Search found 30 matches
- Fri Jun 08, 2018 3:48 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxalate Bidentate?
- Replies: 1
- Views: 487
Oxalate Bidentate?
Why is oxalate bidentate? Aren't there four oxygens with lone pairs, meaning there are four potential binding sites, thus making it tetradentate?
- Fri Jun 08, 2018 3:38 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate
- Replies: 5
- Views: 850
Re: Polydentate
How exactly would you be able to identify where it can form a bond, in order to determine if it is polydentate? For example, how do you know that the molecule N(CH2CH2NH2)2 is tetradentate.
- Fri Jun 08, 2018 3:13 pm
- Forum: Bronsted Acids & Bases
- Topic: J.1
- Replies: 1
- Views: 363
J.1
Identify each compound as either a Brønsted acid or a Brønsted base: (a) NH3; (b) HBr; (c) KOH; (d) H2SO3; (e) Ca(OH)2.
For part (a), I'm having some trouble understanding why NH3 is a Brønsted base. I thought it would be an acid because of the hydrogens present in the molecule?
For part (a), I'm having some trouble understanding why NH3 is a Brønsted base. I thought it would be an acid because of the hydrogens present in the molecule?
- Fri Jun 01, 2018 3:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pair Placement [ENDORSED]
- Replies: 2
- Views: 415
Lone Pair Placement [ENDORSED]
I remember that we learned about how for some molecular shapes, it doesn't matter where you choose to place the lone pair, whereas for others, it does. For example, I believe that in molecules with a tetrahedral shape, the placement of the lone pair doesn't matter, but in molecules with trigonal bip...
- Fri Jun 01, 2018 3:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: How is this linear?
- Replies: 2
- Views: 333
Re: How is this linear?
You have to imagine it in a three-dimensional perspective, rather than how it looks in a Lewis structure. In a trigonal bipyramidal 3D shape, there are 3 atoms in a trigonal planar arrangement, 1 atom on top, and the other atom below. In this molecule, which has 3 lone pairs, these lone pairs are in...
- Fri Jun 01, 2018 2:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lewis Structure for VSEPR
- Replies: 2
- Views: 353
Lewis Structure for VSEPR
I noticed in the solution manual that many of the Lewis structures are not the most stable structure. I know that this does not make a difference when it comes to making the VSEPR formula, but I had been drawing the most stable ones out of habit. Does this not matter as much in this unit? As in, wou...
- Fri May 25, 2018 3:51 pm
- Forum: Sigma & Pi Bonds
- Topic: Covalent or Ionic?
- Replies: 1
- Views: 394
Covalent or Ionic?
I was wondering how sigma and pi bonds fit in with covalent and ionic bonding? Do they only occur in one or the other, or can they be present in any type of bond?
- Fri May 25, 2018 3:46 pm
- Forum: Lewis Structures
- Topic: Why Resonance for SO2?
- Replies: 3
- Views: 3476
Re: Why Resonance for SO2?
You are correct that the structure with 2 double bonds is the most stable structure. However, since the question specifically asks for three resonance structures, you should also include the two resonance structures that have 1 single bond and 1 double bond between the S and each O, even though they...
- Fri May 25, 2018 3:37 pm
- Forum: Bond Lengths & Energies
- Topic: 3.87
- Replies: 5
- Views: 632
Re: 3.87
I'm confused about this. I thought that it would be Br, because Br is the largest atom? If the centers of the F and Br atoms are in the same place in both cases, since the F atom is smaller, there would be a greater distance between the C and F, and F would be the longer and weaker bond. Whereas wit...
- Fri May 18, 2018 4:00 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Covalent Character
- Replies: 3
- Views: 1968
Re: Covalent Character
Ok, that clears it up, thank you!
Just a follow-up question: what is the general trend for increasing covalent character of an ionic bond? (In other words, what in the bond changes in order for covalent character to increase?)
Just a follow-up question: what is the general trend for increasing covalent character of an ionic bond? (In other words, what in the bond changes in order for covalent character to increase?)
- Fri May 18, 2018 3:59 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Covalent Character
- Replies: 3
- Views: 1968
Covalent Character
In class, we talked a bunch about how ionic bonds have covalent character. What exactly does it mean for a bond to have "covalent character"? There was something about "highly distorted electrons" and "highly polarizable" but I'm having some trouble understanding this.
- Fri May 18, 2018 3:28 pm
- Forum: Resonance Structures
- Topic: 3.45
- Replies: 1
- Views: 340
3.45
Draw the Lewis structures that contribute to the resonance hybrid of nitryl chloride, ClNO2 (N is the central atom). I know that for the Lewis structure, there are two single bonds and one double bond. The answer key shows that the 2 possible resonance structures have the double bond between N and e...
- Sun May 13, 2018 1:48 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy vs. Electron Affinity
- Replies: 4
- Views: 491
Ionization Energy vs. Electron Affinity
I was wondering what the difference is between ionization energy and electron affinity? It seemed somewhat like we were using the two terms interchangeably in class, but I wasn't sure if this is actually correct. Do they have the same periodic trends?
- Sun May 13, 2018 1:39 pm
- Forum: Trends in The Periodic Table
- Topic: Second Ionization
- Replies: 3
- Views: 613
Re: Second Ionization
The 2nd ionization energy is higher because it is more difficult to remove the second electron from the atom. When you remove the first electron, the atom becomes more positively charged, so the remaining electrons are pulled into the nucleus more strongly. As a result, more energy is required to re...
- Sun May 13, 2018 1:38 pm
- Forum: Lewis Structures
- Topic: KCl Lewis formula
- Replies: 6
- Views: 1926
KCl Lewis formula
In one of the first lectures of this unit, we did an example of the Lewis formula of KCl. In this example, Cl ended up with all of the electrons in the final Lewis structure. I was just wondering why this was the case? How often would we have to do this type of Lewis structure rather than what we ha...
- Sat May 05, 2018 3:06 pm
- Forum: Trends in The Periodic Table
- Topic: Practice midterm 6d
- Replies: 2
- Views: 323
Practice midterm 6d
The question asks us to rank C,N,O, and F in order of increasing ionization energies. I know that the solution is C < O < N < F, however I expected the answer to be C < N < O < F because the ionization energy increases across a period. We talked about how this is an exception during the review sessi...
- Sat May 05, 2018 2:48 pm
- Forum: Trends in The Periodic Table
- Topic: Ionic radius trend
- Replies: 2
- Views: 387
Ionic radius trend
I understand the basic idea that ionic radii shows the same trends as atomic radii (radius increases down a group and decreases across a period), but I am confused as to how cations are smaller than the parent atom, and anions are larger. Wouldn't this contradict the atomic radii trend?
- Sat May 05, 2018 2:35 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Anion electron configuration
- Replies: 2
- Views: 606
Anion electron configuration
In lecture, we were told that the rule for electron configurations of anions is to add electrons until the next noble gas configuration. I'm kind of confused about how this was explained, because it seemed it seemed like it was different from the cation electron configuration rule. Are we always goi...
- Thu Apr 26, 2018 11:56 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: HW #1.43
- Replies: 8
- Views: 1279
HW #1.43
What is the minimum uncertainty in the speed of an electron confined to within a lead atom of diameter 350. pm?
When I calculated the answer to this problem, I got an answer of 1.51 x 10^-25 m/s. However, apparently the solution should be 1.65 x 10^5 m/s. How am I getting a value that is so off?
When I calculated the answer to this problem, I got an answer of 1.51 x 10^-25 m/s. However, apparently the solution should be 1.65 x 10^5 m/s. How am I getting a value that is so off?
- Thu Apr 26, 2018 11:32 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes [ENDORSED]
- Replies: 6
- Views: 804
Nodal Planes [ENDORSED]
What exactly is the formal definition of a nodal plane? I understand what they are in the context of looking at an image of an orbital, but I would just like to know what their significance is.
- Thu Apr 26, 2018 11:18 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Indeterminacy of Momentum
- Replies: 2
- Views: 372
Re: Indeterminacy of Momentum
I think that you will always have to calculate the indeterminacy in velocity using delta p = (mass) x (delta v). Momentum includes both mass and velocity in the value, so it is difficult to infer anything useful from just the indeterminacy in momentum. This is why we took the extra step and found th...
- Sat Apr 21, 2018 8:10 pm
- Forum: DeBroglie Equation
- Topic: equations that apply to light only/everything else but light
- Replies: 8
- Views: 939
Re: equations that apply to light only/everything else but light
I don't think that light has momentum (p), because p = mv, and while light has velocity, it does not have mass. So the equation would not apply in this case. I am not sure though.
- Sat Apr 21, 2018 7:50 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation [ENDORSED]
- Replies: 3
- Views: 572
Rydberg Equation [ENDORSED]
I remember that in class, we did example where we found the frequency of light being emitted when an electron changes energy levels. In this example, we used the equation E = -hR/n^2 at each energy level and then subtracted them to find the frequency using E = hv. I understand how the Rydberg equati...
- Sat Apr 21, 2018 7:16 pm
- Forum: Einstein Equation
- Topic: Planck's Constant Value [ENDORSED]
- Replies: 7
- Views: 3331
Planck's Constant Value [ENDORSED]
When we are doing calculations involving Planck's constant, h, I was just wondering if it is better to use 6.626 x 10^-34 J.s or 6.63 x 10^-34 J.s? I've seen it both ways and I was just curious. Thanks!
- Sun Apr 15, 2018 3:51 pm
- Forum: Photoelectric Effect
- Topic: Practice Problem [ENDORSED]
- Replies: 1
- Views: 163
Practice Problem [ENDORSED]
Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 10^5 m/s. The work function for sodium is 150.6 kJ/mol. A. What is the kinetic energy of the ejected electron? For this problem, I want to use the equation E(k)=(1/2)(m(e-))(v(e-)^2) to find kinetic energy. The velo...
- Sun Apr 15, 2018 3:41 pm
- Forum: Photoelectric Effect
- Topic: Threshold Energy Definition
- Replies: 3
- Views: 1507
Re: Threshold Energy Definition
Threshold energy is the amount of energy per photon that is required to eject electrons from a metal surface.
This is the same thing as the work function, and is represented by the symbol Φ.
This is the same thing as the work function, and is represented by the symbol Φ.
- Sun Apr 15, 2018 2:55 pm
- Forum: Limiting Reactant Calculations
- Topic: Finding Excess Reactant [ENDORSED]
- Replies: 2
- Views: 1453
Finding Excess Reactant [ENDORSED]
I understand how to find the amount of product formed from a limiting reactant. But how exactly do you calculate the mass of the excess reactant that is leftover once this reaction takes place?
- Sun Apr 08, 2018 2:15 pm
- Forum: Empirical & Molecular Formulas
- Topic: Rounding molar ratios
- Replies: 3
- Views: 12661
Rounding molar ratios
When finding the ratio of moles in order to determine an empirical formula, what are the rules for rounding? For example, if i were to divide by the smallest number while calculating the ratios and one of my results is 15.80, how do I know if I can round this up to the nearest whole number, or if I ...
- Sun Apr 08, 2018 1:56 pm
- Forum: Empirical & Molecular Formulas
- Topic: Order of Elements in Empirical Formula [ENDORSED]
- Replies: 4
- Views: 12461
Re: Order of Elements in Empirical Formula [ENDORSED]
I believe that the general rule is that, if there is carbon present in the compound, the order of elements is carbon first, then hydrogen, the the rest of the elements in alphabetical order. If there is no carbon in the compound, then the elements just go in alphabetical order in the formula. Howeve...
- Sun Apr 08, 2018 1:33 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G.5 [ENDORSED]
- Replies: 1
- Views: 249
G.5 [ENDORSED]
I am still a bit confused as to the setup of this problem. How do you find the molarity of the Na2CO3 solution using the mass and volume given? I know that n=m/M and c=n/V, but I don't understand how to find the concentration using these equations.