Search found 20 matches

by Matt_Coopersmith_4H
Thu Mar 09, 2017 1:00 am
Forum: *Cycloalkenes
Topic: neo vs tert
Replies: 3
Views: 676

Re: neo vs tert

The prefix "neo" is used when all but two carbons form a continuous chain, whereas the prefix "tert" is used when the functional group is bonded to a tertiary carbon. In other words, “neo” is used during any part of the hydrocarbon chain whereas "tert" is used only for ...
by Matt_Coopersmith_4H
Tue Mar 07, 2017 2:14 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Molecular Shape of Complex Molecules
Replies: 1
Views: 264

Molecular Shape of Complex Molecules

Today is class we went over an example of Ethoxy-3-Methylpentane. We discussed that the pentane is the primary chain because it is the longest uninterrupted carbon chain. Looking at the oxygen, we decided that there were C-O-C bonds, leaving two sets of lone pairs on the oxygen molecule. From 14A, a...
by Matt_Coopersmith_4H
Fri Feb 24, 2017 2:54 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7609
Views: 1020343

Re: Post All Chemistry Jokes Here

I asked the guy sitting next to me if he had any Sodium Hypobromite…

He said NaBrO!
by Matt_Coopersmith_4H
Fri Feb 24, 2017 2:43 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Reaction Mechanism Energy Trends
Replies: 1
Views: 286

Reaction Mechanism Energy Trends

In class today we discussed the fact that the first step would be considered the slow step not only because of the electron rearrangement, but because the breaking of bonds has a larger energy than the formation of bonds. Is this always true? For example, if there are more bonds being broken than be...
by Matt_Coopersmith_4H
Mon Feb 20, 2017 3:35 pm
Forum: General Rate Laws
Topic: Homework 15.85
Replies: 2
Views: 342

Re: Homework 15.85

Page 70 discusses elementary steps and molecularity, but it doesn't discuss the activated complex. The answers in the answer book are different from the elementary steps, thus do you have any other pages worth looking at?
by Matt_Coopersmith_4H
Fri Feb 17, 2017 7:22 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Calculating reaction rates from initial concentrations
Replies: 1
Views: 250

Re: Calculating reaction rates from initial concentrations

In actuality, there will be reactions that experimentally have a reaction order that have non-integer values. However, one of the TAs told me that although this happens in chemistry labs, this is above 14B and we should not have to worry about it! Hope this helps!
by Matt_Coopersmith_4H
Fri Feb 17, 2017 7:19 pm
Forum: General Rate Laws
Topic: Presence of a Catalyst
Replies: 1
Views: 242

Presence of a Catalyst

How do you write the rate law reaction when a catalyst is present? After finding the rate law reaction, do you include the catalyst into calculations to find k, the rate, or various concentrations? Thanks!
by Matt_Coopersmith_4H
Fri Feb 17, 2017 7:15 pm
Forum: General Rate Laws
Topic: -k value and Half Life
Replies: 1
Views: 334

-k value and Half Life

Would a negative value of k denote the reaction occurring in the reverse direction? If so, can you calculate half life with the -k value? For example, for a 1st order reaction, the half life equation is t(1/2) = .693/k, therefore a negative k would produce a negative time. Is this correct? Thanks!
by Matt_Coopersmith_4H
Fri Jan 27, 2017 5:09 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: HW 9.35
Replies: 1
Views: 280

HW 9.35

Hi, I have a quick question regarding the homework question 9.35. The question talks about various beakers having 1.0 mol of a monatomic gas (A), 1.0 mol of a diatomic gas without being vibrationally active (B), and 1.0 mol of a diatomic gas being vibrationally active (C). The answer says B < C < A....
by Matt_Coopersmith_4H
Mon Jan 16, 2017 7:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating enthalpy of formation with resonance
Replies: 1
Views: 256

Re: Calculating enthalpy of formation with resonance

The first step in this question would be to find the types of bonds present in the benzene ring with resonance, and without resonance. For part C, there would be 3 C-C (single) bonds and 3 C--C (double) bonds, which you can look up. However, for part D, resonance is included and thus there would be ...
by Matt_Coopersmith_4H
Mon Nov 28, 2016 8:08 pm
Forum: Lewis Acids & Bases
Topic: Question 12.49
Replies: 1
Views: 326

Re: Question 12.49

With the information given, you would have to rely on the experimentally obtained values of Kb. One easy way to calculate which base is stronger is to find the pKb of the different bases and compare. When looking at the pKb, the smaller the pKb, the stronger the base. For Morphine, the pKb is 5.79 F...
by Matt_Coopersmith_4H
Mon Nov 28, 2016 7:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 11.41
Replies: 3
Views: 328

Re: Homework 11.41

Hi! When looking at the problem, make sure to play close attention to the units. For the NH4(NH2CO2), the question gives you 25.0 g, so you find the molarity by dividing by the molar mass to get moles, then by diving by liters (.250). However, the problem also gives you 17.4 mg. 17.4 mg translates i...
by Matt_Coopersmith_4H
Mon Nov 28, 2016 3:05 pm
Forum: Identifying Acidic & Basic Salts
Topic: Shortcut for determining acidity/basicity of salts
Replies: 1
Views: 843

Re: Shortcut for determining acidity/basicity of salts

So, the shortcut will work for equations with equal molarity of acids and bases. For those with equal molarities: Strong Acid + Weak Base = Acidic Solution Weak Acid + Strong Base = Basic Solution Strong Acid + Strong Base = Neutral Solution An explanation can be as followed: Let’s look at the first...
by Matt_Coopersmith_4H
Mon Nov 28, 2016 2:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium concentrations
Replies: 1
Views: 197

Re: Equilibrium concentrations

ICE tables are only used for weak acids and bases because unlike strong acids and bases, weak acids and bases only PARTIALLY disassociate. Because of this property of weak acids/bases, you must use an equilibrium equation and the Ka or Kb of the acid/base to determine the final concentrations at equ...
by Matt_Coopersmith_4H
Sun Nov 13, 2016 3:51 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: e- configuration with pi & sigma bonds
Replies: 1
Views: 268

Re: e- configuration with pi & sigma bonds

Hi Salma! There is actually no difference between (pi, 2p)^4 and (pi, 2px)^2,(pi, 2py)^2. The electron configuration for molecular orbitals follows a similar patterns as regular electron configurations. In the question above, you simply split up the sub orbitals within the molecular diagram. This is...
by Matt_Coopersmith_4H
Sun Nov 13, 2016 3:42 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Finding Coordination Number and Oxidation State [ENDORSED]
Replies: 7
Views: 1216

Re: Finding Coordination Number and Oxidation State [ENDORSED]

Hi Julia! You are absolutely right. With the equation, [Pt(CN)(NH3)3]+ , the overall charge of the coordination compound is a 1+ charge. In order to find the oxidation state, you have to look at each individual component of the compound as suggested by Helena. To break it up, it would look like this...
by Matt_Coopersmith_4H
Wed Nov 02, 2016 3:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Fall Midterm 2014 Q7
Replies: 1
Views: 261

Fall Midterm 2014 Q7

For question 7 on the 2014 Fall Midterm, I was wondering why you couldn't make Cl the central atom and have the 3 Oxygen atoms and the Hydrogen atom bonded to the Cl. All the atoms would have a formal charge of 0. This would produce a tetrahedral shape instead of a trigonal planar. Any ideas? Thank ...
by Matt_Coopersmith_4H
Wed Oct 12, 2016 5:02 pm
Forum: Trends in The Periodic Table
Topic: Exceptions to the Periodic Trends
Replies: 3
Views: 3837

Exceptions to the Periodic Trends

Hello All. I was reviewing notes from today's lecture and started noticing various exceptions to periodic trends. This made me question: What factors leads to irregularities in periodic trends? Examples: When looking at the trends of atomic radius, the radius should decrease across a period. However...
by Matt_Coopersmith_4H
Sun Oct 02, 2016 8:04 pm
Forum: Molarity, Solutions, Dilutions
Topic: L.35 Homework Question
Replies: 1
Views: 267

L.35 Homework Question

Hello everyone! I am going over the review problems in the textbook and have come across question L.35. I am not sure what the unit "t" is, and was wondering if anyone had any guesses. I thought it could possibly be metric tons, but I am not entirely sure. In terms of solving the problem, ...
by Matt_Coopersmith_4H
Sun Oct 02, 2016 7:59 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Spectral Fingerprint
Replies: 2
Views: 1250

Re: Spectral Fingerprint

Dr. Lavelle, I have a follow up question in terms of the spectral fingerprint. I understand that each element has its own spectral fingerprint due to the unique quantum energy levels that emit very specific wavelengths. However, I do not understand why different elements have individual and unique e...

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