## Search found 19 matches

Sat Mar 12, 2016 8:04 pm
Forum: General Rate Laws
Topic: Rate cannot be negative
Replies: 1
Views: 562

### Rate cannot be negative

In the Winter 2015 Practice Final #7A, the question asks if the rate constant can ever be negative. The answer says no, the rate constant can never be negative because the Rate can never be negative, since Rate=k[R] n . I don't feel completely comfortable with this answer/reasoning, mostly because t...
Wed Mar 02, 2016 5:44 pm
Forum: *Cycloalkanes
Topic: Combining IUPAC with Common Name iso, neo, sec...
Replies: 2
Views: 919

### Combining IUPAC with Common Name iso, neo, sec...

I have trouble identifying the correct ways to include the common names into the IUPAC names. One specific problem I ran into was with a tert-butyl substituent (the one that looks like a plus sign). In section 1.1, it stated that a (CH3)3C- bond has the title neo, so would neobutyl be the same thing...
Sat Feb 27, 2016 10:11 am
Forum: *Alkenes
Topic: The common name
Replies: 1
Views: 377

### The common name

If a question tells you to identify the molecular formula, structural formula, and line structure of a certain organic molecule, the IUPAC name of the structure gives away the basis of how to figure out everything else. Does the common name give away any information? (the configuration, order of sub...
Wed Feb 17, 2016 2:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm distribution
Replies: 3
Views: 637

### Midterm distribution

Will the average and distribution of the midterm grades be posted?
Wed Feb 17, 2016 2:16 pm
Forum: First Order Reactions
Topic: Understanding the graph of First Order Integrated Rate Law
Replies: 1
Views: 413

### Understanding the graph of First Order Integrated Rate Law

How can the graph of the first order integrated rate law be interpreted? I understand that for the graph, ln[A] is graphed against time, and the negative slope is k, but the ln function graphed against time confuses me-- the concentration for the graph isn't one-to-one, as [A] doesn't decrease at a ...
Wed Feb 10, 2016 10:05 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Reaction Entropy Possibility
Replies: 1
Views: 440

### Reaction Entropy Possibility

In the 2015 Winter Midterm Question 5D, Professor Snape asked Harry to calculate the entropy of vaporization for 1 mole of water at room temperature. While the question suggested that I knew better than Harry, who thought this was impossible, I didn't know better and agreed that it was impossible. I...
Fri Feb 05, 2016 1:03 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Very Lost
Replies: 2
Views: 634

### Re: Very Lost

I think I understand a lot more than when I posted this; thank you very much for the clear and extensive explanation!
Mon Feb 01, 2016 11:47 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Diagrams
Replies: 1
Views: 419

### Cell Diagrams

Some cell diagrams have more than just a solid metal electrode and an aqueous ion form on either side of the salt bridge double line. When is this the case and is there a good guide to follow when writing cell diagrams?
Mon Feb 01, 2016 11:38 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Very Lost
Replies: 2
Views: 634

### Very Lost

Can someone summarize or explain in lay terms/easily understood how the Nernst equation works, real-life application wise AND what the equation symbolizes as it relates electric potential and concentration? :(
Sun Jan 24, 2016 1:27 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy Changes of a Physical State
Replies: 1
Views: 503

### Entropy Changes of a Physical State

The book covers how to calculate the entropy of transition at a temperature other than the normal transition temperature. As an example, the entropy of vaporization of water at 25 degrees Celsius and 1bar would be: \Delta Svap(25degrees)=\Delta S(heating liquid from 25 to 100)+\Delta...
Sat Jan 16, 2016 5:07 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversibility
Replies: 1
Views: 613

### Reversibility

I think I understand the term reversibility. It refers to a system that is in constant equilibrium and can be "reversed" by only changing infinitesimally. A reversible system also needs to be isothermal. What I don't understand is the significance and importance of a reversible system for ...
Sun Jan 10, 2016 4:12 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Thinking Point: Potential energy and isothermal expansion.
Replies: 1
Views: 294

### Re: Thinking Point: Potential energy and isothermal expansio

I have no 100% sureness on this, but is it dependent on the fact that it's isothermal? The constant temperature means that there is no change in temperature while it expands, so heat is transferred to compensate for the expansion's releasing of heat.
Sun Dec 06, 2015 2:22 pm
Forum: Polyprotic Acids & Bases
Topic: Concept Question Q7B 2009 Final
Replies: 2
Views: 709

### Re: Concept Question Q7B 2009 Final

This also confused me as well, but remember how autoprotolysis just refers to water's reaction within itself as an acid or a base-- losing or gaining a proton. Kw of neutral water is 10^-14, where [H+]=[OH-]=10^-7. If either [H+] or [OH-] concentration is off, I conceptualize that it triggers autopr...
Sun Dec 06, 2015 2:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Final Exam Fall 2012 #8
Replies: 1
Views: 727

### Re: Final Exam Fall 2012 #8

I'm sure using the Katotal is acceptable in solving the problem, but since the problem specifically states the method of how it wants the approximation of the answer, I'm guessing that's why the answer shows how the answer is derived from following the step-by-step method
Sun Dec 06, 2015 2:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Difference Between Polar and Nonpolar Bonds
Replies: 2
Views: 1340

### Re: Difference Between Polar and Nonpolar Bonds

Adding on to the post above, in determining polarity, you want to look at all the VSEPR shapes depending on the number of electron density and how the number of lone pairs affects the shape of the molecule. For CS2, it's nonpolar because the two double bonds that form between C and S create a linear...
Thu Nov 12, 2015 5:36 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate Ligands
Replies: 2
Views: 424

### Re: Polydentate Ligands

To Chem-Mod, Could you explain how something becomes available for coordination? If the element in a structure has a formal charge not equal to zero, does that mean it is a potential ligand? I am having trouble identifying polydentates and conceptualizing the idea of chelating. During office hours, ...
Sun Nov 08, 2015 1:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating Chemical Equilibrium
Replies: 2
Views: 465

### Re: Calculating Chemical Equilibrium

Hi Monica, based on a chemistry lecture I found from a source from University of Texas, one way to comprehend why solids and liquids aren't included in equilibrium calculations is because pure solids and liquids don't have changing concentrations-- they're always considered to be 1. On the other han...
Sun Nov 01, 2015 8:47 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Domains of Molecular Orbital Theory
Replies: 1
Views: 393

### Domains of Molecular Orbital Theory

This question is primarily out of curiosity/for better understanding; Are there molecular orbital diagrams for diatomic molecules involving transition metals or is the diagram constrained to diatomic molecules within the p- and s- orbitals? Also, is the MO diagram constrained to diatomic molecules s...
Sun Oct 11, 2015 11:27 pm
Forum: Empirical & Molecular Formulas
Topic: Quiz 1 Preparation: Naming Simple Compounds
Replies: 1
Views: 443

### Re: Quiz 1 Preparation: Naming Simple Compounds

Hi Rachel, I think based on the fundamentals assignment that we had to complete over the summer (and in the course reader review of introductory chemistry), it's important (or at least good/useful) to know common polyatomic ions/oxoanions... Ammonium is NH4+. There are also sulfate (SO4^2-), Chlorat...

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