Search found 30 matches
- Fri Nov 30, 2018 11:30 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: sigma composition
- Replies: 2
- Views: 577
sigma composition
When writing the composition of a sigma bond, I understand that you write the atom involved in the bind, the hybridization according to the number of electron density around that atom, and include the number associated with the period of that element. For example, sigma( C 2sp2, ...). However if we ...
- Fri Nov 30, 2018 11:04 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Square Planar
- Replies: 12
- Views: 2013
Re: Square Planar
If you think of the structure of the square planar molecule, the lone pairs lie 180 degrees apart at the bottom and top of the structure and the four bonded atoms are in the equatorial plane in the form of a square. Generally a lone pair will distort the angles between the bonded atoms, however beca...
- Fri Nov 30, 2018 11:00 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Axial and equatorial atoms
- Replies: 2
- Views: 510
Re: Axial and equatorial atoms
Equatorial bonds are perpendicular to axis of the ring. Axial bonds are parallel to the axis of the ring.
- Wed Nov 28, 2018 6:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 4.13 homework
- Replies: 1
- Views: 258
4.13 homework
In question 4.13 6th edition the problem asks for VSEPR of I3^- (iodine 3, 1 negative charge). The lewis structure in the solution shows 2 bonds with 3 lone pairs. However, couldn't the lewis structure be 2 triple bonds and one lone pair, changing the shape to bent?
- Sun Nov 25, 2018 11:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: AXE vsepr
- Replies: 2
- Views: 293
AXE vsepr
I'm confused on the VSEPR of AXE. I'm assuming the electronic geometry is linear because it has 2 regions of electron density, but I'm confused about the molecular shape. Mozt of the VSEPR charts I saw online do not even have this classification. Does AXE exist and what is its molecular shape?
- Sun Nov 25, 2018 10:59 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trigonal Shape
- Replies: 3
- Views: 371
Re: Trigonal Shape
trigonal planar has 3 regions of electron density, while trigonal pyramidal has 4. Their hybridizations are sp2 and sp3 respectively. Trigonal pyramidal has alone pair attachment.
- Sun Nov 25, 2018 7:23 pm
- Forum: Lewis Acids & Bases
- Topic: How do we know something is a lewis acid or base?
- Replies: 4
- Views: 731
Re: How do we know something is a lewis acid or base?
Bases donate pairs of electrons and acids accept pairs of electrons. A Lewis acid is therefore any substance, such as the H+ ion, that can accept a pair of nonbonding electrons. In other words, a Lewis acid is an electron-pair acceptor. A Lewis base is any substance, such as the OH- ion, that can do...
- Sun Nov 25, 2018 7:17 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 4.19 6th edition
- Replies: 4
- Views: 474
Re: 4.19 6th edition
Remember that determining molecular shape is based on the number of regions of electron density around the central atom, not necessarily the number of elements associated with the ion.
- Sun Nov 25, 2018 7:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polarity
- Replies: 3
- Views: 376
Polarity
When analyzing a lewis structure of a given compound, what feature most obviously determines whether or not it is polar?
- Fri Nov 16, 2018 11:21 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Distance from Central Atom
- Replies: 8
- Views: 587
Re: Distance from Central Atom
The shaded triangle and the hatched triangle are opposites. Shaded illustrates a bond that is in front of the central atom, while hatched illustrates a bond behind the central atom.
- Fri Nov 16, 2018 11:17 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Octahedral
- Replies: 3
- Views: 534
Octahedral
Can an octahedral also be classified as square bipyramidal? In the same way that a trigonal bipyramidal is named fittingly for its shape, couldn't an octahedral be named this?
- Fri Nov 16, 2018 11:12 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Models with 5 bonding regions
- Replies: 3
- Views: 375
Re: VSEPR Models with 5 bonding regions
When you have bonding pairs including a lone pair, for example four bonding pairs and one lone pair, the correct shape is that with the least amount of repulsion (more stable). This may be why the trend you're talking about is broken. 5 pairs electrons are located in trigonal bipyramidal geometry. L...
- Fri Nov 09, 2018 11:12 am
- Forum: Lewis Structures
- Topic: Electrons on Least EN Atom
- Replies: 3
- Views: 547
Re: Electrons on Least EN Atom
Putting electrons on the central atom all depends on the total valence electrons and the position of the central atom on the periodic table. If the central atom is in period 3 it has an exception to the octet rule due to the 3d orbital being empty, in these cases it's likely you would put lone pair ...
- Fri Nov 09, 2018 11:07 am
- Forum: Lewis Structures
- Topic: Placement of Elements?
- Replies: 5
- Views: 606
Re: Placement of Elements?
Based on what we learned today, a central atom with 3 bonding pairs would be trigonal planar, with all elements havong angles of 120 degrees.
- Fri Nov 09, 2018 11:02 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Boiling point
- Replies: 12
- Views: 2192
Re: Boiling point
I have in my notes that Instantaneous dipoles in two nearby rod shaped molecules are closer and therefore stronger than those in two nearby spherical shapes . Hope this helps!
- Fri Nov 02, 2018 11:26 am
- Forum: *Shrodinger Equation
- Topic: Midterm
- Replies: 6
- Views: 1023
Re: Midterm
Schrodingers Eqaution is an equation regarding wavelength. ψ= wave function (orbital) representing e- Represents the height of a wave at position x,y,z ψ^2 represents the probability of finding an e- I wouldnt be surprised if there was a question on the midterm regarding this relation to orbitals or...
- Fri Nov 02, 2018 11:19 am
- Forum: Octet Exceptions
- Topic: The center atom
- Replies: 20
- Views: 3305
Re: The center atom
Cl is not at the center of the Lewis Structure for HClO, O is at the center and O is most electronegative
- Fri Nov 02, 2018 11:05 am
- Forum: Dipole Moments
- Topic: Midterm Dipole Moments?
- Replies: 4
- Views: 431
Re: Midterm Dipole Moments?
It is my understanding that the lectures corresponding to the midterm ended on Wednesday October 31, so I don't believe they are.
- Fri Oct 26, 2018 11:24 am
- Forum: *Shrodinger Equation
- Topic: Schrodinger and quantum numbers
- Replies: 3
- Views: 680
Re: Schrodinger and quantum numbers
ψ= wave function (orbital) representing e-
Represents the height of a wave at position x,y,z
ψ^2 represents the probability of finding an e-
Represents the height of a wave at position x,y,z
ψ^2 represents the probability of finding an e-
- Fri Oct 26, 2018 11:22 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: atomic orbital and molecular orbital?
- Replies: 2
- Views: 453
Re: atomic orbital and molecular orbital?
Atomic spectra (electronic transitions between atomic orbitals) apply to molecular spectra (electronic transitions between molecular orbitals) Electrons in both atoms and molecules can be excited to higher energy states (n=1,2, etc.) so when they emit electromagnetic radition, it gives detail to spe...
- Fri Oct 26, 2018 11:17 am
- Forum: DeBroglie Equation
- Topic: wavelike properties
- Replies: 4
- Views: 650
Re: wavelike properties
Although they may not be detectable, the wavelength can be calculated. A car for example, does have mass and could have velocity and therefore could apply to the equation, the wavelength will not be detectable however.
- Fri Oct 19, 2018 11:31 am
- Forum: DeBroglie Equation
- Topic: Wavelength unit conversion
- Replies: 4
- Views: 452
Wavelength unit conversion
When calculating wavelength using the formula wavelength= h/(mass x velocity), I'm uncertain what units my given mass should be? I noticed that the Joules contains the units kg, so would that mean my mass needs to be in units of kg to cancel out, resulting in a end result unit of wavelength mass? Or...
- Fri Oct 19, 2018 11:19 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: How to Find the Number of Orbitals
- Replies: 3
- Views: 299
Re: How to Find the Number of Orbitals
Start with identifying the principle quantum number (n) to determine the shell
Next identify the shape using the allowed values: l= 0,1,2,..., n-1
Use the l you calculated to find the different orbitals of a subshell (ml)
ml has the allowed values: ml= l, l-1, ..., -l
Next identify the shape using the allowed values: l= 0,1,2,..., n-1
Use the l you calculated to find the different orbitals of a subshell (ml)
ml has the allowed values: ml= l, l-1, ..., -l
- Fri Oct 19, 2018 11:11 am
- Forum: DeBroglie Equation
- Topic: Momentum of protons
- Replies: 2
- Views: 227
Momentum of protons
After reviewing my lecture notes, I'm having trouble understanding how protons have momentum if they don't have mass?
- Thu Oct 11, 2018 12:36 pm
- Forum: Photoelectric Effect
- Topic: Threshold energy
- Replies: 5
- Views: 4488
Threshold energy
I have in my notes that (E=hv) - work function = (Ek= 1/2me-ve^2), however there was mention of threshold energy that I didn't quite understand. What is this threshold energy and how does it factor in to the above equation?
- Thu Oct 11, 2018 12:31 pm
- Forum: Limiting Reactant Calculations
- Topic: Percent Yield [ENDORSED]
- Replies: 13
- Views: 2894
Re: Percent Yield [ENDORSED]
Theoretical yield can be calculated by 1. balancing chemical equation 2. finding moles of reactant 3. use molar ratio of reactants from balanced equation to find how many moles it takes each reactant to use up the other 4. the reactant with not enough moles to use up the other is the limiting reacta...
- Thu Oct 11, 2018 12:23 pm
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reagent
- Replies: 10
- Views: 1613
Re: Limiting Reagent
After calculating the moles of each reactant, use the lowest number of moles to help find the limiting reagent. Alternatively, use a molar ratio from the balanced chemical equation to determine how much of each product is needed to use up the others, the reactant without enough moles to use up the o...
- Fri Oct 05, 2018 1:14 am
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reactant
- Replies: 8
- Views: 1299
Re: Limiting Reactant
In regards to a limiting reactant problem, you won't always be asked to calculate percent yield, as it may just be asking you to determine whether a limiting reactant is present. However, if asked to find percent yield, the most efficient way in my opinion is as follows: 1. Balance equation 2. Calcu...
- Thu Oct 04, 2018 11:15 pm
- Forum: SI Units, Unit Conversions
- Topic: Hecto as SI Unit [ENDORSED]
- Replies: 4
- Views: 269
Hecto as SI Unit [ENDORSED]
After reviewing SI units in lecture today, I realized that Hecto (10^2) was not listed. Does this mean this unit is rarely used, or not even an SI unit at all?
- Thu Oct 04, 2018 11:11 pm
- Forum: Significant Figures
- Topic: Number of Sig Fig
- Replies: 8
- Views: 629
Re: Number of Sig Fig
The rule for trailings zeroes for sig figs can be a little misleading, but the best indicator is always the presence or absence of a decimal point. Lack of a decimal point can lead to uncertainty, but any time there is a decimal point, count the trailing zeroes regardless of whether they are before ...