Search found 22 matches

by hannaluong4E
Sat Mar 12, 2016 5:46 pm
Forum: *Alkenes
Topic: identifying functional groups
Replies: 1
Views: 342

Re: identifying functional groups

I think we would include alkenes and alkynes but not methyl substituents!
by hannaluong4E
Sun Mar 06, 2016 10:55 am
Forum: *Chem3D
Topic: Steric Strain
Replies: 3
Views: 892

Re: Steric Strain

I don't think they purposely bump into each other, just that the atoms are too close and are physically trying to occupy the same space, and this leads them to bump each other.
by hannaluong4E
Sun Feb 28, 2016 4:08 pm
Forum: *Alkenes
Topic: Naming
Replies: 1
Views: 364

Re: Naming

The double bond gets priority and has the lower number!
by hannaluong4E
Sun Feb 21, 2016 4:27 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Electrophilic aromatic substition
Replies: 1
Views: 267

Electrophilic aromatic substition

In these reactions as shown on p. 158, during step 2, why does the base remove a proton instead of being electrostatically attracted to and attaching to the positively charged C? Also, if we want to know how many valence e- for a certain atom in a molecule do we count the bonds formed between that a...
by hannaluong4E
Mon Feb 15, 2016 12:13 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: HW 15.19 (c)
Replies: 1
Views: 377

HW 15.19 (c)

In finding the value of k, why is it necessary to convert all the concentrations and rate into units of moles instead of leaving them all in in terms of mmol? I thought as long as you kept them all consistent it would yield the same answer but I get different k values when using all mmol vs. using a...
by hannaluong4E
Sat Feb 06, 2016 4:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Need help on galvanic cells
Replies: 1
Views: 224

Re: Need help on galvanic cells

Yes! The left side of the cell diagram represents the anode (oxidation reaction) and the right side represents the cathode (reduction reaction). So oxidation H2 --> 2H+ + 2e- and reduction Cl2 + 2e- --> 2Cl- The C(gr) and Pt(s) are not part of either half reactions because they are the inert electro...
by hannaluong4E
Sun Jan 31, 2016 12:43 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: HW 14.13 (d)
Replies: 1
Views: 265

HW 14.13 (d)

For the reduction half reaction I got Au+ + 1e- -> Au and for the oxidation half reaction I got Au+ -> Au3+ + 2e-. But the solution manual said that the oxidation reaction is Au -> Au3+ + 3e-.

Am I doing something wrong/missing something?

Thanks!
by hannaluong4E
Sun Jan 31, 2016 12:32 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Converting cell diagrams to redox reactions
Replies: 1
Views: 232

Re: Converting cell diagrams to redox reactions

There are two halves on a cell diagram separated by the double line for the salt bridge, with the left being the anode and the right being the cathode. Each half represents the oxidation or reduction half reaction. I think Lavelle said in his lecture that we wouldn't be responsible for knowing the c...
by hannaluong4E
Sat Jan 23, 2016 3:05 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Practice Quiz 1 2015, #9
Replies: 1
Views: 292

Practice Quiz 1 2015, #9

The answer to the problem says that delta G and delta S of the system are zero, but can someone give me an explanation as to why? From what I understand from the problem it seems delta V and delta T are both equal to zero but I don't know how to go from there to knowing delta G and delta S are zero....
by hannaluong4E
Thu Jan 14, 2016 3:28 pm
Forum: Phase Changes & Related Calculations
Topic: Calculating Work
Replies: 4
Views: 1892

Re: Calculating Work

First step would be to consider the work formula, w=-P∆V. And we know to use this formula because there's a constant ext. pressure of 2 atm. Then to find the unknown ∆V, we use the formula for the volume of the cylinder V=πr 2 h, where ∆V=πr 2 ∆h because the pi and r are constants. ∆V=π(1.5 cm) 2 (-...
by hannaluong4E
Fri Jan 08, 2016 11:26 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calculating heat with heat capacities percentage
Replies: 1
Views: 386

Re: Calculating heat with heat capacities percentage

Yes they did! The answer is (heat supplied to water)/(heat supplied to copper kettle + heat supplied to water) =
130420 J/(14820 + 130420 J) = .90.
by hannaluong4E
Fri Dec 04, 2015 8:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Question on molecules with linear shape
Replies: 2
Views: 613

Question on molecules with linear shape

If a molecule has a linear shape does that guarantee the bond angle will be 180 degrees and non polar? An example would be XeF2 (AX2E3) which has a trigonal bipyramidal electron arrangement but a linear shape, with bond angle 180 degrees. I just wanted to clarify because I always determined bond ang...
by hannaluong4E
Sun Nov 29, 2015 8:36 pm
Forum: *Indicators
Topic: Stoichiometric point explanation [ENDORSED]
Replies: 5
Views: 1745

Re: Stoichiometric point explanation [ENDORSED]

So would it be correct to also say that at the stoichiometric point the amount of salt present is equal to the amount of titrant added?
by hannaluong4E
Sun Nov 22, 2015 6:39 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Base Strength
Replies: 1
Views: 562

Re: Base Strength

You would look at their K B values. Higher K B values indicate stronger bases. Table 12.2 lists the K B values for (C 2 H 5 ) 3 N and N 2 H 4 . And for the other two you would look at their conjugate acid K A values from Table 12.1 and convert it to K B through the relationship K A x K B = K w , whe...
by hannaluong4E
Sat Nov 14, 2015 12:20 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 2013 Quiz 3 Preparation #10
Replies: 10
Views: 1203

Re: 2013 Quiz 3 Preparation #10

I also am having trouble with this problem. I got K from the equilibrium values given as 31.9273. And then I made an ICE box keeping the original chemical equation given 2BrCl -> Br2 + Cl2 with new equilibrium values of (.54-2x) bar for BrCl, (4.9+x) bar for Br2, and (7.6+x) bar for Cl2. And solving...
by hannaluong4E
Fri Nov 06, 2015 8:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW 11.11
Replies: 1
Views: 311

HW 11.11

A .1 mol sample of pure ozone, O 3 , is placed in a sealed 1 L container and the reaction 2O 3 -> 3O 2 is allowed to reach equilibrium. A .5 mol sample of pure ozone is placed in a second 1 L container at the same temperature and allowed to reach equilibrium. Without doing any calculations, predict ...
by hannaluong4E
Sat Oct 31, 2015 6:58 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: heteronuclear diatomic molecules
Replies: 1
Views: 224

Re: heteronuclear diatomic molecules

When one atom is Z<8 and the other is Z>8 you would use the MO diagram for Z<8. And in that one the bonding sigma is higher in energy than the bonding pi. I'm not sure what you mean by the VSEPR on the sides? For the atomic orbitals on the side, the more electronegative of the two will be closer to ...
by hannaluong4E
Mon Oct 26, 2015 6:19 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Paramagnetic vs Diamagnetic
Replies: 1
Views: 304

Re: Paramagnetic vs Diamagnetic

I use the MO valence electron configuration which includes both elements to figure out if there's unpaired e- or not (diamagnetism vs. paramagnetism). CO+ has 9 valence e-. The configuration would be (sigma2s)2(sigma2s*)2(pi2p)4(sigma2p)1. Paramagnetic because there's one unpaired e-.
by hannaluong4E
Sun Oct 18, 2015 8:52 pm
Forum: Octet Exceptions
Topic: About radicals
Replies: 1
Views: 336

About radicals

Can radicals/biradicals have resonance structures? And how can you tell/will it usually be clear which atom in a substance has the lone unpaired electron?

Thanks!
by hannaluong4E
Sun Oct 11, 2015 4:08 pm
Forum: Octet Exceptions
Topic: Expanded Valence Shells
Replies: 4
Views: 949

Re: Expanded Valence Shells

Can you clarify this more for me? So how many maximum bonds can P, S, and Cl have with other atoms? And how do you figure that out (for these elements and others too)? I read in a different post that typically, the maximum number of e- attached is 12, so 6 bonds?
by hannaluong4E
Sun Oct 11, 2015 3:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orientation of the lobes
Replies: 1
Views: 523

Re: Orientation of the lobes

The lobes of the p-orbitals are in the shape of a 3D infinity sign in which the lobes of the px- lie along the x-axis, the py- lie along the y-axis, and the pz- lie along the z-axis.
by hannaluong4E
Fri Oct 02, 2015 9:29 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Question 1.15
Replies: 1
Views: 316

Re: Question 1.15

102.6 nm is within the UV part of the hydrogen spectrum or the Lyman series, which begins with n=1. Using that wavelength to calculate velocity through c=λv gets v=2.924x10 15 The textbook has the Rydberg formula of v=R(1/n 2 -1/n 2 ). 2.924x10 15 =R(1/1-1/n 2 ) .88879=1-1/n 2 .11121=1/n 2 n=2.998 T...

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