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by sbottomley3a
Sat Dec 07, 2019 11:58 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radii
Replies: 10
Views: 248

Re: Atomic Radii

It's very useful for determining bond strength and length! I don't think they can ask us to calculate it because it would need to be experimentally confirmed.
by sbottomley3a
Sat Dec 07, 2019 11:49 pm
Forum: *Shrodinger Equation
Topic: schrodingers equation
Replies: 8
Views: 208

Re: schrodingers equation

My TA said that we should know the concept behind the equation, but that we won't be asked to solve anything with it.
by sbottomley3a
Sat Dec 07, 2019 11:47 pm
Forum: Properties of Electrons
Topic: Mass of an electron
Replies: 9
Views: 325

Re: Mass of an electron

It will be given on the reference sheet! It's listed as "constants and equations sheet" on his website if you want to practice with it before the exam.
by sbottomley3a
Sat Dec 07, 2019 11:45 pm
Forum: Empirical & Molecular Formulas
Topic: Rounding
Replies: 6
Views: 244

Re: Rounding

I would only round if it was very close to a whole number. I think anything above 0.9 is safe, but anything less should be multiplied to get whole numbers across the board.
by sbottomley3a
Sat Dec 07, 2019 11:43 pm
Forum: General Science Questions
Topic: Curve
Replies: 9
Views: 341

Re: Curve

In his syllabus, Lavelle says that he sets a C- at a 50% in the class (raw score). He doesn't make the scale for what qualifies as an A or B until after the final exams are graded. Each exam isn't curved, but the entire class is. Hope this helps :)
by sbottomley3a
Sun Dec 01, 2019 7:52 pm
Forum: Calculating the pH of Salt Solutions
Topic: PH
Replies: 5
Views: 63

Re: PH

pH = -log[H3O+]

pH is a measure of the amount of hydrogen ions in the solution! A pH of 1 to 6.9 is acidic, 7 is neutral, and 7.1 to 14 is basic.
by sbottomley3a
Sun Dec 01, 2019 7:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Studying for final exam
Replies: 8
Views: 104

Re: Studying for final exam

In general there is a lot of material that we need to memorize for the final from the last few weeks, so I think that flash cards are going to be very helpful. I'm also going to be doing the practice problems, and attending as many review sessions as possible. Good luck on the final!
by sbottomley3a
Sun Dec 01, 2019 7:43 pm
Forum: Bronsted Acids & Bases
Topic: Conjugate acids and bases
Replies: 5
Views: 85

Re: Conjugate acids and bases

For a conjugate acid, write the formula for the base but add a proton with an H+, and for the conjugate base of an acid, take away an H+.
Example: HCO3– ion.
Conjugate acid: H2CO3,
Conjugate base: CO32–
by sbottomley3a
Sun Dec 01, 2019 7:38 pm
Forum: General Science Questions
Topic: Week 10 Classes
Replies: 7
Views: 168

Re: Week 10 Classes

Friday is definitely a review day!
by sbottomley3a
Sun Dec 01, 2019 7:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Points
Replies: 11
Views: 166

Re: Points

My TA said that we should try to make the 5 posts per week, but was very vague on the way that they were being graded. If you have 50 points by the end of the quarter, you should be okay!
by sbottomley3a
Sun Nov 24, 2019 3:30 pm
Forum: Biological Examples
Topic: Heme complex
Replies: 8
Views: 121

Re: Heme complex

On a test we would most likely have to identity which ligands were bound to which transition metal, and identify if this had any biological significance based on what we know about it's properties (given the charge and any background info the question gives us on where in the body this works or what...
by sbottomley3a
Sun Nov 24, 2019 3:26 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Hydrogen Bonding/Pi bonds
Replies: 11
Views: 267

Re: Hydrogen Bonding/Pi bonds

Pi bonds are also only present in double and triple bonds, since it needs an unhybridized P orbital, while hydrogen bonds are technically sigma bonds since they're only single bonds.
by sbottomley3a
Sun Nov 24, 2019 3:21 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: AXE formula
Replies: 32
Views: 4634

Re: AXE formula

Yes, you can determine the molecular shape from the formula. The subscript off of Xn tells you how many things are bonded to the central atom, and the subscript off of Em tells you how many lone pairs there are on the central atom. With this information, we can figure out the molecular shape. I sugg...
by sbottomley3a
Sun Nov 24, 2019 3:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Shape
Replies: 29
Views: 728

Re: Bent Shape

One or two, depending on it's VSEPR formula. It can be either AX2E or AX2E2.
by sbottomley3a
Sun Nov 24, 2019 3:14 pm
Forum: Naming
Topic: Homework problems Week 9
Replies: 4
Views: 46

Re: Homework problems Week 9

Technically, the university doesn't officially cancel any class that is before 3pm on Wednesday. My TA said that he would make this week's discussion optional, and collect week 9 and 10 homework together during week 10. I would ask your TA to be sure if you need to go on Wednesday!
by sbottomley3a
Fri Nov 15, 2019 11:06 am
Forum: Resonance Structures
Topic: Orbitals
Replies: 4
Views: 99

Re: Orbitals

In the terms of this class, it's an electron that isn't associated with a bond or single atom, so it's free to move about in the atom's space. It isn't "localized" or held to a specific region, like it would most likely be if it were in a bond.
by sbottomley3a
Fri Nov 15, 2019 11:03 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Will polarizability/polarizing power be on test 2?
Replies: 3
Views: 124

Re: Will polarizability/polarizing power be on test 2?

Because it wasn't on the midterm, I believe that it will show up on test 2.
by sbottomley3a
Fri Nov 15, 2019 10:59 am
Forum: Bond Lengths & Energies
Topic: Bond lengths
Replies: 8
Views: 84

Re: Bond lengths

I think we need to know it concept-wise, like which are stronger and shorter and which are longer and weaker.
by sbottomley3a
Fri Nov 15, 2019 10:57 am
Forum: Sigma & Pi Bonds
Topic: Drawing
Replies: 6
Views: 67

Re: Drawing

I think we're responsible for knowing how to identify the shape and the bond angles.
by sbottomley3a
Fri Nov 15, 2019 10:56 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 2
Replies: 11
Views: 109

Re: Test 2

I'm using lots of flashcards to memorize the specific shapes and bond angles. Do you think that this will be the same level of difficulty as test 1 or will it be closer to what we had for the midterm?
by sbottomley3a
Fri Nov 08, 2019 10:29 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: D Subshell
Replies: 7
Views: 197

Re: D Subshell

The D subshell can hold 10 electrons because it has 5 orbitals, each holding a max of 2 electrons.
by sbottomley3a
Fri Nov 08, 2019 10:27 am
Forum: Properties of Light
Topic: Frequency vs. Velocity
Replies: 8
Views: 243

Re: Frequency vs. Velocity

The velocity of light is equal to the constant c, while we can find the frequency of light given it's wavelength.
by sbottomley3a
Fri Nov 08, 2019 10:26 am
Forum: SI Units, Unit Conversions
Topic: Photons
Replies: 3
Views: 164

Re: Photons

eV is another unit that can measure energy, with 1 ev=1.602×10−19 J. We usually convert them to Joules so that we can solve the problem using SI units.
by sbottomley3a
Fri Nov 08, 2019 10:24 am
Forum: Balancing Chemical Reactions
Topic: Balancing This Equation
Replies: 11
Views: 298

Re: Balancing This Equation

Combustion reactions always indicate that the reactant will be burned in O2, and the products at minimum are CO2 and H2O, but there may be others, depending on what exactly was burned in oxygen.
by sbottomley3a
Fri Nov 08, 2019 10:22 am
Forum: General Science Questions
Topic: Test 2
Replies: 20
Views: 252

Re: Test 2

It's only covering topics after the first midterm!
by sbottomley3a
Fri Nov 01, 2019 10:47 am
Forum: Significant Figures
Topic: Sig Figs on Tests
Replies: 24
Views: 1099

Re: Sig Figs on Tests

Always use the lowest number of sig figs stated in the problem! I know that most TAs are lenient on sig figs, but they may grade harsher for the midterm.
by sbottomley3a
Fri Nov 01, 2019 10:46 am
Forum: Bond Lengths & Energies
Topic: Lattice Energy
Replies: 9
Views: 73

Re: Lattice Energy

Lattice energy is the energy stored in the bonds of a crystalline solid ionic compound
by sbottomley3a
Fri Nov 01, 2019 10:42 am
Forum: Resonance Structures
Topic: Delocalization vs. Resonance
Replies: 8
Views: 381

Re: Delocalization vs. Resonance

Resonance represents the tendency of electrons to move within a molecule, so we draw out all possible locations. Decolonization represents the tendency of atoms to delocalize, or spread out.
by sbottomley3a
Fri Nov 01, 2019 10:41 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge equation
Replies: 9
Views: 81

Re: Formal Charge equation

One way to simplify the equation that Lavelle gave us in class is to take the total number of valence electrons in your compound, and then subtract the number of 'sticks' (or bonds) and subtract the number of 'dots' (lone electrons). For me, this saves time and I always get the same formal charge th...
by sbottomley3a
Fri Nov 01, 2019 10:36 am
Forum: Administrative Questions and Class Announcements
Topic: DINO NUGGETS Review Session! Download Problems HERE [ENDORSED]
Replies: 52
Views: 4905

Re: DINO NUGGETS Review Session! Download Problems HERE [ENDORSED]

How will the difficulty of these problems compare to the difficulty of the midterm?
by sbottomley3a
Fri Oct 25, 2019 11:04 pm
Forum: Ionic & Covalent Bonds
Topic: Meaning of Brackets
Replies: 7
Views: 69

Re: Meaning of Brackets

We do this as an easy way to shorten the written electron configuration. Inside of the brackets is the closest noble gas from the row above, since their electron configuration doesn't change, and then next to it we write out the next electrons that our element has above the noble gas.
by sbottomley3a
Fri Oct 25, 2019 11:01 pm
Forum: Electronegativity
Topic: Nonmetals?
Replies: 6
Views: 366

Re: Nonmetals?

Generally, nonmetals are more electronegative because they are closer to a full outershell/ octet, so they have a stronger pull on electrons and are far more likely to gain electrons.
by sbottomley3a
Fri Oct 25, 2019 10:58 pm
Forum: Octet Exceptions
Topic: Resonance structures
Replies: 5
Views: 49

Re: Resonance structures

I think it depends on what the problem asks for, but in general always indicate resonance if there is any and explain why you included the structure that you did (assuming you included one in place of all of them).
by sbottomley3a
Fri Oct 25, 2019 10:56 pm
Forum: Resonance Structures
Topic: Lewis Structure vs. Resonance Structure
Replies: 4
Views: 67

Re: Lewis Structure vs. Resonance Structure

Resonance structures show us multiple forms of a molecule, where the chemical connectivity is the same but the electrons are distributed differently around the structure.
by sbottomley3a
Fri Oct 25, 2019 10:53 pm
Forum: Lewis Structures
Topic: Denoting charge on ions
Replies: 2
Views: 25

Re: Denoting charge on ions

My understanding of it is that this process is going to make it easier as we move on to more complex problems, like how we write out every single step in math when we are learning a new topic or how to use a new equation.
by sbottomley3a
Fri Oct 18, 2019 10:27 am
Forum: Photoelectric Effect
Topic: Spectrum of light
Replies: 6
Views: 71

Re: Spectrum of light

A helpful mnemonic device to remember the order is "I saw my Grandma's X-rated Underpants Visible In My Room" (Gamma, x-ray, uv, visible, infrared, micro, radio). It's a little wacky, but it works!
by sbottomley3a
Fri Oct 18, 2019 10:21 am
Forum: Balancing Chemical Reactions
Topic: Determining the state of matter
Replies: 4
Views: 157

Re: Determining the state of matter

I don't think we are required to know unless it is specifically stated or indicated in the problem given. The question might give the compound's state explicitly, or it may tell us that it has a very high boiling temp, so that we know it may be liquid at room temperature. Some states of compounds we...
by sbottomley3a
Fri Oct 18, 2019 10:15 am
Forum: Molarity, Solutions, Dilutions
Topic: What is Molarity?
Replies: 11
Views: 393

Re: What is Molarity?

Molarity is a measure of the concentration of a solution, is given in moles of solute per liter of solvent, and usually is denoted by "M".
by sbottomley3a
Fri Oct 18, 2019 10:13 am
Forum: Ionic & Covalent Bonds
Topic: Bonds
Replies: 4
Views: 153

Re: Bonds

Most ionic bonds are formed between a metal and a nonmetal element, when the electron is given/not shared. Covalent bonds are usually formed between two nonmetal elements, and they share the electrons.
by sbottomley3a
Fri Oct 18, 2019 10:11 am
Forum: SI Units, Unit Conversions
Topic: Calculate using kg or g?
Replies: 13
Views: 441

Re: Calculate using kg or g?

I think that a good rule of thumb is to give the answer in grams, unless the question specifies kilograms. We usually need to convert to grams to use the molar mass conversions, so at least we're already there!
by sbottomley3a
Fri Oct 11, 2019 10:35 am
Forum: Properties of Light
Topic: Speed of light
Replies: 9
Views: 85

Re: Speed of light

If the question specifically states that it's not in a vacuum, then we can calculate the speed based on the index of the material that it's travelling through. However I think that we'll always be asked about light in a vacuum for the scope of this class? We should ask the TAs for clarification.
by sbottomley3a
Fri Oct 11, 2019 10:31 am
Forum: Administrative Questions and Class Announcements
Topic: Week 2 Homework Problems [ENDORSED]
Replies: 67
Views: 3447

Re: Week 2 Homework Problems [ENDORSED]

For week 3 we should only be submitting problems from the quantum section. We were allowed to submit fundamentals problems for week 2 because so many students were still preparing for the test, and he didn't want us to have to confuse ourselves with new material before it.
by sbottomley3a
Fri Oct 11, 2019 10:26 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Theoretical vs. Actual Yield
Replies: 38
Views: 3368

Re: Theoretical vs. Actual Yield

We calculate theoretical yield based on the limiting reagent. We use however many moles of the LR and the molar ration of the balanced equation to determine how much product we could make under perfect conditions. Actual yield needs to be given in the question, since we don't know it without doing t...
by sbottomley3a
Fri Oct 11, 2019 10:18 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Test 1 [ENDORSED]
Replies: 107
Views: 5074

Re: Test 1 [ENDORSED]

We don't need a blue book or a scantron, and a fact sheet with equations and things like Avogadro's number will be provided. Don't forget your scientific calculator! Good luck everyone!
by sbottomley3a
Fri Oct 11, 2019 10:15 am
Forum: Administrative Questions and Class Announcements
Topic: Weekly Posts
Replies: 4
Views: 76

Re: Weekly Posts

I doubt that our posts carry over. I think the objective is for us to be engaging with our class each week, but we should ask the TAs for clarification.
by sbottomley3a
Fri Oct 04, 2019 9:17 am
Forum: Empirical & Molecular Formulas
Topic: Test Materials
Replies: 13
Views: 223

Re: Test Materials

Don't forget to bring your bruincard to major exams! Some classes/proctors require it to prove that you are indeed the student who is supposed to be taking the exam that you're turning in.
by sbottomley3a
Fri Oct 04, 2019 9:12 am
Forum: Empirical & Molecular Formulas
Topic: 100 gram Method?
Replies: 9
Views: 125

Re: 100 gram Method?

Just be careful and read the problem thoroughly! This trick only works if you are given mass percentage composition but aren't given any specific mass of your sample.
by sbottomley3a
Fri Oct 04, 2019 9:08 am
Forum: Empirical & Molecular Formulas
Topic: What decimal place to round to when taking masses from the Periodic Table?
Replies: 19
Views: 395

Re: What decimal place to round to when taking masses from the Periodic Table?

I use all of the decimal places given usually, but I stop at 3 if pressed for time. I think using sig figs at the end is the best way to ensure accuracy in your calculations. But, on the exam we all should be given the same table so any problems from slight differences in masses we see on the homewo...
by sbottomley3a
Fri Oct 04, 2019 9:04 am
Forum: Empirical & Molecular Formulas
Topic: Tips for Finding Which Number to Multiply a Decimal By to Get a Whole Number
Replies: 10
Views: 240

Re: Tips for Finding Which Number to Multiply a Decimal By to Get a Whole Number

With odd decimals, I usually go back to check my work just to make sure that it's all correct before I begin sorting out the odd decimal. Other posters have mentioned visualizing it as a fraction, and I think that that's a great way to go. For instance, if you get 0.636, that's 7/11. To quickly get ...
by sbottomley3a
Fri Oct 04, 2019 8:55 am
Forum: Empirical & Molecular Formulas
Topic: When should one start rounding in a problem?
Replies: 11
Views: 221

Re: When should one start rounding in a problem?

It's a good rule of thumb to always round at the end of solving. That way, your numbers are as precise as possible and you don't lose anything important in the actual calculation portion.

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