## Search found 20 matches

Tue Mar 08, 2016 8:16 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Determining Steric/Torsional Interactions
Replies: 3
Views: 655

### Re: Determining Steric/Torsional Interactions

If you're not given the Newman projections but you have the formula of the molecule it is helpful to draw it out and see where the atoms would be positioned in order to determine the type of interactions it would have.
Wed Mar 02, 2016 10:07 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Problem 1.16 and 1.17
Replies: 1
Views: 435

### Re: Problem 1.16 and 1.17

When you name organic compounds you want the numbers to be as low as possible. So for 1.16 even though isopropyl comes before methyl alphabetically it is better to have a 1,1,2 instead of a 1,2,2. In 1.17 the same rule applies. Tert-butyl comes before methyl alphabetically but having 1,2,4 is better...
Thu Feb 25, 2016 9:26 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Equivalent H
Replies: 2
Views: 526

### Re: Equivalent H

Equivalent H's are those that are in the same chemical environment. For example in CH3-CH2-CH3, the H's on the CH3's are both connected by a single bond to carbon which is also connected by a single bond to another carbon. The environment is basically how the bonds connect the atoms. In this case, t...
Sat Feb 20, 2016 4:34 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Problem 15.63
Replies: 1
Views: 341

### Re: Problem 15.63

That may be a typo because I solved the problem without subtracting .59 and got the same answer
Tue Feb 09, 2016 10:00 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell notation
Replies: 1
Views: 304

### Re: cell notation

Yes, when you write out the cell diagram the left will always be the anode and the right is always the cathode
Fri Feb 05, 2016 11:31 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.35 discrepancy with constants
Replies: 2
Views: 407

### Re: 14.35 discrepancy with constants

I think you may have messed up plugging in Faraday's constant. The correct value is F=96,485 C/mol.
Fri Jan 29, 2016 8:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Max Potential
Replies: 1
Views: 265

### Re: Max Potential

You can calculate the max potential of a cell using the equation E(cell)=E(cathode)-E(anode). It's important because it allows you to see whether a reaction is favorable or not
Sat Jan 23, 2016 11:25 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Quiz Question
Replies: 1
Views: 332

### Re: Quiz Question

We don't necessarily have to know how to derive all the formulas, but we need to know how to use them and when they are used. Dr. Lavelle spends time deriving them to show us where they come from and what they mean in the context of different problems.
Sat Jan 16, 2016 9:06 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homeowork question 8.77
Replies: 1
Views: 683

### Re: Homeowork question 8.77

For this question you need to use bond enthalpies to show that benzene is more stable with resonance than without. Without resonance benzene has 3 carbon double bonds and 3 carbon single bonds, and using bond enthalpies you can calculate the energy: 3(348 kJ)+3(612 kJ)= 2880 kJ. With resonance benze...
Sat Jan 09, 2016 11:00 pm
Forum: Phase Changes & Related Calculations
Topic: Why does a phase change graph have mutiple plateaus?
Replies: 2
Views: 3710

### Re: Why does a phase change graph have mutiple plateaus?

In the phase change graph there are multiple plateaus because there are multiple phase changes where the temperature is constant under controlled conditions. For example, water as a solid can change into a liquid or a vapor, each of which is indicated by a plateau.
Mon Nov 30, 2015 10:04 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Seesaw Converse
Replies: 1
Views: 373

### Re: Conjugate Seesaw Converse

Yes, I believe the converse is also true. Usually when you have a strong acid or base, its conjugate is weaker and vice versa.
Sat Nov 28, 2015 9:33 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Homo vs. Lumo
Replies: 1
Views: 2629

### Re: Homo vs. Lumo

HOMO stands for highest unoccupied molecular orbital and LUMO stands for the lowest unoccupied molecular orbital. When you draw out a molecular orbital diagram for F2, you will see that the last orbital electrons occupy is the π*2p orbital, which makes it the highest occupied molecular orbital. The ...
Fri Nov 20, 2015 11:41 am
Forum: Determining Molecular Shape (VSEPR)
Topic: T-Shaped Molecule and its Dipole Moments
Replies: 3
Views: 2003

### Re: T-Shaped Molecule and its Dipole Moments

AX2E3 is linear because the three lone pairs repel each other. The linear shape minimizes this repulsion.
Tue Nov 10, 2015 11:29 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Writing oxidation numbers for transition metals
Replies: 2
Views: 482

### Re: Writing oxidation numbers for transition metals

Yes, if the question asks for oxidation number then you write it as either +3 or -3, I think either is fine.
Sun Nov 08, 2015 11:34 am
Forum: Ideal Gases
Topic: Equilibrium
Replies: 2
Views: 485

### Re: Equilibrium

Yes the chemical reaction is at a state of dynamic equilibrium where the forward and reverse reactions occur at the same rate.
Fri Oct 30, 2015 8:46 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Radical vs. Higher Bond Order
Replies: 1
Views: 363

### Re: Radical vs. Higher Bond Order

Yes, the atom with the higher bond order is more stable even if it is a radical.
Wed Oct 21, 2015 11:57 pm
Forum: Bond Lengths & Energies
Topic: Pi bonds
Replies: 3
Views: 780

### Re: Pi bonds

A double bond will have one pi bond and one sigma bond. A pi bond is where two orbitals overlap side-by-side, which takes place in a double or triple bond.
Fri Oct 16, 2015 10:58 am
Forum: Resonance Structures
Topic: 3.57 part B
Replies: 1
Views: 450

### 3.57 part B

In this question you're supposed to write the Lewis structure including typical contributions to the resonance structure for hydrogen sulfite. In the solutions manual it shows that there are two resonance structures for this molecule, but I didn't understand why sulfur couldn't form a double bond wi...
Fri Oct 09, 2015 6:40 pm
Forum: Trends in The Periodic Table
Topic: shielding
Replies: 2
Views: 523

### Re: shielding

The higher the value for l, the higher the orbital is, so it's further away from the nucleus. When l=1, an electron is in the p orbital, and when l=2, an electron is in the d orbital. For an electron to be in the d orbital, the p orbital at that energy level would have to already be full, meaning th...
Fri Oct 02, 2015 10:02 pm
Forum: Significant Figures
Topic: Number of sig figs for 1.23
Replies: 1
Views: 382

### Number of sig figs for 1.23

1.23: The y-ray photons emitted by the nuclear decay of a technetium-99 atom used in radiopharmaceuticals have an energy of 140.511keV. Calculate the wavelength of these y-rays. For this question I assumed that the answer should have 6 sig figs because the energy given in the problem has 6 sig figs,...