Search found 67 matches
- Sat Dec 12, 2020 12:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Are all questions on the final multiple choices?
- Replies: 29
- Views: 1370
Re: Are all questions on the final multiple choices?
Yes they are, just like the same format as the 2 midterms.
- Wed Dec 09, 2020 8:20 pm
- Forum: General Science Questions
- Topic: midterm 2 answers
- Replies: 30
- Views: 2077
Re: midterm 2 answers
You have to go to your TA's office hours. I don't think you can get access to them any other way.
- Wed Dec 09, 2020 8:16 pm
- Forum: Lewis Structures
- Topic: H2SeO4
- Replies: 2
- Views: 501
Re: H2SeO4
It is because if you have single bonds, it would not be the most stable lewis structure.If you double bond the SE and O together, you are able to get the most stable lewis structure. I was confused at first also.
- Tue Dec 08, 2020 11:48 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Negative Ka values
- Replies: 2
- Views: 481
Re: Negative Ka values
I believe it is possible and PKa can actually be a small negative number.
- Tue Dec 08, 2020 11:47 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Content
- Replies: 18
- Views: 963
Re: Final Content
I believe it is confirmed. Material will be proportional to the amount of time that was spent on the topic in the lectures.
- Tue Dec 08, 2020 11:45 pm
- Forum: Naming
- Topic: Naming quizlet
- Replies: 41
- Views: 1693
Re: Naming quizlet
Thank you! This helped a ton!
- Sat Dec 05, 2020 4:38 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: pH formula?
- Replies: 69
- Views: 3620
Re: pH formula?
The pH forumla is pH = - log [H3O+].
- Wed Dec 02, 2020 7:51 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis Acids & Bases
- Replies: 12
- Views: 1077
Re: Lewis Acids & Bases
Lewis acids are electron poor and can be positively charged. Lewis bases are electron rich and can be negatively charged.
- Wed Dec 02, 2020 7:48 pm
- Forum: Student Social/Study Group
- Topic: How are you?
- Replies: 154
- Views: 12408
Re: How are you?
It feels so intense with finals coming up.
- Tue Dec 01, 2020 8:51 pm
- Forum: SI Units, Unit Conversions
- Topic: How to memorize prefixes
- Replies: 36
- Views: 3487
Re: How to memorize prefixes
I like what others have mentioned about using quizlet. I think it is a great tool with memorizing prefixes.
- Tue Dec 01, 2020 8:48 pm
- Forum: Ionic & Covalent Bonds
- Topic: Polar and Nonpolar
- Replies: 37
- Views: 1722
Re: Polar and Nonpolar
You have to look at the shapes and see if the dipole force cancel each other out. If they cancel out each other than it is non-polar. If they don't cancel out they are polar.
- Tue Dec 01, 2020 8:45 pm
- Forum: Hybridization
- Topic: Sigma and Pi bonds
- Replies: 29
- Views: 2634
Re: Sigma and Pi bonds
Sigma bonds are formed by the linear or overlapping of the atomic orbitals. Pi bonds are a covalent bond where the electrons connect to the nuclei of the joined atoms.
- Sat Nov 28, 2020 12:27 pm
- Forum: Bond Lengths & Energies
- Topic: Ionic Character
- Replies: 12
- Views: 15216
Re: Ionic Character
If a molecule has greater ionic character than it has higher electronegativity. So, for NaBr or NaI, NaBr would be more ionic because it is has a higher electronegativity difference.
- Wed Nov 25, 2020 6:26 pm
- Forum: Lewis Structures
- Topic: NO2 Polarity
- Replies: 6
- Views: 2696
Re: NO2 Polarity
This is because of lone pair electrons whose repulsions cause a bent structure. This causes the charges to be unequal throughout the molecule. If the charges had equal distribution, then it would be a nonpolar molecule. However, since it is not equally distributed it would be a polar molecule.
- Tue Nov 24, 2020 11:02 pm
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 9
- Views: 586
Re: Resonance
Resonance is when more than one correct lewis structure can be drawn for a molecule. This can happen by rearranging single, double and triple atoms among atoms. It is possible to make one lewis structure representing all of the possible lewis structures by drawing a resonance hybrid. A resonance hyb...
- Tue Nov 24, 2020 10:56 pm
- Forum: Octet Exceptions
- Topic: Phosphate
- Replies: 7
- Views: 447
Re: Phosphate
Phosphate is in period 3 so it can have an expanded octet and hold up to 18 electrons theoretically.
- Tue Nov 24, 2020 10:52 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 8 Participation Points
- Replies: 6
- Views: 397
Re: Week 8 Participation Points
Week 8 is still 5 points and you should post 5 times this week to make sure you get your points.
- Tue Nov 24, 2020 10:49 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Expanded Octets
- Replies: 9
- Views: 400
Re: Expanded Octets
Yes, elements in Period 3 can have up to 18 electrons compared to the octet rule which states up to 8 electrons per atom. The trend continues for periods 4 and below.
- Sat Nov 21, 2020 1:33 pm
- Forum: Coordinate Covalent Bonds
- Topic: What is a coordinate Covalent Bond
- Replies: 11
- Views: 743
Re: What is a coordinate Covalent Bond
A coordinate covalent bond is a bond formed between a Lewis base and a Lewis acid. A Lewis base donates electrons while a Lewis acid accepts an electron. A good example is BF3 since fluorine can not be double bonded Boron only has 6 valence electrons and it needs 8. However F- can attract to BF3 whi...
- Thu Nov 19, 2020 6:13 pm
- Forum: Lewis Acids & Bases
- Topic: Valence electrons needed
- Replies: 3
- Views: 197
Re: Valence electrons needed
H,He,Bi or Li don't have to follow the octet rule also if the element is in third row. The element can theoretically have a maximum of 18 electrons but its usually 10-12 electrons. The higher amount of electrons are an expanded octet.
- Wed Nov 18, 2020 9:50 pm
- Forum: Dipole Moments
- Topic: Dipole Dipole Interactions
- Replies: 7
- Views: 422
Re: Dipole Dipole Interactions
Dipole Dipole interactions occur when there are two polar molecules that interact with each other.
- Tue Nov 17, 2020 5:52 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: d vs s orbitals
- Replies: 7
- Views: 989
Re: d vs s orbitals
Yes, 4s fills up before 3d. I was a little confused at first also. The trend also continues for 5s,4d and 6s,5d.
- Tue Nov 17, 2020 5:50 pm
- Forum: Student Social/Study Group
- Topic: grade worries
- Replies: 119
- Views: 14907
Re: grade worries
Same, I am worried about this midterm a lot. Its good to see I am not alone which helps a bit.
- Tue Nov 17, 2020 4:01 pm
- Forum: Dipole Moments
- Topic: dipoles and polarity
- Replies: 2
- Views: 171
Re: dipoles and polarity
Yes, if a molecule has a permanent dipole moment, then the molecule would be considered polar covalent.
- Sat Nov 14, 2020 12:59 pm
- Forum: Electronegativity
- Topic: Periodic Table Trend
- Replies: 40
- Views: 2283
Re: Periodic Table Trend
They both follow the same trend which is that if you go diagonally across the periodic table then both will increase.
- Wed Nov 11, 2020 2:23 pm
- Forum: Sigma & Pi Bonds
- Topic: sigma and pi bonds
- Replies: 27
- Views: 1623
Re: sigma and pi bonds
Yes, you are right. All single bonds are sigma bonds and all double bonds are sigma and pi bonds.
- Wed Nov 11, 2020 2:18 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: F-block?
- Replies: 7
- Views: 284
Re: F-block?
No, you don't have to worry about the F-Block. Its just the s, d and p blocks.
- Tue Nov 10, 2020 2:14 pm
- Forum: Ionic & Covalent Bonds
- Topic: Size of Bonds
- Replies: 28
- Views: 829
Re: Size of Bonds
Double bonds are shorter than single bonds because they have a stronger attractive force. This causes to come closer together which leads to shorter bond lengths.
- Tue Nov 10, 2020 2:07 pm
- Forum: Bond Lengths & Energies
- Topic: Radicals
- Replies: 5
- Views: 486
Re: Radicals
For radical stability, the order from least to greatest stability: Methyl < Primary < Secondary < Tertiary. This is due to the delocalization of the odd electrons.
- Tue Nov 10, 2020 2:02 pm
- Forum: Lewis Structures
- Topic: Central Atom
- Replies: 20
- Views: 626
Re: Central Atom
In order to find which atom to put in the center, you need to find the one that has the least electronegativity.
- Sat Nov 07, 2020 12:07 pm
- Forum: Electronegativity
- Topic: Noble Gases
- Replies: 40
- Views: 12570
Re: Noble Gases
Noble gases already have eight electrons in their outer shells (full octet). So, they won’t be able to attract any more electrons.
- Thu Nov 05, 2020 5:24 pm
- Forum: Octet Exceptions
- Topic: Identifying Radicals
- Replies: 24
- Views: 1139
Re: Identifying Radicals
If an atom or molecule has an unpaired valence electron, then it would be a radical. This is the same for ions also.
- Thu Nov 05, 2020 5:19 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma vs. Pi
- Replies: 20
- Views: 1185
Re: Sigma vs. Pi
Sigma bonds are stronger because they allow for electron density to be more concentrated between the two nuclei. A pi bond also has a weaker covalent bond than a sigma bond.
- Wed Nov 04, 2020 11:29 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Are there subshells past f?
- Replies: 28
- Views: 1038
Re: Are there subshells past f?
There are subshells that are past f but you won’t have to worry about that for this class.
- Wed Nov 04, 2020 11:24 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic v. Covalent Bonds`
- Replies: 10
- Views: 914
Re: Ionic v. Covalent Bonds`
The main difference really is ionic bonds are the transfer of electrons. While on the other hand, covalent bonds are the sharing of electrons.
- Wed Nov 04, 2020 11:20 pm
- Forum: Lewis Structures
- Topic: First 3 elements' octet
- Replies: 4
- Views: 154
Re: First 3 elements' octet
H and Hi are exceptions to the octet rule because a full shell for them is only 2 electrons which is the 1s shell. Li loses one electron because they are metals and likely to become cations they then only have 2 electrons. This makes Li an exception to the octet rule.
- Sat Oct 31, 2020 3:25 pm
- Forum: Einstein Equation
- Topic: de Broglie and neutrons
- Replies: 8
- Views: 496
Re: de Broglie and neutrons
Yes, De Brogile’s equation can be used for neutrons. It can also be used for protons in addition. Since you know the mass of protons and neutrons you can use the De Brogile’s equation.
- Thu Oct 29, 2020 4:37 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: l=4
- Replies: 13
- Views: 502
Re: l=4
It is possible it could be. However, you only have to worry about the l = 0,1,2,3 values for this class.
- Thu Oct 29, 2020 4:36 pm
- Forum: Student Social/Study Group
- Topic: external camera
- Replies: 5
- Views: 224
Re: external camera
Yes, you can use your phone. You just have to have another device that has respondus.
- Wed Oct 28, 2020 2:41 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical Formula - Whole Number Ratio
- Replies: 9
- Views: 710
Re: Empirical Formula - Whole Number Ratio
No, there isn't really a specific cutoff for empirical formulas. I think in most cases if you do the steps right you should be able to get a pretty good ratio. I wouldn't worry too much about it.
- Wed Oct 28, 2020 2:39 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 10
- Views: 502
Re: Electron Affinity
Yes, having higher electron affinity correlates to electrons being able to easier accept ions. Also, they further up and more right of the periodic table you go the higher the electron affinity goes. This is because the electrons added to the energy levels are closer to nucleus which then leads to h...
- Wed Oct 28, 2020 2:34 pm
- Forum: Trends in The Periodic Table
- Topic: In class question
- Replies: 8
- Views: 231
Re: In class question
No, you can't calculate the atomic radius for one lone atom. You would need two other atoms that are close and then you just take half the distance between those two. They also have to be bonded together.
- Sun Oct 25, 2020 6:11 pm
- Forum: Photoelectric Effect
- Topic: Mass of atoms
- Replies: 18
- Views: 571
Re: Mass of atoms
You use standard SI units, So I would just stick to kg for the mass.
- Fri Oct 23, 2020 11:58 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Rydberg Constant
- Replies: 13
- Views: 552
Re: Rydberg Constant
I think you use 3.29 x 10^ 15 as the Rydberg Constant for Hz.
- Wed Oct 21, 2020 11:47 am
- Forum: Properties of Light
- Topic: Electrons Emitted
- Replies: 7
- Views: 283
Re: Electrons Emitted
The maximum number of electrons that are released would be the total amount of energy divided by the work function. The work function is the minimum amount of energy that is required to release an electron from the surface of a metal.
- Tue Oct 20, 2020 9:52 pm
- Forum: Student Social/Study Group
- Topic: How to memorize formulas?
- Replies: 7
- Views: 373
Re: How to memorize formulas?
I am pretty sure Dr. Lavelle said that we just need to understand the concept and not worry about the formulas . So, most likely the formulas will be provided on the exams.
- Tue Oct 20, 2020 9:50 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: delta E
- Replies: 10
- Views: 2103
Re: delta E
Delta E is negative because photons are being emitted which is an exothermic reaction. If photons were being absorbed then you would have an endothermic reaction. In this case Delta E would then be positive.
- Mon Oct 19, 2020 6:40 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 17600
Re: How are you studying?
I think the modules are instrumental in understanding the material. Those problems go well in-depth in the material and I think if you get those then you really understand the material. I was wondering also on more ways to study everyone has some great tips!
- Mon Oct 19, 2020 6:33 pm
- Forum: DeBroglie Equation
- Topic: De Broglie Equation Assumption
- Replies: 3
- Views: 80
Re: De Broglie Equation Assumption
You can use the De Broglie Equation to find the wavelength of any moving object. That is one the key concepts of what De Broglie Equation is used for. The equation uses mass (m) and Planck's Constant (h) and velocity (v) to find the wavelength.
- Sun Oct 18, 2020 8:19 pm
- Forum: Significant Figures
- Topic: rounding during equations
- Replies: 14
- Views: 552
Re: rounding during equations
I try my best not to round too much because it will help get you more precise answers. I would use your sig figs to get your final answer.
- Thu Oct 15, 2020 8:31 pm
- Forum: SI Units, Unit Conversions
- Topic: Webcam
- Replies: 11
- Views: 373
Re: Webcam
You can use an external device but I think it is recommended that you get a webcam. I think webcams are easier to show your work than an external device.
- Wed Oct 14, 2020 10:04 pm
- Forum: Einstein Equation
- Topic: m vs nm
- Replies: 66
- Views: 3353
Re: m vs nm
Unless the problem states otherwise, I think both forms are acceptable. They just need to be the correct value. I would just make sure on the test to use the correct unit if it specifies in the problem.
- Wed Oct 14, 2020 9:57 pm
- Forum: General Science Questions
- Topic: Balancing equations
- Replies: 19
- Views: 2501
Re: Balancing equations
I just take the compound with the highest element and go from there. Also, you can count the amount of atoms in reactant and products and try to balance it that way. I agree with the other person who commented there are many ways but they should lead to one equation only.
- Tue Oct 13, 2020 7:27 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: mmol
- Replies: 14
- Views: 1531
Re: mmol
Mmol is millimole. Milli- means 1/1000th of. So, it would be 1/1000th of a mole. Also, another example of “milli” is milliliter which is one thousandth of a liter.
- Tue Oct 13, 2020 12:20 am
- Forum: Properties of Light
- Topic: Photoelectric effect
- Replies: 8
- Views: 257
Re: Photoelectric effect
I think that means that the energy of the photon must be greater than or equal the required energy to remove an electron( Threshold energy).Once the threshold energy is met, then electrons will be emitted.
- Tue Oct 13, 2020 12:12 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Wavelengths and Electromagnetic Spectrum
- Replies: 5
- Views: 114
Re: Wavelengths and Electromagnetic Spectrum
I think you just have to know that 400nm to roughly 700nm is visible radiation or visible light anything higher than 700nm would be the Infrared Radiation and anything lower than 400nm would be your Ultraviolet Radiation.
- Mon Oct 12, 2020 9:22 pm
- Forum: Empirical & Molecular Formulas
- Topic: Finding Empirical Formula
- Replies: 10
- Views: 466
Re: Finding Empirical Formula
He multiplied all of them by 3 because you can only have whole numbers when you write out your empirical formula.
- Sun Oct 11, 2020 12:10 am
- Forum: Balancing Chemical Reactions
- Topic: Periodic Table
- Replies: 66
- Views: 4722
Re: Periodic Table
I think we are provided a periodic table for quizzes and exams. You aren’t required to memorize the periodic table only the very basic ones if anything.
- Sun Oct 11, 2020 12:05 am
- Forum: SI Units, Unit Conversions
- Topic: Do I need to do very single textbook question on the syllabus?
- Replies: 34
- Views: 1459
Re: Do I need to do very single textbook question on the syllabus?
The textbook problems aren’t graded. They are highly recommended though because they will be very similar to what you will see on the exams.
- Fri Oct 09, 2020 10:00 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: What does mmol stand for? [ENDORSED]
- Replies: 43
- Views: 5956
Re: What does mmol stand for? [ENDORSED]
The unit is “milli” so mmol would be 1/1000th of a mole. Another example of “milli“ is millimeter which would be 1/1000th of millimeter.
- Fri Oct 09, 2020 12:06 am
- Forum: Empirical & Molecular Formulas
- Topic: Empirical and Molecular Formula
- Replies: 17
- Views: 684
Re: Empirical and Molecular Formula
Yes, the empirical formula can be the same as the molecular formula. The molecular formula will never be less than the empirical formula. This is because the empirical formula is already the lowest possible ratio.
- Mon Oct 05, 2020 6:53 pm
- Forum: Balancing Chemical Reactions
- Topic: Stoichemetric Coeffiecients
- Replies: 12
- Views: 454
Re: Stoichemetric Coeffiecients
You have to multiply to get a whole number if you have a fraction of atoms. For example, in the lecture, if you end up with 13/2 O2 then you must multiply the whole reaction by 2 to get a whole number. I think most likely you will have to do this on the test if you get a fraction of atoms.
- Mon Oct 05, 2020 6:39 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Determining Molar Mass
- Replies: 19
- Views: 595
Re: Determining Molar Mass
I honestly think it really doesn’t make too much of a difference. I personally use 15.999g just to be safe. However, since the difference between the numbers are extremely small. I doubt it would cause your answer to be significantly off if you used 16g instead of 15.999g.
- Mon Oct 05, 2020 12:48 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Question about Moles of Solute
- Replies: 10
- Views: 361
Re: Question about Moles of Solute
The moles of solute will always stay the same. If you add water that will only decrease the concentration of that solution but will not change the moles of solute. If you add the water the volume will increase also. In general, the volume and concentration( Molarity) can change but it is not possibl...
- Mon Oct 05, 2020 12:37 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: VInitial and VFinal
- Replies: 13
- Views: 517
Re: VInitial and VFinal
Yes, M1V1 = M2V2 is typically used as a dilution equation. Concentration can be interchanged with Molarity to give C1V1 = C2V2.
- Mon Oct 05, 2020 12:11 pm
- Forum: Balancing Chemical Reactions
- Topic: Stoichiometric Coefficients
- Replies: 20
- Views: 439
Re: Stoichiometric Coefficients
We cannot assume anything in Chemistry. If a problem has an equation, we should check and see if it is balanced. There will be instances where equations will not be balanced.
- Mon Oct 05, 2020 12:06 pm
- Forum: Empirical & Molecular Formulas
- Topic: Emprical Formulas Ever Larger than Molecular? [ENDORSED]
- Replies: 26
- Views: 1877
Re: Emprical Formulas Ever Larger than Molecular? [ENDORSED]
No, it is not possible for empirical formulas to be greater than molecular formulas. Empirical formula is the simplest whole number ratio of atoms in a compound. On the other hand, molecular formula is exactly the whole number ratio of various types. It is possible for the molecular formula to be eq...