## Search found 60 matches

Fri Jan 15, 2021 8:23 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Simplifying Expressions: K<10^?
Replies: 6
Views: 40

### Re: Simplifying Expressions: K<10^?

The more common rule is to use when K<10^-3, that is what most sources say is the when it will become negligible, so I would stick to that.
Fri Jan 15, 2021 8:21 am
Forum: Student Social/Study Group
Topic: Study Habits
Replies: 82
Views: 194

### Re: Study Habits

The week before the midterms, I make myself do all of the assigned textbook problems, and then re-do any of the ones I got wrong the first time, because he usually puts at least a few textbook problems in the midterms. So I think it is definitely work practicing those, as well as re-doing any ones y...
Fri Jan 15, 2021 8:18 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pa, bar, atm for Kp
Replies: 6
Views: 27

### Re: Pa, bar, atm for Kp

Yes, he said typically we will be using atm and bar to calculate Kp, the other units I don't believe we should be using.
Fri Jan 15, 2021 8:17 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Neglecting Water
Replies: 14
Views: 64

### Re: Neglecting Water

There is much more water than the other molecules in the reaction, so we take it out because it would cause the other molecules to become negligible. Also something else that might help you think about it, water is a liquid and we never use pure liquids when solving any equilibrium constant.
Fri Jan 15, 2021 8:14 am
Forum: Ideal Gases
Topic: n/V = concentration
Replies: 13
Views: 55

### Re: n/V = concentration

n=moles and V=volume, which can be liters. And since concentration is mol/L, n/V can mean the exact same thing.
Sat Jan 09, 2021 1:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs. Q
Replies: 53
Views: 141

### Re: K vs. Q

Yes, Q is used anytime the reaction is not in equilibrium and K is only used when the reaction is in equilibrium. You can use the Q value to comparatively to the K value, to see where you are in the reaction (to see if it needs to shift right or left).
Sat Jan 09, 2021 1:02 pm
Forum: Ideal Gases
Topic: reversing reactions
Replies: 56
Views: 331

### Re: reversing reactions

when you take a reverse reaction, you will inverse the K value (1/K) to get the new K value.
Sat Jan 09, 2021 1:01 pm
Forum: Ideal Gases
Topic: Units of Temperature
Replies: 78
Views: 243

### Re: Units of Temperature

I believe he mentioned in lecture that it should be in Kelvin, and most likely we should know how to covert from celsius if the problem gives us temperature in that unit.
Sat Jan 09, 2021 1:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5H.1
Replies: 2
Views: 8

### Re: 5H.1

When whole equations are being multiplied or divided by a value, then that value becomes an exponent to the previous K value. For example if an equation was multiplied by 2, then the new K value would be K^2.
Thu Jan 07, 2021 2:32 pm
Forum: Ideal Gases
Topic: Kc vs Kp
Replies: 106
Views: 882

### Re: Kc vs Kp

Use Kp when all products and reactants are in the gas phase, and you Kc in any other circumstance. But remember, you never include solids and liquids when determining the equilibrium constant, only molecules in aqueous or gaseous form.
Fri Dec 11, 2020 2:41 pm
Forum: Lewis Structures
Topic: Tips on drawing Lewis structures
Replies: 20
Views: 122

### Re: Tips on drawing Lewis structures

Make sure you count up all of your valence electrons on your atoms in the molecule. Then add any electrons if you have anion (the number of electrons you add is equal to the charge of your anion) or subtract any electrons if you have a cation (again the number of electrons you remove is equal to the...
Fri Dec 11, 2020 2:35 pm
Forum: Dipole Moments
Topic: Drawing Arrows?
Replies: 5
Views: 44

### Re: Drawing Arrows?

The atoms in the molecule with the highest electronegativity will pull the electrons more, creating a negative dipole at that atom. And since that atom is pulling electrons, other parts of the molecule will have a positive dipole since electrons are being pulled away from them. To draw the arrow, th...
Fri Dec 11, 2020 2:28 pm
Forum: Lewis Structures
Topic: Aluminum Chloride
Replies: 2
Views: 12

### Re: Aluminum Chloride

Ionic molecules are considered to have an electronegativity difference of 2. Since aluminum has an electronegativity of 1.61 and chlorine has an electronegativity has a difference of 3.16, their difference isn't big enough, and wouldn't be considered an ionic bond.
Fri Dec 11, 2020 2:17 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Sapling Week 9 HW Question 2
Replies: 11
Views: 94

### Re: Sapling Week 9 HW Question 2

A coordination number relates to how many bonds the TM makes. Since there are 4 Br, you can assume Fe bonds with 4 Br and forms 4 bonds. Thus, creating a coordination number of 4.
Fri Dec 11, 2020 2:12 pm
Forum: Industrial Examples
Topic: Chemotherapy
Replies: 18
Views: 376

### Re: Chemotherapy

The only one I remember being in his lecture was cisplatin. And on the course outline it says we should know chemotherapy drugs, so it might be helpful to remember this for the final.
Sat Dec 05, 2020 6:01 pm
Forum: Student Social/Study Group
Replies: 24
Views: 234

Jason_Glass_3H wrote:He said our grade would be a raw score right? Like he wouldn't curve it?

Yeah he never mentioned anything about a curve, nor has my TA, so I wouldn't count on it.
Sat Dec 05, 2020 6:00 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: pH Chart
Replies: 16
Views: 111

### Re: pH Chart

I don't think we will have to know pH for specific foods or drinks, but I think you should probably know common acids and bases. Also he mentioned that basically everything we consume is acidic, if that helps.
Sat Dec 05, 2020 5:58 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 21
Views: 133

### Re: Final

I believe it will be fairly similar to the two midterms, just with more questions, I think 30 this time, and it will be cumulative . And most likely we will be using a secondary device for the test.
Sat Dec 05, 2020 5:42 pm
Forum: Amphoteric Compounds
Topic: Bismuth and Arsenic
Replies: 3
Views: 34

### Re: Bismuth and Arsenic

My TA was telling us that if there are any discrepancies between Dr. Lavelle's lectures and the textbook, or some other source, always follow what Dr. Lavelle is saying.
Sat Dec 05, 2020 5:41 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids
Replies: 8
Views: 67

### Re: Strength of Acids

Yes, you're right, since Br is a bigger atom, it is farther away from H, making the bond length longer, and thus creating a weaker bond. Since it is a weaker bond, it is easier to dissociate the molecule and create hydronium ions.
Sat Nov 28, 2020 4:40 pm
Forum: Hybridization
Topic: Question 11 sapling
Replies: 5
Views: 16

### Re: Question 11 sapling

It is considered an sp3 hybridization because it has 4 areas of electron density, 3 bonds to oxygen and 1 lone pair. Sp3 orbitals indicate that there are 4 areas of electron density, one provided by the s and 3 others provided by the p.
Sat Nov 28, 2020 3:11 pm
Forum: Sigma & Pi Bonds
Topic: rotation with pi bonds
Replies: 4
Views: 30

### Re: rotation with pi bonds

Since pi bonds are bonded side to side, if one half tries to rotate it will break split from the other side. Sigma bonds can rotate because they are bonded at one point and they won't break.
Sat Nov 28, 2020 3:05 pm
Forum: Bond Lengths & Energies
Topic: Higher Melting Point
Replies: 27
Views: 202

### Re: Higher Melting Point

CHI3 has a higher melting point because it is bigger, and thus more polarizable. Additionally, when atoms are bigger, they have stronger london dispersion forces. since I is bigger than F, CHI3 has stronger london dispersion forces than CHF3, and thus is harder to dissociate and harder to melt.
Sat Nov 28, 2020 3:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Delocalized Pi Bond
Replies: 7
Views: 38

### Re: Delocalized Pi Bond

Delocalized pi bonds occur when a structure has resonance. They are considered delocalized because they do not have a single permanent location, due to the fact that the actual molecule is usually a mix of the resonance structures.
Sat Nov 28, 2020 2:54 pm
Forum: Hybridization
Topic: hybridization
Replies: 5
Views: 59

### Re: hybridization

I don't think he taught us that, and I believe he mentioned we would only have to know s and p orbital hybridizations for the final.
Sun Nov 22, 2020 4:43 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 33
Views: 194

### Re: Covalent Character

Atoms who have a smaller difference in electronegativity tend to have more covalent character. Also atoms that are more polarizable can create more covalent bonds, because they can distort the electron distribution.
Sun Nov 22, 2020 4:39 pm
Forum: Bond Lengths & Energies
Topic: Bond Length vs Size of Molecule
Replies: 14
Views: 121

### Re: Bond Length vs Size of Molecule

In this example, the larger molecules have stronger london dispersion forces, making it more difficult to dissociate than the smaller molecule, the one with weaker london dispersion forces, thus the larger molecule has a higher boiling temperature.
Sun Nov 22, 2020 4:37 pm
Forum: Administrative Questions and Class Announcements
Topic: final
Replies: 5
Views: 26

### Re: final

My TA told me it will be cumulative, so we will have to know everything back to the first week.
Sun Nov 22, 2020 4:36 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Best Formal Charge Equations
Replies: 24
Views: 121

### Re: Best Formal Charge Equations

I think the easiest way to calculate would just be the valence electrons -(number of bonds or lines) - (number of lone pair electrons or dots) to give you formal charge
Sun Nov 22, 2020 4:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Thanksgiving week lectures
Replies: 5
Views: 59

### Re: Thanksgiving week lectures

Technically we have Thursday and Friday off, so I would expect to have lectures Monday and Wednesday.
Sun Nov 15, 2020 11:49 am
Forum: Student Social/Study Group
Topic: Final Jitters
Replies: 226
Views: 35580

### Re: Final Jitters

Feeling really prepared helps me. Usually doing as many practice problems as you can, so you feel like there is nothing you haven't seen. But besides that, you could try going for a quick walk before the test, or doing some deep breathing to help calm your nerves.
Sun Nov 15, 2020 11:44 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Memorizing the Different Shapes
Replies: 4
Views: 36

### Re: Memorizing the Different Shapes

I believe, he does want us to remember the name, and most likely the bond angle. He was basically saying from his lecture you can intuitively figure out the name of the structure based on its shape. I'm not completely sure about the bond angles. I think most of them are pretty straight forward, besi...
Sun Nov 15, 2020 11:40 am
Forum: Significant Figures
Topic: 0's
Replies: 21
Views: 188

### Re: 0's

Yes they do count, you have 4 sig figs since the 0's come after the decimal place.
Sun Nov 15, 2020 11:39 am
Forum: Formal Charge and Oxidation Numbers
Topic: Clarification
Replies: 8
Views: 37

### Re: Clarification

That's right, the sum of all the formal charges in a molecule will give you the overall charge for that molecule.
Sun Nov 15, 2020 11:35 am
Forum: Resonance Structures
Topic: Resonance
Replies: 19
Views: 100

### Re: Resonance

Resonance shows that there are multiple structures for a single molecule. However, the way we draw resonance structures isn't completely accurate, and the actual structure is usually a blend of the resonance structures, which provides the molecule with more stability.
Sun Nov 08, 2020 10:42 am
Forum: Administrative Questions and Class Announcements
Topic: Second Midterm Date
Replies: 9
Views: 73

### Re: Second Midterm Date

It is during week seven whenever you have your discussion section.
Sun Nov 08, 2020 10:31 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: F orbitals?
Replies: 21
Views: 109

### Re: F orbitals?

I think he said we would only be responsible for knowing s, p, and d orbitals for electron configuration. I don't think we would have to know the f orbital.
Sun Nov 08, 2020 10:23 am
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 7
Views: 23

### Re: Ionization Energy

When an atom loses its first electron, the effective nuclear charge has a greater effect on the other electrons. Thus, they are held more tightly to the atom, and they require more energy than the first energy to be removed from the electron
Sun Nov 08, 2020 12:44 am
Forum: Student Social/Study Group
Topic: Studying From Home
Replies: 91
Views: 462

### Re: Studying From Home

Definitely give yourself some breaks. Your brain can easily get fried staring at a screen all day. Also I would recommend exercising, or just going for a walk. Personally, I always feel really refreshed after I go on a run. But anything that helps clear your mind. Whether that be just going outside ...
Sun Nov 08, 2020 12:41 am
Forum: Resonance Structures
Topic: Electron spin
Replies: 12
Views: 47

### Re: Electron spin

I don't believe there is a way to determine the spin, at least not where we are yet. I think it is just important to know that those are the only numerical options for the spin quantum number.
Sun Nov 01, 2020 11:28 am
Forum: Lewis Structures
Topic: Octet Rule
Replies: 12
Views: 74

### Re: Octet Rule

The elements that do no coincide with the octet rule are H, He, Li, and Be, they cannot get a full valence shell.
Sun Nov 01, 2020 11:22 am
Forum: Properties of Light
Topic: Is c always the speed of light?
Replies: 88
Views: 446

### Re: Is c always the speed of light?

Yes for us, c will always be synonymous with speed of light.
Sun Nov 01, 2020 11:08 am
Forum: SI Units, Unit Conversions
Topic: eV to Joules (Defining these Units) Question
Replies: 12
Views: 96

### Re: eV to Joules (Defining these Units) Question

eV stands for electric volts. The conversion is 1 eV=1.60218x10^-19 J
Sun Nov 01, 2020 11:03 am
Forum: Administrative Questions and Class Announcements
Topic: Offline Lecture Content
Replies: 4
Views: 58

### Re: Offline Lecture Content

I don't think there is a way to access the lecture offline, since they are posted on CCLE, sorry.
Sun Nov 01, 2020 10:56 am
Forum: Ionic & Covalent Bonds
Topic: Homework due date
Replies: 49
Views: 332

### Re: Homework due date

It's due 12:59 pm on Sunday, not at the end of Saturday.
Sun Oct 25, 2020 5:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Graphs on Midterm
Replies: 4
Views: 45

### Re: Graphs on Midterm

I really haven't heard anything about graphs. My TA told me it would be a mix of computational and conceptual questions, so I'm pretty sure there won't be graphs.
Sun Oct 25, 2020 5:24 pm
Forum: Einstein Equation
Topic: m vs nm
Replies: 66
Views: 412

### Re: m vs nm

Check the question, it will most likely tell you which units your answer should be in. But make sure when you are doing your calculations that you are using the standard meters for it, and only cover to nm after you have finished your calculations.
Sun Oct 25, 2020 5:20 pm
Forum: Administrative Questions and Class Announcements
Topic: Printouts for Midterm
Replies: 8
Views: 69

### Re: Printouts for Midterm

We aren't allowed to bring any note sheets we make ourselves. However, I believe he sent us an email with two page attachments that we are supposed to print out. One is a periodic table, and the other is an equation and constants sheet. Also we are not allowed to write anything on these sheets befor...
Sun Oct 25, 2020 11:08 am
Forum: SI Units, Unit Conversions
Topic: Do I need to do very single textbook question on the syllabus?
Replies: 34
Views: 254

### Re: Do I need to do very single textbook question on the syllabus?

Hey I kind of have a similar question, but couldn't figure out how to make a new post. Does anyone know if there are answers to the questions in the textbook to check if we are doing them correctly?
Sun Oct 25, 2020 11:04 am
Forum: Properties of Light
Topic: Constants
Replies: 21
Views: 106

### Re: Constants

I don't think it has ever been specified how many to use. Bu the more you use, the more accurate your answer will be. So if possible, I think it would be better to use more.
Sun Oct 18, 2020 2:21 pm
Forum: Photoelectric Effect
Topic: photoelectric effect
Replies: 17
Views: 115

### Re: photoelectric effect

Yes, they mean the same thing, it is just two different ways to say it.
Sun Oct 18, 2020 2:18 pm
Forum: Limiting Reactant Calculations
Topic: Difference between limiting reactant and limiting reagent?
Replies: 14
Views: 108

### Re: Difference between limiting reactant and limiting reagent?

Reactant and reagent mean the same thing. They are just two different ways to say reactant.
Sun Oct 18, 2020 2:15 pm
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 203
Views: 1248

### Re: How are you studying?

For studying I would definitely recommend watching the modules he posts, and doing the post/pre-assesments that go with them, because they have practice problems and you can get more experience by doing them, and sometimes in those videos he will include things he doesn't include in the normal lectu...
Sun Oct 18, 2020 2:11 pm
Forum: Administrative Questions and Class Announcements
Topic: Exams
Replies: 12
Views: 79

### Re: Exams

I think you should try to stick to a paper and pencil, because if you are using device for the exam they won't be able to be sure if you are being honest. However, you could talk to your TA and see with them if it's ok, because our workspace will be monitored during the exams anyways.
Sun Oct 18, 2020 2:09 pm
Forum: Properties of Light
Topic: Word Problems
Replies: 7
Views: 34

### Re: Word Problems

Usually in a word problem they will indicate whether a value is a wavelength or frequency. However, you can also tell by the units given. Frequency will always be in Hertz (Hz or s^-1) and wavelength will usually be given in nanometers (nm) or possibly some other variation of meters.
Sat Oct 10, 2020 8:54 pm
Forum: Student Social/Study Group
Topic: Chemistry basics
Replies: 6
Views: 58

### Re: Chemistry basics

I would check out the audio-visual topics he has on his website, they are very informative and they go over all of the fundamentals in detail. They also have pre-assessments and post-assessments, which will help you to discern what you need more practice with.
Sat Oct 10, 2020 8:52 pm
Forum: Balancing Chemical Reactions
Topic: Molar Mass
Replies: 23
Views: 177

### Re: Molar Mass

In his examples, he usually uses 4 or 5 sig figs (usually 3 numbers after the decimal place), so I would say stick to that amount.
Fri Oct 09, 2020 2:45 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity test question
Replies: 8
Views: 86

### Re: Molarity test question

I believe he said that you should be able to solve for any of the variables in the equation by substituting the numbers given in the problem in for the correct corresponding variables.
Fri Oct 09, 2020 2:38 pm
Forum: SI Units, Unit Conversions
Topic: Volume vs. Density
Replies: 6
Views: 60

### Re: Volume vs. Density

An extensive property depends the on the amount of substance. Volume is an extensive property, because if you have more of a substance, then its volume will be greater. An intensive property doesn't depend on the amount of substance that is present. Density is an intensive property, because if you k...
Fri Oct 09, 2020 2:26 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Reactions Order
Replies: 31
Views: 232

### Re: Balancing Chemical Reactions Order

I think when balancing equations, you should start with balancing the element that occurs the least in the chemical equation, and then go on to balance the other elements in the equation.