Search found 119 matches

by sarahsalama2E
Fri Jan 17, 2020 4:08 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas does not change pressure?
Replies: 7
Views: 24

Re: Inert Gas does not change pressure?

I believe adding an inert gas does not alter the pressure in a rxn system, because the inert gas is not really reactive and does not participate in the reaction that is happening. But, what would happen if you added a reactant that did participate in the reaction, such as a non-inert gas?
by sarahsalama2E
Fri Jan 17, 2020 4:06 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic and exothermic reactions
Replies: 11
Views: 29

Re: Endothermic and exothermic reactions

Because as you can see in the graph the energy of the products is higher than that of the reactants in an endothermic reaction than you know that you require heat to go to this higher energy state. On the other hand, in an exothermic reaction, you are going from a higher energy state to a lower ener...
by sarahsalama2E
Fri Jan 17, 2020 4:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc & Kp
Replies: 11
Views: 21

Re: Kc & Kp

You can tell which one to use by what's given in the question; if the values are given in brackets, then you know the values are concentrations rather than partial pressures and you should use Kc.
by sarahsalama2E
Fri Jan 17, 2020 4:01 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: ICE table
Replies: 6
Views: 21

Re: ICE table

The strong acids are:
HClO4
HCL
HBR
HI
HNO3
H2SO4

The strong bases are:
LiOH
NaOH
KOH
Ca(OH)2
Sr(OH)2
Ba(OH)2
---------
Everything else does not dissociate/ionize completely and is therefore a weak acid and/or a base.
by sarahsalama2E
Mon Jan 13, 2020 10:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: volume and K value
Replies: 3
Views: 22

volume and K value

how does changing the volume affect the equilibrium constant? Say, for example the volume of the container in which the rxn is taking place is halved.
by sarahsalama2E
Mon Jan 13, 2020 2:03 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q=K
Replies: 14
Views: 33

Re: Q=K

Q is calculated the same way as k. If Q is less than K than the reaction proceeds forwards and vice versa if its the opposite.
by sarahsalama2E
Mon Jan 13, 2020 2:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constant for water
Replies: 3
Views: 7

Re: Equilibrium constant for water

you omit the h20 from the expression because its liquid and also the concentration unchanged.
by sarahsalama2E
Sun Jan 12, 2020 11:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Hw for next week
Replies: 19
Views: 58

Re: Hw for next week

As long as you do 5 per week, but make sure to do problems from different sections from the outline so that you get exposed to different types of questions and show that you have done the hw.
by sarahsalama2E
Sun Jan 12, 2020 11:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Concentration
Replies: 6
Views: 20

Re: Concentration

concentration does have units, moles per liter, but equilibrium constant does not.
by sarahsalama2E
Wed Jan 08, 2020 2:10 pm
Forum: Ideal Gases
Topic: Understanding Q
Replies: 13
Views: 56

Re: Understanding Q

Yes you would also leave out solids and liquids because their concentrations do not change. Also just to refresh, Q is the reaction quotient when the reaction is NOT at equilibrium and if Q <K, reaction favors the forward direction, and if Q>K, then reaction favors the backwards direction, and if Q=...
by sarahsalama2E
Wed Jan 08, 2020 2:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Module: Chemical Equilibrium Part 3
Replies: 2
Views: 15

Re: Module: Chemical Equilibrium Part 3

Typically a good rule of thumb is to always assume "x" is negligible when you have a cubic equation so that you can just solve a quadratic equation as normal.
by sarahsalama2E
Wed Jan 08, 2020 2:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Small K value and Large K value
Replies: 10
Views: 45

Re: Small K value and Large K value

Additionally, it's very rare that k=1 because that would mean that the two compounds which are different have the same stability.
by sarahsalama2E
Wed Jan 08, 2020 2:06 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 3
Views: 20

Re: Le Chatelier's Principle

For example, if you have a reaction and you want there to be more product to be made you can cause this to happen by removing some of the product, the reactions wants to be as stable as possible and it does so by creating more product to reach this sort of equilibrium state. As mentioned in lecture,...
by sarahsalama2E
Wed Jan 08, 2020 2:05 pm
Forum: Ideal Gases
Topic: Solids and Liquids
Replies: 7
Views: 29

Re: Solids and Liquids

Solids and Liquids are left out when writing the equilibrium expressions because essentially their concentrations stay the same during the reaction. Also, pure substances such as pure liquids and pure solids are left out when writing equilibrium expressions because their concentrations can't change....
by sarahsalama2E
Wed Jan 08, 2020 1:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Concentrations at Equilibrium
Replies: 6
Views: 41

Re: Concentrations at Equilibrium

Essentially equilibrium concentrations are the concentrations that you determine using the ice table.
by sarahsalama2E
Tue Jan 07, 2020 10:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K
Replies: 13
Views: 75

Re: Q vs K

Yes, as mentioned above Q is not the same as K. Q is the reaction quotient and K is when the chemical reaction is at equilibrium ONLY. If q is less than K, then the reaction will proceed to the right and if q is greater than K then the reaction will proceed to the left.
by sarahsalama2E
Thu Dec 05, 2019 3:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity for a trigonal planar molecule
Replies: 2
Views: 17

Re: Polarity for a trigonal planar molecule

I am wondering if it is because the H that is attached to one of the O, so then the dipoles wouldn't cancel?
by sarahsalama2E
Thu Dec 05, 2019 3:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity for a trigonal planar molecule
Replies: 2
Views: 17

Polarity for a trigonal planar molecule

I had a question regarding a question about HNO3, When I drew the lewis structure I got that it is a trigonal planar structure, and the N is sp2 hybridized. Because all the atoms attached to the N are the same (they are all O), and the structure is trigonal planar, I thought that that the molecule o...
by sarahsalama2E
Thu Dec 05, 2019 12:58 am
Forum: Hybridization
Topic: Pi bonds
Replies: 1
Views: 24

Re: Pi bonds

pi orbitals are also involved in the mixing of orbitals that occurs when the creation of hybridized orbitals happen. It is important to note that a pi bond occurs between two overlapping p-bonds, and no s-bonds, to my knowledge, are involved in pi bonds. So, for example a pi bond between two carbons...
by sarahsalama2E
Thu Dec 05, 2019 12:55 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: monodentate vs bidentate
Replies: 1
Views: 27

Re: monodentate vs bidentate

I think a good way to go about these problems when you are trying to see what kind of polydentate a particular ligand is, is to first draw the lewis structure. If you see that the two attachments are on roughly the same side, then it can be bidentate, etc.. If you can visualize the ligand acting as ...
by sarahsalama2E
Thu Dec 05, 2019 12:51 am
Forum: Bronsted Acids & Bases
Topic: Relative strength of base?
Replies: 3
Views: 34

Re: Relative strength of base?

Yes you would look at the same characteristics to determine the strength of a base. Essentially a stronger base, wants to accept a proton easier, and will give off more hydroxide ion.
by sarahsalama2E
Tue Dec 03, 2019 11:31 pm
Forum: Biological Examples
Topic: hemoglobin and myoglobin
Replies: 3
Views: 40

hemoglobin and myoglobin

what is the difference in the chemical structures of hemoglobin and myoglobin? Both consist of the same heme complex and a binded protein correct?
by sarahsalama2E
Tue Dec 03, 2019 10:57 pm
Forum: Identifying Acidic & Basic Salts
Topic: Classifying Salts
Replies: 5
Views: 34

Re: Classifying Salts

Seeing if OH- or H+ ion is produced is a way to see if the salt given will act as an acid or a base in water. You must write out the reaction in order to see this.
by sarahsalama2E
Tue Dec 03, 2019 10:55 pm
Forum: Polyprotic Acids & Bases
Topic: How can you tell
Replies: 11
Views: 91

Re: How can you tell

Are polyprotic acids stronger or weaker with the more hydrogens that they have? I thought that if something has multiple hydrogens it is more likely to give off a proton, therefore dissociates more, and is therefore stronger of an acid.
by sarahsalama2E
Tue Dec 03, 2019 10:54 pm
Forum: Air Pollution & Acid Rain
Topic: Final
Replies: 8
Views: 349

Re: Final

Where can I find the acid rain problems in the textbook?
by sarahsalama2E
Tue Dec 03, 2019 10:53 pm
Forum: Air Pollution & Acid Rain
Topic: Options to Reduce Acid Rain
Replies: 2
Views: 63

Re: Options to Reduce Acid Rain

Potential options to reduce acid rain are the following--> reducing the use of fossil fuels (i.e. burning of coal), using renewable energy sources, coal burning plants, etc. Keep in mind that acid rain can be neutralized if it reacts with something that is more alkaline (closer to the very basic sid...
by sarahsalama2E
Tue Dec 03, 2019 10:50 pm
Forum: Ionic & Covalent Bonds
Topic: polarity of shapes
Replies: 3
Views: 23

Re: polarity of shapes

Also, remember that typically shapes that have lone pairs are usually always polar even if all the attached atoms are the same; however AX4E2, square planar, is an exception to that rule because it becomes nonpolar because the dipole moments cancel. You can see this if you draw the 3-D shape.
by sarahsalama2E
Tue Dec 03, 2019 10:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Rotation and Ligands
Replies: 1
Views: 18

Rotation and Ligands

I remember in lecture that the most stable configuration for a ligand was LP-SPACER-SPACER-LP. But i was wondering if it's more stable/better for a ligand to have only sigma bonds (to allow for rotation?) or is pi bonds just as stable?
by sarahsalama2E
Tue Dec 03, 2019 10:47 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands and lone pairs?
Replies: 2
Views: 28

Re: Ligands and lone pairs?

how do you determine if a ligand is polydentate? i.e. if it is monodentate, bidentate, polydentate? Do you look at how many lone pairs it has (i.e. that function as bonding sites?). Also, when a ligand bonds to an atom, if it has multiple attachments (i.e. its polydentate), can it only bind on the s...
by sarahsalama2E
Tue Dec 03, 2019 10:45 pm
Forum: Naming
Topic: Bis, Tris, Tetrakis, Pentakis
Replies: 3
Views: 42

Re: Bis, Tris, Tetrakis, Pentakis

would someone be able to provide examples of when you would use these examples? I understand the concept but I actually haven't seen any problems in the HW or have come across any problems that deal with this...
by sarahsalama2E
Tue Dec 03, 2019 10:43 pm
Forum: Properties of Light
Topic: photons
Replies: 3
Views: 35

Re: photons

Yes, as mentioned above intensity is NOT the determining factor as to whether or not electrons will be ejected from a given material, but it is rather the frequency as the frequency is the determinant of whether or not the threshold energy, or the work function will be met which is needed to eject e...
by sarahsalama2E
Tue Dec 03, 2019 10:41 pm
Forum: Hybridization
Topic: hybridization of lone pairs
Replies: 2
Views: 17

hybridization of lone pairs

I am a bit unclear on how to determine the hybridization of lone pairs in a given structure. For instance, in formic acid, I understand the hybridization of all the bonds, such as the C-H bond is sigma and is (H1S, C2SP2), but why is the lone pair on the oxygen that is in between the C and the H hav...
by sarahsalama2E
Sat Nov 30, 2019 8:57 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: Why is CBr2Cl2 polar?
Replies: 7
Views: 44

Re: Why is CBr2Cl2 polar?

if all the atoms attached to the central are not the same, then the molecule is polar. As you can see in the tetrahedral diagram, the differing attaching atoms creates dipole moments, resulting in the atom being polar as a whole.
by sarahsalama2E
Sat Nov 30, 2019 8:53 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: en and edta
Replies: 2
Views: 20

Re: en and edta

en = Ethylenediamine (abbreviated as en when a ligand) is C2H4(NH2)2. (first photo shown)



edta= Ethylenediaminetetraacetic acid; C10H16N2O8
by sarahsalama2E
Sat Nov 30, 2019 8:50 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: strong or weak base?
Replies: 13
Views: 53

Re: strong or weak base?

the weaker the bond between the atoms in the acid, the stronger of an acid it is because that means it dissociates easier. If you have a stronger bond between the atoms, you would then have a weaker acid because that acidic compound is less likely to dissociate completely. When looking at the relati...
by sarahsalama2E
Sat Nov 30, 2019 8:46 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH and a calculator
Replies: 3
Views: 26

Re: pH and a calculator

make sure you are putting adequate parenthesis.
by sarahsalama2E
Sat Nov 30, 2019 8:44 pm
Forum: Amphoteric Compounds
Topic: determining if compounds are acids, bases, or amphoteric
Replies: 3
Views: 29

determining if compounds are acids, bases, or amphoteric

is the only way to determine if compounds are acids, bases, or amphoteric is if you draw the lewis structure for them and see if they give off or accept a lone pair? or is there another way to do so?
by sarahsalama2E
Sun Nov 24, 2019 11:23 pm
Forum: Naming
Topic: Roman numerals
Replies: 6
Views: 31

Re: Roman numerals

When it is a transition metal, because the oxidation number can change. So, denoting the oxidation number through roman numerals and parentheses is necessary to denote exactly what compound you are talking about.
by sarahsalama2E
Sun Nov 24, 2019 11:22 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cisplatin and Transplatin
Replies: 2
Views: 20

Re: Cisplatin and Transplatin

Cisplatin has the Cl atoms on the same side while trans-diamine dichloro-platinum (ii) has them located on opposite, or diagonal sides from one another. Cisplatin is a well-known chemotherapy drug that works by forming a coordinate compound with DNA. Cisplatin binds to the exposed N in guananine and...
by sarahsalama2E
Sun Nov 24, 2019 11:20 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Difference Between TM complex and organometallic complex
Replies: 1
Views: 12

Re: Difference Between TM complex and organometallic complex

TM complex --> transition metal --bond with ions or molecules linked
organometallic complex--> compounds with carbon-metal bond
by sarahsalama2E
Sun Nov 24, 2019 11:18 pm
Forum: Biological Examples
Topic: biological functions
Replies: 1
Views: 37

Re: biological functions

I think so yes,
Cr--> assists insulin in control of blood sugar
Fe--> myoglobin, hemoglobin, electron transfer in the oxidation of carbohydrates, proteins, fats (respiratory chain)
Co--> vitamin B12
Mn, Ni, Cu, Zn--> critical for enzyme function
by sarahsalama2E
Sun Nov 24, 2019 11:17 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelating compounds
Replies: 1
Views: 21

chelating compounds

when determining what can form a chelating complex, should the lone pairs be as close to one another as possible so that way it can attach to the atom on the same side? do the attachments have to happen on the same side of the atom always?
by sarahsalama2E
Sun Nov 24, 2019 11:15 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 4
Views: 23

Re: Ligands

how do you determine the number of dentate sites on a ligand?
by sarahsalama2E
Thu Nov 21, 2019 11:59 am
Forum: Electronegativity
Topic: Determining Polarity
Replies: 3
Views: 39

Determining Polarity

Is CH2I2 polar or nonpolar?
by sarahsalama2E
Thu Nov 21, 2019 10:23 am
Forum: Dipole Moments
Topic: Polar or nonpolar
Replies: 8
Views: 67

Re: Polar or nonpolar

Is CH2I2 polar or nonpolar? the lewis structure has the I atoms opposite from each other and the H atoms opposite from each other.
by sarahsalama2E
Thu Nov 21, 2019 9:57 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: Homework 3F3
Replies: 5
Views: 35

Re: Homework 3F3

Would CH2I2 be polar or nonpolar? if the picture in the problem has the I opposite from one another.
by sarahsalama2E
Thu Nov 21, 2019 9:55 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity and Number of Bonds
Replies: 3
Views: 38

Re: Polarity and Number of Bonds

this is a question about polarity: but just wondering would CH2I2 be a polar or nonpolar molecule?
by sarahsalama2E
Wed Nov 20, 2019 5:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles in Square Pyramidal and T-Shaped
Replies: 4
Views: 44

Re: Bond Angles in Square Pyramidal and T-Shaped

I thought T-shaped had more than one bond angle does it not?
by sarahsalama2E
Wed Nov 20, 2019 5:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape vs. Geometry
Replies: 5
Views: 36

Re: Molecular Shape vs. Geometry

you can think of molecular geometry as the actual (bonded vs lone pairs) and the electron geometry as the "parent" structure, so if its AX4E2, it would be octahedral, and the molecular geometry would be square planar.
by sarahsalama2E
Wed Nov 20, 2019 4:57 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: Boiling Point
Replies: 7
Views: 37

Re: Boiling Point

what is an acceptable justification to the question--why does X compound have a higher boiling point?
by sarahsalama2E
Wed Nov 20, 2019 4:56 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polarizability
Replies: 9
Views: 62

Re: polarizability

does the bigger the atom mean the stronger the ldf and dipole-dipole forces?
by sarahsalama2E
Wed Nov 20, 2019 4:53 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: 3F.19
Replies: 5
Views: 40

Re: 3F.19

doesn't the strength of london disperson forces take priority over dipole-dipole forces when determining which compound has a higher boiling point?
by sarahsalama2E
Wed Nov 20, 2019 4:50 pm
Forum: Dipole Moments
Topic: 3F.5
Replies: 2
Views: 36

Re: 3F.5

CHI3 has a higher boiling point because it has stronger/more london dispersion forces. Although F is more electronegative than I, the strength of london disperson forces takes precedence when comparing boiling, melting, freezing points, and etc. Because I is a bigger atom than F, it has more surface...
by sarahsalama2E
Wed Nov 20, 2019 4:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-Shaped ??
Replies: 9
Views: 74

Re: T-Shaped ??

What are the bond angles for T-shaped?
by sarahsalama2E
Wed Nov 20, 2019 4:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.21
Replies: 1
Views: 14

Re: 2E.21

In this case, technically there are two central atoms (the 2 C atoms), and both are trigonal planar structures. So i would write both.
by sarahsalama2E
Mon Nov 18, 2019 12:01 am
Forum: Ionic & Covalent Bonds
Topic: types of bonds
Replies: 4
Views: 48

Re: types of bonds

what is the difference between dipole-dipole and induced dipole-induced dipole?
by sarahsalama2E
Sun Nov 17, 2019 11:57 pm
Forum: Ionic & Covalent Bonds
Topic: types of bonds
Replies: 4
Views: 48

Re: types of bonds

also, are basically LDF in everything?
by sarahsalama2E
Sun Nov 17, 2019 11:37 pm
Forum: Ionic & Covalent Bonds
Topic: types of bonds
Replies: 4
Views: 48

types of bonds

so basically in a covalent compound, the types of bonds that can be present are the following?
-LDF
-Dipole-dipole
-H Bond
by sarahsalama2E
Sun Nov 17, 2019 11:35 pm
Forum: Dipole Moments
Topic: CH3Cl & CHCl3
Replies: 2
Views: 32

Re: CH3Cl & CHCl3

because cl is more electronegative it pulls the other delta positive atoms towards it. the molecules are not symmetrical, so the dipole moments do not cancel, therefore the entire molecule is polar.
by sarahsalama2E
Sun Nov 17, 2019 11:34 pm
Forum: Ionic & Covalent Bonds
Topic: Bond Order?
Replies: 2
Views: 38

Bond Order?

We didn't really go over bond order in lecture, and haven't really seen it come up much in the HW, but I was wondering if we need to know what bond order is and its calculation?
by sarahsalama2E
Sun Nov 17, 2019 11:33 pm
Forum: Bond Lengths & Energies
Topic: 2D. 19
Replies: 3
Views: 39

Re: 2D. 19

im also wondering if this will be on Test 2?
but I just added the covalent radii to get the bond length.
by sarahsalama2E
Sun Nov 17, 2019 11:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.27A
Replies: 1
Views: 20

Re: 2E.27A

Typically when there are a lot of carbons in a molecule, it forms a carbon structure, like a benzene ring. But however, it can also form chains. I have noticed that typically when there are more than 4 carbons, a ring is formed. Also, pay attention to how the molecule is written out. The way that py...
by sarahsalama2E
Sun Nov 17, 2019 11:28 pm
Forum: Dipole Moments
Topic: Hydrogen Bonds and Polarity
Replies: 1
Views: 20

Re: Hydrogen Bonds and Polarity

You would have to look at the molecule to make sure that the dipole moments do not cancel out to see if whether or not the molecule as an entirety is polar or not. But yes, hydrogen bond is a polar covalent bond.
by sarahsalama2E
Thu Nov 14, 2019 10:04 am
Forum: Properties of Light
Topic: Chemistry Community Posts
Replies: 10
Views: 112

Re: Chemistry Community Posts

for example, i posted 3 times before sunday 9/29 midnight so do i get 3 points?
by sarahsalama2E
Thu Nov 14, 2019 10:03 am
Forum: Properties of Light
Topic: Chemistry Community Posts
Replies: 10
Views: 112

Re: Chemistry Community Posts

when was the first week that posts were due?
by sarahsalama2E
Wed Nov 13, 2019 10:03 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: Intermolecular Forces vs Bonding???
Replies: 5
Views: 47

Re: Intermolecular Forces vs Bonding???

Do all molecules have London Dispersion Forces and only certain ones have dipole moments (i.e. you must draw the lewis structure to see that).
by sarahsalama2E
Wed Nov 13, 2019 10:02 pm
Forum: Ionic & Covalent Bonds
Topic: HW #2.25
Replies: 2
Views: 25

Re: HW #2.25

I had the same reasoning. Bond size also increases/decreases directly with atomic size (i.e. atomic #).
by sarahsalama2E
Wed Nov 13, 2019 10:01 pm
Forum: Sigma & Pi Bonds
Topic: Recognizing Sigma and Pi bonds
Replies: 4
Views: 43

Re: Recognizing Sigma and Pi bonds

did we cover sigma and pi bonds? Are we going to cover them this week?
by sarahsalama2E
Wed Nov 13, 2019 10:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: arrangment and strength of IMFS
Replies: 4
Views: 44

arrangment and strength of IMFS

How does the arrangement of molecules affect the strength of intermolecular forces?
by sarahsalama2E
Wed Nov 13, 2019 10:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Tetrahedral VSPER model
Replies: 7
Views: 56

Re: Tetrahedral VSPER model

will we cover shapes with lone pairs and bonding regions as well? like AX4E1 for example.
by sarahsalama2E
Wed Nov 13, 2019 9:59 pm
Forum: Administrative Questions and Class Announcements
Topic: Test #2
Replies: 22
Views: 235

Re: Test #2

Correct, it will be on IMF'S, VESPR, and the rest of bonding that was not covered on the midterm.
by sarahsalama2E
Mon Nov 11, 2019 2:45 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: intermolecular forces/polarity
Replies: 2
Views: 24

Re: intermolecular forces/polarity

Higher attraction (aka dipole moment) means that it takes more energy to disassociate the bond, which results in a higher melting or boiling point. Like what was mentioned before, you must draw the lewis structure to see if the bonds cancel out, because the particular bonds could be polar but the mo...
by sarahsalama2E
Mon Nov 11, 2019 2:43 pm
Forum: Electronegativity
Topic: Noble Gases
Replies: 19
Views: 148

Re: Noble Gases

Noble gases are not included in the e-negativity trend, because they are already full (p6 electrons) they do not want to add any more, because that would make them unstable. The goal is always to be as stable as possible.
by sarahsalama2E
Mon Nov 11, 2019 2:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moment
Replies: 4
Views: 30

Re: Dipole moment

So when an atom is not bonded to itself, does that always result in a dipole moment?
by sarahsalama2E
Mon Nov 11, 2019 2:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H2O and Ionic Compounds
Replies: 3
Views: 19

Re: H2O and Ionic Compounds

The strongly different polar charges are able to interact with BOTH positive and negative charged ions, therefore disassociating them.
by sarahsalama2E
Mon Nov 11, 2019 2:41 pm
Forum: Octet Exceptions
Topic: More then 8 electrons
Replies: 5
Views: 40

Re: More then 8 electrons

Yes, this is allowed because it has an expanded octet due to the d orbital which can hold up to 10 electrons.
by sarahsalama2E
Mon Nov 11, 2019 2:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar bonds and molecular shape
Replies: 2
Views: 19

polar bonds and molecular shape

I know we haven't covered this yet, but just wondering how exactly polar bonds affect the shape of a molecule?
by sarahsalama2E
Wed Nov 06, 2019 4:47 pm
Forum: Quantum Numbers and The H-Atom
Topic: Equations we need for midterm
Replies: 7
Views: 103

Re: Equations we need for midterm

Yes it is
by sarahsalama2E
Sun Nov 03, 2019 10:39 pm
Forum: Trends in The Periodic Table
Topic: Electron affinity vs electronegativity
Replies: 7
Views: 42

Re: Electron affinity vs electronegativity

Do we need to know the actual or formal definitions of terms like this for the exam?
by sarahsalama2E
Sun Nov 03, 2019 10:38 pm
Forum: Formal Charge and Oxidation Numbers
Topic: How to know where a double bond should go?
Replies: 10
Views: 71

Re: How to know where a double bond should go?

You have to check that the double bond wouldn’t violate a particular atoms octet rule, also you should draw the double bond so that it stabilizes the molecule the most and reduces the formal charge as much as possible.
by sarahsalama2E
Sun Nov 03, 2019 10:36 pm
Forum: Resonance Structures
Topic: Drawing the resonance hybrid
Replies: 2
Views: 35

Drawing the resonance hybrid

Will we need to draw the actual resonance hybrid on the exam, or can we just draw the arrows between the resonance structures signifying that the structures are contributing to the final resonance structure...
by sarahsalama2E
Sun Nov 03, 2019 10:34 pm
Forum: Resonance Structures
Topic: Including resonance structures
Replies: 2
Views: 19

Including resonance structures

So do we need to draw the resonance structures for each time there are resonance structures, or only when it
Is asked for in the specific question?
by sarahsalama2E
Sun Nov 03, 2019 10:33 pm
Forum: Bond Lengths & Energies
Topic: Why Are Double Bonds Shorter
Replies: 16
Views: 167

Re: Why Are Double Bonds Shorter

Should we also know the relative strengths of polar covalent vs non polar covalent forces
by sarahsalama2E
Wed Oct 30, 2019 11:41 pm
Forum: Properties of Electrons
Topic: Knowing masses
Replies: 2
Views: 46

Re: Knowing masses

no, i asked today in a review session and the UA's said that they would be given on the formula sheet.
by sarahsalama2E
Wed Oct 30, 2019 11:39 pm
Forum: Resonance Structures
Topic: Delocalized Electrons
Replies: 4
Views: 26

Re: Delocalized Electrons

I think that electrons are not really stationary like we draw them in lewis structures, but rather they move around (meaning that they are delocalized). You can see this in resonance structures and resonance hybrid.
by sarahsalama2E
Wed Oct 30, 2019 11:38 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Will we have to do calculations with the wave functions?
Replies: 1
Views: 21

Re: Will we have to do calculations with the wave functions?

I believe no (if you are referring to psi), however make sure to know de broglie's, heisenberg. Also make sure to use SI units for those !
by sarahsalama2E
Wed Oct 30, 2019 11:35 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 4
Views: 24

Re: Drawing Lewis Structures

Place the least electronegative element in the middle of the lewis structure. Also the single available element is in the middle of the structure.
by sarahsalama2E
Wed Oct 30, 2019 11:33 pm
Forum: Resonance Structures
Topic: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?
Replies: 4
Views: 33

Re: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?

This is because the actual structure is a resonance hybrid where the bonds are all roughly the same length. Also in a real structure, electrons move around as well.
by sarahsalama2E
Wed Oct 30, 2019 11:31 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Why does 3d come before 4s?
Replies: 2
Views: 18

Re: Why does 3d come before 4s?

That is correct, it is also important to note that when 4s begins to fill with electrons, 4s has higher energy than 3d. So, we right 3d before 4s. Also this is for ease of removing an electron when we are forming anions.
by sarahsalama2E
Tue Oct 22, 2019 6:30 pm
Forum: DeBroglie Equation
Topic: DeBroglie Equation
Replies: 11
Views: 63

Re: DeBroglie Equation

Just wondering that when we use DeBroglie Equation and Heisenberg Uncertainty Equation, we are using Kg and m as these are the SI units?
by sarahsalama2E
Tue Oct 22, 2019 6:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Excited state vs ground state
Replies: 4
Views: 28

Re: Excited state vs ground state

Like what was mentioned above by others, pay attention to the written electron configuration to notice an electron "jumping" levels. Additionally, when looking at drawn orbital diagrams, making sure that each orbital is filled before moving on to the next ensures that it is in the ground s...
by sarahsalama2E
Tue Oct 22, 2019 6:27 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Balmer and Lyman series
Replies: 5
Views: 28

Re: Balmer and Lyman series

The Balmer series releases electrons to the n=2 level and happens in visible light while the Lyman series releases electrons to the n=1 level and happens in UV light.
by sarahsalama2E
Tue Oct 22, 2019 6:25 pm
Forum: Properties of Light
Topic: Combining Different Equations
Replies: 8
Views: 59

Re: Combining Different Equations

Personally, I just write down all the equations i know or see fit and use which ones make sense given the variables that I have in the problem at hand. Make sure that you are using reasonable equations at each step of the problem.
by sarahsalama2E
Tue Oct 22, 2019 6:23 pm
Forum: Trends in The Periodic Table
Topic: Effective Nuclear Charge
Replies: 7
Views: 36

Re: Effective Nuclear Charge

atomic radius increases down a group and decreases down a period. Because the # of shells stays the same across a period, the effective nuclear charge is increasing because the atomic # (therefore charge of nucleus) is increasing. Because this is happening, the atomic radius decreases due to attract...
by sarahsalama2E
Tue Oct 22, 2019 6:20 pm
Forum: Properties of Electrons
Topic: x,y,z for Electrons
Replies: 10
Views: 76

Re: x,y,z for Electrons

x,y,z is essentially the planes that the different p-orbitals could be oriented on. There are three orientations or planes--> px,py,pz.This is also just being more specific regarding the electron placement in the p-orbital. Because we know hund's rule, each px,py,pz must be filled with one e- before...
by sarahsalama2E
Tue Oct 22, 2019 6:18 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energies Trend
Replies: 5
Views: 31

Re: Ionization Energies Trend

ionization energy is the energy required to remove an electron from an atom in the gas phase. The further away an electron is from the nucleus the easier it is to remove. Ionization energy increases across a period because the nuclear charge is greater and the electrons are still being added to the ...
by sarahsalama2E
Mon Oct 21, 2019 2:11 pm
Forum: Properties of Electrons
Topic: Problem 1E.5
Replies: 3
Views: 35

Re: Problem 1E.5

(a) false--> the effective nuclear charge is the nuclear charge - shielding e- (b) true--> because electrons in the s-orbital are closer to the nucleus and can penetrate to the nucleus of the atom, compared to electrons that are farther away (c) false, l=1 is closer (d) true= because s orbital is sh...
by sarahsalama2E
Mon Oct 21, 2019 1:55 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 7
Views: 67

Re: Atomic Radius

Atomic radius is 1/2 the distance between the centers of neighboring atoms, and increases as you go down a group and decreases across a period. It is important to know that that ionic radii also shows the same trends.

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