Search found 51 matches

by LReedy_3I
Fri Dec 06, 2019 10:33 am
Forum: Sigma & Pi Bonds
Topic: Sigma & Pi Bonds Role in structure and shape
Replies: 2
Views: 119

Re: Sigma & Pi Bonds Role in structure and shape

I think the biggest thing is that pi bonds can't rotate, so molecules with pi bonds can't change shape, and can't rotate to bond with things unless the pi bond is broken.
by LReedy_3I
Fri Dec 06, 2019 10:26 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelation
Replies: 4
Views: 62

Re: Chelation

Chelating is a specific shape polydentate complexes can form, in which two bonding sites are positioned in order to be able to form a ring. It's common in nature, and I think some chelating molecules (EDTA) can be used to purify water because they can bond cations tightly.
by LReedy_3I
Fri Dec 06, 2019 10:20 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Atoms in the same plane
Replies: 1
Views: 81

Re: Atoms in the same plane

I think it has to do with the types of bonds holding them. Sigma bonds are able to rotate freely, but pi bonds cannot rotate.
by LReedy_3I
Fri Dec 06, 2019 10:19 am
Forum: Trends in The Periodic Table
Topic: Atomic Radius vs Ionic Radius
Replies: 3
Views: 138

Re: Atomic Radius vs Ionic Radius

Atomic radius is half the difference between neighboring atoms, while ionic radius is one half the distance of two atoms joined by an ionic bond.
by LReedy_3I
Fri Dec 06, 2019 10:17 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Resonance and Acidity
Replies: 2
Views: 54

Re: Resonance and Acidity

Greater electronegative atoms delocalize the charge more effectively across the molecule, and as a result the bonds are easier to break bonds, and therefore are more acidic.
by LReedy_3I
Fri Nov 29, 2019 2:25 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Inorganic vs Organic Acids
Replies: 3
Views: 53

Re: Inorganic vs Organic Acids

Inorganic acids also usually involve more electronegative atoms
by LReedy_3I
Fri Nov 29, 2019 2:14 pm
Forum: Lewis Acids & Bases
Topic: Lecture Question
Replies: 2
Views: 38

Re: Lecture Question

Cl is better at delocalizing the charge of the molecule. The high electronegativity of Cl stabilizes the negative charge.
by LReedy_3I
Fri Nov 29, 2019 2:11 pm
Forum: Bronsted Acids & Bases
Topic: Weak Acid Strength
Replies: 3
Views: 44

Re: Weak Acid Strength

Following periodic trends is a good way to determine this. Atoms with smaller radii will form weaker acids because the bonds are stronger.
by LReedy_3I
Fri Nov 29, 2019 2:08 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Carboxylic Acids
Replies: 5
Views: 68

Re: Carboxylic Acids

Additionally, the bond strength affects an acids strength, because strong acids will have weaker bonds that allow them to lose protons more easily, and fully dissociates in water.
by LReedy_3I
Fri Nov 29, 2019 2:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: polydentate and shape
Replies: 3
Views: 40

Re: polydentate and shape

I think most polydentates form chelate shapes, so if you see this shape there is more than one bonding site being occupied. I'm not sure how to determine the exact number.
by LReedy_3I
Wed Nov 20, 2019 5:46 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen bonding
Replies: 2
Views: 38

Re: Hydrogen bonding

In the example of water, the positive H atoms can bond to either pair of lone electrons, meaning there are four points that can participate in hydrogen bonding.
by LReedy_3I
Wed Nov 20, 2019 5:43 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: IMFs and properties
Replies: 2
Views: 44

Re: IMFs and properties

Stronger IMFs mean a higher melting point, so higher london forcers would increase boiling point. But London forces are sill weak compared to dipole-dipole or hydrogen bonding.
by LReedy_3I
Wed Nov 20, 2019 5:40 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: cis- and trans- molecules
Replies: 2
Views: 65

Re: cis- and trans- molecules

Cis- molecules refer to a layout of a molecule in which like atoms are on the same side, while trans- refers to when they are on opposite sides of the molecule.
by LReedy_3I
Wed Nov 20, 2019 5:38 pm
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 Points
Replies: 7
Views: 60

Re: Boiling Points

The shape affects the type and strength of forces in the molecules. Because NO2 is polar, it has dipole-dipole interactions rather than just London forces, and these stronger forces make the boiling point higher
by LReedy_3I
Wed Nov 20, 2019 5:06 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: 3F.5 part c)
Replies: 2
Views: 43

3F.5 part c)

In part C of question 3F.5, why exactly are the London forces in CHI3 stronger than those in CHF3? Is it because of the size of the atoms or the polarizability?
by LReedy_3I
Thu Nov 14, 2019 1:50 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Polar Vs Nonpolar
Replies: 7
Views: 82

Re: Polar Vs Nonpolar

Also, if the shape/geometry of a molecule is even (like CH4 where they are spread equally around the central atom) it will not be polar because the charge/electronegativity is equal on all sides
by LReedy_3I
Thu Nov 14, 2019 1:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance VSEPR
Replies: 6
Views: 66

Re: Resonance VSEPR

It doesn't matter because all bonds are treated as equivalent, and the resonance would affect all the bonds equally in a real molecule anyway
by LReedy_3I
Thu Nov 14, 2019 1:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Question 2.E.7
Replies: 3
Views: 63

Re: Question 2.E.7

There is no calculation involved, just recognizing that because it is a central atom with 5 regions of electron density, it is a trigonal pyramidal shape, and so all the OSCL bonds would be about 109.5 degrees
by LReedy_3I
Thu Nov 14, 2019 1:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 10
Views: 106

Re: bond angles

Being able to visualize how the molecules look 3 dimensionally is really helpful, and being able to apply that to the Lewis structure to understand where in the molecule each atom it is. There are diagrams in the book for each shape we've talked about
by LReedy_3I
Thu Nov 14, 2019 1:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.7
Replies: 2
Views: 35

2E.7

For part c), would the bonds be exactly 109.5 degrees because it's trigonal pyramidal, or does the fact that its 3 bonds and a lone pair affect the angle?
by LReedy_3I
Thu Nov 07, 2019 10:00 pm
Forum: Octet Exceptions
Topic: radicals
Replies: 3
Views: 69

Re: radicals

I have heard that one strategy when drawing a Lewis structure for a radical is to start filling in electrons on the most electronegative atom first, and then moving on from there, so the least electronegative atom gets the radical because the more electronegative atoms want to pull the electrons more.
by LReedy_3I
Thu Nov 07, 2019 9:57 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Determining which bonds are more polar
Replies: 4
Views: 83

Re: Determining which bonds are more polar

The difference in electronegativity is the main thing that makes Mg-O more polar. This difference causes the electrons to be more strongly pulled to one nucleus rather than the other, giving the bond ionic character and making it polar.
by LReedy_3I
Thu Nov 07, 2019 9:54 pm
Forum: Dipole Moments
Topic: Induced Dipole
Replies: 4
Views: 40

Re: Induced Dipole

induced dipole happens in London Dispersion forces, but it is very weak and short lived. It is much stronger in a dipole-induced-dipole scenario, where a polar molecule interacts with a non-polar molecule and creates an induced dipole.
by LReedy_3I
Thu Nov 07, 2019 9:51 pm
Forum: Octet Exceptions
Topic: Homework Problem 2.C.3
Replies: 2
Views: 57

Re: Homework Problem 2.C.3

To go about solving all of these, you would first draw a structure that obeys the octet rule, and then use double bonds to lower the formal charges to as close to zero as they can be. Then draw resonance structures for all of them.
by LReedy_3I
Thu Nov 07, 2019 9:45 pm
Forum: Electronegativity
Topic: How to compare electronegativity difference
Replies: 2
Views: 57

Re: How to compare electronegativity difference

You have to use the periodic trend of electronegativity. The trend is the same as ionization energy (growing left to right, bottom to top). Comparing which elements are farther apart will be the way to tell which has the larger electronegativity difference.
by LReedy_3I
Thu Oct 31, 2019 2:37 pm
Forum: Lewis Structures
Topic: valence electrons of nonmetals
Replies: 3
Views: 37

Re: valence electrons of nonmetals

You can also count the number of electrons in the highest s and p orbitals to find the number of valence electrons
by LReedy_3I
Thu Oct 31, 2019 2:34 pm
Forum: Ionic & Covalent Bonds
Topic: 2A 1
Replies: 5
Views: 55

Re: 2A 1

It's because the d block is valence in c), but in a) it is full, so the energy is lower and it is not a valence shell. In a), only the s and p orbitals contain the valence electrons.
by LReedy_3I
Thu Oct 31, 2019 12:09 pm
Forum: Ionic & Covalent Bonds
Topic: D-orbital electrons counting as valence or not.
Replies: 2
Views: 55

Re: D-orbital electrons counting as valence or not.

I think it has to do with the d orbital being a lower energy level when it is full, so its no longer a valence shell.
by LReedy_3I
Thu Oct 31, 2019 11:51 am
Forum: Ionic & Covalent Bonds
Topic: 2A 19b
Replies: 3
Views: 43

Re: 2A 19b

The two aren't the same because once one valence shell is empty, the next shell becomes the valence shell. The only time an ion would have zero valence electrons is if it lost all its electrons, like in the case of H+
by LReedy_3I
Thu Oct 31, 2019 11:50 am
Forum: Ionic & Covalent Bonds
Topic: Textbook question 2A.19 part e
Replies: 2
Views: 29

Re: Textbook question 2A.19 part e

4s has a higher energy than 3d, so the s orbital loses its electrons first.
by LReedy_3I
Thu Oct 24, 2019 9:37 pm
Forum: Trends in The Periodic Table
Topic: types of radii
Replies: 4
Views: 55

Re: types of radii

atomic radii is calculate by half the distance between two nuclei, and the other two are the same concept except for elements in ionic and covalent bonds.While the trend for all of these is the same, it isn't systematic in the d-block. Also, atomic radii of cations are always smaller than their pare...
by LReedy_3I
Thu Oct 24, 2019 9:31 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.15
Replies: 3
Views: 51

Re: 1D.15

The number is the principle quantum number, and the letter corresponds to the orbital angular momentum quantum number. If l=0 its s, l=1 its p, if l=2 its d, and if l=3 its f. From there you can find the answers for all of them.
by LReedy_3I
Thu Oct 24, 2019 9:23 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations
Replies: 2
Views: 53

Re: Electron Configurations

It requires less energy for the electrons to be opposite, so because they are both up it must be excited.
by LReedy_3I
Thu Oct 24, 2019 9:22 pm
Forum: Trends in The Periodic Table
Topic: Question 1F.3
Replies: 5
Views: 76

Re: Question 1F.3

Although they have the same number of electrons, the charge is different, and the interaction with the nucleus is different because some will have more protons and hold the electrons tighter.
by LReedy_3I
Thu Oct 24, 2019 9:20 pm
Forum: Ionic & Covalent Bonds
Topic: Understanding the electron affinity equation
Replies: 3
Views: 62

Re: Understanding the electron affinity equation

A higher electron affinity means a lot of energy will be released if an electron is added. Because of this, high EA means it's more likely to add an electron.
by LReedy_3I
Thu Oct 17, 2019 8:47 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1D.25
Replies: 2
Views: 22

Re: 1D.25

4g and 2d cannot exist, because the value of l can be 0,1,...n-1, so for both of these the l value is too high to exist for that n.
by LReedy_3I
Thu Oct 17, 2019 6:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: #1D.21
Replies: 2
Views: 43

Re: #1D.21

The notation is first the n value, and then s, p, d, f, ect based on the l value (eg l=0 is s). The number of orbitals is found by options for the magnetic quantum number, which are -l,...0,....+l, so they change based on the l value
by LReedy_3I
Thu Oct 17, 2019 6:49 pm
Forum: *Shrodinger Equation
Topic: Electron Distribution Definition
Replies: 4
Views: 103

Re: Electron Distribution Definition

It's the electron density, which is what is drawn in diagrams
by LReedy_3I
Thu Oct 17, 2019 6:39 pm
Forum: Quantum Numbers and The H-Atom
Topic: Schrodinger's Wave Equation
Replies: 2
Views: 39

Re: Schrodinger's Wave Equation

A more complicated formula is needed for many electron atoms because the electrons shield other electrons in the atom, so the energies of the different levels are different.
by LReedy_3I
Thu Oct 17, 2019 6:33 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital shapes
Replies: 3
Views: 56

Re: Orbital shapes

Also, the number of nodal planes is related to the value of l. As it increases, there are more conical nodes.
by LReedy_3I
Thu Oct 10, 2019 2:10 pm
Forum: Properties of Light
Topic: Problem 1A, #15
Replies: 3
Views: 50

Re: Problem 1A, #15

When plugging into the equation, I found it was much easier if I used the fact that the emission was in the UV region to assume that it was part of the Lyman series and n1=1. From there I plugged into the equation and solved for n2.
by LReedy_3I
Thu Oct 10, 2019 2:04 pm
Forum: Properties of Light
Topic: Problem 1A.15 and the Rydberg formula
Replies: 3
Views: 49

Re: Problem 1A.15 and the Rydberg formula

Because the wavelength is in the UV spectrum, I knew it was in the Lyman series and so at some point n = 1. Then, using c=λv, I calculated the frequency to be 2.924x10^15 Hz. From there it was just plugging all these numbers into the Rydberg equation and solving for n1.
by LReedy_3I
Thu Oct 10, 2019 1:58 pm
Forum: Properties of Light
Topic: Hw Question 1A.9
Replies: 5
Views: 78

Re: Hw Question 1A.9

All of the information for this problem can be found using E = hv and λv = c. First, find the frequency using E = hv, by plugging in planck's constant and 3.3x10^-19 J for E. This gives the frequency as 5.0x10^14Hz, which can then be plugged into λv=c to find the wavelength (600nm).
by LReedy_3I
Wed Oct 09, 2019 8:52 pm
Forum: Properties of Light
Topic: Double-slit experiment
Replies: 2
Views: 51

Re: Double-slit experiment

The double slit experiment demonstrates light behaving as a wave. When diffraction patterns appear when particles such electrons pass through a crystal it also demonstrates them acting as a wave.
by LReedy_3I
Wed Oct 09, 2019 5:17 pm
Forum: Properties of Light
Topic: 1A.15
Replies: 2
Views: 54

1A.15

Is question 1A.15 referring to an emission or absorption spectrum, and would it affect the final answer? I got n(final) to be 3, but if it is an emission spectrum would this be n(initial) = 3 and n(final) = 1?
by LReedy_3I
Thu Oct 03, 2019 12:34 pm
Forum: Molarity, Solutions, Dilutions
Topic: Textbook question G25
Replies: 2
Views: 34

Re: Textbook question G25

When diluting a solution, the moles of the solute always remain the same. So as the volume continues to rise, there are fewer and fewer mols per liter, and by 90 doublings there is almost no solute in 10 mL of solution.
by LReedy_3I
Thu Oct 03, 2019 12:24 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Avogadro's Number
Replies: 8
Views: 197

Re: Avogadro's Number

Yes, Avogadro's number is the number of atoms in one mole. For E7, I divided 2.1x10^9 atoms of carbon by 6.022x10^23 to determine the number of moles to be 3.5x10^-15 mol.
by LReedy_3I
Thu Oct 03, 2019 12:21 pm
Forum: Limiting Reactant Calculations
Topic: Fundamentals M7
Replies: 3
Views: 60

Re: Fundamentals M7

I found the limiting reactant in the same way, I don't know of a faster way than using the molar masses to convert to mols. I also had 37.06 kg of B as the product of the reaction, using the 2:3 molar ratio and the molar mass of Boron.
by LReedy_3I
Thu Oct 03, 2019 12:14 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Accuracy vs. Precision
Replies: 3
Views: 86

Re: Accuracy vs. Precision

Precision describes how close a series of measurements are to each other, while accuracy describes how close measurements are to the true value. Additionally, precision and accuracy can reflect different types of error. For example, high precision but low accuracy would be a high amount of systemati...
by LReedy_3I
Wed Oct 02, 2019 2:01 pm
Forum: Molarity, Solutions, Dilutions
Topic: Please clarify what M means
Replies: 5
Views: 90

Re: Please clarify what M means

Capital M is molarity, so mol/L
by LReedy_3I
Wed Oct 02, 2019 1:25 pm
Forum: Limiting Reactant Calculations
Topic: Homework M11
Replies: 4
Views: 59

Re: Homework M11

I first converted P4 and O2 to moles, giving me 0.047 moles of P4 and 0.18 moles of 02. Because the molar ration is 1:3, 0.138 moles O2 are needed to react with 0.047 moles of P4, leaving 0.039 moles oxygen for the second reaction, and 0.047 moles of P4O6. The molar ratio is 1 mol P4O6 : 2 mol O2. T...

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