Search found 60 matches

Mon Dec 02, 2019 1:31 pm
Forum: Lewis Acids & Bases
Topic: Difference
Replies: 4
Views: 105

Re: Difference

I think knowing the concepts behind bronzed acids and bases as well as lewis acids and bases is also important.
Mon Dec 02, 2019 1:30 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 9C.9
Replies: 1
Views: 52

Re: 9C.9

It basically asks you the coordination number that is the number of points at which ligands are attached to the central metal atom. For instance, the coordination number for part a would be 4 and so on
Mon Dec 02, 2019 1:28 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Final Study Methods
Replies: 11
Views: 215

Re: Final Study Methods

What helped me the most was going to the workshop sessions which go over specific concepts in detail and also assign problems.
Mon Dec 02, 2019 1:25 pm
Forum: Conjugate Acids & Bases
Topic: Ligands
Replies: 12
Views: 128

Re: Ligands

All the ligands that are directly attached to the central metal atom are part of the coordination sphere.
Mon Dec 02, 2019 1:24 pm
Forum: General Science Questions
Topic: Practice Final
Replies: 3
Views: 121

Re: Practice Final

They will go over the solutions of the final on Friday from 7:30-10pm!
Mon Dec 02, 2019 1:21 pm
Forum: Bronsted Acids & Bases
Topic: Lecture 12/2
Replies: 3
Views: 44

Re: Lecture 12/2

I think he said conjugate bases of weak acids affect the ph of a solution.
Wed Nov 27, 2019 3:38 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: How to take the log to get the pH?
Replies: 8
Views: 101

Re: How to take the log to get the pH?

If you were given a Hydrogen concentration of [H+]=0.1M, for example, and asked to find the pH, you would plug the concentration into the formula pH=-log[H+]; pH=-log[0.1M], and just plug it into your calculator. So would our answer just be 1? Also, would this be interpreted as our pH being 1? This...
Tue Nov 26, 2019 8:39 pm
Forum: Hybridization
Topic: double bonds
Replies: 7
Views: 105

Re: double bonds

The second bond formed as a result of an unhybridized orbital would be a pi- bond.
Tue Nov 26, 2019 8:38 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Summary for Naming Coordination Compounds
Replies: 3
Views: 67

Re: Summary for Naming Coordination Compounds

Another important rule to remember is that, If the ligand name already contains prefixes such as di-, tri-, etc. (as in ethylene diamine) or if it is a polydentate then the prefixes bis-, tris-, tetrakis-, pentakis- are used.
Tue Nov 26, 2019 8:34 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelate
Replies: 3
Views: 61

Re: Chelate

EDTA is an important example for a chelating ligand.
Tue Nov 26, 2019 8:29 pm
Forum: Biological Examples
Topic: EDTA
Replies: 8
Views: 134

Re: EDTA

EDTA- Ethylene Diamine Tetra Acetate is an example of a chelating ligand.
Tue Nov 19, 2019 6:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: SO3(2-)
Replies: 3
Views: 50

Re: SO3(2-)

The presence of a lone pair is what makes it polar.
Tue Nov 19, 2019 6:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma & Pi bonds
Replies: 5
Views: 68

Re: Sigma & Pi bonds

The main reason is because sigma bonds are formed when orbitals overlap end-to-end and pi bonds are formed when orbitals overlap side- by -side. This therefore, makes it difficult for pi bonds to rotate since they would break if rotated.
Tue Nov 19, 2019 6:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.19
Replies: 2
Views: 42

Re: 2E.19

In addition to the previous answer, the bond angle for linear would be 180 degrees and for tetrahedral will be 109.5 degrees
Tue Nov 19, 2019 6:21 pm
Forum: Dipole Moments
Topic: H-bonding & temperature
Replies: 1
Views: 61

Re: H-bonding & temperature

H2O will have the highest boiling point due to hydrogen bonding. For the remaining 3 compounds we consider London forces, which depends on the size of the atom. In this case, atoms grow bigger as we go down a group and so Te will be bigger than Se which will be bigger than S. Therefore of the remain...
Tue Nov 19, 2019 6:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 2
Replies: 2
Views: 76

Re: Test 2

Yes, it is better to know both since they were both covered in lecture.
Tue Nov 19, 2019 6:15 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: Hydrocarbons
Replies: 1
Views: 53

Re: Hydrocarbons

Not really, the example that Doctor Lavelle gave in class of dichloro-ethane. In this case, the cis-dichloroethane will be polar since the dipole moments do not cancel. However, in case of trans-dichloroethane- it is non-polar since the dipole moments cancel each other.
Mon Nov 11, 2019 9:50 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs and Molecular Shape
Replies: 3
Views: 51

Re: Lone Pairs and Molecular Shape

According to the VSEPR theory, lone pairs of electrons repel each other and therefore should be placed as far apart from each other as possible, thus impacting shape of the molecule. The textbook also states it precisely as, "Lone pairs distort the shape of a molecule so as to reduce lone pair–...
Mon Nov 11, 2019 9:45 am
Forum: Bond Lengths & Energies
Topic: Double and Triple Bonds
Replies: 3
Views: 87

Re: Double and Triple Bonds

This is because of the increase in number of electrons shared. Precisely, the textbook defines the reason as, "A multiple bond is almost always stronger than a single bond because more electrons bind the multiply bonded atoms."
Hope that helps
Mon Nov 11, 2019 9:40 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Anions
Replies: 7
Views: 86

Re: Anions

In the textbook it states that, "When a small, highly charged cation is close to a large anion, the electron cloud of the anion is distorted in the process we call polarization." This implies that the anion is polarizable while the cation should have the polarizing power. Smaller atoms wit...
Mon Nov 11, 2019 9:33 am
Forum: Sigma & Pi Bonds
Topic: Chemical Bonds in chemistry
Replies: 3
Views: 62

Re: Chemical Bonds in chemistry

I think we have studied only about two types of chemical bonds that is covalent and ionic. Ionic bonds results from the transfer of electrons between two atoms while covalent bonds result from the sharing of electrons between two atoms. I do not know about the third kind of bonds.
Mon Nov 11, 2019 9:30 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Difference Between Lewis Structure and VSEPR Model
Replies: 3
Views: 1164

Re: Difference Between Lewis Structure and VSEPR Model

According to my understanding of it, the Lewis structure tells us about the electronic structure of an atom, it tells us about about bond lengths, bond strengths etc.
The VSEPR model tells us about the molecular geometry- that is the shape of the molecule.
Mon Nov 11, 2019 9:27 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Bond Angles
Replies: 2
Views: 40

Re: Determining Bond Angles

I also think this might appear when Dr Lavelle begins to discuss the shape of molecules and structures in class.
Mon Nov 04, 2019 1:50 pm
Forum: Resonance Structures
Topic: Octet
Replies: 13
Views: 261

Re: Octet

Atoms like Boron and Aluminum are also exceptions, since they can accommodate only 6 electrons in their valence shell.
Mon Nov 04, 2019 1:47 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 2
Views: 56

Re: Midterm

He has also posted a similar sheet on his website under "Constants and Equations" in case you need to use it for practice problems!
Mon Nov 04, 2019 1:46 pm
Forum: Octet Exceptions
Replies: 6
Views: 105

An example of this can be oxygen I think, because it has 2 unpaired electrons in its valence shell. The textbook also defines radicals as any species having unpaired spins.
Mon Nov 04, 2019 1:41 pm
Forum: Bond Lengths & Energies
Topic: Midterm
Replies: 8
Views: 140

Re: Midterm

I think he said there would be 8 questions on the midterm.
Mon Nov 04, 2019 1:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 5
Views: 89

Re: Midterm

It covers upto and including focus 2D in chemical bonds.
Mon Nov 04, 2019 1:39 pm
Forum: General Science Questions
Topic: Concept Questions
Replies: 2
Views: 65

Re: Concept Questions

I think Dr Lavelle sent out an email about Sapling learning which is an online resource, and he has created multiple assignments and objectives on those. I hope that helps!
Mon Oct 28, 2019 5:01 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 5
Views: 89

Re: Midterm

One of the UA's at yesterday's workshop said that it would be till whatever he covers this week, but he would definitely let us know in class sometime during this week.
Mon Oct 28, 2019 4:57 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectroscopy
Replies: 2
Views: 51

Re: Atomic Spectroscopy

In addition to the previous reply, after getting the frequency you need to use speed of light= frequency times wavelength to obtain the wavelength since that is what we are precisely asked for.
Mon Oct 28, 2019 4:56 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge equation?
Replies: 5
Views: 73

Re: Formal Charge equation?

I think it might refer to the number of bonds, but I'm not entirely sure.
Mon Oct 28, 2019 4:54 am
Forum: Student Social/Study Group
Topic: Will different midterm review sessions cover the same material?
Replies: 8
Views: 126

Re: Will different midterm review sessions cover the same material?

I am not sure if all the midterm review sessions cover the exact same materials or problems since they might be conducted by different UA's or TA's. However, the broad topics covered should be the same, only the specifics might differ.
Mon Oct 28, 2019 4:51 am
Forum: Ionic & Covalent Bonds
Topic: Mnemonics for the period table trends
Replies: 3
Views: 57

Re: Mnemonics for the period table trends

Put simply, there are only two types of trends we observe. Atomic radius which increases down a group and decreases across a period from left to right. The remaining three that is electronegativity, electron affinity, and ionization energy decrease down a group, and increase across a period from lef...
Mon Oct 28, 2019 4:46 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Post Assesment Question (Atomic Spectroscopy)
Replies: 1
Views: 42

Re: Post Assesment Question (Atomic Spectroscopy)

For this question, to begin with you would use the equation E= h times frequency, so convert the given frequency in terms of energy. This is the change in energy, that is the amount of energy emitted when an electron jumps from a higher energy level to a lower one. This change in energy= energy fina...
Mon Oct 21, 2019 10:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Where to find what material you missed if you missed a class?
Replies: 4
Views: 66

Re: Where to find what material you missed if you missed a class?

I think attending the workshops too would be helpful since they sort of summarize what has been done in lecture.
Mon Oct 21, 2019 10:23 pm
Forum: Trends in The Periodic Table
Topic: Homework #4
Replies: 5
Views: 78

Re: Homework #4

Professor Lavelle mentioned that the quantum unit would be a couple of weeks long. And since we haven't already begun chemical bonds, I think this weeks homework should be from the quantum unit too.
Mon Oct 21, 2019 10:20 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 6
Views: 159

Re: Electron Affinity

He also defined electron affinity in class as the difference between the energy of the neutral atom and energy of the cation.
Mon Oct 21, 2019 10:18 pm
Forum: Quantum Numbers and The H-Atom
Topic: f- orbitals?
Replies: 7
Views: 81

Re: f- orbitals?

I also feel that on the midterm or final we would only be tested on s, p, and d orbitals since those are mainly what he covered in class.
Mon Oct 21, 2019 10:16 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4s before 3d
Replies: 4
Views: 48

Re: 4s before 3d

The reason for this is the difference in energies. According to Aufbau's principle, the 4s shell has a lower energy than the 3d shell and hence it gets filled first.
Mon Oct 21, 2019 10:12 pm
Forum: DeBroglie Equation
Topic: Velocity
Replies: 13
Views: 396

Re: Velocity

In this case, I guess such an answer would be unreasonable or not possible because there is nothing that can have a speed greater than that of light.
Fri Oct 18, 2019 9:25 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: how to prepare
Replies: 22
Views: 277

Re: how to prepare

Even the workshops are really helpful to review the material learnt. Also, there are review sessions before the midterm so I think that would help too.
Good Luck!
Mon Oct 14, 2019 6:52 pm
Forum: Properties of Light
Topic: Symbol review
Replies: 3
Views: 51

Re: Symbol review

Momentum- p has units kg m/s
Mon Oct 14, 2019 6:51 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Momentum
Replies: 2
Views: 70

Re: Momentum

The whole idea behind bringing momentum into the picture is to emphasize the fact that an uncertainty in velocity results in an uncertainty in momentum, since we know the mass of the object and it does not change. Moreover, we need the change in momentum to calculate the uncertainty because, accordi...
Mon Oct 14, 2019 6:45 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: *Lowest possible energy?
Replies: 2
Views: 52

Re: *Lowest possible energy?

Could please elaborate what you exactly mean by "energy of a particle?"
Mon Oct 14, 2019 6:43 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Positive and Negative signs?
Replies: 5
Views: 76

Re: Positive and Negative signs?

You would have a negative sign when energy is emitted- electron moves from. higher to lower energy level- and a positive sign when energy is absorbed- electron moves from lower to higher energy level.
Mon Oct 14, 2019 6:40 pm
Forum: *Shrodinger Equation
Topic: Midterm
Replies: 14
Views: 508

Re: Midterm

On his website, it also says that the midterm will be held from 6-8pm on Wednesday, November 6th. So it will not be held during lecture I guess.
Mon Oct 14, 2019 6:37 pm
Forum: Properties of Light
Topic: Variables and Constants for this Unit
Replies: 2
Views: 34

Re: Variables and Constants for this Unit

Just as a reminder, v can also represent velocity so one should be careful while using the variable in an equation.
Fri Oct 11, 2019 4:02 pm
Forum: Student Social/Study Group
Topic: Best Sessions
Replies: 12
Views: 193

Re: Best Sessions

I find the workshops to be most effective, since the UA's make a worksheet relating to the material taught in class which serves as a good test for the material learnt.
Fri Oct 11, 2019 3:59 pm
Forum: Properties of Light
Topic: Converting units
Replies: 8
Views: 85

Re: Converting units

To convert 400 nm to Angstroms, you would first convert it to meters by multiplying it by 10^-9. This would give you the answer in meters. Now you would convert it to angstrom. You would do this by dividing by 10^-10. This would give you the answer in Angstrom which should be 4000A.
Fri Oct 11, 2019 3:56 pm
Forum: Significant Figures
Topic: Sig Figs in % Yield
Replies: 10
Views: 913

Re: Sig Figs in % Yield

You would round up to 64%. This because when number ends in 5, you would round it up to the closest even number according to the rule.
Fri Oct 11, 2019 3:55 pm
Forum: DeBroglie Equation
Topic: When to use DeBroglie Equation
Replies: 16
Views: 321

Re: When to use DeBroglie Equation

You can use De Broglie's equation to find the wavelength of anything hat has a rest mass. For example, an electron has a rest mass. However, light does not have a rest mass and so you cannot use De Broglie's equation to find its wavelength eve though the derivation we did in class involved light.
Fri Oct 11, 2019 1:49 pm
Forum: Limiting Reactant Calculations
Topic: percent yield
Replies: 10
Views: 354

Re: percent yield

It depends on what's given to us. Usually to find the percent yield you would need the actual yield. Through limiting reaction problems, you can usually only find the theoretical yield.
Fri Oct 11, 2019 1:47 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Accuracy and Precision
Replies: 8
Views: 239

Re: Accuracy and Precision

Accuracy is its closeness of measurements to the true value. While, precision is the closeness of measurements to each other. The reason why it was mentioned is that, it is more important to be precise than be accurate with your measurements, especially in a lab.
Fri Oct 04, 2019 1:17 pm
Forum: SI Units, Unit Conversions
Topic: Fundamental E.1
Replies: 5
Views: 108

Re: Fundamental E.1

You have to multiply Avogadro's number with the diameter of the atoms which would be ( two times 144pm= 288pm) and also convert the diameter to meters by multiplying it by (10 to the power of negative 12). Once you multiply these three figures, you should get the answer.
Fri Oct 04, 2019 1:12 pm
Forum: SI Units, Unit Conversions
Topic: Fundamental F.1
Replies: 2
Views: 78

Re: Fundamental F.1

You do not proceed that way, because you can easily find the molecular formula by looking at the structure given to us. We know that dark gray corresponds to carbon, white to hydrogen, and red to oxygen hence you simply count the respective number of atoms for each from the diagram and that gives yo...
Thu Oct 03, 2019 9:10 pm
Forum: Limiting Reactant Calculations
Replies: 14
Views: 277

Khan Academy seems like a good option.
Thu Oct 03, 2019 9:04 pm
Forum: Balancing Chemical Reactions
Topic: HW question M15
Replies: 2
Views: 79

Re: HW question M15

The reactant that is present in lesser quantity, that is the limiting reagent determines the quantity of the product formed. This is because, the reaction would come to a stop once once one of the reactants is completely used up, hence it is important to know which reactant is in lesser quantity bec...
Thu Oct 03, 2019 9:00 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Actual Yield vs Theoretical Yield
Replies: 6
Views: 156

Re: Actual Yield vs Theoretical Yield

The theoretical yield is also known as the maximum yield or the best-case scenario yield.
Thu Oct 03, 2019 1:22 pm
Forum: Properties of Light
Topic: Quantum homework
Replies: 4
Views: 86

Re: Quantum homework

Next week in discussion I think