Search found 39 matches

by Kate Zeile 2D
Fri Mar 16, 2018 7:29 am
Forum: *Alkanes
Topic: Organic Molecules in general
Replies: 1
Views: 176

Organic Molecules in general

Just to make sure, all organic molecules have carbons that always have four bonds, correct? No lone pairs on carbon allowed? I know this was emphasized in class, but I just want to make sure it applies to all organic molecules.
by Kate Zeile 2D
Fri Mar 16, 2018 7:25 am
Forum: *Amines
Topic: Heterocyclic amines
Replies: 1
Views: 174

Heterocyclic amines

I was watching a nutrition/health video the other day that mentioned the carcinogenic effects of heterocyclic amines, and I want to know more. How are heterocyclic amines produced and why are they carcinogenic?
by Kate Zeile 2D
Fri Mar 16, 2018 7:19 am
Forum: *Aldehydes
Topic: Toxicity
Replies: 1
Views: 168

Toxicity

Are aldehydes toxic to humans? Or rather, does it depend on the type and/or quantity of aldehyde?
by Kate Zeile 2D
Sat Mar 10, 2018 9:05 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Steady-state vs. Pre-equilibrium [ENDORSED]
Replies: 2
Views: 103

Steady-state vs. Pre-equilibrium [ENDORSED]

In lecture, Dr. Lavelle said that the pre-equilibrium approach is simpler than the steady-state approach, but it is also less flexible. What did he mean by "less flexible"?
by Kate Zeile 2D
Sat Mar 10, 2018 8:56 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Microscopic Reversibility [ENDORSED]
Replies: 1
Views: 97

Microscopic Reversibility [ENDORSED]

When going over reaction profiles, Dr. Lavelle said that "microscopic reversibility" was being assumed, meaning that we assume that the reaction has the same intermediates in the forward and reverse directions. This effectively means that the forward and reverse reactions follow the same p...
by Kate Zeile 2D
Sat Mar 10, 2018 8:39 am
Forum: Experimental Details
Topic: Experimental Techniques
Replies: 3
Views: 210

Experimental Techniques

What are some experimental techniques to measure the rate of the reaction? How would one monitor the concentration at precise instances after the reaction has initiated?
by Kate Zeile 2D
Wed Feb 28, 2018 7:40 am
Forum: First Order Reactions
Topic: Half-life of first order reactions [ENDORSED]
Replies: 4
Views: 168

Half-life of first order reactions [ENDORSED]

I understand from the half-life equation that the half-life of a first order reaction does not depend on concentration and that, therefore, it has the same value at all stages of the reaction. However, this does not make sense to me. How can the half-life be the same at all stages of the reaction, e...
by Kate Zeile 2D
Wed Feb 28, 2018 7:33 am
Forum: Second Order Reactions
Topic: Rate of Second-order reactions [ENDORSED]
Replies: 1
Views: 85

Rate of Second-order reactions [ENDORSED]

In the textbook, when discussing the rate of second-order reactions, it says that "the larger the rate constant, the greater the dependence of the rate on the concentration of the reactant." Can someone please explain this to me? I have been trying to find this relationship when looking at...
by Kate Zeile 2D
Wed Feb 28, 2018 7:28 am
Forum: Second Order Reactions
Topic: Half-life of Second-Order
Replies: 2
Views: 98

Half-life of Second-Order

In the textbook, at the end of section 15.6, it gives a table detailing all the components of each order of a reaction. For the half-life of a second-order reaction, it writes that the equation is t 1/2 = \frac{1}{k[A]} . However, underneath that, it says "(not used)." Does anyone know wha...
by Kate Zeile 2D
Wed Feb 28, 2018 7:24 am
Forum: Zero Order Reactions
Topic: Half-life of Zero Order [ENDORSED]
Replies: 4
Views: 130

Half-life of Zero Order [ENDORSED]

In the textbook, at the end of section 15.6, it gives a table detailing all components of each order of a reaction. When writing the half-life of a zero-order reaction, it stated that it was t 1/2 = \frac{[A]}{2k} , but underneath that it says "(not used)." Does anyone know what this means...
by Kate Zeile 2D
Wed Feb 28, 2018 7:18 am
Forum: General Rate Laws
Topic: 15.3(c)
Replies: 2
Views: 114

Re: 15.3(c)

Sorry I would like to make a correction. The unique rate of the reaction refers to any one of the parts of this equation: -\frac{1}{a}\frac{\Delta [A]}{\Delta t}=-\frac{1}{b}\frac{\Delta [B]}{\Delta t}=\frac{1}{c}\frac{\Delta [C]}{\Delta t}=\frac{1}{d}\frac{\Delta [D]}{\Delta t} ; all are equal. How...
by Kate Zeile 2D
Thu Feb 22, 2018 8:46 pm
Forum: General Rate Laws
Topic: 15.3(c)
Replies: 2
Views: 114

Re: 15.3(c)

In the textbook, the unique average reaction rate for reaction aA+bB\rightarrow cC+dD is : -\frac{1}{a}\frac{\Delta [A]}{\Delta t} = -\frac{1}{b}\frac{\Delta [B]}{\Delta t} = \frac{1}{c}\frac{\Delta [C]}{\Delta t} = \frac{1}{d}\frac{\Delta [D]}{\Delta t} In problem 15.3, the unique rate of the react...
by Kate Zeile 2D
Thu Feb 22, 2018 8:32 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Plotting Reaction Rate
Replies: 1
Views: 105

Plotting Reaction Rate

Are we going to have to plot the reaction rates (concentration versus time) like the example we did in lecture? If so, is it going to be more specific with precise numbers or is it going to be rough (similar to the example in lecture) to just create a general visual of the change in concentration fo...
by Kate Zeile 2D
Thu Feb 22, 2018 8:28 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Instantaneous Rate
Replies: 4
Views: 188

Instantaneous Rate

What is the value of knowing the instantaneous rate of a reaction? I understand how knowing the average reaction rate would be helpful but I do not understand the importance of knowing the reaction rate at a single point in time.
by Kate Zeile 2D
Sun Feb 18, 2018 3:59 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram
Replies: 2
Views: 92

Re: Cell diagram

You add an inert metallic component (like Pt(s), for example) to the cell with the half reaction that does not have conducting solids. In some reactions, conducting solids such as Zn(s) and Cu(s) are part of the reaction so they make the electrode in that cell and an inert metallic component is not ...
by Kate Zeile 2D
Sun Feb 18, 2018 3:38 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: w Max Equation
Replies: 1
Views: 114

Re: w Max Equation

The work done when a certain number of moles of electrons travels through a potential difference is their total charge times the potential difference. The charge of one electron is -e so the charge per mole of electrons is -eN A (N A being Avogadro's constant). So putting these together, the work do...
by Kate Zeile 2D
Sun Feb 18, 2018 3:16 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: "Molar" form/ Pure number
Replies: 2
Views: 97

"Molar" form/ Pure number

The textbook writes the equation r = -nrFE. What does the subscript "r" mean? The textbook stated that the subscript "r" is the "molar" form that made nr a pure number, but I do not understand the significance of this either.
by Kate Zeile 2D
Fri Feb 09, 2018 9:28 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrical energy to chemical energy
Replies: 2
Views: 98

Electrical energy to chemical energy

Dr. Lavelle said that we are focusing more on Galvanic cells, where a chemical reaction produces an electrical current. However, can someone give an example of the opposite situation, where electrical energy is converted to chemical energy?
by Kate Zeile 2D
Fri Feb 09, 2018 9:17 am
Forum: Biological Examples (*DNA Structural Transitions, etc.)
Topic: Biological systems
Replies: 2
Views: 223

Biological systems

The textbook states that a reaction that produces a lot of entropy can drive a non spontaneous reaction forward, and that this is used extensively in biological systems. Can someone please explain to me how this coupling works? I do not understand how a reaction with excess entropy can make another ...
by Kate Zeile 2D
Fri Feb 09, 2018 9:08 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy Phase Change
Replies: 2
Views: 97

Entropy Phase Change

The graph below shows entropy changes having to do with phase changes of a substance. Can someone please explain why entropy increases vertically (AKA why there is a vertical line) at \Delta S fus and \Delta S vap ? [img]https://2012books.lardbucket.org/books/principles-of-general-chemistry-v1.0/sec...
by Kate Zeile 2D
Fri Feb 09, 2018 8:53 am
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: Statistical entropy
Replies: 1
Views: 82

Statistical entropy

The textbook states that entropy calculated from the Boltzmann formula is statistical entropy. What exactly does this mean?
by Kate Zeile 2D
Fri Feb 02, 2018 9:15 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Trouton's Rule
Replies: 1
Views: 67

Trouton's Rule

The textbook states that according to Trouton's Rule, "approximately the same increase in positional disorder occurs when any liquid is converted into a vapor, so we can expect \Delta S to be much the same in each case." Therefore, the value of \Delta S vap is similar for many liquids. Cou...
by Kate Zeile 2D
Fri Feb 02, 2018 9:05 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Assume ideal gas?
Replies: 4
Views: 112

Assume ideal gas?

When calculating entropy changes due to changes in volume and temperature of a gas, do we always have to assume that the gas behaves as an ideal gas?
by Kate Zeile 2D
Fri Feb 02, 2018 9:01 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Thermal and positional disorder
Replies: 2
Views: 141

Thermal and positional disorder

The textbook refers to thermal disorder as disorder arising from the thermal motion of the molecules and positional disorder as the disorder relating to the locations of the molecules.
Can these be thought of as types, or subcategories, of entropy? If so, are there any other types?
by Kate Zeile 2D
Sat Jan 20, 2018 5:11 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity for atoms and molecules
Replies: 1
Views: 84

Heat Capacity for atoms and molecules

In the textbook, a table is given with equations for the molar heat capacities of atoms, linear molecules, and nonlinear molecules in terms of constant volume and constant pressure. Why do CV,m and CP,m have different equations for atoms, linear molecules, and nonlinear molecules?
by Kate Zeile 2D
Sat Jan 20, 2018 5:08 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity for monatomic ideal gas
Replies: 2
Views: 93

Heat capacity for monatomic ideal gas

The book states that for a monatomic ideal gas, both Cp and Cv are independent of temperature and pressure. Would someone please break this down for me?
by Kate Zeile 2D
Sat Jan 20, 2018 4:55 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat "flow" [ENDORSED]
Replies: 1
Views: 110

Heat "flow" [ENDORSED]

The textbook remarks that it is incorrect to say that heat "flows." Why is this incorrect/ what is the reasoning behind this statement?
by Kate Zeile 2D
Sat Jan 20, 2018 4:44 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Reversible Processes
Replies: 2
Views: 121

Re: Reversible Processes

When a system is at equilibrium, an infinitesimal change in a variable can cause the process to reverse. I do not know if this correlates exactly, but I like to think of it this way: Let's say you have two piles of rocks that weigh the same amount and are each placed on one side of a see-saw. The se...
by Kate Zeile 2D
Tue Jan 16, 2018 8:41 am
Forum: Phase Changes & Related Calculations
Topic: Heat and Enthalpy
Replies: 3
Views: 125

Re: Heat and Enthalpy

The equation for enthalpy, H, is H=U+PV, where U is internal energy, P is pressure, and V is volume. U, P, and V are all state functions, so enthalpy (with equation H=U+PV) must be a state function as well. Heat is not a state function because it DOES matter what path is taken to achieve the change ...
by Kate Zeile 2D
Sat Jan 13, 2018 8:32 am
Forum: Phase Changes & Related Calculations
Topic: Sublimation
Replies: 4
Views: 218

Sublimation

How does sublimation occur? In other words, how can a subliming substance just skip the liquid phase?
by Kate Zeile 2D
Sat Jan 13, 2018 8:21 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Periodic Trend for Heat Capacity
Replies: 2
Views: 149

Periodic Trend for Heat Capacity

Is there a periodic trend for heat capacity? Does heat capacity relate to size of the atom, the electronegativity of the atom, etc.?
by Kate Zeile 2D
Sat Jan 13, 2018 8:12 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q=mCdeltaT
Replies: 2
Views: 428

q=mCdeltaT

Hello! How many different versions of this equation: are there? I know there are different heat capacities and different units of measurement, but I do not know if I am aware of all the options.
by Kate Zeile 2D
Sun Nov 26, 2017 4:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant units
Replies: 2
Views: 131

Equilibrium Constant units

Why doesn't the equilibrium constant, K, have units? In previous chapters, the constants have had units (such as Planck's constant), so why is this one different?
by Kate Zeile 2D
Sun Nov 26, 2017 4:09 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate ligands
Replies: 2
Views: 156

Polydentate ligands

If a ligand is polydentate, does it have to have molecules binding to every binding site available when making compounds? In other words, if a ligand is hexadentate, does it need six atoms/molecules to bind to it or can there be less?
by Kate Zeile 2D
Thu Nov 02, 2017 7:50 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Increasing Covalent Character of Silver Halides
Replies: 1
Views: 353

Increasing Covalent Character of Silver Halides

I am still a little confused as to why the covalent character of silver halides increases as you go down the group of halides (for example, from AgF to AgCl to AgBr). Please clarify :)
Thank you!
by Kate Zeile 2D
Sun Oct 29, 2017 5:25 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Spins [ENDORSED]
Replies: 2
Views: 155

Electron Spins [ENDORSED]

Why do electrons with parallel spins tend to avoid each other and occupy different orbitals? Why would the direction of spin influence this repulsion?
by Kate Zeile 2D
Sun Oct 29, 2017 5:17 pm
Forum: Ionic & Covalent Bonds
Topic: Noble Gases
Replies: 6
Views: 366

Noble Gases

I know that noble gases have a completely filled outer shell and are therefore stable. However, can noble gases ever form bonds and create compounds?
by Kate Zeile 2D
Fri Oct 20, 2017 3:56 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Effective Nuclear Charge
Replies: 1
Views: 116

Effective Nuclear Charge

Today in lecture Professor Lavelle used the term "effective nuclear charge." He used it in relation to the inner electrons shielding the outer electrons from the electrostatic attraction of the nucleus, but the meaning of the term is still unclear to me. Can someone please further explain ...
by Kate Zeile 2D
Fri Oct 20, 2017 3:52 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electrostatic potential energy [ENDORSED]
Replies: 2
Views: 149

Electrostatic potential energy [ENDORSED]

Hello! Today in lecture Professor Lavelle gave this equation: Ep is proportional to (q1)(q2) / r I understand that Ep represents electrostatic potential energy, q represents charge, and r represents distance. However, I need further clarification. What charges are we talking about and what is the di...

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