Search found 50 matches
- Fri Dec 06, 2019 2:29 pm
- Forum: Student Social/Study Group
- Topic: Equation Memorization
- Replies: 2
- Views: 210
Re: Equation Memorization
We are given a sheet that has most of the equations we need to know for the test. I've attached this sheet below.
- Fri Dec 06, 2019 2:21 pm
- Forum: Bronsted Acids & Bases
- Topic: Hydrogen Bonding
- Replies: 16
- Views: 1027
Re: Hydrogen Bonding
I do not think it is the same thing because hydrogen bonding is an intermolecular force, whereas with acids and bases, the molecule is changing and hydrogen is moved to a different molecule.
- Fri Dec 06, 2019 2:16 pm
- Forum: Biological Examples
- Topic: Roman numerals
- Replies: 1
- Views: 166
Re: Roman numerals
You just need to add up all of the charges (not including the metal) and then, find out what value needs to be added to get to the total charge of the compound. That value (almost always positive) will be the roman numeral you use.
- Fri Dec 06, 2019 2:13 pm
- Forum: Lewis Acids & Bases
- Topic: Identifying Acids and Bases
- Replies: 3
- Views: 247
Re: Identifying Acids and Bases
I would assume Bronsted-Lowry or Lewis because they are just expanded definitions of the Arrhenius definition. We have also extensively covered Bronsted-Lowry and Lewis and have not spoken of Arrhenius as much in lectures.
- Fri Dec 06, 2019 2:11 pm
- Forum: Bond Lengths & Energies
- Topic: Hydrogen Bonding
- Replies: 13
- Views: 1023
Re: Hydrogen Bonding
As stated by others, hydrogen bonding can only occur with N, O, and F. The hydrogen that is going to bond must bond to one of those three atoms AND must already be bonded to either N, O, or F. Also, hydrogen will never be the central atom so you don't have to worry about that coming up:)
- Sun Dec 01, 2019 9:56 pm
- Forum: Lewis Acids & Bases
- Topic: Final
- Replies: 4
- Views: 303
Re: Final
I am not 100% sure but I would guess that the stuff we have recently covered will be more prevalent on the final since we have been tested on the other stuff already, but I would still strongly recommend studying all of the material in case some curveballs are thrown. I would ask your TA for a more ...
- Sun Dec 01, 2019 9:53 pm
- Forum: Student Social/Study Group
- Topic: Week 10 Chemistry Community
- Replies: 9
- Views: 699
Re: Week 10 Chemistry Community
It is usually Sunday at midnight so I am pretty sure week 10 is no exception. We should have 50 since we have 5 due per week over 10 weeks
- Sun Dec 01, 2019 9:50 pm
- Forum: Lewis Acids & Bases
- Topic: Strong versus weak
- Replies: 5
- Views: 366
Strong versus weak
What are the indicators of a strong acid/base versus a weak acid/base?
- Sun Dec 01, 2019 9:46 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma Bond
- Replies: 10
- Views: 575
Re: Sigma Bond
Yes, every single bond is immediately a sigma bond, but there are also sigma bonds in double and triple bonds.
- Sun Dec 01, 2019 9:44 pm
- Forum: Bronsted Acids & Bases
- Topic: Final
- Replies: 13
- Views: 784
Re: Final
Everything we have covered in the lectures up to this point and the stuff up until Wednesday is fair game to my understanding! All the homework problems are fair questions to be asked and such.
- Sun Nov 24, 2019 5:21 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Replacing H2O
- Replies: 2
- Views: 213
Replacing H2O
What are some examples of species that can replace H2O ligands to make coordination compounds, and how do you identify which ones will be able to replace it?
- Sun Nov 24, 2019 5:20 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Negative coordination compound
- Replies: 1
- Views: 146
Negative coordination compound
Why is it uncommon for coordination compounds to be negatively charged?
- Sun Nov 24, 2019 5:14 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordinate covalent bonds
- Replies: 5
- Views: 309
Re: Coordinate covalent bonds
A coordinate covalent bond is when one of the atoms provides both electrons for the bond.
- Sun Nov 24, 2019 5:04 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis and Bronsted
- Replies: 5
- Views: 346
Lewis and Bronsted
What is the difference between Lewis and Bronsted acids and bases?
- Sun Nov 24, 2019 5:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw
- Replies: 23
- Views: 927
Re: Seesaw
Yes it is "about" 90 and 120, so if you want to be more precise you can say "slightly less than 90" or "slightly less than 120".
- Sun Nov 17, 2019 9:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Geometry versus shape
- Replies: 3
- Views: 210
Geometry versus shape
What are the differences between molecular geometry and molecular shape?
- Sun Nov 17, 2019 9:28 pm
- Forum: Bronsted Acids & Bases
- Topic: Test2
- Replies: 7
- Views: 366
Re: Test2
It will cover everything from after the midterm to the material we just learned on Friday, and they will test on shapes so my TA highly recommended making flashcards to go through and make sure you can determine all of the shapes we have learned.
- Sun Nov 17, 2019 9:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar vs. Nonpolar
- Replies: 8
- Views: 459
Re: Polar vs. Nonpolar
If the dipoles of two atoms are pointing in the same direction (such as the hydrogens in water) the dipoles do not cancel out and therefore water is polar, but if two vectors do cancel, the molecule is nonpolar.
- Sun Nov 17, 2019 9:23 pm
- Forum: Dipole Moments
- Topic: How to tell
- Replies: 2
- Views: 253
How to tell
How can you tell which kind of dipole interaction is going on? Like dipole-dipole, induced dipole-induced dipole, etc?
- Sun Nov 17, 2019 9:20 pm
- Forum: Bond Lengths & Energies
- Topic: Electron Density
- Replies: 10
- Views: 602
Re: Electron Density
Yes, I believe that lone pairs of electrons are considered regions of electron density since they influence the molecular shape. Please see the attached image. Thank you so much! Do you think we are going to have to know all of the shapes? I think we are supposed to know all of the shapes we have c...
- Sat Nov 09, 2019 12:49 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: instantaneous dipoles
- Replies: 3
- Views: 234
Re: instantaneous dipoles
I don't know which one is "more important" per se, but Dr. Lavelle pointed out that while shape impacts the difference in boiling/melting points, the number of electrons impacts it more drastically.
- Sat Nov 09, 2019 12:46 pm
- Forum: Lewis Structures
- Topic: Lewis Structures
- Replies: 4
- Views: 336
Re: Lewis Structures
You put the negative formal charge on the more electronegative atom.
- Fri Nov 08, 2019 7:38 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Magnetic Quantum numbers
- Replies: 13
- Views: 751
Re: Magnetic Quantum numbers
The magnetic quantum number can be determined by the angular momentum quantum number. ml can be from -l to l.
E.g. If l=2, ml can be -2,-1,0,1,2.
E.g. If l=2, ml can be -2,-1,0,1,2.
- Fri Nov 08, 2019 7:34 pm
- Forum: Trends in The Periodic Table
- Topic: atomic radius
- Replies: 7
- Views: 512
Re: atomic radius
It decreases across a period because the electrons are in the same orbital across a period but the number of protons increases across a period, so the pull from the positive nucleus on the negative electrons pulls the electrons closer, decreasing radius.
- Fri Nov 08, 2019 7:29 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: Fluctuating dipoles
- Replies: 2
- Views: 143
Fluctuating dipoles
What does it mean for dipoles to fluctuate due to fluctuating electrons?
- Fri Nov 08, 2019 5:47 pm
- Forum: Student Social/Study Group
- Topic: Midterm
- Replies: 3
- Views: 270
Re: Midterm
Since you were provided the mass of the compound, I think it was riboflavin, and you had the mass of each of the products, H 2 O, CO 2 , and N 2 , plus you had the balanced chemical equation , you could solve for the number of moles of C in CO 2 using a conversion factor of 1 mol C per one mol CO 2 ...
- Fri Nov 08, 2019 5:39 pm
- Forum: Photoelectric Effect
- Topic: Frequency and number of electrons ejected
- Replies: 2
- Views: 304
Re: Frequency and number of electrons ejected
No, increasing frequency of the light does not change the number of electrons ejected from a metal surface. Once the minimum frequency required to eject an electron is met, other electrons will be ejected as long as the frequency stays at that threshold level or above it. In order to eject more elec...
- Fri Nov 08, 2019 5:34 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: Dispersion
- Replies: 3
- Views: 131
Dispersion
How does dispersion explain why the three hydrocarbons in the picture in the lecture today (pentane, pentadecane, octadecane) all had different viscosities? I understand that they all have a different number of carbons but how does that play a role in dispersion?
- Fri Nov 08, 2019 5:30 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: Difference in terminology
- Replies: 1
- Views: 71
Difference in terminology
Dr. Lavelle said that Induced dipole-induced dipole, London, Dispersion, and Van de Waals are all interchangeable but also said they have some differences. What are the differences and why can we call them interchangeable?
- Wed Nov 06, 2019 12:33 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Bohr Frequency Condition
- Replies: 1
- Views: 108
Bohr Frequency Condition
What does the Bohr Frequency condition explain or prove?
- Sun Oct 27, 2019 4:17 pm
- Forum: Lewis Structures
- Topic: Dots vs Lines in Lewis Structures
- Replies: 6
- Views: 397
Re: Dots vs Lines in Lewis Structures
Using lines helps to show that there is a covalent bond because it represents the sharing of electrons while dots represent lone pairs of electrons in covalent bonds. In ionic bonds, you do not use lines because there is no sharing of electrons.
- Sun Oct 27, 2019 4:10 pm
- Forum: Bond Lengths & Energies
- Topic: C-C bond lengths
- Replies: 4
- Views: 186
C-C bond lengths
In his example of resonance in benzene, Dr. Lavelle drew a resonance structure and labeled the length of the double bond between two carbons as 1.34Å and the length of the single bond between two carbons as 1.54Å. Then he went on to say that experimentally observed C-C bond lengths all equal 1.39Å. ...
- Sun Oct 27, 2019 4:04 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Shielding
- Replies: 3
- Views: 169
Re: Electron Shielding
Electron shielding is just the concept that electrons closer to the nucleus act as a shield to those further from the nucleus, making the outermost electrons have less of a pull toward the positive nucleus because the magnetic pull is basically being blocked by the closer electrons.
- Sun Oct 27, 2019 4:01 pm
- Forum: Lewis Structures
- Topic: Ionic vs. Covalent Lewis Structures
- Replies: 2
- Views: 649
Re: Ionic vs. Covalent Lewis Structures
Lewis structures for covalent bonding use lines to represent the sharing of electrons. Lewis structures for ionic bonding do not use lines because electrons are either lost or gained, not shared, so the dots (aka electrons) are moved from one element to the other to represent bonds, and brackets are...
- Sun Oct 27, 2019 3:51 pm
- Forum: Resonance Structures
- Topic: Determining Resonance
- Replies: 3
- Views: 129
Determining Resonance
How do you determine which resonance structure is the most stable?
- Sun Oct 20, 2019 4:27 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: What does the H mean?
- Replies: 9
- Views: 745
Re: What does the H mean?
The h with the dash through the stem is planck's constant divided by 2 times pi, which is equal to h/2π
- Sun Oct 20, 2019 4:24 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Spin
- Replies: 3
- Views: 158
Re: Spin
It is not that it necessarily affects the behavior of the electron, but it is to even out the magnetic field created by the positive nucleus with the negative electrons. If electrons are in the same orbital, the spins must be opposite. If they are in different orbitals, they must be parallel, theref...
- Sun Oct 20, 2019 12:30 pm
- Forum: Properties of Electrons
- Topic: Wave-like and particle-like properties
- Replies: 7
- Views: 230
Wave-like and particle-like properties
Does every single thing have both wave-like and particle-like properties? Or do only things that are quantized have wave-like properties?
- Sun Oct 20, 2019 12:23 pm
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 9
- Views: 585
Re: Work Function
If you are talking about work function and threshold energy rather than threshold frequency, they are virtually the same thing, nearly interchangeable. Threshold energy is the minimum amount of energy needed to eject an electron from a metal surface, and that is denoted by the work function.
- Fri Oct 18, 2019 8:44 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: How to Name Electron Configurations
- Replies: 5
- Views: 259
Re: How to Name Electron Configurations
I believe both ways will be sufficient in the class but to find out what element you use to write the shorthand version, you use the noble gas (the elements in the rightmost columns on the periodic table) that is in the row above the element you are writing the configuration for.
- Fri Oct 11, 2019 5:49 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Negative Energy Value for Hydrogen Energy Levels
- Replies: 2
- Views: 124
Re: Negative Energy Value for Hydrogen Energy Levels
From what Dr. Lavelle described on Wednesday, the reference point for the energy of an electron is 0 because we assume it is not interacting with anything. The negative energy of the electron represents that an electron bound to an atom has a lower energy than that of a "free" electron, on...
- Fri Oct 11, 2019 3:22 pm
- Forum: Properties of Electrons
- Topic: Circular Standing Wave
- Replies: 3
- Views: 106
Circular Standing Wave
Today in the lecture we were told that an electron is described as a circular standing wave around the nucleus. How does this describe why electrons have quantized energy states in atoms? Dr. Lavelle said it was from the line spectra but I do not understand how this is modeled.
- Thu Oct 10, 2019 3:56 pm
- Forum: Limiting Reactant Calculations
- Topic: general questions
- Replies: 11
- Views: 964
Re: general questions
Finding the limiting reactant allows you to find out how much product you will be able to make because the limiting reactant will run out the fastest, determining how much product is made. The next step would generally to find out how much of the product can be produced based on how much of the limi...
- Thu Oct 10, 2019 3:48 pm
- Forum: Properties of Light
- Topic: Energy of light
- Replies: 4
- Views: 165
Energy of light
Is it always true that light with shorter wavelengths have higher energy? And why would that be?
- Thu Oct 10, 2019 3:40 pm
- Forum: Photoelectric Effect
- Topic: threshold energy
- Replies: 4
- Views: 150
Re: threshold energy
Threshold energy, also called work function, is the energy needed to remove an electron from a metal surface using a light.
- Thu Oct 03, 2019 10:22 pm
- Forum: Significant Figures
- Topic: Sig Fig Addition and Subtraction
- Replies: 5
- Views: 451
Sig Fig Addition and Subtraction
If there is a problem that includes addition/subtraction AND multiplication/division, which sig fig rule is supposed to be followed since there are different rules?
- Wed Oct 02, 2019 11:11 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Chemical Equations Formatting
- Replies: 6
- Views: 488
Re: Balancing Chemical Equations Formatting
You should interpret that as 1 Mg and 6 N since the parentheses do not surround the Mg at all
- Wed Oct 02, 2019 11:03 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molar Mass
- Replies: 10
- Views: 1035
Re: Molar Mass
If you are given the substance you should be able to figure out the molar mass by using the periodic table. You just need to figure out how many of each element you have so that you can multiply the molar mass of one atom of that element by the total number in the formula and add it all together for...
- Wed Oct 02, 2019 10:59 pm
- Forum: Ideal Gases
- Topic: Reading the textbook
- Replies: 262
- Views: 146782
Re: Reading the textbook
The textbook definitely has some valuable information that goes in depth on all of the topics covered so I think it is definitely worth it to read the book and view the examples. The examples are super helpful.
- Wed Oct 02, 2019 10:51 pm
- Forum: SI Units, Unit Conversions
- Topic: Sig figs
- Replies: 18
- Views: 604
Re: Sig figs
I think you are supposed to do the sig figs only at the end so that your rounding doesn't get messed up but if you want to be super sure Dr. Lavelle has a Sig Fig review link on his 14A website