Search found 52 matches
- Sat Dec 07, 2019 4:39 pm
- Forum: Biological Examples
- Topic: Hydrogen Bonding sites
- Replies: 11
- Views: 797
Re: Hydrogen Bonding sites
Each hydrogen that is attached to either N, O, or F counts as a potential binding site and every lone pair on a N, O, or F atom
- Sat Dec 07, 2019 4:26 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: pH formula?
- Replies: 69
- Views: 4086
Re: pH formula?
pH=-log[H3O+]
- Sat Dec 07, 2019 4:23 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: pH vs. pOH
- Replies: 17
- Views: 2502
Re: pH vs. pOH
pH is a measure of hydrogen ion concentration while pOH is a measure of hydroxide ion concentration.
- Sat Dec 07, 2019 4:20 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Calculating pH
- Replies: 1
- Views: 193
Re: Calculating pH
if you are given the concentration of hydronium ions in a solution then pH= -log[H3O+]. If you are given the concentration of hydroxide ions then pH=-log[OH-]
- Sat Dec 07, 2019 3:18 pm
- Forum: Lewis Acids & Bases
- Topic: Concept of Acid and Bases
- Replies: 1
- Views: 144
Re: Concept of Acid and Bases
Lewis acids would actually have more protons than lewis bases since the definition for a lewis acid is that it accepts electron pairs while lewis bases donate electron pairs
- Fri Nov 29, 2019 2:33 am
- Forum: Lewis Acids & Bases
- Topic: HCl vs HF
- Replies: 19
- Views: 1402
Re: HCl vs HF
Chlorine has a larger atomic radius than Fluorine which makes it easier for chlorine to lose its hydrogen atom making it a stronger acid than fluorine.
- Fri Nov 29, 2019 2:28 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Strength and Weakness
- Replies: 12
- Views: 1126
Re: Strength and Weakness
the strength of an acid is indicated by its Ka. The higher the Ka, the more it dissociates which means that it is a stronger acid
Re: Oxidation
Oxidation numbers indicate the number of electrons gained or lost by an atom in a molecule
- Fri Nov 29, 2019 2:19 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid Strength
- Replies: 6
- Views: 430
Re: Acid Strength
Besides memorizing the list of strong acids, they are also usually associated with longer and weaker bonds which indicates that it gives up hydrogen atoms easier.
- Fri Nov 29, 2019 2:16 am
- Forum: Conjugate Acids & Bases
- Topic: Acids and Bases
- Replies: 10
- Views: 567
Re: Acids and Bases
Equilibrium arrows are used in reactions in which weak acids and bases are involved since they do not dissociate completely.
- Fri Nov 22, 2019 6:49 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: How to tell?
- Replies: 11
- Views: 956
Re: How to tell?
Acids usually contain hydrogen since acids are defined as substances that donate hydrogen ions.
- Fri Nov 22, 2019 6:43 pm
- Forum: Hybridization
- Topic: Valance Bond Theory
- Replies: 2
- Views: 225
Re: Valance Bond Theory
Valence bond theory basically states how atoms bond together through the combination of half filled orbitals to form hybrid orbitals which then create sigma and pi bonds.
- Fri Nov 22, 2019 6:37 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Induced dipoles
- Replies: 7
- Views: 936
Re: Induced dipoles
Electrons randomly distribute around a nucleus continuously. By that logic there are moments when there are more electrons concentrated in one area than another which creates a slightly uneven charge distribution which will cause a momentary dipole at one instantaneous second.
- Fri Nov 22, 2019 6:33 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Condition for pi bond
- Replies: 4
- Views: 334
Re: Condition for pi bond
No because pi bonds are formed in the presence of p orbitals and p orbitals are always preceded by s orbitals which create sigma bonds
- Fri Nov 22, 2019 6:31 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Sigma and Pi Bonds
- Replies: 33
- Views: 1698
Re: Sigma and Pi Bonds
You just need to know that triple bonds consist of one sigma bond and two pi bonds
- Fri Nov 15, 2019 5:24 pm
- Forum: Ionic & Covalent Bonds
- Topic: Hydrogen Bond Strength
- Replies: 8
- Views: 481
Re: Hydrogen Bond Strength
Hydrogen bonds are weaker than ionic and covalent bonds mainly because hydrogen bonds are an intermolecular force while ionic and covalent bonds are an intramolecular force which are generally way stronger than intermolecular forces.
- Fri Nov 15, 2019 5:22 pm
- Forum: Ionic & Covalent Bonds
- Topic: Why is the ionization energy of nitrogen higher than that of oxygen's?
- Replies: 11
- Views: 1008
Re: Why is the ionization energy of nitrogen higher than that of oxygen's?
When you look at the electron configurations for nitrogen and oxygen you can see that oxygen has one group of paired electrons. Due to the electron electron repulsions that occur as a result of the paired electrons, it is pushed to a higher energy level which causes it to require less energy to remo...
- Fri Nov 15, 2019 5:19 pm
- Forum: Ionic & Covalent Bonds
- Topic: London Dispersion
- Replies: 13
- Views: 690
Re: London Dispersion
All molecules have london dispersion forces due to the randomized dispersion of electrons at a singular moment which can strengthen the dipole towards a certain direction due an increased density of electrons.
- Fri Nov 15, 2019 5:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: Bond Strength
- Replies: 8
- Views: 511
Re: Bond Strength
Ionic is stronger than covalent bonds since they have a greater attraction towards each other due to the opposite charges that ionic bonds possess that covalent bonds don't
- Fri Nov 15, 2019 5:13 pm
- Forum: Ionic & Covalent Bonds
- Topic: Types of Covalent Bonds
- Replies: 4
- Views: 311
Re: Types of Covalent Bonds
Polar bonds are stronger than nonpolar bonds. Coordinate covalent bonds are generally weaker than ionic/covalent bonds.
- Fri Nov 08, 2019 3:36 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 specificity
- Replies: 3
- Views: 186
Re: Hydrogen bonding specificity
Hydrogen bonds only form between N, O, and F due to its high electronegativity. The high electronegativity results in an increased negative charge in those atoms which heavily attracts H atoms in adjacent molecules.
- Fri Nov 08, 2019 3:34 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: Interaction Potential Energy
- Replies: 3
- Views: 228
Re: Interaction Potential Energy
alpha represents the polarizability of the atom which correlates with the amount of electrons that are present in the molecule. This is because more electrons allow for more distribution around the molecule which can create stronger momentary dipoles between other molecules. r represents the distanc...
- Thu Nov 07, 2019 1:38 pm
- Forum: Bond Lengths & Energies
- Topic: Bond strengths
- Replies: 9
- Views: 554
Re: Bond strengths
Usually when a bond is shorter it is stronger, because there are more electrons that are shared between ions which result in a stronger pull between the electrons and the atoms' nuclei. The same goes for why a longer bond is weaker.
- Thu Nov 07, 2019 1:33 pm
- Forum: Octet Exceptions
- Topic: Easy way to remember octet exceptions
- Replies: 4
- Views: 382
Re: Easy way to remember octet exceptions
Also it is helpful to check the formal charge on the central ion as expanded octets usually contribute to decreasing the formal charge to 0.
- Thu Nov 07, 2019 1:31 pm
- Forum: Electronegativity
- Topic: Trend of Electronegativity
- Replies: 22
- Views: 2135
Re: Trend of Electronegativity
Electronegativity decreases as you move down a group and increases as you move across a period. It increases as you move across a period because the nuclear charge increases as you move right. It decreases as you move down a group because the electrons are increasingly experiencing weaker attraction...
- Fri Nov 01, 2019 7:20 pm
- Forum: Bond Lengths & Energies
- Topic: Lattice Energy
- Replies: 9
- Views: 460
Re: Lattice Energy
When ions form bonds they release energy. Lattice energy is basically the amount of energy that is released when ions form a compound.
- Fri Nov 01, 2019 7:18 pm
- Forum: Bond Lengths & Energies
- Topic: Bond energies
- Replies: 4
- Views: 231
Re: Bond energies
In terms of bond energy triple bonds have the largest bond energy while single bonds have the smallest bond energy. Lone pair electrons also repel other lone pair electrons on adjacent atoms which contributes to single bonds having weaker bonds.
- Fri Nov 01, 2019 7:14 pm
- Forum: Electronegativity
- Topic: Polarity
- Replies: 5
- Views: 214
Re: Polarity
Basically atoms have different electronegativities and the difference in electronegativities between two atoms is what causes a bond to be polar. So yes, they are correlated but they aren't the same.
- Fri Nov 01, 2019 7:12 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charge purpose
- Replies: 40
- Views: 7197
Re: Formal charge purpose
A formal charge of 0 indicates that the molecule is at its most stable structure.
- Fri Nov 01, 2019 7:09 pm
- Forum: Ionic & Covalent Bonds
- Topic: Midterm
- Replies: 28
- Views: 1331
Re: Midterm
The midterm will include everything including Friday's lecture besides the last slide that was shown.
- Fri Oct 25, 2019 6:00 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2nd electron
- Replies: 4
- Views: 170
Re: 2nd electron
Whenever you remove the first electron, you create a cation. So technically, the nuclear charge is greater which is why the second ionization energy is always significantly larger than the first.
- Fri Oct 25, 2019 5:56 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Noble Gas Configuration
- Replies: 10
- Views: 908
Re: Noble Gas Configuration
My TA mentioned how you can use the noble gas configuration whenever you want. You arent required to use the fully written out notation unless inquired to.
- Fri Oct 25, 2019 5:05 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 1E25
- Replies: 1
- Views: 142
Re: 1E25
Unless they specifically ask you to show the arrangement of electrons in the orbital, you should use the "s2p6d10" notation.
- Fri Oct 25, 2019 4:56 pm
- Forum: Properties of Light
- Topic: Speed of light
- Replies: 13
- Views: 378
Re: Speed of light
All electromagnetic radiation is light itself which is why they all travel at 3*10^8 m/s. The factors that distinguishes the types of EM waves are frequency and wavelength.
- Fri Oct 25, 2019 4:53 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes
- Replies: 7
- Views: 397
Re: Nodal Planes
a nodal plane is an area where the probability of finding electrons is zero. S orbitals are the only orbitals that have nodal planes considering how the orbital itself is spherical and doesn't intersect the nucleus in any way
- Fri Oct 25, 2019 4:48 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: s, p, d, f orbitals
- Replies: 15
- Views: 783
Re: s, p, d, f orbitals
The 3d orbital should have more energy than 4s since the electrons in the 3d orbital experience heavy repulsion from electron interactions between the other electrons in the 3d and 3p orbitals. As a result, it requires less energy for electrons to occupy the 4s orbital.
- Fri Oct 18, 2019 7:09 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Nodal Plane
- Replies: 4
- Views: 170
Re: Nodal Plane
A nodal plane is an area where there is no chance of finding an electron. S orbitals do not have this because they are spherical and don't have any gaps that p,d, and f orbitals possess
- Fri Oct 18, 2019 7:03 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Spectral Series
- Replies: 3
- Views: 228
Re: Spectral Series
Considering how the Balmer series is associated with visible light and the Lyman series is associated with UV light, wavelengths in the Balmer series should range from around 400 nm to 740 nm while wavelengths in the Lyman series should range from 10 nm to 400 nm.
- Fri Oct 18, 2019 6:59 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Advice for studying
- Replies: 92
- Views: 7597
Re: Advice for studying
One routine that helped me get through chem was to just do as many practice problems as possible and to review the problems that you weren't able to solve initially or struggled with.
- Fri Oct 18, 2019 6:56 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Spin State
- Replies: 17
- Views: 428
Re: Spin State
Do the positive and negative values relate to the arrows he draws in class? I'm confused as to how that relates to the spin state. The positive and negative values don't necessarily correlate to a certain direction such as "up" or "down" that most people refer to, it just convey...
- Fri Oct 18, 2019 6:52 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Energy of 4s and 3d
- Replies: 1
- Views: 146
Re: Energy of 4s and 3d
Basically electrons in the 3d orbital have a lot of repulsion because of the electrons that occupy the 3s and 3p orbitals. Considering how the 4s orbital is further away and experiences less repulsion, it requires less energy for electrons to occupy it than the 3d orbital.
- Fri Oct 11, 2019 4:06 pm
- Forum: Properties of Light
- Topic: Energy Levels
- Replies: 8
- Views: 466
Re: Energy Levels
It is in the ultraviolet region because the gap between n=1 and n=2 has the greatest gap compared to the other energy which results in the greatest energy release which can be associated to the ultraviolet region.
- Fri Oct 11, 2019 3:56 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Decreasing gap between energy level
- Replies: 6
- Views: 1452
Re: Decreasing gap between energy level
Electrons closer to the nucleus are more affected by the pull and thus require more energy to remove. The further the electrons are from the nucleus, the weaker the pull, which results in less energy required to remove electrons.
- Fri Oct 11, 2019 3:52 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy: Na vs. Al
- Replies: 3
- Views: 3972
Re: Ionization Energy: Na vs. Al
Simply put, aluminum has 3 valence electrons while sodium only has 1. It takes more energy for aluminum to lose 3 electrons to complete its octet shell than it does for sodium to lose one electron.
- Fri Oct 11, 2019 3:49 pm
- Forum: Trends in The Periodic Table
- Topic: Electronegativity vs. Electron Affinity?
- Replies: 11
- Views: 1713
Re: Electronegativity vs. Electron Affinity?
Basically electron affinity is the amount of energy that is released when an electron is added to an atom while electronegativity is an atom's ability to attract electrons
- Fri Oct 11, 2019 3:28 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 9124
Re: Rydberg equation [ENDORSED]
Can someone clarify why the Rydberg equation is always negative? Because you're "losing" energy because it's being transferred somewhere else? The Rydberg equation is negative because it is comparing the energy difference between the two levels the electrons transitioned between. When an ...
- Fri Oct 11, 2019 3:27 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 9124
Re: Rydberg equation [ENDORSED]
Can someone clarify why the Rydberg equation is always negative? Because you're "losing" energy because it's being transferred somewhere else? The Rydberg equation is negative because it is comparing the energy difference between the two levels the electrons transitioned between. When an ...
- Fri Oct 04, 2019 5:01 pm
- Forum: SI Units, Unit Conversions
- Topic: which unit to use
- Replies: 9
- Views: 526
Re: which unit to use
Back in high school, I was told to always put your answer in the original units stated in the problem if not given a specific unit to use.
- Fri Oct 04, 2019 4:58 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molar mass vs. Molecular Weight
- Replies: 5
- Views: 1294
Re: Molar mass vs. Molecular Weight
Molecular weight is basically the mass of one molecule. Molar mass would be the mass of a mole of a molecule.
- Fri Oct 04, 2019 4:50 pm
- Forum: SI Units, Unit Conversions
- Topic: Sig figs
- Replies: 18
- Views: 660
Re: Sig figs
How important is it to know all the rules for sig figs? I feel like I know some basics but not the more specific rules that pertain to addition/subtraction or multiplication/division? Back in high school, I know that sig figs account for a lot of points so I believe that it is important that you fo...
- Fri Oct 04, 2019 4:39 pm
- Forum: SI Units, Unit Conversions
- Topic: Sig Fig Mistakes
- Replies: 17
- Views: 875
Re: Sig Fig Mistakes
One important thing to note is that when determining the number of sig figs to use in your final answer, you don't consider the amount of sig figs in constants such as Avogadro's number.
- Fri Oct 04, 2019 4:36 pm
- Forum: SI Units, Unit Conversions
- Topic: Question about Showing Work
- Replies: 22
- Views: 1073
Re: Question about Showing Work
My TA mentioned how partial credit is possible to earn so it would be best if you show your work for every problem. When it comes to balancing chemical equations, you can earn partial credit if you write down the oxidation numbers for each compound/element.