Search found 82 matches

by 704320688
Wed Dec 04, 2013 12:27 am
Forum: Naming
Topic: Latin Names
Replies: 6
Views: 782

Re: Latin Names

Those prefixes, however, may not be sufficient as they are more or less used as examples rather than an exhaustive list. I would honestly recommend just knowing the transition metal latin prefixes. There are really not very many (10 max) and transition metals are honestly the only ones you would nee...
by 704320688
Wed Dec 04, 2013 12:22 am
Forum: Bronsted Acids & Bases
Topic: NH3+ + HCl ---> NH4Cl
Replies: 4
Views: 4185

Re: NH3+ + HCl ---> NH4Cl

Furthermore, aren't all Bronsted Acid Lewis Acids? Or am I thinking about this in the wrong way?
by 704320688
Wed Dec 04, 2013 12:19 am
Forum: Bronsted Acids & Bases
Topic: NH3+ + HCl ---> NH4Cl
Replies: 4
Views: 4185

Re: NH3+ + HCl ---> NH4Cl

But I believe it would be a lewis acid in an aqueous solution.

HCl + H2O --> H3O+ + Cl-

The H2O would act still act at the electron pair donor in an aqueous solution and the HCl would continue to act at a lone pair acceptor.
by 704320688
Wed Dec 04, 2013 12:16 am
Forum: Administrative Questions and Class Announcements
Topic: Are we expected to know
Replies: 2
Views: 694

Re: Are we expected to know

Thank you!
by 704320688
Wed Dec 04, 2013 12:16 am
Forum: Bronsted Acids & Bases
Topic: H2O + SO2 --> H2SO3
Replies: 10
Views: 9222

Re: H2O + SO2 --> H2SO3

Thank you both for your help!
by 704320688
Wed Dec 04, 2013 12:15 am
Forum: Properties of Electrons
Topic: Electrons and Frequency
Replies: 3
Views: 422

Re: Electrons and Frequency

Question: No electrons are emitted from the surface of the metal until the frequency of the radiation reaches 2.50 x 10^6 Hz. How much energy is required to remove the electron from the metal surface?" The solutions manual states that you should plug in the given frequency into E=hv, and E woul...
by 704320688
Tue Dec 03, 2013 11:59 pm
Forum: Properties of Light
Topic: Fall 2010, Q5A
Replies: 2
Views: 473

Re: Fall 2010, Q5A

In general for the Quantum world, temperature (at least of what we've learned) isn't an issue. I would however be careful with it when comes to Le Chat's Principle where an increase in temperature has an effect on an endothermic rxn. I'd also be careful with it on PV=nRT equations. Other than that, ...
by 704320688
Tue Dec 03, 2013 11:56 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: When would we use net equations
Replies: 2
Views: 284

Re: When would we use net equations

Thank you for your reply! Can I ask, are we required to do so? I mean, would be graded down if we did?
by 704320688
Tue Dec 03, 2013 8:19 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: When would we use net equations
Replies: 2
Views: 284

When would we use net equations

I've noticed that in some excersizes (especially in acidic/basic salt in water equations), only the net equation is used. In what other cases do we use net equations? In which cases do we not?
by 704320688
Tue Dec 03, 2013 7:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Are we expected to know
Replies: 2
Views: 694

Are we expected to know

Hello Professor Lavelle,
I found the formula pH=1/2(Pka1 +Pka2) in the book; but I couldn't find it in the course reader or in my lecture notes. Is that a formula that we are expected to know? If it is, would you mind terribly explaining to me when we would use it?
by 704320688
Tue Dec 03, 2013 2:38 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Do we balance these reactions?
Replies: 1
Views: 303

Do we balance these reactions?

I've noticed that a lot of the problems we've been doing aren't balanced. For example, in the midterm of Fall 2008, the equation H2PO4^- + H2O ---> HPO4^2- + H3O+, isn't balanced. Is it just because water is in excess that it doesn't matter if we balance? Would we then balance other things but not w...
by 704320688
Tue Dec 03, 2013 10:55 am
Forum: Bronsted Acids & Bases
Topic: H2O + SO2 --> H2SO3
Replies: 10
Views: 9222

Re: H2O + SO2 --> H2SO3

When would we dissociate the H2SO3 further and when would we just keep it as H2SO3?
by 704320688
Mon Dec 02, 2013 10:31 pm
Forum: Bronsted Acids & Bases
Topic: H2O + SO2 --> H2SO3
Replies: 10
Views: 9222

Re: H2O + SO2 --> H2SO3

Hi Poweryberry, First of all, thank you so much for the quickly reply! I am, however, a bit confused by the SO3 stuff because my question is about SO2 and H2O. Specifically, my question is about the rxn H2O + SO2 --> H2SO3 and whether or not it fits within the bronsted definition of a acid and bases.
by 704320688
Mon Dec 02, 2013 10:09 pm
Forum: Bronsted Acids & Bases
Topic: H2O + SO2 --> H2SO3
Replies: 10
Views: 9222

Re: H2O + SO2 --> H2SO3

What I mean by that is that weak acids and bases dissociate so negligibly that we wouldn't split them up in the end reaction.
by 704320688
Mon Dec 02, 2013 10:08 pm
Forum: Bronsted Acids & Bases
Topic: H2O + SO2 --> H2SO3
Replies: 10
Views: 9222

H2O + SO2 --> H2SO3

Question 1: I know that the SO2 is the lewis acid and the H2O is the lewis base; however, is SO2 also a bronsted acid?? Does it make a difference if it is aqueous or not because if it is aqueous, it will dissociate further into SO3^2- + 2 H3O+ Also, I have a separate question if you don't mind: Ques...
by 704320688
Mon Dec 02, 2013 10:02 pm
Forum: Bronsted Acids & Bases
Topic: NH3+ + HCl ---> NH4Cl
Replies: 4
Views: 4185

NH3+ + HCl ---> NH4Cl

Is NH3 + HCl ---> NH4Cl

Is NH3 both a lewis base and Bronsted base? Or is NH3 only a bronsted base if it is in an aqueous solution so that the NH4+ and the Cl- split up.

Is HCl both a lewis acid and a Bronsted Acid?
by 704320688
Mon Dec 02, 2013 3:26 pm
Forum: Bronsted Acids & Bases
Topic: 11.13
Replies: 2
Views: 462

Re: 11.13

Also why would the NH2 be amphoteric? Isn't very unlikely that the N would lose another proton since an N with one H and 3 lone pairs is highly unstable.
by 704320688
Mon Dec 02, 2013 2:47 pm
Forum: Bronsted Acids & Bases
Topic: 11.13
Replies: 2
Views: 462

11.13

The two strands of the nucleic acid DNA are held together by four organic bases. The structure of one of these bases is shown below. How many protons can this base accept? The base is a 4 carbon, 2 NH ring. It also has two individual Oxygen molecules, each of which is bonded to two different carbon ...
by 704320688
Mon Dec 02, 2013 2:59 am
Forum: Lewis Acids & Bases
Topic: How can we identify if a compound is amphiprotic?
Replies: 2
Views: 325

Re: How can we identify if a compound is amphiprotic?

Adding on to that, you should generally expect the conjugates of polyprotic compounds to be amphiprotic. Water is also amphiprotic.
by 704320688
Mon Dec 02, 2013 2:55 am
Forum: Lewis Acids & Bases
Topic: HCl
Replies: 4
Views: 612

HCl

Is HCl a lewis acid or is the actual molecule, H+, the lewis acid?
by 704320688
Mon Dec 02, 2013 1:35 am
Forum: Amphoteric Compounds
Topic: NH4I as an amphoteric molecule
Replies: 3
Views: 2087

Re: NH4I as an amphoteric molecule

Why wouldn't the reaction disassociate into NH4+ and I-. Then since I- is the conjugate base of a strong acid (i.e. neutral), NH4+ would be the only significant ion since it is the conjugate acid of a weak base. So it would then go to NH4+ + H2O--><--- H3O+ + NH3. Wouldn't this happen? Or would it n...
by 704320688
Sun Dec 01, 2013 11:20 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: What about autoprotolysis
Replies: 3
Views: 414

Re: What about autoprotolysis

When do we not ignore it? For weak acid-weak base reactions? For strong acid-weak base reactions? For strong acid-strong base reactions?
by 704320688
Sun Dec 01, 2013 11:19 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Due to twice protonation, how're conc. of H2CO3 ionic comp.?
Replies: 3
Views: 332

Re: Due to twice protonation, how're conc. of H2CO3 ionic co

But don't you ignore the second two concentrations because like Ka2 and Ka3, there too small to make a difference unless it is for sulfuric acid?
by 704320688
Sun Dec 01, 2013 11:16 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Autoprotlysis Questions (2)
Replies: 1
Views: 250

Autoprotlysis Questions (2)

Q1: At what point would you count the autoprotlysis of water? How small would it have to be, I mean?

Also..

Q2: Do we only need to take the autoprotlysis of water into account when we have weak acids or do we also take it into account for weak/strong bases?

Thank you for any help!
by 704320688
Sun Dec 01, 2013 11:15 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: When to account for autoprotolysis
Replies: 5
Views: 531

Re: When to account for autoprotolysis

Q1: At what point would you count the autoprotlysis of water? How small would it have to be, I mean?

Also..

Q2: Do we only need to take the autoprotlysis of water into account when we have weak acids or do we also take it into account for weak/strong bases?

Thank you for any help!
by 704320688
Tue Nov 19, 2013 12:00 pm
Forum: Naming
Topic: Is Carbonate bicarbonato or bis(carbonato) [ENDORSED]
Replies: 4
Views: 543

Re: Is Carbonate bicarbonato or bis(carbonato) [ENDORSED]

But carbonate is a bidentate and when you have bi/polydentates, the book says to use bis- tris- tetrakis-
by 704320688
Mon Nov 18, 2013 7:45 pm
Forum: Naming
Topic: What latin names should we know?
Replies: 1
Views: 323

What latin names should we know?

What latin names are we required to know? The first row of the d-block or all the transition metals?
by 704320688
Mon Nov 18, 2013 7:36 pm
Forum: Naming
Topic: when to write Ion and writing the order of the ligands
Replies: 3
Views: 500

Re: when to write Ion and writing the order of the ligands

You can have neutral ions; they are just deprotonized. You should write it in alphabetical order.
by 704320688
Mon Nov 18, 2013 12:32 am
Forum: Naming
Topic: Is Carbonate bicarbonato or bis(carbonato) [ENDORSED]
Replies: 4
Views: 543

Is Carbonate bicarbonato or bis(carbonato) [ENDORSED]

As a ligand is carbonate bicarbonato or bis(carbonato). I think it is the latter because it is a bidentate but I am not sure? Can someone verify or correct me?
by 704320688
Sun Nov 17, 2013 5:44 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Applying Le Chat to Solids and Pure Liquids
Replies: 1
Views: 365

Applying Le Chat to Solids and Pure Liquids

In the workbook question 5 of the practice quiz from Fall 2012, we are given the reaction NaAlH4 (s) --><--- NaH(s) + Al (s) +(3/2)H2 (g) and are asked if the reaction proceeds towards reactants or products if the amount of H2 is increased. I believe that the reaction will proceed towards neither be...
by 704320688
Sun Nov 17, 2013 4:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When do you cancel x's?
Replies: 1
Views: 302

When do you cancel x's?

I know that we can cancel x's from an equilibrium reaction equation when K is very small--like below 1*10^-5 small. But are we only allowed to cancel x's when Q=K as well as when we start off with initial concentrations only on side of the rxn? Can we not cancel x's even if K is very small if Q is n...
by 704320688
Sun Nov 17, 2013 1:12 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Does Nickel always form square planar complexes w/ 4 bonds
Replies: 2
Views: 999

Does Nickel always form square planar complexes w/ 4 bonds

Nickel is a d8 metal and I know we said in class that d8 transition metals are really the only ones that form square planar complexes but does that mean that whenever we see nickel bonded to 4 ligands that it is forming a square planar complex? Does Nickel always form a square planar complex then or...
by 704320688
Sun Nov 17, 2013 1:03 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: number 3 on quiz 3 prep
Replies: 1
Views: 431

Re: number 3 on quiz 3 prep

Dien is short for diethylenetriammine. It is often shorthanded as dien in chemical formulas and you would chelate the dien structure around the central metal atom (Cu) when drawing it. Since you have 2 diens you are chelating them both around the central metal atom (Cu). Also the chemical formula fo...
by 704320688
Sun Nov 17, 2013 4:39 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: module 55
Replies: 1
Views: 213

Re: module 55

A concentration value is another way of saying molarity and since n/V is molarity, your answer is C. :) Hope I helped.
by 704320688
Sun Nov 17, 2013 3:01 am
Forum: Naming
Topic: Why is it called an ion?
Replies: 1
Views: 346

Why is it called an ion?

In Question 5 of the Fall 2011 practice quiz in our workbooks, [Cr(F)3(I)(H2O)2] is named an diaquatrifluoroiodochromium (IV) ion. Why is it called an ion if it has no charge?
by 704320688
Sun Nov 17, 2013 2:53 am
Forum: Naming
Topic: Am I alphabetizing Wrong
Replies: 5
Views: 743

Am I alphabetizing Wrong

Question 4 in the practice Quiz 3 section of the workbook asks for the chemical formula of a Diamminetetrahydroxochromate (II) ion and it says that the answer is [Cr(OH)2 (NH3)2]^2-. Shouldn't the answer be [Cr(NH3)2(OH)2]^2- however since NH3 comes before OH- alphabetically.
by 704320688
Sun Nov 17, 2013 2:47 am
Forum: Naming
Topic: CN vs NC
Replies: 1
Views: 1121

CN vs NC

If we have to right the formula for something that has isocyano in it. Would we write CN- in the formula or NC-? Also would we order it based off of CN- or NC-
by 704320688
Sun Nov 17, 2013 2:46 am
Forum: Naming
Topic: Cyanido vs. Isocyanido
Replies: 3
Views: 525

Re: Cyanido vs. Isocyanido

If we have to right the formula for something that has isocyano in it. Would we write CN- in the formula or NC-? Also would we order it based off of CN- or NC-
by 704320688
Sun Nov 17, 2013 2:43 am
Forum: Naming
Topic: Problem from textbook ch.16, 16.29 d
Replies: 3
Views: 534

Re: Problem from textbook ch.16, 16.29 d

I agree with Robert. The aqua should have been named before the oxalate. I think that the rules for naming change a lot overtime as we see within our own class chloro vs. chlorido and so sometimes name order issues can ensue in the same that naming preferences (flouro over flourido) can.
by 704320688
Sun Nov 17, 2013 12:40 am
Forum: Naming
Topic: Do we only need to know the names in the chart?
Replies: 2
Views: 367

Do we only need to know the names in the chart?

Do we only need to know the names for the compounds on the chart on Professor's Lavelle's website? If not, what else do we need to know? Also, how do you name bonded ligands that aren't halides or oxygen? For example, if we have Nitrogen in a compound, how do we write it? It would be Chloro for Cl^-...
by 704320688
Sat Nov 16, 2013 10:56 pm
Forum: Naming
Topic: Number of Binding Spots for CO3(2-)
Replies: 3
Views: 862

Re: Number of Binding Spots for CO3(2-)

There ARE three oxygens, but only two of them have a (-) formal charge and thus attract other compounds to come bind. The last one is double bonded and has a zero formal charge and thus it has no reason for forming a coordinate covalent bond with anything. It is the same reason why something like ED...
by 704320688
Sat Nov 16, 2013 10:27 pm
Forum: Naming
Topic: Latin Names
Replies: 6
Views: 782

Re: Latin Names

I would know what's in the course reader but Professor Lavelle said that we do not need to know all the Latin elements in 2D of the textbook. Also that's like 6 pages of names; there are way more beneficial ways to spend your time. ;)
by 704320688
Tue Nov 05, 2013 7:48 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: When drawing the molecular orbital for HF
Replies: 1
Views: 308

When drawing the molecular orbital for HF

How would we draw the orbitals for HF. I understand that we use the structure for Z<8 in class but H doesn't have p orbitals and F does so how would everything end up looking like?
by 704320688
Tue Nov 05, 2013 7:21 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: When drawing MO and writing out the configurations...
Replies: 4
Views: 391

Re: When drawing MO and writing out the configurations...

Do you know if we have to draw in the p-orbitals for compounds like Li2 where they are not used at all? In dihydrogen, we did not draw them in, but I'm confused as to whether we would for Li2. It only occupies sigma 2s and sigma * 2s, so would need to draw everything else or can we just draw those t...
by 704320688
Tue Nov 05, 2013 7:12 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Quick Question about Li (subscript 2)
Replies: 1
Views: 272

Quick Question about Li (subscript 2)

For molecular orbitals where Li is bonded to Li, do we have to draw the p lines since they are not used at all? With diHydrogen we did not, but would we have to for dilithium? (The extra lines are drawn in the textbook for Lithium when question 51 asks for the M.O. diagram of Li, but Lithium only u...
by 704320688
Tue Nov 05, 2013 2:34 pm
Forum: Ionic & Covalent Bonds
Topic: Fall 2011 Midterm Exam Q6B(c)
Replies: 2
Views: 595

Re: Fall 2011 Midterm Exam Q6B(c)

Can't you think of Lithium and Hydrogen as an actual ionic bond (metal + nonmetal) so it fits the definition and hydrogen and Chlorine (nonmetal + nonmetal) so no matter the differences, an actual ionic bond beats any trend on the periodic table?
by 704320688
Tue Nov 05, 2013 12:24 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Possible Error on Question 3.15
Replies: 2
Views: 300

Re: Possible Error on Question 3.15

On Quiz 2, there was a similar question except we had to decide the formal charge of a C-C-C bond instead of shape. I assumed that there was an unsaid electron pair on the the carbon because Carbon needs to have an octet, but there in fact wasn't supposed to be one and the carbon did in fact only ha...
by 704320688
Tue Nov 05, 2013 10:53 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: When drawing MO and writing out the configurations...
Replies: 4
Views: 391

When drawing MO and writing out the configurations...

When drawing MO and writing out the corresponding configurations, do we only use valence electrons? Also, why does the Bonding sigma Pz orbital get pushed up when Z is less than 8?
by 704320688
Mon Nov 04, 2013 10:09 pm
Forum: Hybridization
Topic: Do we need to know how to do the hybridization of lone pairs
Replies: 2
Views: 431

Do we need to know how to do the hybridization of lone pairs

In question 6 of the Midterm from 2010, you are asked to write the hybridization of the lone pairs on Oxygen in CH2=CHCHO; do we need to know this for the Fall midterm as I don't believe we've covered it. If we do, would anyone mind explaining how to do it to me?
by 704320688
Mon Nov 04, 2013 8:07 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration of Fe2+
Replies: 4
Views: 1423

Electron Configuration of Fe2+

Would the electron configuration of Fe2+ be [Ar] 3d6 or [Ar] 3d5 4s1

Wouldn't it be the latter because electron configurations of elements prefer half-full or full d-orbitals?
by 704320688
Mon Oct 28, 2013 1:35 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Possible Error on Question 3.15
Replies: 2
Views: 300

Possible Error on Question 3.15

The question shows an Acetylacetonate ion and asks for the angle on the middle <C-C-C angle. I believe the angle should be less then 109.5 degrees instead of 120 degrees because it is trigonal pyramidal shaped due to the extra lone electron pair along with the bond on the H, the C, and the other C. ...
by 704320688
Sun Oct 27, 2013 1:15 am
Forum: Resonance Structures
Topic: NSO2^-
Replies: 1
Views: 323

NSO2^-

If given a compound like NSO2^- (I'm not sure if this is an actual compound, this is more of a conceptual question), there are multiple ways to draw it. The most favorable way is with a double bond on the O and a single bond on the N and the other O. I realize that there are already two possible res...
by 704320688
Sat Oct 26, 2013 6:22 pm
Forum: Lewis Structures
Topic: Question on Midterm from Fall 2012 (in back of course reader
Replies: 3
Views: 415

Question on Midterm from Fall 2012 (in back of course reader

I have a question on Question 5B in the midterm test from Fall 2012. The questions asks: Molecules with dipole moments can absorb infrared radiation and contribute to global warming. All of the following gasses are present in air, which of them can contribute to global warming as "greenhouse ga...
by 704320688
Fri Oct 25, 2013 1:28 am
Forum: Resonance Structures
Topic: 2.47
Replies: 1
Views: 336

2.47

I am confused with question 2.47: Draw the lewis structures that contribute to the resonance hybrid of nitryl chloride, ClNO2 (N is central atom)? In the answers, It says that the only resonance structures are ones where there is a single bond in chlorine and one of the oxygens and a double bond on ...
by 704320688
Fri Oct 25, 2013 12:40 am
Forum: Resonance Structures
Topic: Quick Resonance Structure Question
Replies: 1
Views: 271

Quick Resonance Structure Question

Is SO4^2- with two double bonds and two single bonds a resonance structure of SO42- with three single bonds and 1 double bond? This is an example we did in class but I'm confused if the two are indeed resonance structures of each other since when calculating one has a lower formal charge of more ato...
by 704320688
Thu Oct 24, 2013 11:58 pm
Forum: Electronegativity
Topic: Polarity of Compound with different terminal atoms
Replies: 2
Views: 612

Polarity of Compound with different terminal atoms

How do you determine the polarity of a compound with terminal atoms of different electronegativity? I cannot find an example at the moment but if you had a compound like POS or BClN or PSF (I know many of these are not actual compounds), how would you determine whether it was polar or not--especiall...
by 704320688
Thu Oct 24, 2013 11:49 pm
Forum: Ionic & Covalent Bonds
Topic: How do you bracket Ionic Bonds
Replies: 1
Views: 860

How do you bracket Ionic Bonds

Do you bracket just the one that receives the electrons? Or do you bracket both? What if you have a positive/negative compound bonding with another ion. Do you bracket both or do you bracket just the compound?
by 704320688
Thu Oct 24, 2013 11:47 pm
Forum: Sigma & Pi Bonds
Topic: C2H2Cl2
Replies: 3
Views: 3736

Re: C2H2Cl2

Also are trans and cis resonance structures of each other; or does the double bond that doesn't allow rotation inhibit them from being so? I feel like they should be because they are equal energy and have the same number of bonds.
by 704320688
Thu Oct 24, 2013 11:45 pm
Forum: Bond Lengths & Energies
Topic: Size and Dissociation Energy
Replies: 1
Views: 816

Size and Dissociation Energy

I am confused about the distinction between weak bonds and low disassociation energies. I believe that the bigger the anion, the longer the ionic bond between two atoms will be. Thus, the weaker and easier to break it will also be. However, when put into water it is the smaller, stronger, more ionic...
by 704320688
Thu Oct 24, 2013 11:40 pm
Forum: Sigma & Pi Bonds
Topic: C2H2Cl2
Replies: 3
Views: 3736

C2H2Cl2

The compound that was an example in class had two variations: cis and trans. Trans was non-polar and cis was polar. If we get a question that asks us to draw the compound C2H2Cl2, how would we know which version to draw as the two have clear distinction between them (polar v. nonpolar)?
by 704320688
Thu Oct 24, 2013 11:30 pm
Forum: Sigma & Pi Bonds
Topic: Can we rotate CH2Cl2 and make it nonpolar?
Replies: 3
Views: 895

Re: Can we rotate CH2Cl2 and make it nonpolar?

But didn't we have a compound similar to this in class where the trans version was non-polar molecule and cis version was polar?? I thought that it all depended on where you placed the atoms when you created the lewis dot structure ..................................................H Would placing th...
by 704320688
Thu Oct 24, 2013 10:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Workbook Problems
Replies: 1
Views: 408

Workbook Problems

A lot of the workbook problems have to do with hybridization, will that be covered next class?
by 704320688
Wed Oct 16, 2013 11:59 pm
Forum: Trends in The Periodic Table
Topic: Do we need to memorize the periodic table?
Replies: 4
Views: 676

Re: Do we need to memorize the periodic table?

Yes, this is especially true given the time constraints. Personally, I think it would be a good to just have a basic idea of where to find an element.
by 704320688
Tue Oct 15, 2013 2:00 pm
Forum: Trends in The Periodic Table
Topic: Do Be and Al exhibit a Diagonal Relationship?
Replies: 1
Views: 491

Do Be and Al exhibit a Diagonal Relationship?

This is question 1.102 but the part of it I'm having difficulty with is understanding whether or Be and Al have a diagonal relationship.
by 704320688
Tue Oct 15, 2013 12:40 pm
Forum: Trends in The Periodic Table
Topic: Ionic Radius Trend
Replies: 1
Views: 368

Ionic Radius Trend

In class, Lavelle said that Ionic Radius follows the same trends as atomic radius. As in, it increases down a group and decreases across a period. The same is said in the course reader. In the textbook and other online resources, however, ionic radius seems to decrease and then increase and then dec...
by 704320688
Sun Oct 13, 2013 12:14 pm
Forum: Empirical & Molecular Formulas
Topic: Molecular Formula for Xyltitol
Replies: 4
Views: 687

Re: Molecular Formula for Xyltitol

You asked : Okay so if 2.4 is left as 2.4, are decimals always left in that form? Because I know we round but if its 2.6 we leave it as 2.6 and then multiply to get rid of the decimal? As opposed to rounding up to 3? You should only round up to 3 if you have anything higher than about 3.85. Anythin...
by 704320688
Sun Oct 13, 2013 12:07 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula for a Hydrocarbon
Replies: 3
Views: 641

Re: Empirical Formula for a Hydrocarbon

No problem! :) Walking through it increased my understanding of it too.
by 704320688
Sun Oct 13, 2013 3:43 am
Forum: Quantum Numbers and The H-Atom
Topic: Order of s, p, d, and f
Replies: 3
Views: 446

Re: Order of s, p, d, and f

Elaborating on what Robert said, the d-orbitals are always acting a bit funky. In the case of electron configurations, they are almost always written before the s. This is because when the s-orbitals are filled and the d-orbitals are in the process of being filled, the d orbitals become lower in ene...
by 704320688
Sun Oct 13, 2013 3:36 am
Forum: Empirical & Molecular Formulas
Topic: possible error on fall 2012 quiz prep Q1
Replies: 2
Views: 328

Re: possible error on fall 2012 quiz prep Q1

You asked : A 0.2500g sample of a compound known to contain carbon, hydrogen and oxygen undergoes a complete combustion to produce 0.3664 g of CO2 and 0.1500g of H2O. What is the empirical formula of this compound? The molar mass of the hydrocarbon is 180.16g/mol, what is the molecular formula? My ...
by 704320688
Sun Oct 13, 2013 3:25 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: D-Orbitals
Replies: 1
Views: 322

D-Orbitals

I know that in class, Professor Lavelle said that the order of the p-orbitals are px, py, pz. As in, when the electron is occupying -1 of the p-orbital, that translates to px. In s, there is only one orbital so I'm not worried about knowing the order for that, but what about d. What is the order for...
by 704320688
Sun Oct 13, 2013 3:19 am
Forum: *Particle in a Box
Topic: What is the equation: En= (n^2*h^2)/(8*m*L^2) used for? [ENDORSED]
Replies: 5
Views: 1027

Re: What is the equation: En= (n^2*h^2)/(8*m*L^2) used for? [ENDORSED]

You asked : I noticed that the energy of the particle approaches infinity as the limit of the length of the box approaches zero-- would this imply that the size of the 'box' affects the energy of the particle? I believe that the size of the box and the energy of the particle are directly related as...
by 704320688
Sun Oct 13, 2013 3:12 am
Forum: Trends in The Periodic Table
Topic: Determing electron affinity
Replies: 4
Views: 496

Re: Determing electron affinity

What do you mean by the diagonal relationship of elements. I looked in the course reader and I can't seem to find anything related to it. Would you mind elaborating on it as I'd really like to know about this relationship too.
by 704320688
Sun Oct 13, 2013 12:32 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: number of atoms need to be added (E3)
Replies: 4
Views: 1016

Re: number of atoms need to be added (E3)

Yes, it's exactly like what Robert said. On the left side of the scale if you look at the picture closely, it shows that the Br atoms are resting on the scale but on the left side there's space between the Ca atoms and the scale, suggesting that there are no atoms resting there yet. That said, looki...
by 704320688
Sat Oct 12, 2013 3:54 pm
Forum: Empirical & Molecular Formulas
Topic: Molecular Formula for Xyltitol
Replies: 4
Views: 687

Re: Molecular Formula for Xyltitol

Adding on to that, you know the empirical formula is the molecular formula because the molar mass of the empirical formula matches the mass given to you as the weight of the molecular formula.
by 704320688
Sat Oct 12, 2013 3:52 pm
Forum: Significant Figures
Topic: Regarding precision
Replies: 3
Views: 474

Re: Regarding precision

I'm not sure if Powerberry answered this or not since I have yet to click on the link, but just in case that link ever stops working, you need to use what's given to you on a quiz or a test. For example, if 3.0E8 is given on the sheet of equations/constants then you only have 2 sigfigs where as if 2...
by 704320688
Sat Oct 12, 2013 3:48 pm
Forum: SI Units, Unit Conversions
Topic: What prefixes do I need to know? [ENDORSED]
Replies: 6
Views: 840

Re: What prefixes do I need to know? [ENDORSED]

What do you mean by prefixes. Do you mean metric prefixes?
by 704320688
Sat Oct 12, 2013 3:32 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: number of atoms need to be added (E3)
Replies: 4
Views: 1016

Re: number of atoms need to be added (E3)

You asked: Fundamentals E3: In a nanotechnology lab you might have the capability to manipulate individual atoms. The atoms on the left are bromine atoms (molar mass 80 g/mol), those on the right are atoms of calcium (molar mass 40 g/mol). How many calcium atoms would have to be added to the pan on...
by 704320688
Sat Oct 12, 2013 2:51 pm
Forum: Significant Figures
Topic: How to round when "5" is the last number
Replies: 2
Views: 384

Re: How to round when "5" is the last number

This is a common question at Professor Lavelle's last office hour and during usual TA office hours (at least the ones I attend :) ) It is best in a mathematical sense to round up or down to nearest even number when you have something like .5 or .35 or .55. This is because, if you always round up, yo...
by 704320688
Sat Oct 12, 2013 2:41 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula for a Hydrocarbon
Replies: 3
Views: 641

Re: Empirical Formula for a Hydrocarbon

You asked: "What is the empirical formula of a hydrocarbon which produces 3.006 g CO2 and 1.003 g H2O when combusted?" I just don't know where to start for this question. I know the reaction is HC + O2 --> CO2 + H2O, but I don't know where to go from there. I converted the masses of the w...
by 704320688
Sat Oct 12, 2013 1:58 pm
Forum: SI Units, Unit Conversions
Topic: Why is g mol written with a negative 1 (g mol^-1)
Replies: 4
Views: 4312

Re: Why is g mol written with a negative 1 (g mol^-1)

Adding on to that, grams/mole is another way of denoting the amu (Atomic Mass Unit) of an element. All the elements on the periodic table are measured in units of amu or as you put it gram * moles-1.

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