Search found 36 matches

by Alex Hitti 3E
Wed Nov 13, 2019 4:28 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: Similar terms
Replies: 3
Views: 20

Re: Similar terms

London Dispersion Forces (and van der Waals) are temporary attractive forces that occur when very slight opposing charges are adjacent for a brief amount of time to create short-lived dipoles. Induced dipole - induced dipoles can be referred to as LDF/van der Waals because of this.
by Alex Hitti 3E
Wed Nov 13, 2019 4:10 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 Point
Replies: 6
Views: 40

Re: Boiling Point

Concept: The stronger the bond, the higher the boiling point.

From highest to lowest boiling point:

ion - ion
ion - dipole
hydrogen bond
dipole - dipole
induced dipole - dipole
induced dipole - induced dipole
by Alex Hitti 3E
Wed Nov 13, 2019 4:00 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: Intermolecular Forces vs Bonding???
Replies: 5
Views: 32

Re: Intermolecular Forces vs Bonding???

Ion-dipole, LDF, and dipole-dipole, etc are intermolecular forces: forces between two different molecules meanwhile polar/nonpolar are intramolecular forces (within the molecule).
Also, dipole-dipole: interactions between 2 polar molecules
LDF: interactions between 2 non polar molecules
by Alex Hitti 3E
Wed Nov 13, 2019 3:51 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: Dipole-Dipole Moments
Replies: 3
Views: 19

Re: Dipole-Dipole Moments

The larger the molecule means a greater amount of electrons to be polarized, and therefore a stronger induced dipole-dipole moment?

Yes, the molecular size is proportional to the strength of the dipole moment. As one increases, so does the others.
by Alex Hitti 3E
Wed Nov 13, 2019 3:49 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: H-bonding & Dipole-Dipole (Problem 3F.1)
Replies: 4
Views: 30

Re: H-bonding & Dipole-Dipole (Problem 3F.1)

Yes! Hydrogen bonding is a special form of dipole-dipole forces with hydrogen bonding exhibiting stronger intermolecular forces. This is because H (low EN) is paired with N,O, or F (high EN)
by Alex Hitti 3E
Sun Nov 10, 2019 1:20 am
Forum: Dipole Moments
Topic: Hydrogen Bonds, Electronegativity
Replies: 1
Views: 10

Re: Hydrogen Bonds, Electronegativity

A Chlorine-Hydrogen bond cannot form hydrogen bonds because Cl has too large of a radius, thus creating an electron density not sufficient enough to form Hydrogen bonding.
by Alex Hitti 3E
Sun Nov 10, 2019 1:15 am
Forum: Electronegativity
Topic: Electronegativity and hydrogen bonds (3F.11)
Replies: 2
Views: 33

Re: Electronegativity and hydrogen bonds (3F.11)

HNO2 is the only ones that will form Hydrogen bonds because there is a greater electronegativity difference between O and H thus making it polar / able to form H-bonds. In the case of Br, Br is too large to have enough electronegativity to pull the electrons more than the H can. H has to bind to a h...
by Alex Hitti 3E
Sun Nov 10, 2019 1:09 am
Forum: Bond Lengths & Energies
Topic: Bond Lengths
Replies: 8
Views: 29

Re: Bond Lengths

Double bonds are shorter in length than single bonds because they are stronger and harder to break apart due to the atoms sharing more electrons and a greater attraction.
by Alex Hitti 3E
Sun Nov 10, 2019 1:06 am
Forum: Dipole Moments
Topic: Polar
Replies: 9
Views: 32

Re: Polar

How do you know if a molecule is polar or not so you can state whether it is a dipole-dipole or london dispersion? A dipole-dipole interaction between molecules alludes that the molecule is polar while london dispersion forces alludes to the molecular interactions being non polar. An interaction, in...
by Alex Hitti 3E
Sun Nov 10, 2019 1:01 am
Forum: Sigma & Pi Bonds
Topic: Triple bond?
Replies: 18
Views: 465

Re: Triple bond?

A triple bond consists of one sigma bond and one pi bond
by Alex Hitti 3E
Fri Nov 01, 2019 6:58 pm
Forum: Sigma & Pi Bonds
Topic: Difference between sigma and pi bonds
Replies: 4
Views: 37

Re: Difference between sigma and pi bonds

Sigma bonds are the initial bond between 2 atoms and as more bonds (double & triple bonds) form, each bond (except for one) is considered an added pi bond. for example, a double bond would be 1 sigma bond and 1 pi bond; and a triple bond would be 1 sigma bond and 2 pi bonds. sigma bonds are also...
by Alex Hitti 3E
Fri Nov 01, 2019 6:53 pm
Forum: Lewis Structures
Topic: Expanded Valence Shells
Replies: 4
Views: 18

Re: Expanded Valence Shells

If an atom has an incomplete d and 3(+)p orbital(s) in period 3 and down, they can have an expanded valence shell. In the Lewis dot diagram, the number of electrons do not really go past 12, which fortunately helps for space & convenience's sake.
by Alex Hitti 3E
Fri Nov 01, 2019 6:40 pm
Forum: Octet Exceptions
Topic: Octet Exception
Replies: 3
Views: 20

Re: Octet Exception

No, we don't have to memorize the octet exceptions. But it's good to know (not relating to "exceptions") that only atoms in row 2&3 maxes at 8 valence electrons because in row 4, for example, they have more space in their d block.
by Alex Hitti 3E
Fri Nov 01, 2019 6:27 pm
Forum: Electronegativity
Topic: Electronegativity vs. Electron Affinity
Replies: 7
Views: 39

Re: Electronegativity vs. Electron Affinity

Electronegativity is the tendency to gain an electron meanwhile electron affinity is the energy released when an electron is transferred to an anion
by Alex Hitti 3E
Fri Nov 01, 2019 6:24 pm
Forum: Octet Exceptions
Topic: More than 8 valence e-
Replies: 8
Views: 45

Re: More than 8 valence e-

Only the 2nd row in the periodic table can have a maximum of 8 valence electrons because it has the 2s and 2p orbitals
by Alex Hitti 3E
Wed Oct 23, 2019 2:11 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs covalent
Replies: 8
Views: 221

Re: Ionic vs covalent

In a simpler observation (not including any calculations), ionic bonds are bonds between a metal and nonmetal where electrons are donated/transferred. Meanwhile, covalent bonds are bonds between 2 non-metals where electrons are shared. Ionic bonds also tend to have a high boiling point and a large p...
by Alex Hitti 3E
Wed Oct 23, 2019 2:04 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs Covalent
Replies: 29
Views: 277

Re: Ionic vs Covalent

In natural life, covalent bonds are stronger than ionic bonds due to the natural aqueous state that surrounds us. Because ionic bonds become weak when placed in water/polar-aqueous solution. In a theoretical "dry/non-aqueous" world, ionic bonds are stronger than covalent bonds. In other wo...
by Alex Hitti 3E
Wed Oct 23, 2019 2:01 pm
Forum: Ionic & Covalent Bonds
Topic: Back and Fourth Arrows
Replies: 6
Views: 201

Re: Back and Fourth Arrows

Double headed arrows is the symbol that implies that the reaction is reversible. If an arrow is pointing only one way then that implies that the reaction is nonreversible.
by Alex Hitti 3E
Wed Oct 23, 2019 1:59 pm
Forum: Ionic & Covalent Bonds
Topic: Xenon -- why is it the only noble gas that can form bonds?
Replies: 4
Views: 204

Re: Xenon -- why is it the only noble gas that can form bonds?

Xe can form bonds because it has a very large atomic radius compared to other noble gases meaning that the ionization energy of the atom for the outermost electrons is relatively minimal, minimal enough to allow it to create bonds with atoms that have relatively high electronegativity.
by Alex Hitti 3E
Wed Oct 23, 2019 1:55 pm
Forum: Ionic & Covalent Bonds
Topic: Difference Between Ionic and Covalent
Replies: 8
Views: 261

Re: Difference Between Ionic and Covalent

Ionic bonds are bonds between a metal (cation) and a nonmetal (anion) and the cation donates the electron to the anion because of the large difference in electronegativity and ionization energy. Meanwhile, covalent bonds are between two nonmetals and they share the electron(s) by the electron transf...
by Alex Hitti 3E
Fri Oct 18, 2019 11:32 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Best Way To Study?
Replies: 53
Views: 203

Re: Best Way To Study?

It tends to depend on personal preferences and through trying different strategies to see which one clicks the most. Personally, what really helps me is going over youtube videos/his modules and doing many practice problems to get the routines down and know when to use which formula depending on wha...
by Alex Hitti 3E
Fri Oct 18, 2019 11:27 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: heisenberg, calculating kinetic energy
Replies: 3
Views: 25

Re: heisenberg, calculating kinetic energy

I think it isn't working because there is a small error in your formula.
The equation for kinetic energy: KE = (0.5)*mass*velocity^2.
Also, another equation you will need later on: ΔxΔp >= h/(4pi)
by Alex Hitti 3E
Fri Oct 18, 2019 11:17 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Why divide h by 4pi?
Replies: 5
Views: 39

Re: Why divide h by 4pi?

Scientists found out that 4pi is a constant that is consistent whenever using the formula. If you want a more specific answer, Dr. Lavelle said that to discover this we have to fully understand the derivation of the equation which is a long and tedious process since most of the information we haven'...
by Alex Hitti 3E
Fri Oct 18, 2019 11:08 am
Forum: DeBroglie Equation
Topic: 1B.15a
Replies: 2
Views: 36

Re: 1B.15a

During my discussion, the TA said that for anything that has mass (like electrons), we should use the equation: wavlength = h/(mv)
Meanwhile, anything that doesn't have mass (like photons), we use the equation: wavelength = c/(frequency)
mass of electron = 9.11 * 10^-31 kg
by Alex Hitti 3E
Fri Oct 18, 2019 10:59 am
Forum: DeBroglie Equation
Topic: Energy = mv^2
Replies: 2
Views: 44

Re: Energy = mv^2

Dr. Lavelle generalized the concept so I wouldn't use that equation since there are more complicated and accurate ways to achieve the derivation. He said to not worry about it too much since it won't be a main focal point in the midterms and finals.
by Alex Hitti 3E
Tue Oct 08, 2019 4:23 pm
Forum: Properties of Electrons
Topic: Energy of an Electron
Replies: 2
Views: 264

Re: Energy of an Electron

The energy of a photon = (planck's constant) * (speed of light) / wavelength
I think this is probably the closest that you can get to what you are looking for.
by Alex Hitti 3E
Tue Oct 08, 2019 4:19 pm
Forum: Photoelectric Effect
Topic: Post Assessment Problem 28
Replies: 2
Views: 25

Re: Post Assessment Problem 28

For anyone else wondering, the mass of an electron is about 9.11 × 10^(-28) grams.
by Alex Hitti 3E
Tue Oct 08, 2019 4:15 pm
Forum: Properties of Light
Topic: Wave and Photon Models
Replies: 2
Views: 31

Wave and Photon Models

How can we determine if the problem is asking for a wave model or a photon model?
by Alex Hitti 3E
Tue Oct 08, 2019 4:07 pm
Forum: Properties of Electrons
Topic: Electron Gaining/Losing energy
Replies: 5
Views: 268

Re: Electron Gaining/Losing energy

When atoms absorb energy, the electrons go into an "excited" state which moves them up electron orbitals. In short, when an atom is excited, electrons have absorbed energy.
by Alex Hitti 3E
Tue Oct 08, 2019 4:04 pm
Forum: Einstein Equation
Topic: Planck's constant
Replies: 9
Views: 102

Re: Planck's constant

Planck's constant is critical as a constant because it relates the energy of a photon to its frequency.
by Alex Hitti 3E
Fri Oct 04, 2019 12:06 am
Forum: Properties of Light
Topic: Spectroscopy
Replies: 4
Views: 28

Re: Spectroscopy

There is an acronym for visible light from longest to shortest wavelength is ROY-G-BIV (red, orange, yellow, green, blue, indigo, violent). I don't know any acronyms for the rest but the general graph/chart from shortest to longest is: gamma rays, x-rays, ultraviolet, visible light (ROY-G-BIV backwa...
by Alex Hitti 3E
Wed Oct 02, 2019 4:32 pm
Forum: Properties of Electrons
Topic: Polar vs Non polar
Replies: 15
Views: 613

Re: Polar vs Non polar

A polar molecule is when there are slight positive and/or negative charges within the atoms. This is formed when one of the atoms tends to attract the electrons more than the others due their electronegativity levels. Hydrogen and Carbon tend to have low electronegativity levels that is why all hydr...
by Alex Hitti 3E
Wed Oct 02, 2019 4:20 pm
Forum: Properties of Light
Topic: Electric Field and Magnetic Field
Replies: 3
Views: 43

Electric Field and Magnetic Field

What is the difference between the electric and magnetic fields? In other words, what are the electric and magnetic fields and what role does each of them play?
by Alex Hitti 3E
Wed Oct 02, 2019 4:12 pm
Forum: Balancing Chemical Reactions
Topic: Equations Balancing
Replies: 6
Views: 93

Re: Equations Balancing

I use variables to associate all of the coefficient together with. Usually, I assign the most complex compound the variable 'x' then I go step by step linking the other molecules to 'x'. And then I assign them the coefficient that all the different molecules had for 'x'. And for what is left (or doe...
by Alex Hitti 3E
Wed Oct 02, 2019 3:55 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7609
Views: 1019885

Re: Post All Chemistry Jokes Here

Oxygen, Hydrogen, Sulfur, Sodium, and Phosphorus walk into a bar.
The bartender exclaims "OH SNaP!"
by Alex Hitti 3E
Wed Oct 02, 2019 3:35 pm
Forum: SI Units, Unit Conversions
Topic: Question about Showing Work
Replies: 22
Views: 146

Re: Question about Showing Work

It's always better to show work than not because you can earn at least partial credit even though you may have got the answer wrong by making an incorrect step/calculation.

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