Yes, joseph was referring to kforward and kreverse as the reaction rate constants! :)
Also, Brian, I thought there was supposed to be a negative sign on the right side of your equation?
Search found 101 matches
- Sat Mar 13, 2021 7:49 pm
- Forum: Student Social/Study Group
- Topic: Equations for the Final
- Replies: 5
- Views: 448
- Thu Mar 11, 2021 3:00 pm
- Forum: General Rate Laws
- Topic: Intermediate
- Replies: 59
- Views: 4832
Re: Intermediate
An intermediate is first formed in one step, then consumed as a reactant in the next step. It does not show up in the overall reaction.
- Wed Mar 10, 2021 5:59 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Frequency Factor, A
- Replies: 9
- Views: 522
Re: Frequency Factor, A
After doing all the textbook problems, there were not really any problems that gave the frequency factor or required us to solve for the frequency factor. Though, I would assume that if it were given to us, that we could use the equation to solve for k, Ea, or T depending on what else was given.
- Wed Mar 10, 2021 5:54 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode always on left in cell diagram?
- Replies: 6
- Views: 566
Re: Anode always on left in cell diagram?
I would think that the problem has a typo, the anode is always on the left side of the cell diagram.
- Tue Mar 09, 2021 9:00 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Half Reactions in Acidic/Basic Solution
- Replies: 3
- Views: 372
Re: Balancing Half Reactions in Acidic/Basic Solution
Yeah, it seems like you have it down pretty good. I guess I would add that for the basic conditions, make sure you know which side you are adding H2O and which side you are adding OH-. I believe that depending on how many more H's you need on one side in a basic solution, you add instead H20's. Then...
- Sun Mar 07, 2021 8:34 pm
- Forum: First Order Reactions
- Topic: Equation Confusion
- Replies: 16
- Views: 902
Re: Equation Confusion
The first equation is for zero order reactions and the second equation is for first order reactions. On Dr. Lavelle's outline for Kinetics, he has the equations with their respective order. Hope this helps! https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14B/Chem14B_Outline6_Kinetics.pdf
- Sun Mar 07, 2021 8:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridges
- Replies: 12
- Views: 690
Re: Salt Bridges
A salt bridge is important in a galvanic cell because it allows charges to transfer to prevent build up of charges. For example, at the anode, there would be a build up of + charges because electrons are leaving to go to the cathode, where a build up of - will also occur. The salt bridge allows for ...
- Sun Mar 07, 2021 8:25 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: E naught
- Replies: 13
- Views: 1047
Re: E naught
At equilibrium, the E naught will be zero!
- Sun Mar 07, 2021 6:06 pm
- Forum: First Order Reactions
- Topic: Textbook Problem 7B.3
- Replies: 2
- Views: 286
Textbook Problem 7B.3
Determine the rate constant for each of the following first-order reactions, in each case expressed for the rate of loss of A: (a) A → B, given that the concentration of A decreases to one-half its initial value in 1000. s; (b) A → B, given that the concentration of A decreases from 0.67 mol⋅L−1 to ...
- Sun Mar 07, 2021 3:42 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Ecell vs. E˚cell
- Replies: 2
- Views: 244
Re: Ecell vs. E˚cell
You could use the equation Ecell = E^ocell-(RT)/(nF)ln Q, where more products makes a larger Q, which leads to a lower Ecell. More reactants would lead to a lower Q, which would make the Ecell larger. As for your question, I would think that depending on what -(RT)/(nF)ln Q is, it would lead cause E...
- Fri Mar 05, 2021 8:01 pm
- Forum: First Order Reactions
- Topic: Slope
- Replies: 24
- Views: 1207
Re: Slope
For the zero and first-order reactions, the slope = -k. For the second-order reaction, slope = +k
- Sat Feb 27, 2021 8:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Textbook Problem 6O.1
- Replies: 1
- Views: 162
Textbook Problem 6O.1
6O.1 A 1.0 M NiSO4(aq) solution was electrolyzed by using inert electrodes. Write (a) the cathode reaction; (b) the anode reaction. (c) With no overpotential at the electrodes, what is the minimum potential that must be supplied to the cell for the onset of electrolysis? How do determine whether Ni ...
- Fri Feb 26, 2021 10:08 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Textbook Problem 6L.3
- Replies: 1
- Views: 173
Textbook Problem 6L.3
6L.3 Write the half-reactions and the balanced equation for the cell reaction for each of the following galvanic cells:
(d) Pt(s)|O2(g)|H+(aq)∥OH−(aq)|O2(g)|Pt(s)
Can someone show me how to do the half reaction for the anode of (d)? I do not understand how the answer key got 2H2O -> O2 + 4H+ + 4e-
(d) Pt(s)|O2(g)|H+(aq)∥OH−(aq)|O2(g)|Pt(s)
Can someone show me how to do the half reaction for the anode of (d)? I do not understand how the answer key got 2H2O -> O2 + 4H+ + 4e-
- Fri Feb 26, 2021 10:05 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Textbook Problems 6L #3
- Replies: 2
- Views: 279
Re: Textbook Problems 6L #3
Thank you!
- Fri Feb 26, 2021 9:58 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Textbook Problems 6L #3
- Replies: 2
- Views: 279
Textbook Problems 6L #3
For topic 6L #3, where do we find the Ecell information that the answer key has? Are we supposed to look them up?
- Fri Feb 26, 2021 9:35 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Gibbs Free Energy Equation and n
- Replies: 13
- Views: 709
Re: Gibbs Free Energy Equation and n
I think it is the moles of electrons transferred, which you can find my looking at the redox reaction?
- Sat Feb 20, 2021 5:44 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: R gas constant and kPa or Pa
- Replies: 9
- Views: 3539
Re: R gas constant and kPa or Pa
When give kPa, convert it to atm using 1 atm = 101.325 kPa. Then you can use the gas constant of R = 8.206 * 10^-2 L·atm·K-1·mol-1 to cancel out the atm and the other units. Hope this helps!
- Sat Feb 20, 2021 5:40 pm
- Forum: Van't Hoff Equation
- Topic: Application of Van't Hoff Equation
- Replies: 11
- Views: 4042
Re: Application of Van't Hoff Equation
The Van't Hoff Equation can be used to find the K2 value at a different temperature, assuming that you know the temperatures of K1 and K2, and the deltaH. Then you could solve for the right side of the equation, put that result as an exponent of e, then multiply it by K1 to get K2. Hope this helps!
- Sat Feb 20, 2021 5:36 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 4J.13 Textbook
- Replies: 3
- Views: 289
Re: 4J.13 Textbook
You would not calculate the gibbs free energy of formation, but you can calculate deltaG rxn by doing the gibbs free energy of formation of the products - the gibbs free energy of formation of the reactants. I believe that the deltaG has to be negative for stability, not positive, since a negative d...
- Sat Feb 20, 2021 5:30 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta H and Delta S both positive
- Replies: 31
- Views: 9510
Re: Delta H and Delta S both positive
The reaction will be spontaneous above a certain temperature, since you would need a greater TdeltaS to subtract from deltaH to make deltaG negative!
- Fri Feb 12, 2021 8:47 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Textbook Problem 4.37
- Replies: 1
- Views: 173
Textbook Problem 4.37
Under what conditions, if any, does the sign of each of the following quantities provide a criterion for assessing the spontaneity of a reaction? (a) ΔG°; (b) ΔH°; (c) ΔS°; (d) ΔStot.
For (d), can someone explain to me why if ΔStot. > 0, that the reaction would be spontaneous? Thank you!
For (d), can someone explain to me why if ΔStot. > 0, that the reaction would be spontaneous? Thank you!
- Wed Feb 10, 2021 5:56 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: deltaS and deltaU
- Replies: 2
- Views: 230
deltaS and deltaU
In Dr. Lavelle's lecture, why does he draw a curve facing upwards for deltaU and a downward facing curve for deltaS?
- Tue Feb 09, 2021 10:10 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: Textbook Problem 4G.3
- Replies: 1
- Views: 145
Textbook Problem 4G.3
Which would you expect to have a higher molar entropy at T=0, single crystals of BF3 or of COF2? Why?
So the answer is COF2 and not BF3 because the oxygen and fluorine can change places while the fluorine in BF3 will just occupy the same place? So there's more disorder in COF2?
So the answer is COF2 and not BF3 because the oxygen and fluorine can change places while the fluorine in BF3 will just occupy the same place? So there's more disorder in COF2?
- Tue Feb 09, 2021 8:34 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Self-test 4F.5A
- Replies: 2
- Views: 180
Self-test 4F.5A
Calculate the change in entropy when the volume of 2.00molAr(g) is decreased from 10.00 L to 5.00 L, while the temperature decreases from 300. K to 100. K. Assume ideal behavior.
The answer is −38.9J⋅K−1, but I do not know how to get it. Can someone explain how to do this?
The answer is −38.9J⋅K−1, but I do not know how to get it. Can someone explain how to do this?
- Tue Feb 09, 2021 4:57 pm
- Forum: Student Social/Study Group
- Topic: When is Midterm 2?
- Replies: 4
- Views: 311
When is Midterm 2?
When is the next midterm? Just to know so I can prepare myself with workloads. Thank you!
- Sun Feb 07, 2021 4:14 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Textbook Problem 4D.11
- Replies: 1
- Views: 172
Textbook Problem 4D.11
4D.11 The oxidation of nitrogen in the hot exhaust of jet engines and automobiles occurs by the reaction N2(g)+O2(g)→2NO(g)ΔH°=+180.6kJ (c) When the oxidation of N2 to NO was completed in a bomb calorimeter, the heat absorbed was measured as 492 J. What mass of nitrogen gas was oxidized? Can someone...
- Sun Feb 07, 2021 2:02 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: deltaU=nCvdeltaT
- Replies: 9
- Views: 724
Re: deltaU=nCvdeltaT
We know that the volume is constant in the equation because of the subscript V in Cv. Cv means the heat capacity at a constant volume.
- Fri Feb 05, 2021 9:17 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Self-test 4B.3A in Topic 4B.3
- Replies: 1
- Views: 117
Self-test 4B.3A in Topic 4B.3
Estimate the contribution of motion to the molar internal energy of water vapor at 25 °C. [Answer: 7.44 kJ⋅mol−1]
Can someone explain this to me? I tried to understand how to calculate Um, but I do not get it still. Please help, and thank you!
Can someone explain this to me? I tried to understand how to calculate Um, but I do not get it still. Please help, and thank you!
- Fri Feb 05, 2021 8:21 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Thermochemistry Equations?
- Replies: 7
- Views: 558
Thermochemistry Equations?
How are you guys remembering the various equations for Thermochemistry? Since the equations do not seem to be on the constants and equations sheet, are there any tricks to remembering all the equations?
- Fri Feb 05, 2021 8:02 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling Week 3 and 4 #8
- Replies: 4
- Views: 355
Re: Sapling Week 3 and 4 #8
So since you know that for every 358.8 kJ absorbed, you get 4 moles of CS2. With this, you take the energy they give you times that conversion factor to get the # of moles: (379 kJ ) x (4 moles CS2/358.8 kJ) = 4.23 mol Cs2 Now that you have moles of CS2, you multiply the moles by the molar mass of C...
- Thu Feb 04, 2021 10:39 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: W
- Replies: 14
- Views: 678
Re: W
Yep, N means the molecules in the system!
- Sun Jan 31, 2021 2:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Factors that affect the equilibrium constant
- Replies: 31
- Views: 4810
Re: Factors that affect the equilibrium constant
The equilibrium constant, K, will only be affected by a change in temperature, not change in volume or pressure.
- Sun Jan 31, 2021 2:22 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Memorize bond enthalpies / standard enthalpies of formation?
- Replies: 39
- Views: 2091
Re: Memorize bond enthalpies / standard enthalpies of formation?
Nope, you do not need to memorize bond enthalpies. The values will be provided for you :)
- Sun Jan 31, 2021 12:00 pm
- Forum: Ideal Gases
- Topic: Reversing Reactions
- Replies: 68
- Views: 3880
Re: Reversing Reactions
The K for a reverse equation is the reciprocal of K, so 1/K. Hope this helps!
- Thu Jan 28, 2021 8:45 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Matthew's Workshop Week 3 #3b
- Replies: 2
- Views: 272
Re: Matthew's Workshop Week 3 #3b
In step 2, you need to do the -5000 kJ divided by -2878 kJ/mol, not the other way around. Everything else looks good, so try what I said instead.
- Thu Jan 28, 2021 5:41 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Sapling #8 Weeks 3&4
- Replies: 10
- Views: 645
Sapling #8 Weeks 3&4
Carbon disulfide can be prepared from coke (an impure form of carbon) and elemental sulfur. 4C(s)+S8(s)⟶4CS2(l) ΔH∘=+358.8 kJ Calculate the amount of heat absorbed when 1.31 mol S8 is reacted at constant pressure. Can someone run by me all the steps for this problem? I do not know where to start, pl...
- Sun Jan 24, 2021 9:40 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Textbook Problem 4E.7
- Replies: 1
- Views: 135
Textbook Problem 4E.7
Use the data in Tables 4E.2 and 4E.3 to estimate the reaction enthalpy for (a) N2(g)+3F2(g)→2 NF3(g) (b) CH3CHCH2(g)+H2O(g)→CH3CH(OH)CH3(g)
(c) CH4(g)+Cl2(g)→CH3Cl(g)+HCl(g)
For (b), why did the textbook solution say that a C-C bond was formed? Can someone explain this to me? Thank you!
(c) CH4(g)+Cl2(g)→CH3Cl(g)+HCl(g)
For (b), why did the textbook solution say that a C-C bond was formed? Can someone explain this to me? Thank you!
- Sat Jan 23, 2021 9:55 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Example 4D.3 and converting heat output into moles of fuel molecules
- Replies: 1
- Views: 106
Example 4D.3 and converting heat output into moles of fuel molecules
In example 4D.3, they did n(C4H10) = (350.kJ) × (2mol C4H10/5756kJ) = (350. × 2)/5756 mol C4H10 = 0.122 … molC4H10
Do we need to know how to convert heat output into moles of fuel molecules for the midterm? If we do, could someone explain this process to me since it is completely new?
Do we need to know how to convert heat output into moles of fuel molecules for the midterm? If we do, could someone explain this process to me since it is completely new?
- Sat Jan 23, 2021 8:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Do concentrations change at equilibrium?
- Replies: 9
- Views: 279
Re: Do concentrations change at equilibrium?
At equilibrium, concentrations should not change unless concentration is added or subtracted for the product or reactants. Hope this helps!
- Wed Jan 20, 2021 9:27 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Textbook Problem 5G.1
- Replies: 3
- Views: 203
Re: Textbook Problem 5G.1
You are also correct, you just included how the equilibrium reaction is specifically affected from products, in which the book just states that the equilibrium reaction is affected. You're good!
- Wed Jan 20, 2021 8:12 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Textbook Problem 6D.5
- Replies: 6
- Views: 1488
Textbook Problem 6D.5
Calculate the pH, pOH, and percentage protonation of solute in each of the following aqueous solutions: (a) 0.057 M NH3(aq); (b) 0.162 M NH2OH(aq); (c) 0.35 M (CH3)3N(aq); (d) 0.0073 M codeine, given that the pKa of its conjugate acid is 8.21. Can someone run down the steps on how to approach (a)? T...
- Tue Jan 19, 2021 9:42 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Calculating the pH and percentage deprotonation of a weak acid
- Replies: 8
- Views: 638
Calculating the pH and percentage deprotonation of a weak acid
When you are using the ICE box to solve for x, when do you know to approximate for x? Does the Ka or Kb need to be *10^-4 or smaller? Thank you!
- Sun Jan 17, 2021 5:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Box Polynomials
- Replies: 10
- Views: 610
Re: ICE Box Polynomials
I have not encountered any polynomials larger than x^3, because some equations when putting Products/Reactants can be square rooted to remove the squares on the top and bottom. For x^3, you would assume that x is a very small number, like 10^-10, and can make equations with a number + or - x to just...
- Sun Jan 17, 2021 12:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: textbook 5.35
- Replies: 2
- Views: 154
Re: textbook 5.35
I think Evelyn means the partial pressure of A from around 27 to 17, not 35 to 25. But her explanation of how the change in partial pressure is around 10 for A and C, while B has only a change of 5.
- Sun Jan 10, 2021 10:01 pm
- Forum: Student Social/Study Group
- Topic: Study Tips
- Replies: 32
- Views: 2351
Re: Study Tips
I think it would be best to read the textbook and do the problems, as they enhance what Dr. Lavelle discusses in lecture. Then, you could try to form a study group or attend UA sessions to review what you've learned. Also, make sure to read the section outlines to check what you know and don't know....
- Sun Jan 10, 2021 9:46 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: relationship between reaction, product, and K
- Replies: 7
- Views: 385
Re: relationship between reaction, product, and K
Yep, you got it! What multiplies to the entire reaction equation is put as an exponent to the K value.
- Sun Jan 10, 2021 4:30 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Sapling homework due date
- Replies: 14
- Views: 1135
Re: Sapling homework due date
While the first Sapling homework is due on the 17th, you should try to wrap up the section soon to start working on the next section, since we will be starting the next section soon.
- Thu Jan 07, 2021 8:52 pm
- Forum: Ideal Gases
- Topic: Chemical Equilibrium Part 1A Post-Module Assessment
- Replies: 11
- Views: 2642
Re: Chemical Equilibrium Part 1A Post-Module Assessment
C is false, because the even at equilibrium, forward and reverse reactions are still occurring.
- Thu Jan 07, 2021 8:43 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Audio-Visual Topics
- Replies: 13
- Views: 924
Re: Audio-Visual Topics
I do not think there will be Audio-Focused modules on the upcoming topics, at least not for them all. In Chem 14A, there were not any for the last topics of the quarter, so I think the same will happen for this quarter. I do recommend doing the textbook problems, since they offer practice and have a...
- Tue Jan 05, 2021 6:42 pm
- Forum: Ideal Gases
- Topic: Step 1. Chemical Equilibrium Part 1B Pre-Assessment #40
- Replies: 2
- Views: 209
Step 1. Chemical Equilibrium Part 1B Pre-Assessment #40
Calculate the concentration of CO(g) in mol.m-3 at 423 K and 0.8 atm using R = 8.206 × 10-5 m3.atm.K-1.mol-1 and assuming only CO(g) is present.
Can someone show me the steps to do this problem? I am lost on where to start. Thank you!
Can someone show me the steps to do this problem? I am lost on where to start. Thank you!
- Tue Dec 15, 2020 9:27 pm
- Forum: Student Social/Study Group
- Topic: Study music
- Replies: 59
- Views: 9611
Re: Study music
I just have all my favorite songs in a playlist on YouTube playing at the lowest possible volume. It's perfect for keeping me relaxed without totally distracting me. Hope everyone has an amazing break!
- Fri Dec 11, 2020 12:01 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Textbook 6B.1
- Replies: 8
- Views: 452
Re: Textbook 6B.1
Can someone run down how to do this step by step? This does not make much sense to me.
- Thu Dec 10, 2020 9:33 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Textbook Problem J.17
- Replies: 2
- Views: 253
Re: Textbook Problem J.17
That makes sense, thank you!
- Thu Dec 10, 2020 8:43 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Textbook Problem J.17
- Replies: 2
- Views: 253
Textbook Problem J.17
In each of the following salts, either the cation or the anion is a weak acid or a weak base in water. Write the chemical equation for the proton transfer reaction of this cation or anion with water: (a) NaC6H5O; (b) KClO; (c) C5H5NHCl; (d) NH4Br. How do you figure out whether to use the cation or t...
- Sat Dec 05, 2020 9:51 pm
- Forum: Lewis Acids & Bases
- Topic: KA and pKA
- Replies: 19
- Views: 1191
KA and pKA
In Dr. Lavelle's Friday lecture, he talked about KA and pKA. I do not really understand what these are, can someone explain to me? Also, are we going to be calculating these numbers for the final?
- Fri Dec 04, 2020 10:27 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Textbook Problem 9C.5
- Replies: 1
- Views: 182
Textbook Problem 9C.5
Which of the following ligands can be polydentate? If the ligand can be polydentate, give the maximum number of places on the ligand that can bind simultaneously to a single metal center: a) HN(CH2CH2NH2)2; (b) CO32−; (c) H2O; (d) oxalate. Can someone explain to me how to approach this? I do not und...
- Fri Dec 04, 2020 9:51 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Example 9C.1 in Textbook
- Replies: 3
- Views: 194
Re: Example 9C.1 in Textbook
Thank you! I actually understand that now. So we can find the charge on the TM metal by using the compounds total charge? And we can find the total charge of the compound by adding all the charges of the elements?
- Fri Dec 04, 2020 9:37 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Example 9C.1 in Textbook
- Replies: 3
- Views: 194
Example 9C.1 in Textbook
(b) Write the formula of sodium dichloridobis(oxalato)platinate(IV).
(Book help->) Two Cl− ligands and two C2O42− ions are attached to Pt4+. The charge on the complex is −2.
How did they figure out that Pt has a 4+ charge? Please help.
(Book help->) Two Cl− ligands and two C2O42− ions are attached to Pt4+. The charge on the complex is −2.
How did they figure out that Pt has a 4+ charge? Please help.
- Fri Dec 04, 2020 8:56 pm
- Forum: Naming
- Topic: oxidation number
- Replies: 3
- Views: 265
Re: oxidation number
If you're looking for the oxidation number of Pt, you do -1 times the number of Chlorines there are, which gives you -6. Then the equation is Pt - 6 = -2. The equation equals -2 because that is the charge of the compound. This leaves Pt to equal +4 to make -2. Hope this helps.
- Fri Dec 04, 2020 8:53 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: linear same atoms?
- Replies: 6
- Views: 484
Re: linear same atoms?
Hey! So you are right in that there are three lone pairs on the middle Iodine. This makes five electron densities, and that would be trigonal bipyramidal. The three lone pairs take all the equatorial electron densities, leaving only the axial atoms as Iodine. This makes the linear shape. Hope this h...
- Fri Dec 04, 2020 8:48 pm
- Forum: Sigma & Pi Bonds
- Topic: sigma and pi bonds for benzene molecule
- Replies: 3
- Views: 466
Re: sigma and pi bonds for benzene molecule
I believe it would be 12 sigma bonds and 3 pi bonds because each carbon is also bonded to a hydrogen. Hope this helps!
- Sat Nov 28, 2020 4:40 pm
- Forum: Hybridization
- Topic: Textbook problem 2F.15
- Replies: 4
- Views: 247
Re: Textbook problem 2F.15
Thank you, that really helped! I do not think the textbook talked much about it, so thanks for telling me.
- Sat Nov 28, 2020 3:51 pm
- Forum: Hybridization
- Topic: Textbook problem 2F.15
- Replies: 4
- Views: 247
Textbook problem 2F.15
Noting that the bond angle of an sp3 hybridized atom is 109.5° and that of an sp2 hybridized atom is 120°, do you expect the bond angle between two hybrid orbitals to increase or decrease as the s-character of the hybrids is increased? Can someone explain to me what the question means by s-character...
- Fri Nov 27, 2020 9:55 pm
- Forum: Hybridization
- Topic: 2F.3 Other Common Types of Hybridization
- Replies: 1
- Views: 240
2F.3 Other Common Types of Hybridization
h1=s+21/2py h2=s+(32)1/2px−(12)1/2py h3=s−(32)1/2px−(12)1/2py
Do we need to know about the hybrid orbitals h1, h2, etc.? Like the equations at the beginning of 2F.3?
Do we need to know about the hybrid orbitals h1, h2, etc.? Like the equations at the beginning of 2F.3?
- Fri Nov 27, 2020 8:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Geometry
- Replies: 7
- Views: 453
Re: Molecular Geometry
For me, I just try to memorize it. I try to remember the geometry with no lone pairs on the center atom, and then think of the geometry and it's name when there are lone pairs.
- Fri Nov 27, 2020 8:39 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Bracket Notation
- Replies: 4
- Views: 185
Re: Bracket Notation
Yeah, you would put the charge on the outside, top right of the brackets. You are right!
- Sun Nov 22, 2020 8:13 pm
- Forum: Administrative Questions and Class Announcements
- Topic: 14B Enrollment [ENDORSED]
- Replies: 67
- Views: 22967
Re: 14B Enrollment [ENDORSED]
They are also recorded, so you should be able to take your fiat lux as well!
- Sun Nov 22, 2020 8:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Textbook Problem 2E. 19
- Replies: 3
- Views: 176
Textbook Problem 2E. 19
Predict the shapes and estimate the bond angles of (a) the thiosulfate ion, S2O32−; (b) (CH3)2Be; (c) BH2−; (d) SnCl2.
For (b), do you predict the shapes with the carbons as the central atoms?
For (b), do you predict the shapes with the carbons as the central atoms?
- Sun Nov 22, 2020 5:54 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Textbook Problem 2E. 5
- Replies: 3
- Views: 400
Textbook Problem 2E. 5
2E.5 (a) What is the shape of a ClO2+ ion? (b) What is the expected OClO bond angle?
Is the lewis structure for ClO2+ drawn with one double bond or two? Can someone explain to me why? Thank you!
Is the lewis structure for ClO2+ drawn with one double bond or two? Can someone explain to me why? Thank you!
- Mon Nov 16, 2020 3:34 pm
- Forum: Student Social/Study Group
- Topic: Winter 2021 Classes
- Replies: 20
- Views: 1491
Re: Winter 2021 Classes
Thank you! Also, would it be okay to take the Chem 14BL Lab section from 11am-1:30pm on Friday even though it goes into Chem 14B's friday lecture at 1pm, since the lecture is recorded?
- Mon Nov 16, 2020 3:19 pm
- Forum: Student Social/Study Group
- Topic: Winter 2021 Classes
- Replies: 20
- Views: 1491
Winter 2021 Classes
Hello, I am thinking of taking Chem 14B and Chem 14BL next quarter along with LS30B. Is the minimum units per quarter 12 or 13? If it is 13, then I would have to take another class, probably a GE since Chem 14B is 4 units, Chem 14BL is 3 units, and LS30B is 5 units which equals 12 units. Please help!
- Fri Nov 13, 2020 5:09 pm
- Forum: Lewis Structures
- Topic: Textbook Problem 2C.1
- Replies: 3
- Views: 224
Re: Textbook Problem 2C.1
My book gives me the wrong answers then. Is there a place that I could get the correct answers for the odd numbers?
- Thu Nov 12, 2020 8:50 pm
- Forum: Lewis Structures
- Topic: Textbook Problem 2C.1
- Replies: 3
- Views: 224
Re: Textbook Problem 2C.1
Also, the book says just (a) and (b) are radicals. Is (c) also a radical since the O has one electron by itself?
- Thu Nov 12, 2020 8:45 pm
- Forum: Lewis Structures
- Topic: Textbook Problem 2C.1
- Replies: 3
- Views: 224
Textbook Problem 2C.1
Which of the following species are radicals? (a) NO2−; (b) CH3; (c) OH; (d) CH2O.
Can someone explain to me how (a) is a radical? Thank you!
Can someone explain to me how (a) is a radical? Thank you!
- Thu Nov 12, 2020 7:26 pm
- Forum: Lewis Structures
- Topic: Textbook Problem 2B.21
- Replies: 2
- Views: 214
Textbook Problem 2B.21
Hypochlorous acid, HClO, is found in white blood cells, where it helps to destroy bacteria. Draw two Lewis structures with different atom arrangements for HClO and select the most likely structure by identifying the structure with formal charges closest to zero. Consider only structures with single ...
- Wed Nov 11, 2020 9:35 pm
- Forum: Lewis Structures
- Topic: homework 2B.3
- Replies: 5
- Views: 332
Re: homework 2B.3
In the textbook solutions, it shows one of the F with only two pairs of electrons and one bond with Br. This is a book mistake right?
- Fri Nov 06, 2020 4:44 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm 2 [ENDORSED]
- Replies: 11
- Views: 1004
Re: Midterm 2 [ENDORSED]
When is Midterm 2 going to be? Thanks in advance.
- Fri Nov 06, 2020 4:41 pm
- Forum: Photoelectric Effect
- Topic: Units for energy
- Replies: 11
- Views: 894
Re: Units for energy
HI! It's 1 Hz = 1/second
I hope this helps!
I hope this helps!
- Fri Nov 06, 2020 4:34 pm
- Forum: Ionic & Covalent Bonds
- Topic: Textbook Problem 2A.11
- Replies: 4
- Views: 168
Re: Textbook Problem 2A.11
That really helps, thank you!
- Thu Nov 05, 2020 9:04 pm
- Forum: Ionic & Covalent Bonds
- Topic: Textbook Problem 2A.19
- Replies: 2
- Views: 217
Textbook Problem 2A.19
Give the ground-state electron configuration and number of unpaired electrons expected for each of the following ions: (a) Sb3+; (b) Sn4+; (d) Br−; (e) Ni2+. For (e) Ni2+, the textbook says the answer is [Ar]3d8 and two unpaired electrons. I thought the answer would have been [Ar]3d6 4s2 and four un...
- Thu Nov 05, 2020 8:39 pm
- Forum: Ionic & Covalent Bonds
- Topic: Textbook Problem 2A.11
- Replies: 4
- Views: 168
Textbook Problem 2A.11
Which M3+ ions (where M is a metal) are predicted to have the following ground-state electron configurations:
(a) [Ar]3d6; (b) [Ar]3d5
I'm confused on how to solve this correctly, can someone clarify the exceptions when it comes to the d orbitals? Thank you!
(a) [Ar]3d6; (b) [Ar]3d5
I'm confused on how to solve this correctly, can someone clarify the exceptions when it comes to the d orbitals? Thank you!
- Fri Oct 30, 2020 8:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Exam Scores
- Replies: 15
- Views: 1043
Re: Midterm Exam Scores
Oh I see, thank you for figuring that out. Maybe I'm just bad at figuring things out, but that was a bit obscure. Thanks again though!
- Fri Oct 30, 2020 8:39 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Plane Importance
- Replies: 9
- Views: 314
Re: Nodal Plane Importance
Did Dr. Lavelle say that we do not have to think about nodal planes too much in his lecture? Maybe I'm wrong?
- Fri Oct 30, 2020 8:37 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Exam Scores
- Replies: 15
- Views: 1043
Re: Midterm Exam Scores
Same, I can't find it anywhere. I tried searching google, but still didn't figure it out. Please help!
- Fri Oct 30, 2020 8:30 pm
- Forum: *Shrodinger Equation
- Topic: New Audio-Visual Modules
- Replies: 9
- Views: 723
Re: New Audio-Visual Modules
I also really enjoyed the modules, since they taught me quick and easy, and that I could view them before a quiz or midterm. Too bad he's not making any more.
- Fri Oct 30, 2020 8:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Exam Scores
- Replies: 15
- Views: 1043
Re: Midterm Exam Scores
Hi, apparently there was an error with one of the questions and each individual midterm is being looked at. This means it will probably be next week when we can see our scores.
- Fri Oct 23, 2020 9:10 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Usage of Formula Sheet
- Replies: 5
- Views: 300
Re: Usage of Formula Sheet
In case you need the formula sheet or periodic table:
https://lavelle.chem.ucla.edu/wp-conten ... _IUPAC.pdf
https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf
https://lavelle.chem.ucla.edu/wp-conten ... _IUPAC.pdf
https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf
- Fri Oct 23, 2020 8:53 pm
- Forum: General Science Questions
- Topic: Midterm
- Replies: 5
- Views: 341
Re: Midterm
Like the midterm is still proctored by our TA with our discussion group, but every student takes it on Friday at like 4pm PST? Realistically, we should just prep for our discussion section for the midterm.
- Fri Oct 23, 2020 8:47 pm
- Forum: Administrative Questions and Class Announcements
- Topic: What are the last textbook problems we need to do in the the second outline to prepare for the midterm.
- Replies: 4
- Views: 240
Re: What are the last textbook problems we need to do in the the second outline to prepare for the midterm.
I should read section 1D, but I don't need to do any of the problems until after the midterm?
- Fri Oct 23, 2020 8:22 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Equation Post Module Assessment
- Replies: 2
- Views: 245
Re: Balancing Equation Post Module Assessment
So the coefficients in front of each compound is a mole. All you have to do is add up the total moles on the left and compare them to the total moles on the right. This should be 30->36, so the net moles is 6.
- Fri Oct 23, 2020 8:17 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 42654
Re: How are you studying?
I just watch the lectures, take notes on the modules/do the assessments, and do the problems in the textbook. If I get stuck on a problem, I look at Chemistry Community to get help. Hope this helps!
- Fri Oct 16, 2020 4:01 pm
- Forum: Photoelectric Effect
- Topic: photoelectric experiment post assessment
- Replies: 2
- Views: 181
Re: photoelectric experiment post assessment
I believe it is ultraviolet light. Hope this helps. And if you need it, you can paste your question into google and find a quizlet for the post-assessment.
- Fri Oct 16, 2020 3:59 pm
- Forum: Photoelectric Effect
- Topic: photoelectric effect
- Replies: 17
- Views: 1054
Re: photoelectric effect
Yes work function is the same as the threshold energy.
- Fri Oct 16, 2020 3:55 pm
- Forum: Empirical & Molecular Formulas
- Topic: Question from a Workshop problem
- Replies: 4
- Views: 220
Re: Question from a Workshop problem
Hi! Basically when we calculate the empirical formula, we only want to use individual elements. In other words, instead of O2 you would simply use only O. Your calculations should look like this: 69.9 g Fe (1 mol Fe/55.85 g Fe)= 1.25 mol Fe 30.1 g O (1 mol O/16.00 g O) = 1.88 mol O Dividing by the ...
- Fri Oct 16, 2020 3:47 pm
- Forum: Significant Figures
- Topic: rounding during equations
- Replies: 14
- Views: 816
Re: rounding during equations
I try not to round during the equations, and round the final answer with sig figs. That way, I get the most accurate answer. Hope this helps!
- Thu Oct 15, 2020 10:34 pm
- Forum: Photoelectric Effect
- Topic: Mass of an object
- Replies: 5
- Views: 279
Re: Mass of an object
Hey! On a different post, somebody said this acronym to help remember the prefixes:
Great Mr. Knight Doesn't Cook Me Macaroni Until Nine Pm
(giga, mega, kilo, deci, cent, milli, micro, µ, nano, pico)
(credit: Shreya Patel- 2D)
Hope this helps
Great Mr. Knight Doesn't Cook Me Macaroni Until Nine Pm
(giga, mega, kilo, deci, cent, milli, micro, µ, nano, pico)
(credit: Shreya Patel- 2D)
Hope this helps
- Sun Oct 11, 2020 9:24 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test Accuracy
- Replies: 13
- Views: 930
Re: Test Accuracy
I read on a different post that the midterms and quizzes will be multiple choice, so I don't think we have to worry about sig figs and rounding.
- Thu Oct 08, 2020 9:56 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Concentration Calculations
- Replies: 15
- Views: 8349
Re: Concentration Calculations
How did you find the molarity of Na2CO3?
- Thu Oct 08, 2020 9:35 pm
- Forum: SI Units, Unit Conversions
- Topic: Acronym for prefixes
- Replies: 7
- Views: 567
Re: Acronym for prefixes
Prefix Name Meaning G giga 10^9 M mega 10^6 k kilo 10^3 d deci 10^-1 c centi 10^-2 m milli 10^-3 u micro 10^-6 n nano 10^-9 p pico 10^-12 I'll just leave this here :)
- Thu Oct 08, 2020 9:29 pm
- Forum: Balancing Chemical Reactions
- Topic: Fundamental Question E.17
- Replies: 3
- Views: 246
Re: Fundamental Question E.17
You would convert the grams for each element into moles using the element's molar mass. So take the mass of Phosphorus and divide it by the molar mass to convert it to moles, and do the same with Te. Then you would compare the moles of P to Te and see which moles is bigger.