Search found 100 matches

by Sarah Blake-2I
Fri Jan 17, 2020 10:41 am
Forum: Ideal Gases
Topic: final exam pickup
Replies: 4
Views: 31

final exam pickup

This is just a general question, but when can we pick up our 14A final exams and where? I thought it was this week but I have also heard it is next week so if anyone has gotten theirs or knows exactly when we can pick them out please let me know!
by Sarah Blake-2I
Thu Jan 16, 2020 10:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5 percent rule
Replies: 10
Views: 35

Re: 5 percent rule

The 5% rule refers to the acceptable percentage of x in relation to the initial amount that makes it okay to approximate the percent ionization with weak acid and base calculations.
by Sarah Blake-2I
Thu Jan 16, 2020 9:57 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: ICE table
Replies: 6
Views: 22

Re: ICE table

Yes you should memorize the common strong bases and be able to recognize weak acids and bases, however it is more important to just know the strong ones. Then when you are finding a pH of a weak base or acid, you will need to use an ICE table.
by Sarah Blake-2I
Wed Jan 15, 2020 11:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.35 finding partial pressure
Replies: 2
Views: 13

5.35 finding partial pressure

In question 5.35, you are given a graph for A, B, and C. You are asked to write an equation and calculate the k value. I am just confused as to how I would find the exact partial pressure values for the K equation just by looking at the graph. I am unsure how to add the graph onto this post but the ...
by Sarah Blake-2I
Tue Jan 14, 2020 12:40 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKa
Replies: 3
Views: 13

pKa

What is the significance and meaning of a pKa value when looking at weak acids and bases? I understand what the Ka value means and I know that pKa is the -log of Ka, but what is the importance of that value?
by Sarah Blake-2I
Tue Jan 14, 2020 12:39 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: autoprotolysis
Replies: 1
Views: 12

autoprotolysis

Is water the only molecule able to undergo autoprotolysis or are there other examples of compounds that can be classified under this type of interaction?
by Sarah Blake-2I
Tue Jan 14, 2020 12:37 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Significant Figures
Replies: 1
Views: 11

Re: Significant Figures

From what I can tell, there should be 3 sig figs as that is the minimum amount of sig figs used in the problem. Perhaps the book made a mistake and used two sig figs by accident.
by Sarah Blake-2I
Sun Jan 12, 2020 12:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Write reaction quotient Q
Replies: 2
Views: 8

Re: Write reaction quotient Q

I was wondering the same thing. I think that if all of the reactants and products are gases, the book will just write it in partial pressure, but I do not believe it matters since the question does not specify whether or not you will be given concentration or a pressure value.
by Sarah Blake-2I
Sun Jan 12, 2020 12:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Temperature and K
Replies: 6
Views: 34

Re: Temperature and K

K is constant only at the same temperature. If the temperature changes, you will get a different K value, because the energy being absorbed changes as well as the rate of reactants and products.
by Sarah Blake-2I
Sun Jan 12, 2020 10:53 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: changing conditions
Replies: 6
Views: 17

changing conditions

Can someone explain why taking away product leads to more product? I am just a bit confused on that topic.
by Sarah Blake-2I
Sun Jan 12, 2020 10:48 am
Forum: Ideal Gases
Topic: aqueous elements in eq calculation
Replies: 3
Views: 13

aqueous elements in eq calculation

I know we do not include solids or liquids in the Kc calculation but do we also not include aqueous solutions? Could someone clarify this for me?
by Sarah Blake-2I
Sun Jan 12, 2020 10:39 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: meaning of equilibrium [ENDORSED]
Replies: 3
Views: 20

meaning of equilibrium [ENDORSED]

What does it mean for a reaction to be at equilibrium? Does that mean that there are equal amounts of reactant and product once it hits equilibrium or does it just mean that it is going to products and reactants at an equal rate?
by Sarah Blake-2I
Sun Jan 12, 2020 10:37 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: when to use Kc vs Kp
Replies: 11
Views: 33

when to use Kc vs Kp

When writing out the Kc or Kp, how do we know when to show the values in brackets (concentration) vs using P and a subscript of the element. What I am trying to ask is do we only write the values in brackets if we are calculating Kc?
by Sarah Blake-2I
Sun Jan 12, 2020 10:33 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc vs Kp
Replies: 10
Views: 20

Re: Kc vs Kp

It all just depends on what information is given in the problem. If they give you pressure values then I would assume that the concentration would be a different value than the pressure value thus making Kc and Kp different values.
by Sarah Blake-2I
Wed Dec 04, 2019 10:44 pm
Forum: Hybridization
Topic: Hybridized orbitals
Replies: 2
Views: 24

Re: Hybridized orbitals

The energy level is implied and yes you are correct there would be a 2p in front of the hybridization if it fills up the additional orbital, such as the case with NO2.
by Sarah Blake-2I
Wed Dec 04, 2019 10:43 pm
Forum: Naming
Topic: OH2
Replies: 1
Views: 14

Re: OH2

That just means that the O is bonded to the metal ion instead of the hydrogen. It is written like that to emphasize how it bonds to the metal!
by Sarah Blake-2I
Wed Dec 04, 2019 10:41 pm
Forum: Naming
Topic: Naming Help
Replies: 1
Views: 26

Re: Naming Help

Look at each part of the chemical formula and break it down. I like to name the individual atoms or ligands and then after I get the names, I follow the procedure of putting them in alphabetical order and deciding the charge of the metal ion. Looking at the entire compound as a whole can be overwhel...
by Sarah Blake-2I
Wed Dec 04, 2019 10:39 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: isomers
Replies: 1
Views: 12

Re: isomers

We do not need to know isomers for the final.
by Sarah Blake-2I
Wed Dec 04, 2019 10:26 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: ammine versus amine
Replies: 1
Views: 20

ammine versus amine

Is there a difference between saying ammine with two "m's" versus amine with one "m" when naming ligands? Do both refer to NH3?
by Sarah Blake-2I
Wed Dec 04, 2019 10:22 pm
Forum: Identifying Acidic & Basic Salts
Topic: amphoteric versus amphiprotic
Replies: 1
Views: 15

amphoteric versus amphiprotic

Can someone explain the difference between amphoteric and amphiprotic? What is the difference and what topic does this apply to?
by Sarah Blake-2I
Wed Dec 04, 2019 2:22 am
Forum: Identifying Acidic & Basic Salts
Topic: writing equation
Replies: 1
Views: 25

writing equation

Could someone walk me through how to write out an equation to find out if the solution is acidic or basic? For instance KF in water. How would you write the chemical equation for this and how do you know if it will produce hydronium or hydroxide?
by Sarah Blake-2I
Tue Dec 03, 2019 1:42 pm
Forum: Polyprotic Acids & Bases
Topic: box 6E.1
Replies: 1
Views: 21

box 6E.1

Will we need to know how to do the calculations in box 6E.1? The directions are slightly confusing and I do not remember this from lecture. Thanks!
by Sarah Blake-2I
Tue Dec 03, 2019 1:25 pm
Forum: Identifying Acidic & Basic Salts
Topic: deciding whether the solution of a salt is basic, acidic, or neutral
Replies: 5
Views: 49

deciding whether the solution of a salt is basic, acidic, or neutral

In section 6D.3 in the textbook, they talk about how to decide whether the solution of a salt will be acidic, basic, or neutral. I was a little lost when they explain it in the book, so could someone further explain this concept to me? And will we need to do problems regarding this concept for the f...
by Sarah Blake-2I
Sun Dec 01, 2019 5:07 pm
Forum: Lewis Acids & Bases
Topic: oxoacids
Replies: 1
Views: 21

oxoacids

Could someone explain the concept of oxoacids? Does more electronegativity result in a stronger acid due to this concept or is it part of the concept of oxoacids? This is from 11/27 lecture.
by Sarah Blake-2I
Sun Dec 01, 2019 5:03 pm
Forum: Lewis Acids & Bases
Topic: strong and weak acids
Replies: 3
Views: 20

strong and weak acids

What are some common examples we would need to know for the final for strong/weak acids and bases? How do you tell if an acid or base is strong or weak?
by Sarah Blake-2I
Sun Dec 01, 2019 5:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: coordination compound
Replies: 1
Views: 16

coordination compound

What does it mean to have a compound outside of the coordination sphere and how does that compound come into play when drawing the structure?
by Sarah Blake-2I
Sun Dec 01, 2019 4:51 pm
Forum: Lewis Acids & Bases
Topic: bronsted vs lewis
Replies: 9
Views: 42

bronsted vs lewis

What is the difference between Bronsted acids and bases and Lewis acids and bases? WOuld you be able to tell the differnce in the way they are written out?
by Sarah Blake-2I
Sun Dec 01, 2019 4:41 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: polydentate
Replies: 3
Views: 17

polydentate

What is a polydentate? Does it have to do with ligands and the naming of them? I just need some clarification as I am a bit confused with this unit and topic. Thanks!
by Sarah Blake-2I
Sun Dec 01, 2019 4:37 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelate
Replies: 1
Views: 15

chelate

Can someone explain what a chelate is and how to draw them?
by Sarah Blake-2I
Tue Nov 26, 2019 11:32 pm
Forum: Naming
Topic: Naming coordination compounds
Replies: 1
Views: 31

Naming coordination compounds

Could someone run through the steps of naming a coordination compound. I’m confused on how to get the full name and what gets shortened and what stays in its full name.
by Sarah Blake-2I
Sun Nov 24, 2019 9:27 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: homework
Replies: 3
Views: 34

homework

Is the homework that we turn in week 9 or 10 from this section only or does it also include hybridization?
by Sarah Blake-2I
Sun Nov 24, 2019 9:24 am
Forum: Hybridization
Topic: Hybridization Confusion
Replies: 3
Views: 35

Re: Hybridization Confusion

I think you just need to know what Lavelle went over in lecture. Basically the amount of electron density in a molecule is how many orbitals will be used, so if the molecule has 3 areas of electron density, 3 orbitals need to be used. It will be sp2 hybridized due to the way we put together the orbi...
by Sarah Blake-2I
Thu Nov 21, 2019 12:01 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: cisplatin
Replies: 4
Views: 41

cisplatin

Hi! Could someone explain why the cis model in today's lecture is what forms the chemotherapy drug cisplatin? I was a little confused during the explanation of this in lecture.
by Sarah Blake-2I
Wed Nov 20, 2019 11:57 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: Carbon Monoxide
Replies: 3
Views: 23

Re: Carbon Monoxide

I believe CO should have dipole-dipole interactions since there is a difference in electronegativity between C and O. The O will have a partial negative charge and the C will have a partial positive charge, thus forming a dipole. This dipole does not cancel out, which means the molecule is polar and...
by Sarah Blake-2I
Wed Nov 20, 2019 11:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Name confusion
Replies: 4
Views: 31

Re: Name confusion

It all depends on the lone pairs and how many regions of electron density there are in the molecule. AX4E with 4 bonds and 1 lone pair will be see-saw not tetrahedral due to the presence of the lone pair. Tetrahedral is just AX4 with no lone pairs. AX3E2 with 3 bonds and 2 lone pairs would be t-shap...
by Sarah Blake-2I
Wed Nov 20, 2019 11:46 pm
Forum: Sigma & Pi Bonds
Topic: pi bond locations
Replies: 3
Views: 34

Re: pi bond locations

I do not think we need to know this for the test. Just know what pi and sigma bonds are and how they relate to the molecule in terms of strength and properties (pi bonds make the molecule rigid). Their location and whether or not they are parallel or perpendicular shouldn't matter for the test, but ...
by Sarah Blake-2I
Wed Nov 20, 2019 11:42 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: Ordering Intermolecular Forces Clarification
Replies: 2
Views: 26

Re: Ordering Intermolecular Forces Clarification

You are correct in the order of the forces. I think the numbers he gave us in class were not related to strength of the forces but rather the energy of the forces. Since we do not need to know those values, I would just put those to the side and go off of the fact that dipole-dipole is greater than ...
by Sarah Blake-2I
Wed Nov 20, 2019 11:39 pm
Forum: Electronegativity
Topic: Partial Charge
Replies: 2
Views: 29

Re: Partial Charge

Whenever there is a difference in electronegativity that is noticeable, there will be a partial negative and partial positive charge. So for instance, let's look at CCl3. Cl is very electronegative in comparison to carbon. This will cause the Cl to form a partial negative charge and C to form a part...
by Sarah Blake-2I
Mon Nov 18, 2019 8:56 pm
Forum: Dipole Moments
Topic: non polar dipole moments
Replies: 2
Views: 17

non polar dipole moments

Does a nonpolar molecule have dipole dipole interactions such as AsF5?
by Sarah Blake-2I
Sun Nov 17, 2019 3:40 pm
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 3
Views: 22

Re: Dipole Moments

Dipole moments occur when there is a large difference in electronegativity between the atoms. The more electronegative atom is said to have a partial negative charge and the less electronegative atom will have a partial positive charge. The arrow that signifies a dipole moment is drawn from the part...
by Sarah Blake-2I
Sun Nov 17, 2019 3:34 pm
Forum: Sigma & Pi Bonds
Topic: explanation
Replies: 2
Views: 21

explanation

Can someone give e a brief explanation on sigma and pi bonds. What are they and what are we expected to know about them and their properties? I read the textbook chapter on them and did not get much clarity on what exactly they are. Thank you!
by Sarah Blake-2I
Sun Nov 17, 2019 3:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lewis structure of organic compunds
Replies: 5
Views: 42

Re: lewis structure of organic compunds

For instance, CH3CH2OH. How would I know how to draw this compound?
by Sarah Blake-2I
Sun Nov 17, 2019 3:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: linear versus angular
Replies: 5
Views: 27

linear versus angular

How would you distinguish whether a molecule is linear or bent? Does it have to do with lone pairs or polarizability or something else? I am just a little confused on how you figure out the shape.
by Sarah Blake-2I
Sun Nov 17, 2019 3:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 2
Views: 11

Re: Bond Angles

We will need to memorize the bond angles of the general shapes, but not exact values for specific compounds. You should just know how to determine whether bond angles will be larger or smaller than expected.
by Sarah Blake-2I
Sun Nov 17, 2019 3:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 2
Views: 14

Re: Bond Angles

You must memorize the bond angles for the various shapes, but if dealing with lone pairs, that will cause the bond angle to be less than expected because the lone pairs will cause the atoms to be closer together.
by Sarah Blake-2I
Sat Nov 16, 2019 3:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lewis structure of organic compunds
Replies: 5
Views: 42

lewis structure of organic compunds

Are there any tricks to drawing more complicated lewis structures? I keep drawing them incorrectly and I am not sure how to tell where the bonds go and what is connected to each atom.
by Sarah Blake-2I
Sat Nov 16, 2019 3:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 3
Views: 23

VSEPR

Can someone explain how you can determine what the shape of a molecule is if it has lone pairs. For instance, what makes something seesaw shaped? I am just a bit confused.
by Sarah Blake-2I
Sat Nov 16, 2019 3:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar vs nonpolar
Replies: 6
Views: 34

polar vs nonpolar

How can you predict based on looking at the molecular formula for a compound whether it is polar or nonpolar?
by Sarah Blake-2I
Sun Nov 10, 2019 6:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Reference sheet for test?
Replies: 1
Views: 13

Re: VSEPR Reference sheet for test?

We most likely have to memorize it, but if we don't then I am sure Dr. Lavelle will tell us whether or nor we need to memorize it.
by Sarah Blake-2I
Sun Nov 10, 2019 2:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 7
Views: 56

Re: Test 2

I believe it covers the new stuff we are doing between the midterm and the test. I assume dipoles and the forces will be on it as well as shape and hybridization.
by Sarah Blake-2I
Sun Nov 10, 2019 2:39 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 3
Views: 19

Re: Polarizability

Atoms with small atomic radius will have more polarizing power whereas atoms with a larger atomic radius will be more polarizable. So essentially, you look at the size of the atom and that determines the trend in a way.
by Sarah Blake-2I
Sun Nov 10, 2019 11:01 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dipole Arrows
Replies: 2
Views: 19

Re: Dipole Arrows

Lavelle uses the original way of having the arrow point towards the negative charge as the negative ion will have more pulling power. The other arrow drawing method is more used in physics than chemistry.
by Sarah Blake-2I
Sun Nov 10, 2019 10:52 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: determining what force it is
Replies: 2
Views: 33

determining what force it is

How do we determine what kind of force is present when given the lewis structure of two atoms? How would you distinguish a dipole-dipole from an induced dipole-induced dipole, for instance.
by Sarah Blake-2I
Sun Nov 10, 2019 10:49 am
Forum: Dipole Moments
Topic: HW this week
Replies: 6
Views: 37

HW this week

Is the homework that we turn in this week from chemical bonding or do we have to do the next section?
by Sarah Blake-2I
Sat Nov 09, 2019 10:53 pm
Forum: Sigma & Pi Bonds
Topic: hybridization
Replies: 2
Views: 26

hybridization

Can someone explain hybridization and how to determine what the hybridization of a molecule is? We started this in discussion this past week, and I was just very confused so any help is much appreciated :).
by Sarah Blake-2I
Mon Nov 04, 2019 12:13 am
Forum: Lewis Structures
Topic: 2a on mini dino nuggets sheet
Replies: 1
Views: 31

2a on mini dino nuggets sheet

For the Lewis structures of CH3F and CH3Br, the drawn structures do not contain valence electrons around the halogens and therefore do not meet the total amount of electrons. Why is this? Is this because we are focusing on dipole moments rather then proper lewis structure?
by Sarah Blake-2I
Sun Nov 03, 2019 10:07 pm
Forum: Bond Lengths & Energies
Topic: bond lengths
Replies: 2
Views: 25

bond lengths

What do we need to know about bond lengths for the midterm? Is there a calculation?
by Sarah Blake-2I
Sun Nov 03, 2019 10:05 pm
Forum: Octet Exceptions
Topic: Octet Exceptions
Replies: 7
Views: 62

Re: Octet Exceptions

Elements in period 3 or higher can have an expanded octet due to the inclusion of the d orbital.
by Sarah Blake-2I
Sun Nov 03, 2019 10:03 pm
Forum: *Shrodinger Equation
Topic: past exam questions session
Replies: 2
Views: 44

Re: past exam questions session

The sessions he is holding are in your designated lecture. So he will be doing past exam problems in his lecture instead of doing new material.
by Sarah Blake-2I
Sun Nov 03, 2019 10:02 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Easier way to calculate/remember?
Replies: 7
Views: 75

Re: Easier way to calculate/remember?

Take the valence electrons and subtract how many dots and lines you see connected to the element. This will give you the formal charge.
by Sarah Blake-2I
Sun Nov 03, 2019 6:54 pm
Forum: Properties of Electrons
Topic: Photoelectric effect
Replies: 5
Views: 72

Re: Photoelectric effect

I believe Dr. Lavelle also has a module on this topic as well, but if not then youtube is a great resource as well!
by Sarah Blake-2I
Sun Nov 03, 2019 6:52 pm
Forum: Significant Figures
Topic: Sig figs on midterm
Replies: 5
Views: 66

Re: Sig figs on midterm

Yes you base the sig figs on the numbers given in the question. If there are no numbers given, then base it off the constant you are using.
by Sarah Blake-2I
Sun Nov 03, 2019 6:49 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Copper and Chromium
Replies: 1
Views: 10

Re: Copper and Chromium

Yes you need to know that copper and chromium are more stable with a half filled d orbital and a full d orbital. Know the configurations for those and that the 4s is not a 4s2 but a 4s1.
by Sarah Blake-2I
Sun Nov 03, 2019 6:47 pm
Forum: Trends in The Periodic Table
Topic: Drawing Structures
Replies: 3
Views: 15

Re: Drawing Structures

If a structure can have double bonds in varying locations, then it is said to have resonance and can therefore have multiple drawings representing the location of different double bonds.
by Sarah Blake-2I
Sun Nov 03, 2019 6:33 pm
Forum: Properties of Light
Topic: Electromagnetic raditation
Replies: 1
Views: 16

Re: Electromagnetic raditation

They mean that you can only use c = wavelength x frequency when dealing with EM radiation. That equation does not apply to quantum questions dealing with electrons or particles being ejected. That equation is only used when talking about light.
by Sarah Blake-2I
Sun Nov 03, 2019 6:32 pm
Forum: Lewis Structures
Topic: lone pairs versus double bonds
Replies: 2
Views: 21

lone pairs versus double bonds

In some of the homework questions, instead of adding a double bond, the solutions manual shows an extra set of lone pairs around the central atom. When do we do this and what clues us into being able to know whether or not we use multiple bonds or add extra lone pairs to the central atom?
by Sarah Blake-2I
Sun Nov 03, 2019 6:28 pm
Forum: Lewis Structures
Topic: lowest energy
Replies: 5
Views: 25

Re: lowest energy

This means trying to get the formal charges of the atoms in the lewis structure to 0. If the molecule has a charge such as 2-, then you are trying to make that 2- charge by getting more of the atoms to be 0 FC and having the least possible amount of atoms contribute to the 2- charge if that makes se...
by Sarah Blake-2I
Tue Oct 29, 2019 8:14 pm
Forum: Formal Charge and Oxidation Numbers
Topic: formal charge
Replies: 5
Views: 50

formal charge

In discussion today, to find the formal charge from a lewis structure, we did not use the FC equation. Can someone explain when we use the equation and how we solve for FC by using the equation?
by Sarah Blake-2I
Sun Oct 27, 2019 9:57 pm
Forum: Resonance Structures
Topic: Bond Length of Single Bond, Double Bond, and Tripler Bond.
Replies: 2
Views: 18

Re: Bond Length of Single Bond, Double Bond, and Tripler Bond.

A double bond is stronger than a single bond which would make the bond length shorter than a weaker single bond. For triple bonds, the same idea applies in which the triple bond is stronger than the double bond and even stronger than the single bond, which makes the triple bond the shortest out of t...
by Sarah Blake-2I
Sun Oct 27, 2019 9:54 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Lewis Structures
Replies: 2
Views: 23

Re: Lewis Structures

Make sure that the structure you have drawn is the most stable structure. Sometimes this requires us to use double bonds where necessary to make the structure more stable in which the formal charge of more atoms are 0. However, the overall formal charge does have to be equal to the formal charge of ...
by Sarah Blake-2I
Sun Oct 27, 2019 9:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Questions
Replies: 2
Views: 18

Re: Midterm Questions

There will probably be at least one homework problem on the midterm that is pulled directly from the homework questions we have been assigned.
by Sarah Blake-2I
Sun Oct 27, 2019 3:24 pm
Forum: Ionic & Covalent Bonds
Topic: Double and single bond lengths
Replies: 6
Views: 35

Re: Double and single bond lengths

The double bond is much stronger than a single bond, thus making the double bond have a shorter length than the single bond. And yes triple bonds do have a shorter length than double bonds as triple bonds are even stronger.
by Sarah Blake-2I
Sun Oct 27, 2019 3:22 pm
Forum: Lewis Structures
Topic: expanded-octet
Replies: 4
Views: 28

Re: expanded-octet

The expanded octet is for elements that have d orbitals in the valence shell which accommodate additional electrons.
by Sarah Blake-2I
Sun Oct 27, 2019 3:20 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Bonds
Replies: 11
Views: 74

Re: Covalent Bonds

Yes nonmetals are more likely to form covalent bonds.
by Sarah Blake-2I
Sun Oct 27, 2019 3:17 pm
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 5
Views: 32

Re: Lewis Structure

It makes sulfate more stable to have the double bond rather than lone pairs on the oxygen.
by Sarah Blake-2I
Sun Oct 27, 2019 3:16 pm
Forum: Ionic & Covalent Bonds
Topic: Week 5 HW
Replies: 4
Views: 54

Re: Week 5 HW

I feel like it could be from either since we have only had one homework from quantum and have only had a few lectures on bonding, but probably just emailing your TA to double check is a good idea :).
by Sarah Blake-2I
Sun Oct 27, 2019 3:04 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Special Cases
Replies: 6
Views: 43

Re: Electron Configuration Special Cases

Everything in the group of copper and chromium have the exception except for Tungsten. I am not sure if the exception applies to the elements in the 7th period, but seeing as we haven't talked much about those elements yet, I don't think knowing those are that important.
by Sarah Blake-2I
Sun Oct 27, 2019 2:58 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: many electron atoms
Replies: 2
Views: 25

many electron atoms

I saw on the outline for the quantum world unit we need to know the factors affecting the energy of an electron in a many-electron atom. Can someone explain those factors to me? Is it related to trends at all or is it a separate concept?
by Sarah Blake-2I
Mon Oct 21, 2019 11:06 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: unpaired electrons
Replies: 2
Views: 21

unpaired electrons

How do we calculate the number of unpaired electrons after finding the electron configuration?
by Sarah Blake-2I
Sun Oct 20, 2019 9:29 pm
Forum: Properties of Light
Topic: light regions
Replies: 4
Views: 32

light regions

Do we need to memorize what wavelengths correspond with what light region? Some of the homework questions ask for the region, for instance B.15 d asks to clarify what region 8.8 nm is in (x ray, visible, uv, etc), so I am just a little bit confused on identifying the region and whether we have to me...
by Sarah Blake-2I
Sun Oct 20, 2019 9:20 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Noble Gases in Electron Configurations
Replies: 6
Views: 24

Re: Noble Gases in Electron Configurations

Noble gases are more stable, so that is why we use the closest noble gas to write the shorthand electron configuration. It just makes it easier to write out the configuration when we use the shorthand method using the noble gases.
by Sarah Blake-2I
Sun Oct 20, 2019 9:18 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Negative Energy of Electron
Replies: 1
Views: 15

Re: Negative Energy of Electron

That just means that the electron is losing energy rather than gaining energy. The actual energy of an electron is not negative.
by Sarah Blake-2I
Sun Oct 20, 2019 9:16 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: More than one electron in an orbital
Replies: 2
Views: 19

Re: More than one electron in an orbital

Each orbital has up to 2 electrons and depending on the fourth quantum number, they will be spinning either up or down. So to somewhat answer your question, with two electrons they are either paired or parallel to one another, which is part of their interaction.
by Sarah Blake-2I
Sun Oct 20, 2019 6:23 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework Problem A.15
Replies: 2
Views: 32

Homework Problem A.15

In A.15 from Focus 1, I am wondering how to find n2 from the Rydberg equation. I got 1/n2^2 is .112, but I am now stuck on how to get the value of n2. ( summary of the problem): line is observed for Hydrogen at 102.6 nm. Determine initial and final n values for the emission of energy that leads to t...
by Sarah Blake-2I
Sun Oct 20, 2019 4:49 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum Numbers
Replies: 7
Views: 72

Re: Quantum Numbers

You put the spin number when you are discussing the state of both the electron and the orbital and then just 3 quantum numbers when just discussing the state of the orbital.
by Sarah Blake-2I
Sun Oct 20, 2019 4:42 pm
Forum: DeBroglie Equation
Topic: Units for mass
Replies: 4
Views: 37

Re: Units for mass

Since kg is an SI unit, kg will be used often, however, if the problem does not specify what units, I believe it is okay to use either grams or kilograms.
by Sarah Blake-2I
Sun Oct 13, 2019 9:19 pm
Forum: Limiting Reactant Calculations
Topic: How to find Excess Reactant?
Replies: 5
Views: 52

Re: How to find Excess Reactant?

To find the excess reactant leftover, you take the limiting reactant and compare the mole ratio of the excess to the limiting reactant to find the moles of the excess that is actually used. Then convert to grams and take the theoretical amount (what you calculated at first) - the actual amount using...
by Sarah Blake-2I
Sat Oct 12, 2019 10:46 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Post Module Calculation
Replies: 2
Views: 29

Post Module Calculation

I am wondering how I would solve for delta x in this problem. I approached it by first finding out delta p by doing mass times velocity which was 3 x 10^8 x 1/100. Then I plugged in delta p into Heisenberg's Equation to get delta x. Is this right? I did not get an answer that matched any of the choi...
by Sarah Blake-2I
Sat Oct 12, 2019 10:24 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Negative values for wavelengths and frequencies
Replies: 2
Views: 28

Re: Negative values for wavelengths and frequencies

When solving for frequency, you cannot have a negative E value, so we change it to positive. It is just a conceptual idea that you cannot have negative frequency or wavelength. :)
by Sarah Blake-2I
Sat Oct 12, 2019 4:52 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Video Module
Replies: 1
Views: 41

Atomic Spectra Video Module

How would I go about solving for the wavelength for this problem? Is it just c= wavelength x frequency and then solve for wavelength that way? Also, how do we know what region of the EM spectrum the wavelength is in? 28. The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted ...
by Sarah Blake-2I
Sat Oct 12, 2019 1:03 am
Forum: Photoelectric Effect
Topic: Energy classification
Replies: 2
Views: 20

Energy classification

Number 16 on the Photoelectric Effect module states : When the energy per photon is equal to the energy required to remove an electron what is this energy called? Is this the threshold energy?
by Sarah Blake-2I
Sat Oct 12, 2019 1:01 am
Forum: Photoelectric Effect
Topic: Video Module post assessment 34
Replies: 1
Views: 18

Video Module post assessment 34

Could someone explain to me how I would go about solving for the kinetic energy in problem 34 B on the post assessment of the photoelectric effect? I was able to get the first part of the minimum energy, but I do not know how to get the max kinetic energy after being given the wavelength. Do we have...
by Sarah Blake-2I
Sun Oct 06, 2019 10:49 pm
Forum: SI Units, Unit Conversions
Topic: Test 1
Replies: 9
Views: 129

Re: Test 1

M1V1= M2V2 will be on the test most likely as well as molarity/ molar concentration which is just moles/ liter.
by Sarah Blake-2I
Sun Oct 06, 2019 10:48 pm
Forum: SI Units, Unit Conversions
Topic: Calculate using kg or g?
Replies: 13
Views: 183

Re: Calculate using kg or g?

For when it asks for mass at least for this test and the homework problems, I think we leave the answer in grams :)
by Sarah Blake-2I
Fri Oct 04, 2019 12:50 am
Forum: Balancing Chemical Reactions
Topic: balancing charges
Replies: 4
Views: 55

balancing charges

Could someone explain how to balance charges in a chemical equation? How does that work and when do we do it?
by Sarah Blake-2I
Thu Oct 03, 2019 8:17 pm
Forum: SI Units, Unit Conversions
Topic: Mass % comp accuracy F5
Replies: 5
Views: 81

Re: Mass % comp accuracy F5

Yeah I think it is fine if you get slightly different answers than the solutions manual. I know this happened to me a few times already, but my answers were pretty close to the solution manual, so as long as they are very close, I think it is fine. Also, Dr. Lavelle has a link on his website with mi...
by Sarah Blake-2I
Thu Oct 03, 2019 12:57 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: F.13 homework problem
Replies: 4
Views: 57

F.13 homework problem

In F.13, we are asked to find the empirical formula of a phosphorus and chlorine compound. We get PCl5 but part b asks for the specific name of this compound. Is this something we memorize or supposed to know already? If someone could answer this and try to explain how we name compounds that would b...
by Sarah Blake-2I
Thu Oct 03, 2019 12:49 am
Forum: Significant Figures
Topic: rounding in sig figs
Replies: 5
Views: 98

rounding in sig figs

When you have .4566 or .4565 and need to have 3 sig figs, do you round up? I am just looking for a little bit of help regarding rounding off the end of numbers when using sig figs.
by Sarah Blake-2I
Tue Oct 01, 2019 5:47 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: G.27 practice problem from discussion
Replies: 1
Views: 29

G.27 practice problem from discussion

In G.27, I was completely lost. I just simply do not understand how to go about solving it and figuring out where to start. G.27 states "Concentrated hydrochloric acid is 37.5% HCl by mass and has a density of 1.205 g/cm^3. What volume (mL) of concentrated HCl must be used to prepare 10.0 L of ...
by Sarah Blake-2I
Tue Oct 01, 2019 5:02 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Avogadro's Number [ENDORSED]
Replies: 12
Views: 152

Avogadro's Number [ENDORSED]

I was wondering in what situations do we use Avogadro's number? I am just a bit confused on what it is used for and how to use it after it was used in a practice problem (E-11) in my discussion today.

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