Search found 20 matches

by Peter2715
Sat Mar 12, 2016 12:14 pm
Forum: *Cycloalkanes
Topic: Two cycloalkanes attached to each other
Replies: 12
Views: 5526

Re: Two cycloalkanes attached to each other

What's the difference between using phenyl and benzyl when naming structures that have cyclohexanes connected to longer carbon chains(therefore making the cyclohexane the substituent). We won't be expected to use phenyl or benzyl; rather if you have a cyclic substituent like cyclohexane or cyclopro...
by Peter2715
Sat Mar 12, 2016 12:06 pm
Forum: *Cycloalkanes
Topic: Two cycloalkanes attached to each other
Replies: 12
Views: 5526

Re: Two cycloalkanes

On quiz 3, they asked us to draw the line structure of (C6H11)C(CH3)3, so I drew a cyclohexane with a tert-propyl attached to it. However, they wanted the systematic name so I wrote down (1,1-dimethylethyl)cyclohexane and I got marked wrong on the dimethylethyl part, specifically the ethyl part. Wh...
by Peter2715
Sat Mar 12, 2016 11:54 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 2013 Final 1b Entropy Change
Replies: 1
Views: 312

2013 Final 1b Entropy Change

In this problem we are given a balloon filled with .13 moles of helium into the air. as the balloon rises, the temperature of the helium decreases and the balloon expands due to the decrease in external temperature and pressure at higher altitudes. If the helium in the balloon started at 3.0 L and 2...
by Peter2715
Sun Feb 28, 2016 12:12 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Another possible constitutionl isomer?
Replies: 4
Views: 558

Re: Another possible constitutionl isomer?

Cindy Chen_2I wrote:What you draw is the same isomer as the one right next to it.
If you try to name it, you'll see that they're both named 2-Methyl-1-butene


I do see that now, since that is the case, could my drawing potentially be described as geometric isomer though? Would it be trans (E)?
by Peter2715
Sat Feb 27, 2016 11:32 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Another possible constitutionl isomer?
Replies: 4
Views: 558

Another possible constitutionl isomer?

I drew in another potential constitutional isomer to the right of the book answers on number 1.23, can someone explain why this does not count as an answer? Why can't the double bond be at the end right before the substituent?

See image.
by Peter2715
Sat Feb 27, 2016 11:01 pm
Forum: *Cycloalkenes
Topic: Naming Cycloalkenes
Replies: 1
Views: 510

Naming Cycloalkenes

When naming cycloalkenes, are the numbers of the double bonds prioritized over the numbering of substituents? For example the molecule 5-methyl-1,3-pentadiene could be called 3-methyl-1,4-pentadiene which would be lower numbers (1,3,4) than the true naming (1,3,5). Is this because you look at double...
by Peter2715
Sat Feb 27, 2016 10:38 pm
Forum: *Cycloalkanes
Topic: Substituent naming
Replies: 1
Views: 313

Substituent naming

When ordering substituents alphabetically, are the prefixes di- and tri- (such as in dimethyl) included in the alphabetization? With regards to common names, iso and neo (arbitrarily?) influence the alphabetic priority, but sec and tert do not. Can someone explain in which cases, if any, greek prefi...
by Peter2715
Fri Feb 26, 2016 1:28 pm
Forum: *Alkynes
Topic: Alkyne Structural Formula
Replies: 1
Views: 353

Alkyne Structural Formula

For the molecule 4-methyl-1-pentyne, the answer is given to be CH C CH2 (CH3) CH3 with parentheses to show the methyl substituent. Would it be wrong to write the structural formula as CH C CH2 CH (CH3)2 ? I'm sure I have seen this notation on a few other questions to denote the two possible branches...
by Peter2715
Thu Feb 25, 2016 5:05 pm
Forum: *Alkanes
Topic: Structural Formula parentheses
Replies: 2
Views: 382

Structural Formula parentheses

I normally associated Using parentheses in structural formulas to simply group together long chains of the same molecule like (CH2)5 or so. But in certain cases, molecules from two separate branches are grouped together within parentheses, or only a single molecule is in parentheses; which goes agai...
by Peter2715
Thu Feb 25, 2016 12:08 am
Forum: *Alkanes
Topic: Substituent question
Replies: 1
Views: 285

Re: Substituent question

When looking at alkanes, you first find the longest chain of carbons, this length will give you the root name to use like methane, ethane, propane, etc. Next, you look at what branches off the path of this main chain, which will be your constituents. The way you determine your constituent number is ...
by Peter2715
Wed Feb 24, 2016 11:45 pm
Forum: *Alkanes
Topic: Condensed Structural Formulas
Replies: 1
Views: 302

Condensed Structural Formulas

For Self Test 1.4A a) in the "Introduction to Organic Chemistry" Reader, the question asks, "Write the structural formula for 2-methylpentane." I began by drawing a line structure to visualize the hydrocarbon, and then for my structural formula answered: (CH3)2 CH (CH2)2 CH3 The ...
by Peter2715
Mon Feb 15, 2016 9:42 am
Forum: General Rate Laws
Topic: Units of constant (k) for different overall rxn orders
Replies: 1
Views: 286

Units of constant (k) for different overall rxn orders

It would seem that depending on the order of the reaction, the units of the k constant changes. Is it safe to assume that the EXPONENTS of the units of k (liters/mol x seconds) will always equal (overall reaction order number minus 1) ? Such as in the book for number 15.17, a reaction involving [A] ...
by Peter2715
Fri Feb 12, 2016 1:40 am
Forum: General Rate Laws
Topic: Half Life for 1st Order Reaction
Replies: 1
Views: 361

Half Life for 1st Order Reaction

Does the Half Life T(1/2) always equal 0.693/k for any given first order reaction? By what method would you be able to solve for the constant k?
by Peter2715
Thu Feb 04, 2016 4:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Regarding the salt bridge concept
Replies: 1
Views: 375

Regarding the salt bridge concept

In a galvanic cell I am aware that the salt bridge is used to maintain the gradient of electrons flowing into the positively charged cathode; can someone explain to me the method by which the salt bridge maintains this gradient? If, for example a zinc electrode Zn(s)+2e > Zn^(2+) is being oxidized b...
by Peter2715
Sun Jan 31, 2016 6:20 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram Understanding
Replies: 1
Views: 260

Cell Diagram Understanding

If the double lines on a cell diagram represent the salt bridge, does that mean one side represents the anode and the other the cathode? And does the order of the elements within a phase change (single line, not double) matter on a cell diagram?

Thank you.
by Peter2715
Wed Jan 27, 2016 1:35 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Question Regarding K and Q
Replies: 2
Views: 413

Question Regarding K and Q

For the formula Delta G = Delta G Nought + RTlnQ could someone help clarify the difference between the constants K and Q? since they are supposed to represent (Conc. of Products) / (Conc. of Reactants) right?
by Peter2715
Thu Jan 21, 2016 9:36 pm
Forum: Phase Changes & Related Calculations
Topic: Delta H Nought vs Delta H
Replies: 3
Views: 1192

Delta H Nought vs Delta H

Could somebody help explain to me the difference between Delta H Nought and Delta H? As well as whether these values are usually expressed in kj or kj/mol?
by Peter2715
Sun Jan 10, 2016 10:51 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Extensive and Intensive Properties
Replies: 1
Views: 305

Re: Extensive and Intensive Properties

We can use the example of heat capacity vs specific heat capacity as shown in the course reader to explain intensive and extensive properties. An extensive property only reveals information about a particular case, such as the heat capacity of a certain amount of substance, which would be the amount...
by Peter2715
Sat Nov 28, 2015 11:47 pm
Forum: Trends in The Periodic Table
Topic: Video: Electronegativity, Ionization Energy, Ionic Radii
Replies: 3
Views: 692

Video: Electronegativity, Ionization Energy, Ionic Radii

Here is a video describing fundamental periodic trends along with the reasoning behind each trend.
by Peter2715
Sun Oct 04, 2015 11:32 pm
Forum: Significant Figures
Topic: Rounding when it comes to 5
Replies: 5
Views: 810

Re: Rounding when it comes to 5

As further clarification to the initial reply, I believe we round to even integers in order to prevent biasing numbers on average upward or downwards especially with large sample sizes.

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