Search found 22 matches

by charlottesmith3f
Sat Mar 12, 2016 3:25 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Drawing hydrogens
Replies: 2
Views: 400

Drawing hydrogens

When we're asked to draw conformations, do we need to draw in all hydrogens? Or do we just draw the chair or boat structure with functional groups and leave out all the hydrogens? Some problems include all hydrogens and some leave them out.
by charlottesmith3f
Fri Mar 04, 2016 2:36 pm
Forum: *Alkanes
Topic: Halogen substituents
Replies: 3
Views: 381

Halogen substituents

How do we name halogen substituents? For example, if there is an I and a Cl attached to a cycloalkane and they could be given the number 1 or 3, which gets the smaller number? I thought it was just alphabetical order (so Cl would get the lower number), but some people have said it's based on atomic ...
by charlottesmith3f
Mon Feb 29, 2016 11:02 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 3
Replies: 1
Views: 323

Quiz 3

I've been looking for how the word "attacks" is used, but I can't figure it out. The last question from the workbook says, "the Br- ion attacks at the same face of the bromonium ion" and "Br2 attacks the carbons of the double bond in one step." What does this mean? What...
by charlottesmith3f
Sat Feb 27, 2016 1:48 am
Forum: *Cycloalkenes
Topic: Longest chain of carbons
Replies: 1
Views: 323

Longest chain of carbons

When we find the name for the longest chain of carbons (the butane or pentane or hexane part of the name) do we always only count the carbons in the ring? Even though other carbons may be attached to the ring?
by charlottesmith3f
Sat Feb 20, 2016 2:24 pm
Forum: Zero Order Reactions
Topic: Not zero, first, or second?
Replies: 4
Views: 569

Not zero, first, or second?

What happens if we have a problem in which the rate is multiplied by two but the concentration is multiplied by four?
Is there such thing as not a zero, first, or second order, but, maybe, a half-order reaction or something?
by charlottesmith3f
Fri Feb 12, 2016 10:07 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: When to add Pt(s) to cell diagram
Replies: 1
Views: 1058

When to add Pt(s) to cell diagram

I've had a few problems where Pt(s) is added to one or both sides of the cell diagram. I thought that when metal is involved in the reaction, we don't need to add Pt? Is this only when there is no solid? And why is there sometimes Pt on both sides of the diagram, and sometimes only on one side?
by charlottesmith3f
Fri Feb 05, 2016 7:09 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Workbook problem 5b
Replies: 2
Views: 316

Workbook problem 5b

This problems asked which molecular substance is expected to have the higher molar heat capacity - C4H10 or C5H12. In the equation, q=mcdeltat, C is inversely proportional to mass, so shouldn't C4H10 have the higher heat capacity? That's what I wrote, but it isn't correct. How do we know relative mo...
by charlottesmith3f
Sun Jan 31, 2016 10:41 pm
Forum: Balancing Redox Reactions
Topic: H2O in balancing
Replies: 2
Views: 280

H2O in balancing

When we are balancing redox half-reactions, when do we know to add H2O? Are there rules for adding H2O?
by charlottesmith3f
Sat Jan 23, 2016 5:37 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Problem 9.85
Replies: 1
Views: 364

Problem 9.85

This question asks "potassium nitrate dissolves readily in water and its enthalpy of solution is +34.9kj/mol. Does the enthalpy of solution favor the dissolving process?" The answer says the enthalpy does not favor the dissolution process, but how would we know that? Don't we have to know ...
by charlottesmith3f
Sat Jan 23, 2016 12:47 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Problem 9.13
Replies: 5
Views: 761

Problem 9.13

This question has "3L of nitrogen gas at 18.5C compressed suddenly and irreversibly to .5L" and in the process "the temp is increase to 28.1C." The solution manual has us use delta S = nRlnV2/v1 for the volume change and then uses delta S=nRlnT2/T1. I thought the equation for tem...
by charlottesmith3f
Sun Jan 17, 2016 7:55 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Heat capacity
Replies: 2
Views: 373

Heat capacity

In the book, there is a question about whether NO or NO2 has the higher molar heat capacity. How can we tell? What determines molar heat capacity?
by charlottesmith3f
Sat Jan 09, 2016 2:29 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Reversible and Irreversible Reactions
Replies: 1
Views: 273

Reversible and Irreversible Reactions

Why do reversible reactions always do more work than irreversible reactions?
by charlottesmith3f
Sat Dec 05, 2015 9:51 pm
Forum: *Titrations & Titration Calculations
Topic: pH Sig figs
Replies: 2
Views: 507

pH Sig figs

In our review session yesterday, Lavelle said 2.73 for a pH (for example) is 3 sig figs, but some TAs have said 2 doesn't count as a sig fig in that example, so which is correct?
by charlottesmith3f
Mon Nov 30, 2015 3:58 pm
Forum: Polyprotic Acids & Bases
Topic: Water as a polyprotic acid
Replies: 1
Views: 734

Water as a polyprotic acid

Because OH- can gain a proton in to become H2O (water) and another proton to become H3O+ is it possible for it to gain another proton (H4O) or for OH- to lose a proton to become O2-? In general, how do we know how many protons a polyprotic acid gain gain or lose in total? When does it finally become...
by charlottesmith3f
Sat Nov 21, 2015 4:21 pm
Forum: Lewis Acids & Bases
Topic: Lewis and Bronsted Acids/Bases
Replies: 1
Views: 371

Lewis and Bronsted Acids/Bases

I understand that a Lewis acid is an electron pair acceptor and a Bronsted acid is a proton donor, but which do we refer to when we talk about acids and bases? Are these just two separate definitions that are both correct?
by charlottesmith3f
Fri Nov 13, 2015 4:59 pm
Forum: Lewis Acids & Bases
Topic: Strong acids/bases
Replies: 3
Views: 607

Strong acids/bases

How can we tell if an acid is a strong acid or a base is a strong base? Do we just have to memorize them?
by charlottesmith3f
Sun Nov 08, 2015 10:35 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure increase by adding another gas
Replies: 1
Views: 293

Pressure increase by adding another gas

I understand that by increasing the pressure/decreasing the volume of a reaction vessel, the reaction is shifted in the direction that favors the smaller number of moles of product or reactant. So why is it that when a separate gas is added, which increases the pressure, nothing happens to the equil...
by charlottesmith3f
Sun Nov 01, 2015 6:28 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Valence electron configuration
Replies: 1
Views: 310

Valence electron configuration

On one of the homework problems, it asks for the valence electron configuration, but the answer isn't written as 2s2, 2p6, etc., it is written instead as (sigma2s)^2, (sigma2s*)^2, etc. How do we distinguish this type of configuration from the other?
by charlottesmith3f
Fri Oct 23, 2015 6:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dichloromethane polarity
Replies: 1
Views: 2123

Dichloromethane polarity

Dichloromethane (CH2Cl2) is apparently polar, but can't the molecule be nonpolar, depending on how we draw the Lewis structure? If the two Cl molecules are directly across from each other, the dipole moments cancel, but if they are (on the Lewis structure) 90 degrees from each other, then the dipole...
by charlottesmith3f
Sun Oct 18, 2015 9:32 pm
Forum: Resonance Structures
Topic: What is a resonance structure?
Replies: 1
Views: 318

What is a resonance structure?

How is a molecule a combination of multiple structures? Does the molecule alternate between a number of different structures (like the Lewis structures suggest) or are the electrons moving from atom to atom? It's difficult to understand what a resonance structure actually is.
by charlottesmith3f
Fri Oct 09, 2015 6:39 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity [ENDORSED]
Replies: 3
Views: 439

Electron Affinity [ENDORSED]

Why is it that electron affinity doesn't completely follow the trend of increasing from left to right? Why is nitrogen's electron affinity so low, when both oxygen and carbon's electron affinities are much higher?
by charlottesmith3f
Fri Oct 02, 2015 6:11 pm
Forum: *Shrodinger Equation
Topic: What is the hamiltonian?
Replies: 2
Views: 449

What is the hamiltonian?

What is the hamiltonian in Schrodinger's equation? In the book, it is written as an H before the psi, but what is actually being done to the equation?

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