Search found 99 matches
- Sat Mar 14, 2020 9:30 pm
- Forum: *Free Energy of Activation vs Activation Energy
- Topic: Temperature vs. activation energy
- Replies: 33
- Views: 2689
Re: Temperature vs. activation energy
I do believe increasing T also increases k reaction constant.
- Sat Mar 14, 2020 9:27 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Printing for Final
- Replies: 9
- Views: 768
Re: Printing for Final
I don't think we need to print anything out, it should all be online. Having your notes and scrap paper for work would be helpful though!
- Sat Mar 14, 2020 9:12 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Relationship between work, cell potential, and delta G
- Replies: 6
- Views: 695
Re: Relationship between work, cell potential, and delta G
When delta G is negative, there is energy free to do work. Cell potential wants to go down. IF cell potential goes down there is a release of energy free to do work. I don’t think this is a correct. In the equation delta G= -nFEcell, if cell potential is higher, and more positive, then Gibbs free e...
- Sat Mar 14, 2020 8:54 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: are there standard rates of formation?
- Replies: 4
- Views: 388
Re: are there standard rates of formation?
They should give you this information in the question or somewhere on the test. It would definitely be tedious if we had to look these up by ourselves.
- Sat Mar 14, 2020 8:50 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Mnemonic for Oxidation and Reduction
- Replies: 7
- Views: 632
Re: Mnemonic for Oxidation and Reduction
Thanks! For oxidation reduction I also usually use Leo the lion goes ger. LEO --> lose electrons Oxidation, GER--- gain electrons reduction.
- Sat Mar 14, 2020 8:41 pm
- Forum: Administrative Questions and Class Announcements
- Topic: final exam - question
- Replies: 6
- Views: 715
Re: final exam - question
At the same time, he said the test should be relatively straightforward and open notes. So, maybe we will be okay? Either way, good luck everybody!
- Sat Mar 14, 2020 8:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Exam Time
- Replies: 13
- Views: 966
Re: Final Exam Time
It is timed, from 11:15am and ends 2:45pm, but we have 3 and a half hours. Hopefully that will be enough. Good Luck!
- Sat Mar 14, 2020 8:39 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Reaction order
- Replies: 4
- Views: 370
Re: Reaction order
Yea, it can be used for any reaction order!
- Sat Mar 14, 2020 8:35 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2 Return
- Replies: 20
- Views: 1232
Re: Test 2 Return
Not sure if this helps but here is the link to some of the answer keys for test 2.
viewtopic.php?f=160&t=62122&p=237630&hilit=test+2&sid=398e06555d588269350912837d954689#p237630
viewtopic.php?f=160&t=62122&p=237630&hilit=test+2&sid=398e06555d588269350912837d954689#p237630
- Sat Mar 14, 2020 8:33 pm
- Forum: General Rate Laws
- Topic: Video help
- Replies: 3
- Views: 400
Re: Video help
Okay, thank you I will definitely check them out.
- Sat Mar 14, 2020 8:33 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Qc vs Kc
- Replies: 15
- Views: 5502
Re: Qc vs Kc
If they are equal then the reaction is at equilibrium. If Q>K then the forward reaction or products are favored. The opposite is true for Q<K the reactants are favored.
- Sat Mar 14, 2020 8:30 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Take Home Final
- Replies: 16
- Views: 1068
Re: Take Home Final
It seems like this is just an online test with no scanning, so It seems like it would be hard to show your work and have that be graded. But maybe you will have to put in answers for intermediate steps and that could be counted as work? Im not sure, but Lavelle said the test would be straightforward...
- Sat Mar 14, 2020 8:28 pm
- Forum: Zero Order Reactions
- Topic: Units
- Replies: 9
- Views: 849
Re: Units
This helped me, hope it helps you too. https://users.stlcc.edu/gkrishnan/rateunits.htm
- Sat Mar 14, 2020 8:27 pm
- Forum: General Rate Laws
- Topic: Video help
- Replies: 3
- Views: 400
Video help
Hey does anyone have any good online videos that go over Rates and Rate laws? Thank you! and good luck tomorrow everyone.
- Sat Mar 14, 2020 8:19 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy Equation
- Replies: 3
- Views: 301
Re: Enthalpy Equation
The derivation is:
deltaU = w + q
w= deltaH
q=-P*deltaV
so,
deltaU=deltaH-P*deltaV
which you can rearrange as:
H=U+PV
deltaU = w + q
w= deltaH
q=-P*deltaV
so,
deltaU=deltaH-P*deltaV
which you can rearrange as:
H=U+PV
- Sat Mar 14, 2020 8:17 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: R and Nernst equation
- Replies: 2
- Views: 423
Re: R and Nernst equation
If you write out the units for all the constants in the equation you can see how they cancel out. I believe the final units should simplify out to V. I think you always use 8.314 for R because the J cancels out.
- Sat Mar 14, 2020 8:11 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Catalysts
- Replies: 4
- Views: 309
Re: Catalysts
I believe so, also in a reaction I think it can sometimes be represented on the arrow. It isn't necessarily the opposite of a intermediate, an intermediate is created and consumed. The catalyst is just a substance or molecule that a reaction takes place on. It isn't used up in the reaction.
- Sat Mar 14, 2020 8:03 pm
- Forum: Van't Hoff Equation
- Topic: Equation Sheet
- Replies: 18
- Views: 1185
Re: Equation Sheet
I could be wrong but I remember it being on the equation sheet for test 2? but otherwise it isn't on the current online equation sheet. Although the test is open notes so just make a note of it.
- Sat Mar 14, 2020 8:01 pm
- Forum: Balancing Redox Reactions
- Topic: YouTube videos for Redox Reactions
- Replies: 4
- Views: 526
Re: YouTube videos for Redox Reactions
Oh wow thank you! This video was pretty helpful for me
- Sat Mar 14, 2020 7:36 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: bars
- Replies: 3
- Views: 237
Re: bars
I think you can convert to atm. Cause equilibrium can also be calculated through pressure. Someone correct me if I am wrong
- Sat Mar 14, 2020 7:34 pm
- Forum: General Rate Laws
- Topic: average rate
- Replies: 4
- Views: 380
Re: average rate
You are correct, the negative is used to show that the reactants are being used up.
- Sat Mar 14, 2020 7:33 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q=qP
- Replies: 3
- Views: 451
Re: q=qP
Just like qV Is heat at a constant volume, qP is heat at a constant pressure. Good luck!
- Sat Mar 14, 2020 7:31 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Is pH normally taken at equilibrium concentrations?
- Replies: 7
- Views: 745
Re: Is pH normally taken at equilibrium concentrations?
Usually it should tell you if it isn't taken at equilibrium. This really isn't a big problem, just make sure you put the H+ concentration in the correct place in the ice tables.
- Sat Mar 14, 2020 7:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Conjugate Seesaw
- Replies: 5
- Views: 465
Re: Conjugate Seesaw
Conjugate seesaw has to do with conjugate acids and bases. A weak acid will have a strong conjugate base. A strong acid will have a weak conjugate base. You can see how this is metaphorically related to the idea of a seesaw.
- Sat Mar 14, 2020 7:27 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: intermediates
- Replies: 8
- Views: 597
Re: intermediates
Intermediates are what they sound like. They are molecules that are produced in one reaction and consumed by a second reaction. They occur, because most reactions don't always happen in a single step. Intermediates just represent products in a first reaction and reactants in a second. You can tell, ...
- Sat Mar 14, 2020 7:23 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff Equation
- Replies: 6
- Views: 587
Re: Van't Hoff Equation
You shouldn't really need to manipulate the equation too much. It is used to solve for K values for a certain recreation at different temperatures. So If you know the K at a certain temperature, you can use the equation to solve for K at another temperature.
- Sat Mar 14, 2020 7:15 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Electrolysis
- Replies: 6
- Views: 489
Re: Electrolysis
I would know it since it was on the outline. It is a fairly simple concept, watch some videos on it.
- Sat Mar 14, 2020 7:12 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: ENDGAME Q.10
- Replies: 3
- Views: 266
Re: ENDGAME Q.10
You don't have to flip the values in the table. You can leave them and just plug them straight into the Cathode-Anode Equation.
- Sat Mar 14, 2020 7:04 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Platinum
- Replies: 2
- Views: 176
Re: Platinum
Platinum is also very oxidation stable in comparison to most metals.
- Sat Mar 14, 2020 6:59 pm
- Forum: *Nucleophiles
- Topic: FInal
- Replies: 11
- Views: 1778
Re: FInal
It would obviously be more helpful for the final to know things more in-depth, but for the most part what Lavelle has said during lecture should be sufficient in my opinion. If you have extra time, I would go ahead and look over the textbook though. Lavelle wouldn't put anything in outside of our ca...
- Sat Mar 14, 2020 6:54 pm
- Forum: Balancing Redox Reactions
- Topic: balancing h and o
- Replies: 7
- Views: 583
Re: balancing h and o
I usually balance the Hydrogens based off Oxygens, so I guess you could say balance O2 first then H+
- Sat Mar 14, 2020 6:53 pm
- Forum: Balancing Redox Reactions
- Topic: oh
- Replies: 11
- Views: 833
Re: oh
Generally no, H2O is probably best to be used. OH can create issues with PH if it is an acidic or basic reaction
- Sat Mar 14, 2020 6:48 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: intensive vs extensive
- Replies: 12
- Views: 836
Re: intensive vs extensive
Extensive represents things that are dependent on amount. While intensive represents things that aren't dependent on amount, like density. It is important to consider these when using constants and equations during your calculations.
- Sat Mar 14, 2020 6:45 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: w
- Replies: 12
- Views: 826
Re: w
I think this is because we want to find one mole's worth, which is avagodros number in terms of atoms or molecules.
- Sat Mar 14, 2020 6:41 pm
- Forum: Van't Hoff Equation
- Topic: ln
- Replies: 34
- Views: 2001
Re: ln
it is e to the power, to get rid of Ln. Try some examples on your calculator.
- Sat Mar 14, 2020 6:40 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: negative sign
- Replies: 12
- Views: 702
Re: negative sign
I believe it has to do with the relationship between E and delta G. When E is positive, delta G should be negative meaning it is spontaneous.
- Sat Mar 14, 2020 6:35 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: self-test explanation
- Replies: 1
- Views: 200
Re: self-test explanation
I think it is because delta S is negative. So in the equation DeltaG=DeltaH-TDeltaS, delta S being negative would make delta G positive, increasing T would just make it more positive, because delta G is positive when it is non-spontaneous. (-T*-deltaS is going to equal a positive number)
- Sat Mar 14, 2020 6:30 pm
- Forum: Balancing Redox Reactions
- Topic: Pt in Cell Diagram
- Replies: 14
- Views: 964
Re: Pt in Cell Diagram
There has to be a solid metal present in a cell diagram, Pt just happens to be the most common that is used if one isn't presented in the question.
- Sat Mar 14, 2020 6:28 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic vs Exothermic
- Replies: 2
- Views: 325
Re: Endothermic vs Exothermic
Im not exactly sure if this is what you are asking but I hope this answer helps. A reaction is exothermic if Kc decreases with an increase in temperature, as the reaction shifts left, or Kc increases with a decrease in temperature, as the reaction shifts right. This is because in an exothermic react...
- Sat Mar 14, 2020 6:20 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 6
- Views: 526
Re: Nernst Equation
No it is not necessary. Just make sure you plug in the correct values for R, F, and T. For R you should usually be using the 8.314J/K*mol.
- Sat Mar 14, 2020 6:01 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: intermediate v. catalyst
- Replies: 6
- Views: 458
Re: intermediate v. catalyst
A catalyst is not used up in the reactions. An intermediate is created and later consumed.
- Sat Mar 14, 2020 5:58 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Entropy and complexity
- Replies: 2
- Views: 281
Re: Entropy and complexity
Larger molecules have more entropy, due to them containing more bonds and therefore more ways of orientation. I believe that standard entropy increases with increasing mass
- Thu Feb 27, 2020 9:11 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: When to apply Pt into cell diagrams
- Replies: 9
- Views: 545
Re: When to apply Pt into cell diagrams
Pt is included if their is not a metallic solid in the cell diagram. Hg(l) mercury can also be included but I believe 99% of the time it is a metal solid that is included.
- Thu Feb 27, 2020 9:11 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: When to apply Pt into cell diagrams
- Replies: 9
- Views: 545
Re: When to apply Pt into cell diagrams
Pt is included if their is not a metallic solid in the cell diagram. Hg(l) mercury can also be included but I believe 99% of the time it is a metal solid that is included.
- Sun Jan 26, 2020 10:21 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: endothermic
- Replies: 8
- Views: 354
Re: endothermic
Increasing temperature flows away from "heat", so in an endothermic reaction it flows to the products and increases the equilibrium constant
- Sun Jan 26, 2020 10:20 pm
- Forum: Ideal Gases
- Topic: R Constant
- Replies: 26
- Views: 1265
Re: R Constant
The R constant is dependent on the units of pressure you are given. Looking up a table is helpful and just pay attention to the units you are given in the question. You don't need to memorize this, just know which values correspond to each unit of pressure.
- Sat Dec 07, 2019 6:37 pm
- Forum: Naming
- Topic: (ox) and (en)
- Replies: 2
- Views: 366
Re: (os) and (en)
(en) refers to ethylenediamine
here's its formula: NH2CH2CH2NH2
it is a chelating ligand (bidentate)
Im not sure what (os) but if you meant (ox) then ox is oxalate: C2O4 with a 2- charge, this is also bindendate chelating
Os could also mean Osmium? Where exactly did you see (os)
here's its formula: NH2CH2CH2NH2
it is a chelating ligand (bidentate)
Im not sure what (os) but if you meant (ox) then ox is oxalate: C2O4 with a 2- charge, this is also bindendate chelating
Os could also mean Osmium? Where exactly did you see (os)
- Sat Dec 07, 2019 6:27 pm
- Forum: Air Pollution & Acid Rain
- Topic: acid rain
- Replies: 5
- Views: 539
Re: acid rain
You should know the equation and the idea behind acid rain. Carbon dioxide reacts with water in The atmosphere to form carbonic acid, which is released in acid rain H2O + CO2 --> H2CO3 it may also be helpful to know that H2CO3 can dissociate and give off one of the protons H2CO3 --> HCO3- + H+
- Sat Dec 07, 2019 6:20 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelating Ligands and Coordination Numbers
- Replies: 4
- Views: 316
Re: Chelating Ligands and Coordination Numbers
Yeah it would be six. I think I was a bit confused earlier when I was typing my answer. Sorry!
- Sat Dec 07, 2019 6:19 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: determining dentate
- Replies: 1
- Views: 170
Re: determining dentate
It is just how many times a ligand attaches to the metal in the center.
Example: If it attaches four times its tetradentate
Example: If it attaches four times its tetradentate
- Fri Dec 06, 2019 11:07 pm
- Forum: Conjugate Acids & Bases
- Topic: determining conj. acids& bases
- Replies: 2
- Views: 249
Re: determining conj. acids& bases
The conjugate base of an acid is the form the acid takes after giving up a proton (H). Additionally, a conjugate acid of a base is the form a base takes after gaining a proton (H). for example: CH3CO2H is an Acid and CH3CO2- is its conjugate base, because it lost a proton H2O becoming H3O+ (hydroniu...
- Fri Dec 06, 2019 11:00 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: EDTA
- Replies: 3
- Views: 335
Re: EDTA
It is Hexadentate.
- Thu Dec 05, 2019 4:11 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Content of the final
- Replies: 11
- Views: 1063
Re: Content of the final
Yea I don't believe we need to know about bond order.
- Thu Dec 05, 2019 4:05 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: EDTA
- Replies: 3
- Views: 298
Re: EDTA
I think it is because the non-doublebonded Oyxgens have a -1 formal charge and the double bonded oxygens have a formal charge of 0. The -1 formal charge allows oxygen to want to bind. I also think that the double bonded oxygens are often on the other side of the bonded oxygens this could contribute ...
- Thu Dec 05, 2019 4:01 pm
- Forum: Lewis Acids & Bases
- Topic: 6A13b
- Replies: 2
- Views: 232
Re: 6A13b
Boron is relatively electropositive and especially when it is bounded to fluorine, the negative charge is further distributed away from Boron. This allows it to want to accept an electron pair, making it a Lewis acid.
- Thu Dec 05, 2019 3:58 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelating Ligands and Coordination Numbers
- Replies: 4
- Views: 316
Re: Chelating Ligands and Coordination Numbers
I don't think it would necessarily be raised, but if a molecule chelates then less of that molecule is needed to bond to the metal. So there would just be less ligands needed in the coordinating complex. The coordinate number doesn't increase but there are less ligands, so the charge on the metal se...
- Thu Dec 05, 2019 3:52 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Organic Acids
- Replies: 1
- Views: 146
Organic Acids
What is an Organic acid and what do we need to know about it?
- Thu Dec 05, 2019 3:47 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Equilibrium Tables
- Replies: 1
- Views: 228
Re: Equilibrium Tables
No I don't believe we need to know anything about equilibrium tables in terms of calculations but I think we need a simple grasp on the concept of equilibrium as a whole. Since he didn't cover it in lecture it probably won't be on the final.
- Thu Dec 05, 2019 3:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polarity for a trigonal planar molecule
- Replies: 2
- Views: 188
Re: Polarity for a trigonal planar molecule
The molecule is polar just because of the hydrogen bonded to one of the Oxygens. This makes the entire molecule not symmetrical, making it polar, even though the shape of the central nitrogen is trigonal planar.
- Thu Dec 05, 2019 3:40 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 6B 1
- Replies: 2
- Views: 177
Re: 6B 1
I believe the question says it is reduced TO 12% of its total, not reduced by 12%.
You would use -Log[0.12] and compared to Log(1), which is 0 the difference is just the value of -Log[0.12]
You would use -Log[0.12] and compared to Log(1), which is 0 the difference is just the value of -Log[0.12]
- Thu Dec 05, 2019 3:36 pm
- Forum: Lewis Acids & Bases
- Topic: HW 6.B #9
- Replies: 1
- Views: 188
Re: HW 6.B #9
pH=-Log[Hydronium ion concentration]
pOH=-Log[Hydroxide concentration]
pH+pOH=14, so
14-pOH=pH
You can convert all of these into pH and then rank them.
pOH=-Log[Hydroxide concentration]
pH+pOH=14, so
14-pOH=pH
You can convert all of these into pH and then rank them.
- Thu Dec 05, 2019 3:30 pm
- Forum: Biological Examples
- Topic: Cisplatin binding
- Replies: 1
- Views: 118
Re: Cisplatin binding
The two chlorines in cisplatin get replaced by Water which bonds to the nitrogen lone pairs on two guanines. I believe these are hydrogen bonds with the Oxygen facing towards the Platinum
- Thu Dec 05, 2019 3:24 pm
- Forum: Biological Examples
- Topic: Vitamin B12
- Replies: 1
- Views: 188
Vitamin B12
What is the biological significance of B12?
- Sun Nov 24, 2019 5:48 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Why are inorganic acids stronger?
- Replies: 8
- Views: 1336
Re: Why are inorganic acids stronger?
Elizabeth Johnson 1I wrote:Giselle Littleton 3K wrote:Inorganic compounds are more likely to completely deprotonate.
can someone define what deprotonate means?
Deprotonate is essentially just losing a proton, you can also think of this as losing a hydrogen+. (hydrogen has one proton)
Re: Class
Yeah its probably too late, sorry. But you can still do well in the class if you do well on the final and continue to do the homework and chem community!
- Wed Nov 20, 2019 11:33 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Why is CH2Cl2 polar?
- Replies: 12
- Views: 803
Re: Why is CH2Cl2 polar?
You should think of this molecule in the 3d form. In a tetrahedral, no matter where you put the atoms the Chlorine atoms will always be next to each other. I can't Draw a picture on here, but just look one up it might be helpful. The lewis structure looks like u can orient the chlorines to be opposi...
- Tue Nov 19, 2019 10:30 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: cations
- Replies: 2
- Views: 223
Re: cations
The smaller the cation the higher Polarizing power. Respectively, the larger the anion the higher its polarizability.
Molecules with more polarizability tend to have a more covalent character.
Molecules with more polarizability tend to have a more covalent character.
- Sun Nov 17, 2019 9:47 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Model
- Replies: 3
- Views: 195
Re: VSEPR Model
You have to memorize them, don't rely on a table on the test. I believe you need to know bond angles, shape, and whether molecules are polar or not.
- Sun Nov 17, 2019 9:45 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: london forces
- Replies: 5
- Views: 247
Re: london forces
All atoms have the potential to form temporary dipoles, due to electrons randomly moving into favorable positions. These temporary dipoles are London Forces.
- Sun Nov 17, 2019 9:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape of H20
- Replies: 3
- Views: 331
Re: Molecular Shape of H20
The lone pairs cannot be on opposite sides of each other, this is due to the nature of tetrahedral shapes. if you put two lone pairs into a tetrahedral they will always be next to each other, not on opposite sides. Its hard to draw a tetrahedral model on here but looking one up might be helpful.
- Sun Nov 17, 2019 8:26 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar and Nonpolar
- Replies: 6
- Views: 641
Re: Polar and Nonpolar
The best way to do this is to draw the lewis structures of each molecule. Once you draw the lewis structure and determine the shape you can figure out if its polar or not. Another option is drawing and canceling dipole moments on the lewis structures.
- Sun Nov 17, 2019 8:02 pm
- Forum: Hybridization
- Topic: Pi and sigma bonds
- Replies: 4
- Views: 243
Pi and sigma bonds
Can someone explain why a a single bond is a sigma and why a double bond has a sigma and a pi bond, and the same for triple bonds? thanks
- Sun Nov 17, 2019 7:54 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: types of bonds
- Replies: 14
- Views: 1242
Re: types of bonds
Yes, a triple bond consists of two pi bonds and one sigma bond.
- Sun Nov 10, 2019 5:37 pm
- Forum: Bond Lengths & Energies
- Topic: test 2
- Replies: 16
- Views: 931
Re: test 2
It will probably focus mainly on stuff after the midterm but that doesn't mean you can forget everything else we have learned.
- Sun Nov 10, 2019 5:13 pm
- Forum: Electronegativity
- Topic: Iodine
- Replies: 6
- Views: 676
Re: Iodine
Iodine has a larger atomic radius and more electrons than the other halogens. This makes it stronger.
- Sun Nov 10, 2019 4:49 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Remembering bond angles
- Replies: 1
- Views: 189
Remembering bond angles
Is there any easy way to remember bond angles as they correspond to shape? or do I just have to memorize them as they are.Thanks!
- Wed Nov 06, 2019 2:31 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Dino nuggets 11b
- Replies: 3
- Views: 315
Re: Dino nuggets 11b
Awesome thank you for the responses!
- Wed Nov 06, 2019 2:10 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molarity Formula / Calculation
- Replies: 5
- Views: 2981
Re: Molarity Formula / Calculation
Molarity is Moles/Liters. You can think about it as an amount (moles) that is diluted by a liquid (liters). So in a dilution, only the amount of liters changes and the moles stay constant and you can use the equation m1v1=m2v2. (m being moles and v being volume in liters) . Just be familiar with the...
- Tue Nov 05, 2019 9:47 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Dino nuggets 11b
- Replies: 3
- Views: 315
Dino nuggets 11b
Can someone please explain Dino Nuggets 11.b) Here is the question for reference "If a hydrogen electron goes from n=6 to n=4, will ∆E be negative or positive? Will the energy of the photon emitted be negative or positive?" I don't quite understand how to determine if the energy of the pho...
- Tue Nov 05, 2019 8:37 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizing Power Periodic Trend
- Replies: 4
- Views: 157
Re: Polarizing Power Periodic Trend
Im a bit confused, so do small cations cause greater polarizing power or do larger cations?
- Mon Oct 21, 2019 12:36 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Ionization Energy
- Replies: 4
- Views: 139
Re: Ionization Energy
Second ionization energy is higher, because with one less electron there is greater pull from the nucleus on the remaining electron, and less electron-electron repulsion. This greater pull makes it much harder to remove the second electron.
- Mon Oct 21, 2019 12:34 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Ionization Energy
- Replies: 4
- Views: 139
Re: Ionization Energy
The second ionization energy is higher for all elements
- Mon Oct 21, 2019 12:18 pm
- Forum: Photoelectric Effect
- Topic: 0KE electron?
- Replies: 2
- Views: 161
Re: 0KE electron?
Dr. Lavelle mentioned during lecture that there was a current attached to the detector. I believe the detector was positively charged, possibly attracting the electron and detecting it, without it having a true Kinetic Energy. Although theoretically, it is emitted with 0KE, im not sure that it works...
- Sun Oct 20, 2019 10:13 pm
- Forum: Properties of Light
- Topic: 1F.19
- Replies: 5
- Views: 229
Re: 1F.19
Ionization energy (the energy required to remove an electron) is typically lower for s-block metals. Search up an image of ionization energy in relation to the period table for a more visual answer. But generally, ionization energy gets higher as you move from left to right of the periodic table and...
- Sun Oct 20, 2019 10:03 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: The equation
- Replies: 2
- Views: 139
- Sun Oct 20, 2019 4:31 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: p- orbital
- Replies: 3
- Views: 150
Re: p- orbital
Technically you can label the axes in any order you want, however the general rule is: x, y, z Hund's rule states, however, electrons must fill one in each P axes before they are paired. This means that there has to be one electron in Px, Py, and Pz, before there are paired electrons in Px, for exam...
- Sun Oct 20, 2019 4:24 am
- Forum: Properties of Electrons
- Topic: Shared Electrons
- Replies: 4
- Views: 274
Re: Shared Electrons
You have to refer to Hund's rule. Each orbital (for example Px,Py,Pz) must be filled with one electron before you pair electrons. Take the element Nitrogen for example. Nitrogen's orbital notation at its ground state would be written as 1s1 2s2 2p3 In the P state, nitrogen has three unpaired electro...
- Sun Oct 20, 2019 4:09 am
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 9
- Views: 665
Re: Work Function
Threshold frequency refers to the minimum possible frequency of light needed to eject an electron from a metal's surface. Work function refers to the minimum energy level needed to eject an electron from a metal's surface. Thats the main difference; threshold frequency refers to the minimum frequenc...
- Sun Oct 13, 2019 11:03 pm
- Forum: Properties of Electrons
- Topic: Emission Spectrum
- Replies: 4
- Views: 160
Re: Emission Spectrum
These line groups represent changes in energy levels for electrons. When electrons drop an energy level (n=2 to n=1) then energy is emitted. Depending on which energy level the electron is dropping from and to, the atom emits different frequencies of lights. Experimenters measured these wavelengths ...
- Sun Oct 13, 2019 10:53 pm
- Forum: Properties of Electrons
- Topic: Photons and Electrons
- Replies: 2
- Views: 108
Re: Photons and Electrons
Yes, electrons generally interact with only One proton. Electrons are only ejected if the protons have enough energy, this is gained through increasing the frequency of light, not just the intensity. Once the threshold is passed, increasing intensity produces more photons and more photons interact w...
- Sun Oct 13, 2019 10:44 pm
- Forum: Photoelectric Effect
- Topic: Electrons and High Intensity Light
- Replies: 2
- Views: 178
Re: Electrons and High Intensity Light
I believe this concept refers to the particle properties of light. If light was just a wave then increasing the intensity of light should eject electrons, but that wasn't what happened in experiments. Energy has to be high enough per photon to induce electron removal from a metal surface. Increasing...
- Sun Oct 13, 2019 10:35 pm
- Forum: Photoelectric Effect
- Topic: Symbol N Subscript A
- Replies: 2
- Views: 1010
Re: Symbol N Subscript A
I believe N subscript A refers to avagodro's number.
- Sun Oct 13, 2019 10:26 pm
- Forum: Properties of Light
- Topic: When to use the Planck's Constant?
- Replies: 6
- Views: 353
Re: When to use the Planck's Constant?
Planck's constant is used to relate the relationship between frequency and the energy of a proton, so it is used in the equation E=hv, h being Planck's constant.
- Sun Oct 06, 2019 11:15 pm
- Forum: Empirical & Molecular Formulas
- Topic: Diatomic Molecules Vs. Ions
- Replies: 2
- Views: 152
Re: Diatomic Molecules Vs. Ions
An easy way for me to remember the 7 diatomic elements is: HOFBrINCl - H2,O2,F2,Br2,I2,N2,Cl2. Hydrogen, oxygen, fluorine, bromine, Iodine, Nitrogen, Chlorine
it sounds like Hoffbrinkle, hope this helps!
it sounds like Hoffbrinkle, hope this helps!
- Sun Oct 06, 2019 11:07 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Formula Unit
- Replies: 3
- Views: 215
Re: Formula Unit
No, it is not mathematically different than molecules or atoms. Use avagodro's number and it won't impact your calculations.
- Sun Oct 06, 2019 11:05 pm
- Forum: SI Units, Unit Conversions
- Topic: Calculate using kg or g?
- Replies: 13
- Views: 911
Re: Calculate using kg or g?
It depends on the question. If you are using a formula that requires kg then of course convert to kg for the calculations or vice versa. In terms of your answer, I don't believe you will be marked incorrect for either form. Use proper judgement, if the question asks for your answer in grams then do ...
- Sun Oct 06, 2019 10:07 pm
- Forum: Balancing Chemical Reactions
- Topic: Combustion
- Replies: 17
- Views: 1093
Re: Combustion
Combustion is essentially the reaction between a hydrocarbon or organic compound (C3H4 for example) and oxygen gas (O2), this usually occurs through burning. The products that are formed are always Water (H2O) and Carbon Dioxide (CO2). Here is a simple example combustion reaction with methane: Unbal...
- Sun Oct 06, 2019 9:34 pm
- Forum: Significant Figures
- Topic: When do zeros count?
- Replies: 5
- Views: 226
Re: When do zeros count?
Leading zeroes don't count. For example, "0.001" or "002" each only have one significant figure. Any zeroes coming before a number do not count towards sig figs. Sandwiched zeroes do, however, count "1001" has four sig figs and "202" has three. zeroes coming a...
- Thu Oct 03, 2019 12:46 am
- Forum: Limiting Reactant Calculations
- Topic: M 15
- Replies: 4
- Views: 221
Re: M 15
You need to solve parts a) and b) in order to solve part c. The mass of AlCl2 you calculated in part B) is used as the theoretical yield. The question gives the actual yield as 300g. All you need to do is solve the equation 100% * (Actual Yield)/(Theoretical Yield). For my answer I got 100%* ((300g)...