valence shell. Then you need to determine if the expa...
by hpage204
Sun Oct 25, 2015 5:22 pm
Forum: Electronegativity
Topic: Chlorine and Oxygen
Replies: 1
Views: 451

Chlorine and Oxygen

In 59a, Chlorine has an unpaired electron but oxygen has a full octet. Since they are bonded, I think this means that oxygen is more electronegative than chlorine. I know that the electrons in Cl shield the valence electrons from the nucleus more, but its nuclear charge is higher; why is it less ele...
by hpage204
Sun Oct 11, 2015 12:52 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Question about Heisenberg Equation
Replies: 1
Views: 383

Re: Question about Heisenberg Equation

I think I understand what you're asking, so I hope this helps. When we're given the change in radius, we double it because we dont know if we are increasing or decreasing. So if the radius was 5m (ridiculously large but it's just an example) and the change in radius were 1m, we would say delta x was...
by hpage204
Sun Oct 04, 2015 1:55 pm
Forum: Properties of Light
Topic: What equation to use to find wavelength?
Replies: 1
Views: 492

Re: What equation to use to find wavelength?

The equation E=hc/v pertains to the total energy of the photon. The way you are solving it (which is also the way I first tried to solve it), you are calculating the wavelength as if it only provided enough energy to emit the electron without it having any velocity (i.e. the threshold energy). You n...

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