Search found 30 matches

by Stephen Sirmay 1I
Fri Nov 30, 2018 11:30 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: sigma composition
Replies: 2
Views: 230

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 ...
by Stephen Sirmay 1I
Fri Nov 30, 2018 11:04 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Square Planar
Replies: 12
Views: 235

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...
by Stephen Sirmay 1I
Fri Nov 30, 2018 11:00 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Axial and equatorial atoms
Replies: 2
Views: 58

Re: Axial and equatorial atoms

Equatorial bonds are perpendicular to axis of the ring. Axial bonds are parallel to the axis of the ring.
by Stephen Sirmay 1I
Wed Nov 28, 2018 6:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.13 homework
Replies: 1
Views: 46

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?
by Stephen Sirmay 1I
Sun Nov 25, 2018 11:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AXE vsepr
Replies: 2
Views: 49

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?
by Stephen Sirmay 1I
Sun Nov 25, 2018 10:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Shape
Replies: 3
Views: 64

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.
by Stephen Sirmay 1I
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: 112

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...
by Stephen Sirmay 1I
Sun Nov 25, 2018 7:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.19 6th edition
Replies: 4
Views: 150

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.
by Stephen Sirmay 1I
Sun Nov 25, 2018 7:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 3
Views: 76

Polarity

When analyzing a lewis structure of a given compound, what feature most obviously determines whether or not it is polar?
by Stephen Sirmay 1I
Fri Nov 16, 2018 11:21 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Distance from Central Atom
Replies: 8
Views: 118

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.
by Stephen Sirmay 1I
Fri Nov 16, 2018 11:17 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Octahedral
Replies: 3
Views: 83

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?
by Stephen Sirmay 1I
Fri Nov 16, 2018 11:12 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Models with 5 bonding regions
Replies: 3
Views: 66

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...
by Stephen Sirmay 1I
Fri Nov 09, 2018 11:12 am
Forum: Lewis Structures
Topic: Electrons on Least EN Atom
Replies: 3
Views: 93

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 ...
by Stephen Sirmay 1I
Fri Nov 09, 2018 11:07 am
Forum: Lewis Structures
Topic: Placement of Elements?
Replies: 5
Views: 110

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.
by Stephen Sirmay 1I
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: 274

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!
by Stephen Sirmay 1I
Fri Nov 02, 2018 11:26 am
Forum: *Shrodinger Equation
Topic: Midterm
Replies: 6
Views: 387

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...
by Stephen Sirmay 1I
Fri Nov 02, 2018 11:19 am
Forum: Octet Exceptions
Topic: The center atom
Replies: 20
Views: 617

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
by Stephen Sirmay 1I
Fri Nov 02, 2018 11:05 am
Forum: Dipole Moments
Topic: Midterm Dipole Moments?
Replies: 4
Views: 96

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.
by Stephen Sirmay 1I
Fri Oct 26, 2018 11:24 am
Forum: *Shrodinger Equation
Topic: Schrodinger and quantum numbers
Replies: 3
Views: 312

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-
by Stephen Sirmay 1I
Fri Oct 26, 2018 11:22 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: atomic orbital and molecular orbital?
Replies: 2
Views: 185

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...
by Stephen Sirmay 1I
Fri Oct 26, 2018 11:17 am
Forum: DeBroglie Equation
Topic: wavelike properties
Replies: 4
Views: 300

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.
by Stephen Sirmay 1I
Fri Oct 19, 2018 11:31 am
Forum: DeBroglie Equation
Topic: Wavelength unit conversion
Replies: 4
Views: 99

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...
by Stephen Sirmay 1I
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: 98

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
by Stephen Sirmay 1I
Fri Oct 19, 2018 11:11 am
Forum: DeBroglie Equation
Topic: Momentum of protons
Replies: 2
Views: 62

Momentum of protons

After reviewing my lecture notes, I'm having trouble understanding how protons have momentum if they don't have mass?
by Stephen Sirmay 1I
Thu Oct 11, 2018 12:36 pm
Forum: Photoelectric Effect
Topic: Threshold energy
Replies: 5
Views: 259

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?
by Stephen Sirmay 1I
Thu Oct 11, 2018 12:31 pm
Forum: Limiting Reactant Calculations
Topic: Percent Yield [ENDORSED]
Replies: 13
Views: 787

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...
by Stephen Sirmay 1I
Thu Oct 11, 2018 12:23 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reagent
Replies: 10
Views: 508

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...
by Stephen Sirmay 1I
Fri Oct 05, 2018 1:14 am
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant
Replies: 8
Views: 214

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...
by Stephen Sirmay 1I
Thu Oct 04, 2018 11:15 pm
Forum: SI Units, Unit Conversions
Topic: Hecto as SI Unit [ENDORSED]
Replies: 4
Views: 70

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?
by Stephen Sirmay 1I
Thu Oct 04, 2018 11:11 pm
Forum: Significant Figures
Topic: Number of Sig Fig
Replies: 8
Views: 156

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 ...

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