Search found 30 matches

by Natalie Noble 1G
Fri Jun 08, 2018 3:48 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxalate Bidentate?
Replies: 1
Views: 63

Re: Oxalate Bidentate?

C2O4- is bidentate because the two O that are single bonded to the carbons can bind to a metal, and they chelating ligand, so it is bidentate. It cannot bind in single bond and double bond oxygen because it is not long enough (only 4 atoms) to make a ring. And the O that are double bonded to the car...
by Natalie Noble 1G
Fri Jun 08, 2018 3:39 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 5
Views: 210

Re: Polydentate

An easy way to do this is to draw the structure and see if there are lone pairs, because that means it can bind to a metal at that site.
In N(CH2CH2NH2)3 all the N have one lone pair, and there are 4 N present, so it is tetradentate
by Natalie Noble 1G
Fri Jun 08, 2018 3:14 pm
Forum: Bronsted Acids & Bases
Topic: J.1
Replies: 1
Views: 147

Re: J.1

NH3 is a Brønsted base because it can accept a proton and that is the definition of a Brønsted base.
For example, in NH3 + H20, the NH3 will accept a H from the water creating NH4+ and OH-
by Natalie Noble 1G
Fri Jun 01, 2018 3:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair Placement [ENDORSED]
Replies: 2
Views: 81

Re: Lone Pair Placement [ENDORSED]

So the rule is to make the lone pair in the site that will have the least repulsion, since having the least repulsion is the most stable arrangement. For tetrahedral, it does not matter which area around the central atom is the lone pair, because all of the would cause equal repulsion. In trigonal b...
by Natalie Noble 1G
Fri Jun 01, 2018 3:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: How is this linear?
Replies: 2
Views: 92

How is this linear?

When doing a practice problem for naming shape I ran into some trouble. The molecule had 5 bonding sites which I know is trigonal bipyramidal. However, three of the boding sites were lone pairs, and I know the repulsion from the lone pair changes the shape. So I thought the three lone pairs didn’t c...
by Natalie Noble 1G
Fri Jun 01, 2018 2:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis Structure for VSEPR
Replies: 2
Views: 83

Re: Lewis Structure for VSEPR

I think a good rule of thumb is to always use the most stable lewis structure unless otherwise noted. Just to be safe, and to show you know how to get the most stable structure.
by Natalie Noble 1G
Fri May 25, 2018 3:52 pm
Forum: Sigma & Pi Bonds
Topic: Covalent or Ionic?
Replies: 1
Views: 146

Re: Covalent or Ionic?

Only covalent bonds have sigma and pi bonds, as covalent bonds are formed by the overlapping of orbitals (sharing electrons). There has to be covalent bonding to have this overlap which is characterized by sigma and pi bonds. Ionic bonds do not have sigma and pi bonds because ionic bonds are NOT for...
by Natalie Noble 1G
Fri May 25, 2018 3:45 pm
Forum: Lewis Structures
Topic: Why Resonance for SO2?
Replies: 3
Views: 315

Why Resonance for SO2?

In a UA session there was a problem where it asked for three resonance structures for SO2. But when I made the Lewis Structure for SO2 it's stablest form was the S with double bonds to each O and one lone pair of electrons and the two O had two sets of lone pairs With this the formal charge was all ...
by Natalie Noble 1G
Fri May 25, 2018 3:37 pm
Forum: Bond Lengths & Energies
Topic: 3.87
Replies: 5
Views: 215

Re: 3.87

I see where your confusion is, the thing is, the center of the atoms won’t be in the same place if they are big or small. The number of shells for the atom will help tell you how close it is to another. The distance between the center of the C will be closer to the center of F because there are not ...
by Natalie Noble 1G
Fri May 18, 2018 4:02 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Covalent Character
Replies: 3
Views: 122

Re: Covalent Character

cation’s polarizing power:
Increase in charge and small cation = more charge density (polarizing power)

anion’s polarizability:
larger the anion = easier it is to distort
by Natalie Noble 1G
Fri May 18, 2018 3:59 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Covalent Character
Replies: 3
Views: 122

Re: Covalent Character

Ionic bonds have unequal sharing of electrons, while covalent bonds have equal sharing of electrons. Ionic bonds are a bond between oppositely charged ions, so the electrons are not equally shared, the metal loses electrons to become positively charged (cation), and the nonmetal accepts the electron...
by Natalie Noble 1G
Fri May 18, 2018 3:29 pm
Forum: Resonance Structures
Topic: 3.45
Replies: 1
Views: 116

Re: 3.45

When you do the resonant structures look at the formal charge. When the oxygen is double bonded that oxygens charge is 0 The other oxygen charge is -1 The nitrogen charge is +1 The chloride charge is 0 So the charges are all minimized. And the bonds for the oxygens are hybrid. If you put the double ...
by Natalie Noble 1G
Sun May 13, 2018 1:48 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy vs. Electron Affinity
Replies: 4
Views: 168

Re: Ionization Energy vs. Electron Affinity

Ionization energy has to do with the energy required to remove an electron, while electron affinity has to do with the energy spent/released when an electron is added. They are closely related and follow the same trend on the periodic table (increasing up a group and increasing across the period) (↑...
by Natalie Noble 1G
Sun May 13, 2018 1:39 pm
Forum: Lewis Structures
Topic: KCl Lewis formula
Replies: 6
Views: 479

Re: KCl Lewis formula

This is because it is an ionic bond. Ionic bonds form between metals and nonmetals. In this case, K is the metal and Cl is the nonmetal. To form an octet, K gives up an electron to give to Cl, so now Cl has 8 electrons and gains stability. The reason K is so willing to give up the electron is becaus...
by Natalie Noble 1G
Sun May 13, 2018 1:38 pm
Forum: Trends in The Periodic Table
Topic: Second Ionization
Replies: 3
Views: 175

Second Ionization

I know in class we discussed how the removing the 2nd electron (second ionization energy) is harder than the first, but I didn't quite catch the explanation as to why. I think I remember it having to do with the pull of the nucleus but I just don't quite remember.
by Natalie Noble 1G
Sat May 05, 2018 3:07 pm
Forum: Trends in The Periodic Table
Topic: Practice midterm 6d
Replies: 2
Views: 74

Re: Practice midterm 6d

C < O < N < F The reason the N and O breaks the ionization trend is because N is more stable dues to half shell stability. N has one electron in all three orbitals, which gives it slightly more stability making the ionization energy higher as it is more difficult to remove an electron. (while O has ...
by Natalie Noble 1G
Sat May 05, 2018 2:49 pm
Forum: Trends in The Periodic Table
Topic: Ionic radius trend
Replies: 2
Views: 85

Re: Ionic radius trend

I too get confused by this concept here is what I think is the reasoning but I am not sure The trend is the same as atomic radius (increasing down a group and decreasing across a period) just not when comparing the ion to its parent atom. Cations are smaller than their parent atom because the valenc...
by Natalie Noble 1G
Sat May 05, 2018 2:37 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Anion electron configuration
Replies: 2
Views: 129

Re: Anion electron configuration

The ions are trying to get to the most stable form, which is an octet, which is a noble gas. So the anions (negatively charged ions) and the cations (positively charged ions) are both trying to get to the nearest noble gas to form an octet and have stable electron configuration. For cations, electro...
by Natalie Noble 1G
Thu Apr 26, 2018 11:57 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: HW #1.43
Replies: 8
Views: 413

Re: HW #1.43

You got indeterminacy of momentum which is kg.m/s and speed is m/s so you need velocity Indeterminacy of momentum doesn’t tell you what you were asked for, you are asked to find the speed so that is velocity, so you need to find the indeterminacy of velocity Indeterminacy of momentum = 1.507 x 10^-2...
by Natalie Noble 1G
Thu Apr 26, 2018 11:32 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes [ENDORSED]
Replies: 6
Views: 186

Re: Nodal Planes [ENDORSED]

Its an area where the probability an electron will be found is zero, so it has zero electron density (since its a plane its a flat area with no electron density, whereas a node is a circular area with zero electron density)
by Natalie Noble 1G
Thu Apr 26, 2018 11:16 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Indeterminacy of Momentum
Replies: 2
Views: 84

Indeterminacy of Momentum

For the example of Heisenberg we did in class, we found the indeterminacy of momentum, but then we went on to find the indeterminacy of velocity. I was just wondering why we did that extra step, why didn't we just stop with indeterminacy of momentum?
by Natalie Noble 1G
Sat Apr 21, 2018 7:50 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation [ENDORSED]
Replies: 3
Views: 165

Re: Rydberg Equation [ENDORSED]

I too am not sure what is expected of us, but just to be safe I would know the equation, since it was needed for a hw problem and we talked about it in our discussion sections. I would just know how to derive it from the equation he did give us in class ( E(n)=-Rh/(n^2) ) E(initial) = E(final) E(n(i...
by Natalie Noble 1G
Sat Apr 21, 2018 7:35 pm
Forum: DeBroglie Equation
Topic: Post-Assessment #34 [ENDORSED]
Replies: 5
Views: 171

Re: Post-Assessment #34 [ENDORSED]

This is awkward but you may want to recheck your calculations. The answer shouldn't be negative, it should be 1.00 x 10^5 m/s (if it were negative that would be an extremely slow electron). The reason 1.00 x 10^5 m/s makes sense is because the electron is moving slower that the speed of light, which...
by Natalie Noble 1G
Sat Apr 21, 2018 7:19 pm
Forum: Einstein Equation
Topic: Planck's Constant Value [ENDORSED]
Replies: 7
Views: 2755

Re: Planck's Constant Value [ENDORSED]

I don't think it makes a difference. If we are taking a test, they give us a page with formulas and constants so I would just use whatever is on that. Personally, I prefer to use 6.626 x 10^-34 because it has higher accuracy since it goes to more decimal places.
by Natalie Noble 1G
Sun Apr 15, 2018 3:52 pm
Forum: Photoelectric Effect
Topic: Practice Problem [ENDORSED]
Replies: 1
Views: 49

Re: Practice Problem [ENDORSED]

You are correct to use the formula E(k)=(1/2)(m(e-))(v(e-)^2) The problem gives you the velocity of the electron and you don’t need the work function they give you for this problem. The mass of an electron is a constant and it is: 9.10938 x 10^-31 kg Now you have all the parts for the formula and al...
by Natalie Noble 1G
Sun Apr 15, 2018 3:41 pm
Forum: Photoelectric Effect
Topic: Threshold Energy Definition
Replies: 3
Views: 321

Threshold Energy Definition

What is the formal definition of threshold energy/work function? I know how to use it in equations but I just would like to know the formal definition. I get it's something relating photons and electrons.
by Natalie Noble 1G
Sun Apr 15, 2018 2:57 pm
Forum: Limiting Reactant Calculations
Topic: Finding Excess Reactant [ENDORSED]
Replies: 2
Views: 484

Re: Finding Excess Reactant [ENDORSED]

First you find which is the limiting and excess reactant Take the initial mass of limiting reactant (most likely given to you in the problem) and find how much ER is needed to react all of the LR: (mass of LR) *(1 mol LR/molar mass LR) * ( __mol ER/ __mol LR) * (molar mass ER/1 mol ER) = the mass of...
by Natalie Noble 1G
Sun Apr 08, 2018 2:16 pm
Forum: Empirical & Molecular Formulas
Topic: Rounding molar ratios
Replies: 3
Views: 711

Re: Rounding molar ratios

General rounding rules are if you get 1.99 or .99 of anything you can just round up to the nearest whole number (1.99 becomes 2). However if it turns out to be a recognizable decimal such as .33 .66 .25 .5 etc you multiply it by whatever you need to get a whole number and you multiply the rest of yo...
by Natalie Noble 1G
Sun Apr 08, 2018 1:56 pm
Forum: Empirical & Molecular Formulas
Topic: Order of Elements in Empirical Formula [ENDORSED]
Replies: 4
Views: 684

Order of Elements in Empirical Formula [ENDORSED]

I understand how to find the ratios of elements for the Empirical Formula but I am having trouble knowing what order to write them in once I get those ratios. I know if carbon is present it goes first and is followed by hydrogen but I don't know if there is a rule to the order of the elements after ...
by Natalie Noble 1G
Sun Apr 08, 2018 1:35 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.5 [ENDORSED]
Replies: 1
Views: 140

Re: G.5 [ENDORSED]

Molarity = moles/volume You are given 2.111g Na2Co3 but to put it in the formula above you need to find how many moles there are of Na2Co3 N = m/M or Moles = mass/molar mass 105.99g/mol is the molar mass of Na2Co3 Moles = (2.111g) / ( 105.99g/mol) Moles = .0199 mol Now you have the moles of Na2Co3, ...

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