## Search found 118 matches

Thu Jan 21, 2021 1:38 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Lower pkb is more basic
Replies: 4
Views: 16

### Lower pkb is more basic

I was wondering if someone could explain why a lower pka means that an acid is stronger and why a lower pkb means that a base is stronger? Also, do higher Ka and Kb values correspond to stronger acids and bases or weaker acids and bases?
Thu Jan 21, 2021 12:11 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook 6B.11 part ii.
Replies: 2
Views: 14

### Textbook 6B.11 part ii.

For Problem 6B.11 part ii in the textbook, I used the M*V of the initial solution=M*V of the final solution equation to try to find the molarity of the original solution. I was wondering why the answer key used the 5 ml that was transferred for the volume of the original solution instead of the volu...
Tue Jan 19, 2021 7:15 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Ka vs. Kb
Replies: 26
Views: 68

### Re: Ka vs. Kb

Ka and Kb are both equilibrium constants for reactions, but Ka is used when an acid is involved in the reaction, while Kb is used when a base is involved in the reaction. Their equations are both the ratio of the concentration of products over the concentration of reactants.
Tue Jan 19, 2021 7:11 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Textbook Question Kw
Replies: 5
Views: 20

### Re: Textbook Question Kw

They're always the same in concentration because when H3O forms that means that a water molecule donated a proton to H2O, which also must mean that the water molecule became OH once it donated its proton.
Tue Jan 19, 2021 7:10 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE table values
Replies: 20
Views: 56

### Re: ICE table values

It can also sometimes be in bars, and in that case, you wouldn't need to convert any units and can just write the number directly into the ICE table.
Tue Jan 19, 2021 7:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water in Reactions
Replies: 7
Views: 26

### Re: Water in Reactions

You only include water in reactions when it's not a liquid. Liquids or solids aren't included in k because they're in so much excess that any change to their concentration doesn't change their overall concentration by much so their concentrations would cancel out in the numerator and the denominator...
Tue Jan 19, 2021 7:05 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: conjugate base
Replies: 14
Views: 47

### Re: conjugate base

The conjugate base of a weak acid is a strong base, so they are opposites in strength.
Mon Jan 18, 2021 1:05 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Table- What increases and what decreases
Replies: 3
Views: 14

### ICE Table- What increases and what decreases

I was wondering whenever we form an ICE Table, how do we know which concentrations will increase and which will decrease? At first, I assumed that products' concentrations will always decrease and reactants' concentrations will always increase, but that doesn't seem to always be the case.
Mon Jan 18, 2021 12:50 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook 5.35
Replies: 2
Views: 9

### Textbook 5.35

Can someone explain how to do part a in Number 5.35? I'm confused on how to balance the equation from looking at the graph.
Mon Jan 11, 2021 2:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kw in Lecture
Replies: 5
Views: 36

### Kw in Lecture

In today's lecture for the example that involved the reaction Ba(OH)2--> Ba+2OH, I was wondering why Professor Lavelle wrote Kw as equal to the hydronium concentration multiplied by the hydroxide equation. Why didn't he include Ba in the equilibrium constant when it's not a solid or liquid?
Mon Jan 11, 2021 2:11 am
Forum: Administrative Questions and Class Announcements
Topic: Participation
Replies: 18
Views: 99

### Re: Participation

We get points for both.
Mon Jan 11, 2021 2:08 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: change in K
Replies: 22
Views: 65

### Re: change in K

Yes, only temperature can change K.
Mon Jan 11, 2021 2:06 am
Forum: Student Social/Study Group
Topic: Study Habits
Replies: 91
Views: 245

### Re: Study Habits

Hi! I think breaking up the outline problems in chunks throughout the week makes things a lot more manageable and gives you more time to ask questions if you need to so you can understand the content better, since I personally tended to cram last quarter. I also would recommend to go to workshops to...
Mon Jan 11, 2021 2:03 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Tables
Replies: 11
Views: 54

### Re: ICE Tables

You use it usually when you want to solve for the concentrations of the reactants and products at equilibrium given the initial concentrations of the reactants and products and the k value.
Mon Jan 11, 2021 2:01 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Coefficients for eq constant
Replies: 9
Views: 26

### Re: Coefficients for eq constant

You raise the concentrations of each reactant and each product to the power of that coefficient in the fraction. Make sure that the reaction is balanced first so you have the right coefficients.
Mon Jan 11, 2021 2:00 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Favors
Replies: 10
Views: 45

### Re: Favors

If a reaction favors the left side/reverse reaction, it means that it will try to create more reactants, while if a reaction favors the right side/forward reaction, it will try to create more products.
Mon Jan 11, 2021 1:57 am
Forum: Student Social/Study Group
Topic: Weekly Assignments
Replies: 5
Views: 25

### Re: Weekly Assignments

Yes, but you should also be working on the outline problems on your own since some of them are on the test and they can pile up if you don't work on them throughout the week.
Mon Jan 11, 2021 1:56 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pure substances
Replies: 9
Views: 29

### Re: Pure substances

For liquids, their concentrations don't change because they are in so much excess that the change is very minimal in comparison to their concentrations. When we write the expression for k, since their concentrations don't change on the reactant and product side, they would cancel out in the numerato...
Sun Jan 10, 2021 12:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to use ice table
Replies: 4
Views: 28

### When to use ice table

When do we know when to use the ICE table? I'm not sure how to tell if the concentration that's given in a problem is the concentration at equilibrium already or if its a concentration not at equilibrium.
Sun Jan 10, 2021 12:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Thermodynamically more stable-5I.13
Replies: 1
Views: 18

### Thermodynamically more stable-5I.13

For Problem 5I Number 13 part c, I was wondering how we know which compound is thermodynamically more stable and what does it mean to be thermodynamically more stable?
Sun Jan 10, 2021 12:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units
Replies: 27
Views: 84

### Units

I was wondering why when we calculate partial pressure the answer could be either in bars or moles per liter. Is there any unit out of the two that is preferred?
Sat Jan 09, 2021 6:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5H 1b
Replies: 3
Views: 15

### 5H 1b

For Problem 5H 1b, I was wondering why the reaction has fractions for coefficients since I thought that we shouldn't have fractions as stoichiometric coefficents.
Fri Jan 08, 2021 1:42 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Change in Pressure
Replies: 9
Views: 38

### Change in Pressure

During today's lecture, Professor Lavelle said that a change in pressure would cause an increase in concentration. I was wondering why that is?
Wed Jan 06, 2021 1:38 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 17
Views: 93

### Re: Q and K

Only Q would change since the equilibrium constant,K, will always be the same amount.
Wed Jan 06, 2021 1:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reverse Reactions
Replies: 12
Views: 46

### Re: Reverse Reactions

Since K is the concentration of products over the concentration of the reactants, and the reverse reaction is the same as the forward reaction but the previous "reactants" are now on the products side and vice versa, K for the reverse reaction would just be the reciprocal of K for the forw...
Wed Jan 06, 2021 1:34 pm
Forum: Ideal Gases
Topic: Units of Temperature
Replies: 82
Views: 287

### Re: Units of Temperature

According to the lecture, we should use Kelvin so that the units cancel out properly.
Mon Jan 04, 2021 1:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constants
Replies: 15
Views: 163

### Re: Equilibrium Constants

Yes because we need the correct stoichiometric coefficients in order to raise the concentration of our reactants and products to the correct power.
Mon Jan 04, 2021 1:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids Not Having Concentration
Replies: 7
Views: 61

### Solids Not Having Concentration

In today's lecture, Professor Lavelle said something about how solids can't have a concentration in a reaction, so it's not included in the expression for the equilibrium constant. Could someone clarify what this means?
Fri Dec 11, 2020 10:49 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.5
Replies: 1
Views: 12

### 6B.5

For part c of 6B.5 in the textbook, why would we multiply the molarity of the compound by two before finding the pOH?
Fri Dec 11, 2020 7:13 pm
Forum: Conjugate Acids & Bases
Topic: Amphoteric compounds memorization
Replies: 1
Views: 18

### Amphoteric compounds memorization

Do we need to memorize the amphoteric compounds for the final?
Fri Dec 11, 2020 1:32 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty in position
Replies: 4
Views: 49

### Re: Uncertainty in position

You would just multiply 0.01 to 0.05 nm, which would be the uncertainty in position.
Wed Dec 09, 2020 12:38 pm
Forum: Lewis Acids & Bases
Topic: pH>pKa from Monday's lecture
Replies: 2
Views: 44

### pH>pKa from Monday's lecture

During Monday's lecture, Professor said that the pH is greater than the pKa value for question number two. I was wondering why does pH correspond to the acid, while pKa correspond to the solution? Do pKa values only apply to solutions?
Wed Dec 09, 2020 1:25 am
Forum: Identifying Acidic & Basic Salts
Topic: Neutralization Reactions
Replies: 1
Views: 29

### Neutralization Reactions

For, Fundamentals J 7, I was wondering if someone could explain to me the steps in writing a neutralization reaction? Also, does the base always have to be bonded to an OH and the acid always be bound to a H in the reactants side?
Tue Dec 08, 2020 6:06 pm
Forum: Naming
Topic: What if I don't know?
Replies: 8
Views: 90

### Re: What if I don't know?

I believe on Professor Lavelle's website there should be a list of the names of different ligands in a table on one of his links!
Tue Dec 08, 2020 6:04 pm
Forum: Naming
Topic: coordination compounds with aqua
Replies: 12
Views: 62

### Re: coordination compounds with aqua

Yes, we can write either since they both represent a water molecule.
Tue Dec 08, 2020 6:02 pm
Forum: Dipole Moments
Topic: induced dipole
Replies: 4
Views: 31

### Re: induced dipole

A dipole is when a molecule has an atom(s) with a partially negative charge and an atom(s) with a partially positive charge. For example, H2O has a partially negative oxygen atom and two partially positive hydrogen atoms. An induced dipole is a dipole that is temporarily created when another molecul...
Tue Dec 08, 2020 5:58 pm
Forum: Molarity, Solutions, Dilutions
Topic: Textbook Fundamentals G #13
Replies: 1
Views: 36

### Textbook Fundamentals G #13

Could someone explain how to solve #13 for Fundamentals G of the textbook? Thanks!
Mon Dec 07, 2020 3:43 pm
Forum: Hybridization
Topic: Double bond C 2p-O 2p
Replies: 1
Views: 18

### Double bond C 2p-O 2p

I was wondering why for problem 2.45a, the pi bond between carbon and oxygen is C2p and O2p. Why is it not also C 2sp2 and O 2sp2?
Mon Dec 07, 2020 3:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Stronger Dipole
Replies: 2
Views: 23

### Stronger Dipole

For 29b of Section 2E in the textbook, I was wondering why the first diagram has a stronger dipole? Why is it that atoms that are closer together have a stronger dipole?
Sun Dec 06, 2020 11:24 pm
Forum: Naming
Topic: Textbook 9C Question 3a
Replies: 2
Views: 18

### Textbook 9C Question 3a

For question 3a of 9C, why is the coordinate compound written as K3[Cr(CN)6]? Shouldn't the K3 be inside the brackets since it's also a ligand? Potassium was written in the beginning of the name, so I would assume that it should be within the brackets.
Sun Dec 06, 2020 9:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle
Replies: 4
Views: 46

### Bond angle

Why is the bond angle in Exercise 2.63 for b in the diagram 109.5 degrees? Shouldn't it be 180 degrees since oxygen is bound to two atoms?
Sun Dec 06, 2020 8:06 pm
Forum: Hybridization
Topic: Unhybridized orbital
Replies: 1
Views: 14

### Unhybridized orbital

In what cases would you know that there is an unhybridized orbital involved when drawing hybrid orbitals?
Sat Dec 05, 2020 1:05 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Monodentate vs. Polydentate
Replies: 3
Views: 49

### Monodentate vs. Polydentate

How would we know if a molecule was monodentate or polydentate when finding the coordination number?
Fri Dec 04, 2020 9:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Angular/Bent Shape
Replies: 3
Views: 49

### Angular/Bent Shape

Is an angular shape only when there are two lone pairs on the central atom and two atoms attached to the central atom? The textbook answer key says that problem 5a in section 2E has an angular shape but it only has one lone pair and two atoms attached.
Tue Dec 01, 2020 11:44 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: TM good for electron transfer
Replies: 1
Views: 16

### TM good for electron transfer

Can someone explain why transition metals are good for electron transfer?
Tue Dec 01, 2020 2:33 am
Forum: Student Social/Study Group
Replies: 24
Views: 245

Hi! Does anyone know how we can see our overall grade for the class on Gradescope because I can only see my grades for each assignment. Also, if not, can any math geniuses tell me how we would calculate our grade.
Tue Dec 01, 2020 2:26 am
Forum: Naming
Topic: Oxidation Number while Naming
Replies: 9
Views: 63

### Re: Oxidation Number while Naming

Each Cl atom has a -1 charge and NH3 and H2O are both known to have neutral charges. Since the overall charge must be neutral or equal to zero since there is no charge written and we have a total charge of -2 from both Cl atoms, that means that Co must have a +2 charge.
Tue Dec 01, 2020 2:24 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 9
Views: 73

### Re: Ligands

A ligand is anything that binds to the transition metal cation and it's included within the brackets when writing the coordination compound.
Tue Dec 01, 2020 2:21 am
Forum: Naming
Topic: Identifying Anions
Replies: 4
Views: 38

### Re: Identifying Anions

Anions are written outside of the brackets because what's in the bracket includes a cation and the ligands bound to it.
Tue Dec 01, 2020 2:17 am
Forum: Naming
Topic: Oxidation number of ligands
Replies: 11
Views: 90

### Re: Oxidation number of ligands

I think we should be able to recognize a few, but the test could possibly have the oxidation number of the ligands given to us so that we only have to solve for the oxidation number of the cation, but this is just a guess.
Tue Dec 01, 2020 2:14 am
Forum: Biological Examples
Topic: Biological function of sigma and pi bonds
Replies: 4
Views: 52

### Re: Biological function of sigma and pi bonds

That's a good start, but you should also know that pi bonds are rigid and form when orbitals overlap side-to-side, while sigma bonds are more flexible and form when orbitals overlap end-to-end.
Sun Nov 29, 2020 10:13 pm
Forum: Hybridization
Topic: hydrogen atoms in same plane
Replies: 4
Views: 54

### hydrogen atoms in same plane

For Week 8 Sapling Number 18, why is it that the hydrogen atoms are in the same plane for H2CCH2 and H2CCCCH2 but not for H2CCCH2?
Mon Nov 23, 2020 1:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Axial vs Equatorial atoms
Replies: 8
Views: 91

### Re: Axial vs Equatorial atoms

Axial atoms are atoms on the vertical axis, and equatorial axis are atoms arranged on the horizontal axis. I don't think we'll be provided diagrams. He probably just included them on the lecture to help us better visualize the structures.
Mon Nov 23, 2020 1:22 pm
Forum: Octet Exceptions
Replies: 4
Views: 35

We don't need to know exactly how long they last. We just need to know that they're unstable and highly reactive. They arise because covalent bonds are broken apart, which leaves each atom that was bonded with one electron, and I believe that this occurs in a lot of metabolic processes in the body.
Mon Nov 23, 2020 1:21 pm
Forum: Ionic & Covalent Bonds
Topic: Ionization Energy
Replies: 19
Views: 150

### Re: Ionization Energy

It will be taken from the valence electrons in the outer orbital because these are less tightly held to the nucleus since the other electrons in the inner shells are shielding them from the positive attraction of the protons in the nucleus.
Mon Nov 23, 2020 1:18 pm
Forum: Determining Molecular Shape (VSEPR)
Replies: 4
Views: 40

Yes,we would consider them as single regions of electron density.
Mon Nov 23, 2020 1:12 pm
Forum: Sigma & Pi Bonds
Topic: Double bond- second one is pi
Replies: 2
Views: 40

### Double bond- second one is pi

I was wondering if someone could clarify why in a double bond, the first bond would be a sigma bond, but the second bond has to be a pi bond.
Thu Nov 19, 2020 10:51 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability of anions
Replies: 6
Views: 62

### Polarizability of anions

One of the textbook problems said to put several anions in order of increasing polarizability. I was wondering why nitrogen with a 3- charge is more polarizable than oxygen with a 2- charge. I thought that oxygen had a lower electronegativity than nitrogen, and therefore should be bigger and have a ...
Thu Nov 19, 2020 10:26 pm
Forum: Bond Lengths & Energies
Topic: 2D #13a
Replies: 3
Views: 35

### 2D #13a

I'm confused about how to solve problem 2D #13a. I know that decreasing bond length means that the number of bonds increases. However, when I draw CO3 with a 2- charge it seems to have a single bond between one carbon and oxygen and a double bond between that same carbon and another oxygen, so I don...
Thu Nov 19, 2020 2:48 pm
Forum: Electronegativity
Topic: Electronegativity difference
Replies: 8
Views: 68

### Electronegativity difference

One of the questions in the textbook asked if CH4 or CF4 had bonds with greater ionic character. I know that bonds with greater ionic character have a larger electronegativity difference between its atoms. I was wondering why carbon and fluorine have a greater electronegativity difference than carbo...
Wed Nov 18, 2020 5:49 pm
Forum: General Science Questions
Topic: Which would have lower ionization energy?
Replies: 13
Views: 118

### Re: Which would have lower ionization energy?

I think you could verify by drawing different resonance structures, one with chlorine in the center and the other with oxygen in the center. The one with the overall lower formal charge for each atom would be the molecule with the correct center atom.
Tue Nov 17, 2020 6:09 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures for Long Molecules
Replies: 2
Views: 14

### Drawing Lewis Structures for Long Molecules

For Section 2C Problem 5c, how would we know how to draw ClONO2? I know the problem gives us a hint that the central atom, O, is attached to Cl and N, but how would we know whether to draw the remaining two oxygen atoms horizontally or vertically?
Tue Nov 17, 2020 1:44 am
Forum: Resonance Structures
Topic: 2C #3
Replies: 2
Views: 32

### 2C #3

For problem 3 of 2C, we're supposed to draw the resonance structures in addition to the Lewis dot diagram. For part a, I was wondering why we would have to draw the resonance structure for the periodate ion, since when you draw it normally it doesn't include any double bonds. I thought that you only...
Mon Nov 16, 2020 10:51 pm
Forum: Quantum Numbers and The H-Atom
Topic: subshells and orbitals
Replies: 9
Views: 95

### Re: subshells and orbitals

A subshell would be like the s,p,d, and f subshells. The s subshell has 1 orbital, p has 3 orbitals, d has 5 orbitals, and f has 7 orbitals (add 2 each time). Each orbital can "hold" a different number of electrons. For instance, the s subshell can hold 2 electrons in its one orbital and t...
Mon Nov 16, 2020 10:45 pm
Forum: Quantum Numbers and The H-Atom
Topic: when n=5 and l=4
Replies: 16
Views: 156

### Re: when n=5 and l=4

I don't think we need to know the answer to this question since we usually are given values of l up to 3. l=0 corresponds to the s subshell, and l=1 corresponds to the p subshell. l=2 corresponds to the d subshell, and l=3 corresponds to the f subshell. Since there aren't any other subshells that we...
Mon Nov 16, 2020 10:38 pm
Forum: Student Social/Study Group
Topic: Favorite TV shows
Replies: 176
Views: 874

### Re: Favorite TV shows

I recommend Stranger Things, Avatar the Last Airbender, Crash Landing on You, Friends, Umbrella Academy, and Adventure Time. :))
Mon Nov 16, 2020 10:37 pm
Forum: Student Social/Study Group
Topic: Favorite TV shows
Replies: 176
Views: 874

### Re: Favorite TV shows

I recommend Stranger Things, Avatar the Last Airbender, Crash Landing on You, Friends, Umbrella Academy, and Adventure Time. :))
Sat Nov 14, 2020 10:37 pm
Forum: Lewis Structures
Topic: Central atom in NH4Cl
Replies: 7
Views: 48

### Central atom in NH4Cl

How do I determine the central atom in NH4Cl? I know hydrogen should never be the central atom, but I don't know whether nitrogen or chlorine would be the central atom.
Sat Nov 14, 2020 12:39 am
Forum: Ionic & Covalent Bonds
Topic: Cations and Anions
Replies: 3
Views: 36

### Cations and Anions

Are all metals cations and are all nonmetals anions? Or is it only some metals and some nonmetals?
Fri Nov 13, 2020 11:49 pm
Forum: Ionic & Covalent Bonds
Topic: Metals and Nonmetals in p block
Replies: 3
Views: 32

### Metals and Nonmetals in p block

Are we allowed to draw a jagged line on our periodic table in the p block to distinguish which are nonmetals and metals for the test or are we expected to memorize where the line is and which are the metalloids?
Wed Nov 11, 2020 1:52 pm
Forum: Dipole Moments
Topic: Liquid vs. Solid vs. Gas
Replies: 5
Views: 33

### Liquid vs. Solid vs. Gas

In the lecture, Professor Lavelle was talking about the different states of matter that result from larger amounts of atoms with the tube and stick example. I'm confused about the relationship between the polarizability of a compound and its state of matter.
Mon Nov 09, 2020 7:03 pm
Forum: Student Social/Study Group
Topic: Studying From Home
Replies: 91
Views: 481

### Re: Studying From Home

Hi! I find that playing lofi music while I'm studying helps me concentrate and also using this free app called Flora helps. Basically, it plants a specific kind of tree for every time interval that you study, and I find that it helps me feel a lot more motivated because I'm basing my productivity of...
Mon Nov 09, 2020 6:59 pm
Forum: Student Social/Study Group
Topic: Mid-quarter Check in
Replies: 67
Views: 281

### Re: Mid-quarter Check in

A little overwhelmed because the workload for each class is increasing but I'm glad that each class is only a quarter long so I'm less likely to feel burnt out.
Mon Nov 09, 2020 6:57 pm
Forum: Student Social/Study Group
Topic: Mid-quarter Check in
Replies: 67
Views: 281

### Re: Mid-quarter Check in

A little overwhelmed because the workload for each class is increasing but I'm glad that each class is only a quarter long so I'm less likely to feel burnt out.
Mon Nov 09, 2020 6:53 pm
Forum: Electronegativity
Topic: Electronegativity trends
Replies: 2
Views: 39

### Electronegativity trends

I understand that electronegativity increases across a row and decreases down a group. However, I was wondering if we were given two elements, for example Be and Ni, how would we be able to determine which is more electronegative since Ni is below Be so it should be less electronegative, but it's al...
Mon Nov 09, 2020 6:49 pm
Forum: Dipole Moments
Topic: Dipole clarification
Replies: 6
Views: 31

### Re: Dipole clarification

I think it applies to covalent bonds since dipole refers to molecules where atoms are covalently bonded but the electrons aren't equally shared.
Mon Nov 09, 2020 6:47 pm
Forum: Ionic & Covalent Bonds
Topic: delta + or -
Replies: 12
Views: 71

### Re: delta + or -

I believe oxygen has a more negative charge because it's more electronegative than hydrogen. Oxygen is closer towards the right side of the periodic table than hydrogen, so that means an oxygen atom is smaller in size than a hydrogen atom, so it'll cling to electrons more tightly.
Mon Nov 09, 2020 6:38 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic/Covalent
Replies: 8
Views: 43

### Re: Ionic/Covalent

A molecule can be covalent in the sense that electrons are being shared between the atoms of the molecule. However, this doesn't mean that the atoms are necessarily shared equally, because one atom might pull the electrons more strongly and therefore have a more negative charge. This means that the ...
Mon Nov 09, 2020 6:33 pm
Forum: Lewis Structures
Topic: Confused on a Symbol
Replies: 3
Views: 24

### Re: Confused on a Symbol

It stands for delta. Delta positive means that the atom on that part of the covalent bond has a slightly more positive charge, while delta negative means that the atom on that part of the covalent bond has a slightly more negative charge.
Mon Nov 02, 2020 1:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Lecture cutoff
Replies: 7
Views: 78

### Re: Lecture cutoff

No, that happened to me too. He put at the top of his lecture that he accidentally cut off the lecture and that he'll continue explaining the problem at the beginning of the next lecture.
Mon Nov 02, 2020 1:32 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Extended Octet for Sulfur
Replies: 3
Views: 38

### Extended Octet for Sulfur

I'm a bit confused on why Professor Lavelle said that sulfur has an extended octet, or that it can have more than 8 valence electrons in the example with the sulfate ion.
Mon Nov 02, 2020 1:30 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Electron Configuration
Replies: 10
Views: 184

### Re: Electron Configuration

The textbook is right.When you write the electron configuration, 3d^10 comes before 4s^2. The reason why Professor Lavelle mentioned that 4s^2 comes before 3d^10 is because that's the order if you read from left to right in the periodic table so people might think that that's the order of the electr...
Mon Nov 02, 2020 1:26 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Why do we use formal charge?
Replies: 14
Views: 115

### Re: Why do we use formal charge?

We calculate the formal charge for each atom so that we can modify the structure in order to get a total formal charge for the molecule of zero, which is more stable, and therefore more preferable.
Mon Nov 02, 2020 1:26 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Why do we use formal charge?
Replies: 14
Views: 115

### Re: Why do we use formal charge?

We calculate the formal charge for each atom so that we can modify the structure in order to get a total formal charge for the molecule of zero, which is more stable, and therefore more preferable.
Mon Nov 02, 2020 12:37 pm
Forum: Lewis Structures
Topic: Delocalized Definition
Replies: 4
Views: 45

### Delocalized Definition

In the lecture, Professor Lavelle said that resonance structures are delocalized. Can someone explain what "delocalized" means?
Sat Oct 31, 2020 6:59 pm
Forum: Ionic & Covalent Bonds
Topic: Homework due date
Replies: 49
Views: 336

### Homework due date

Hi, if the Sapling homework is due on Sunday at midnight does that mean it's due Saturday night when it becomes 12 am or is it due Sunday night?
Sat Oct 31, 2020 6:56 pm
Forum: Student Social/Study Group
Topic: How to relax
Replies: 113
Views: 594

### Re: How to relax

I like to watch some TV shows, go hiking/go on a walk, and draw. Following guided meditations on youtube are also really helpful.
Sat Oct 31, 2020 6:04 pm
Forum: Ionic & Covalent Bonds
Topic: Main group elements
Replies: 8
Views: 66

### Main group elements

Can someone explain what main group elements are?
Thu Oct 29, 2020 5:37 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Exercise 1A #15
Replies: 2
Views: 22

### Exercise 1A #15

Hi, I was wondering if someone could explain how to solve #15 for Exercise 1A in the textbook using Professor Lavelle's way? The Rydberg equation is more confusing for me than his method. Basically, I would like to know how to solve the problem without using the Rydberg's equation in the textbook.
Wed Oct 28, 2020 6:01 pm
Forum: Limiting Reactant Calculations
Topic: Cl vs Cl2
Replies: 9
Views: 90

### Cl vs Cl2

When a questions says chlorine gas instead of chlorine, does that mean we write Cl2 instead of Cl? Also, do we do this everytime we see the word "gas"? For example, if the problem says oxygen gas, would we write O2 instead of O?
Wed Oct 28, 2020 12:11 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Equation
Replies: 4
Views: 37

### Re: Bohr Equation

It means that energy was released, so keep in mind that it doesn't represent negative energy since that's a common misconception.
Wed Oct 28, 2020 12:10 am
Forum: SI Units, Unit Conversions
Topic: Angstrom
Replies: 6
Views: 66

### Re: Angstrom

6.001*10^-17 m is correct if you're multiplying those two numbers. 6.001*10^-7 multiplied by 10^-10 is 6.001*10^-17 because since 10^-7 and 10^-10 have the same bases, you can add their exponents to get 10^-17. 10^-17 is multiplied to 6.001 to get the answer your calculator gave you. I'm not sure wh...
Wed Oct 28, 2020 12:05 am
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 13
Views: 119

### Re: Photoelectric Effect

I believe it still gets absorbed, and the electrons in the metal are excited, but they're just not removed.
Wed Oct 28, 2020 12:03 am
Forum: Administrative Questions and Class Announcements
Topic: Way to search posts for similarity?
Replies: 9
Views: 67

### Re: Way to search posts for similarity?

You can type the keywords of the topic of your question into the search bar and there should be similar search results.
Mon Oct 26, 2020 10:03 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital shapes
Replies: 3
Views: 38

### Re: Orbital shapes

I'm not sure if the nuclear charge is responsible for the shape, but I know that the electrons can still be removed because there are other electrons which are bound more tightly that reduce the amount of attraction there is between the nucleus and the outer electrons.
Mon Oct 26, 2020 12:36 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Subshell Definition
Replies: 9
Views: 60

### Subshell Definition

Hi! I'm confused about what a subshell is and how it's different from an orbital.
Wed Oct 21, 2020 12:06 am
Forum: Properties of Light
Topic: Longer wavelength means larger wavelength?
Replies: 5
Views: 52

### Longer wavelength means larger wavelength?

Hi! I was working on a question in the post-test for a module, and it was asking for which object had a longer wavelength. Does a longer wavelength mean the same thing as a larger wavelength? Thanks!
Tue Oct 20, 2020 2:42 am
Forum: Properties of Light
Topic: IR faster than Visible Light?
Replies: 5
Views: 22

### Re: IR faster than Visible Light?

Infrared radiation is actually not faster than visible light, because all light travels at the speed of c, or 3.00x10^8 m*s^(-1). Yes, infrared radiation does have a longer wavelength, but that doesn't mean that it's faster or slower than visible light.
Tue Oct 20, 2020 2:35 am
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 203
Views: 1287

### Re: How are you studying?

Hi! I would recommend doing corresponding practice problems from the textbook after each lecture because then the information is fresh in your mind. I also recommend not checking the answers in the solutions manual until you really can't solve the problem. You can make condensed study outlines/sheet...
Tue Oct 20, 2020 2:25 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Absorption vs Emission Spectrum
Replies: 4
Views: 47

### Re: Absorption vs Emission Spectrum

The absorption spectrum and emission spectrum represent the same spectrum. The absorption spectrum show the specific wavelengths of light that were absorbed, and the emission spectrum shows the specific wavelengths of light that were emitted. The amount of light absorbed is equal to the amount of li...