Search found 117 matches
- Thu Mar 12, 2020 8:44 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 513988
Re: Saying Thank You to Dr. Lavelle
Thank you Dr. Lavelle! I can't say that this class was easy or didn't make me stay up until ungodly hours of the night studying, but it's been a satisfying and enriching experience. I learned more than I ever thought I could within 2 quarters. Your jokes, music outros, smiley faces, and thoughtful p...
- Thu Mar 12, 2020 8:41 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ENDGAME Review Session
- Replies: 71
- Views: 5472
Re: ENDGAME Review Session
Thank you so much for all your hard work Lyndon! You have helped us tremendously and I can't thank you enough. Best of luck to you!
- Tue Mar 10, 2020 5:28 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Situation for Lecture, Discussion, and Final
- Replies: 3
- Views: 332
Situation for Lecture, Discussion, and Final
What is going to be done in regards to lecture, discussion, and our final?
- Tue Mar 10, 2020 3:51 am
- Forum: First Order Reactions
- Topic: kt vs. -kt?
- Replies: 2
- Views: 287
Re: kt vs. -kt?
Never mind... I figured out that it's because they switch between ln([A0]/[A]) or ln([A]/[A0]).
- Tue Mar 10, 2020 3:16 am
- Forum: First Order Reactions
- Topic: kt vs. -kt?
- Replies: 2
- Views: 287
kt vs. -kt?
I'm doing 7B and I've noticed that for first order integrated law, the solutions manual will use the equation ln([A]/[A0]) = kt and other times, ln([A]/[A0]) = -kt. I've been consistently using ln([A]/[A0]) = -kt and will sometimes get a negative value (depending on if I'm calculating k or t). When ...
- Thu Mar 05, 2020 11:00 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Standard Delta G vs Non-Standard Delta G
- Replies: 4
- Views: 316
Re: Standard Delta G vs Non-Standard Delta G
If you are provided delta G, R, T, and Q, then you can find standard delta G. However, if you are given K, it means that the reaction has reached equilibrium and delta G = 0, therefore you would get the equation standard delta G = -RTlnK.
- Thu Mar 05, 2020 10:57 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Inert electrodes
- Replies: 5
- Views: 339
Re: Inert electrodes
Typically, ions are usually aqueous. We can't have an electrode that is aqueous, it needs to be a solid. This is when we would use an inert electrode such as platinum or graphite.
- Thu Mar 05, 2020 10:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2 Grades
- Replies: 22
- Views: 1154
Re: Test 2 Grades
Next week in your discussion section.
- Thu Mar 05, 2020 10:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Excellence in Chemistry Award!
- Replies: 27
- Views: 9833
Re: Excellence in Chemistry Award!
Congratulations Rachana!
- Tue Mar 03, 2020 7:17 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Including Inert Electrodes
- Replies: 2
- Views: 219
Re: Including Inert Electrodes
When you have ions (which are aqueous). We can't have an electrode that aqueous so we can use an inert metal solid such as platinum or graphite. For example, if you have Fe 2+ and Fe, you can have Fe (s) to be the electrode. But if you have Fe 2+ and Fe 3+, you need platinum. There's no difference b...
- Tue Mar 03, 2020 4:48 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Ion-Selective Electrodes
- Replies: 1
- Views: 145
Ion-Selective Electrodes
Can someone explain to me what ion-selective electrodes are and how they work?
Thanks
Thanks
- Sun Mar 01, 2020 8:19 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: How to determine anode and cathode in 6.57?
- Replies: 6
- Views: 408
Re: How to determine anode and cathode in 6.57?
this is the half-reaction for the cathode. We know this because there are electrons being added to the reactants, reducing the Fluorine. Sorry I meant F2 (g) + 2 e- --> 2F- is the cathode and F2(g) + 2 H+ (aq) + 2 e- --> 2HF (aq) is the anode according to the solutions manual. It says the E*cell = ...
- Sun Mar 01, 2020 7:26 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: How to determine anode and cathode in 6.57?
- Replies: 6
- Views: 408
How to determine anode and cathode in 6.57?
6.57: 6.57 Use the data in Appendix 2B and the fact that, for the half- reaction F2(g) + 2 H+ (aq) + 2 e- --> 2HF (aq), E* = + 3.03 V, to calculate the value of Ka for HF.
Based on F2 (g) + 2 e- --> 2F-, E*= +2.87V, how am I suppose to know which one is the cathode and anode?
Thanks
Based on F2 (g) + 2 e- --> 2F-, E*= +2.87V, how am I suppose to know which one is the cathode and anode?
Thanks
- Sun Mar 01, 2020 4:47 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: When to use units of mole?
- Replies: 2
- Views: 217
When to use units of mole?
Whenever the problem asks for a calculation that requires the Nernst's equation, the solution manual never shows n (the number of moles) to be in the units of moles. For example, if the redox reaction used 2 moles, it would be 0.0257 V/2 instead of 0.0257 V/2 moles. Is there a reason why for this? W...
- Thu Feb 27, 2020 5:31 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Possible Solution Error on 6N.1 part b
- Replies: 5
- Views: 388
Possible Solution Error on 6N.1 part b
6N.1.b) Calculate the equilibrium constants for the following reactions: In^3+ (aq) + U^3+ (aq) <--> In^2+ (aq) + U^4+ (aq). My answer differs from the solutions manual. I got 107 instead of the textbook that got 1000 for K. However, I don't understand how they got 2 electrons for the Indium half re...
- Thu Feb 27, 2020 5:28 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Homework 6M.5
- Replies: 2
- Views: 200
Re: Homework 6M.5
I was talking to my TA in section today and he said that there are a lot of errors in the solutions manual in this section along with 6L. He said that if some things just don't make sense at all, be wary of it.
- Tue Feb 25, 2020 9:10 pm
- Forum: Balancing Redox Reactions
- Topic: Help on 6L.7 part a
- Replies: 2
- Views: 244
Help on 6L.7 part a
6L.7.a) Write the half-reactions and devise a galvanic cell (write a cell diagram) to study each of the following reactions: AgBr(s) <--> Ag+ (aq) + Br- (aq). The solutions manual says the half reactions are Ag+(aq) + e- --> Ag(s) and AgBr(s) + e- --> Ag(s) + Br-(aq) but I'm not sure how they were a...
- Tue Feb 25, 2020 12:40 am
- Forum: Balancing Redox Reactions
- Topic: Help on 6K.3 part d [ENDORSED]
- Replies: 3
- Views: 314
Help on 6K.3 part d [ENDORSED]
6K.3.d) Balance each of the following skeletal equations by using oxidation and reduction half-reactions. All the reactions take place in acidic solution. Identify the oxidizing agent and reducing agent in each reaction. Reaction of chlorine in water: Cl2(g) --> HClO(aq) + Cl2(g) How should I procee...
- Tue Feb 25, 2020 12:08 am
- Forum: Balancing Redox Reactions
- Topic: Reducing Agent versus Reduced Species
- Replies: 2
- Views: 259
Reducing Agent versus Reduced Species
Is there a difference between the two? In addition, the oxidizing agent versus oxidized species.
Thanks,
Tiffany Chao
Thanks,
Tiffany Chao
- Sun Feb 23, 2020 10:05 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2
- Replies: 13
- Views: 636
Re: Test 2
The end of thermodynamics (like more in-depth on Gibbs Free Energy) and electrochemistry.
- Sun Feb 23, 2020 10:04 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n
- Replies: 13
- Views: 714
Re: n
You're likely referring to R. In that case, you would use the constant that cancels out your units.
- Tue Feb 18, 2020 7:45 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: reaction at equilibrium
- Replies: 6
- Views: 439
Re: reaction at equilibrium
We calculate delta G by doing G of products - G of reactants. If at equilibrium, the G between products and reactants doesn't change. Therefore, delta G = 0
- Tue Feb 18, 2020 7:44 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Standard Gibbs Free Energy Conditions
- Replies: 4
- Views: 354
Re: Standard Gibbs Free Energy Conditions
Room temperature - 298 K
- Tue Feb 18, 2020 6:34 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Answer is different for 5G.15
- Replies: 5
- Views: 333
Answer is different for 5G.15
I keep getting -2.7 kJ/mol as my answer. However, the book says -27 kJ/mol. Is anyone else getting the same answer as me or did I just calculate something wrong.
Thanks
Thanks
- Wed Feb 12, 2020 12:11 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: different equation in video?
- Replies: 1
- Views: 196
Re: different equation in video?
I think you may be referring to the physics version of the equation. It's technically the same equation, but depends on the perspective of the system for work. I don't think you should worry about that; just focus on the one we have which is delta U = q+w !
Hope this helped
Hope this helped
- Wed Feb 12, 2020 12:00 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Temperature Changes Along Irreversible Pathway
- Replies: 3
- Views: 202
Re: Temperature Changes Along Irreversible Pathway
Makes sense! Thank you!
- Tue Feb 11, 2020 4:17 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Why are exothermic reactions generally spontaneous?
- Replies: 16
- Views: 1125
Why are exothermic reactions generally spontaneous?
I get that exothermic means a -delta H but idk how to interpret the delta S part.
Thanks
Thanks
- Mon Feb 10, 2020 2:39 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Temperature Changes Along Irreversible Pathway
- Replies: 3
- Views: 202
Temperature Changes Along Irreversible Pathway
Why does temperature change along an irreversible pathway? Why does it decrease then increase?
Thanks
Thanks
- Mon Feb 10, 2020 2:30 am
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Why is delta U = 0 for isothermal reactions?
- Replies: 11
- Views: 4219
Why is delta U = 0 for isothermal reactions?
In my notes, it says that it's because delta U = 3/2(nR*delta T) and if delta T = 0, then delta U will be 0. I can understand that logic but where did that delta U = 3/2(nR*delta T) equation come from? And why is it 0?
Thanks
Thanks
- Mon Feb 10, 2020 12:41 am
- Forum: Phase Changes & Related Calculations
- Topic: equation for phase changes
- Replies: 3
- Views: 102
Re: equation for phase changes
The mass should typically be in moles too but just double check it. For example, the enthalpy of fusion for water is known as 6.01 kJ/mol (I believe) so you would need to multiply it by moles.
- Mon Feb 10, 2020 12:39 am
- Forum: Calculating Work of Expansion
- Topic: Derivation of Formula
- Replies: 3
- Views: 124
Re: Derivation of Formula
I don't think we'll be expected to know how to derive it.
- Mon Feb 10, 2020 12:38 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Cv
- Replies: 3
- Views: 196
Re: Cv
Constant pressure may also be called isobaric and constant volume may be called isochoric.
- Sat Feb 08, 2020 5:56 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Calculating Average Kinetic Energy
- Replies: 1
- Views: 124
Calculating Average Kinetic Energy
For 4.19, we're supposed to use average kinetic energy = 3/2*RT. I did 3/2(8.314 J/mol.K)(328.85K) and got 4101.09 J/moles. However, the answer key says 4103.2 J/mol. I'm off by a pretty significant amount and I'm not sure what I'm doing wrong since it seems to be a pretty straightforward calculatio...
- Sat Feb 08, 2020 4:51 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Help on 4.15
- Replies: 1
- Views: 99
Help on 4.15
Can someone help explain how to do 4.15 to me? I don't understand why we have to find the limiting reagent and the tabulated enthalpies of formation.
Thanks!
Thanks!
- Sun Feb 02, 2020 5:26 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calculating q
- Replies: 5
- Views: 214
Calculating q
I'm doing some heat problems from 4A. I've noticed that to calculate q, sometimes you do q = mass x specific heat capacity x delta T. Other times, it's just q = specific heat capacity x delta T. When do you know to multiply mass or not?
Thanks
Thanks
- Sun Feb 02, 2020 4:28 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: w = -P*delta V
- Replies: 4
- Views: 174
w = -P*delta V
This might be a dumb question, but is a negative sign in front of the P*delta V always there? And then if the volume is decreasing (so -deltaV), then work is positive?
Thanks
Thanks
- Sun Feb 02, 2020 4:26 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Positive or negative work?
- Replies: 8
- Views: 264
Positive or negative work?
How do I know when to put a negative or positive sign when calculating work on a system? For example, pushing a piston into a system?
- Sun Feb 02, 2020 3:38 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: delta U = delta H - P delta V
- Replies: 3
- Views: 135
delta U = delta H - P delta V
Am I supposed to use this equation to find internal energy of a system that's at constant pressure?
Thanks
Thanks
- Sun Feb 02, 2020 3:34 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Difference between delta H and q
- Replies: 2
- Views: 90
Difference between delta H and q
If delta H = qp under constant pressure, what's the difference between them? Like when should I use delta H and qp if the system is under constant pressure or does it not matter?
Thanks
Thanks
- Sat Feb 01, 2020 6:29 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Pressure in an open beaker
- Replies: 12
- Views: 736
Re: Pressure in an open beaker
Pressure should be the pressure of the atmosphere
- Tue Jan 21, 2020 11:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Conjugate seesaw
- Replies: 3
- Views: 123
Re: Conjugate seesaw
Yes. Strong base = weak conj. acid. Weak base = strong conj. acid. And the same for strong/weak acids.
- Tue Jan 21, 2020 11:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6D13 part d
- Replies: 2
- Views: 95
Re: 6D13 part d
The reaction is a base + water. Therefore, it's important that you use Kb to figure out this question. From then, you can find pOH and then pH.
Hope this helped!
Hope this helped!
- Tue Jan 21, 2020 11:21 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Prep for Test 1
- Replies: 16
- Views: 608
Re: Prep for Test 1
Nope just be careful that you use Ka for acids and Kb for bases.
- Tue Jan 21, 2020 11:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: If [H3O+] < 10^-7
- Replies: 2
- Views: 98
If [H3O+] < 10^-7
In our notes it says if [H3O+] < 10^-7, then the solution is considered neutral. But if it's less than 10^-7, wouldn't it be considered basic? I don't understand what Dr. Lavelle meant by "neutral".
Thanks
Thanks
- Tue Jan 21, 2020 11:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Where is the Practice WS?
- Replies: 3
- Views: 127
- Tue Jan 21, 2020 11:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Why does changing the stoichiometric coefficients by a factor also change the value of K?
- Replies: 3
- Views: 251
Why does changing the stoichiometric coefficients by a factor also change the value of K?
Doesn't change in concentration not affect K as long as temperature is constant? And if every concentration in the reaction is changed by the same amount, it shouldn't make a difference? I understand it from a mathematical perspective but I don't understand it conceptually.
Thanks
Thanks
- Sat Jan 18, 2020 3:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Getting Back 14A Final Exam
- Replies: 3
- Views: 117
Re: Getting Back 14A Final Exam
I heard it'll be available during Week 3 as well!
- Thu Jan 16, 2020 4:51 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Help on 5.35
- Replies: 5
- Views: 217
Re: Help on 5.35
Rohit Ghosh 4F wrote:You can then use the partial pressures given by the graph along with the reaction A (g) --> B (g) + C (g) to calculate the equilibrium constant.
The answer key says the chemical equation is 2A (g) --> B (g) + 2C (g)
- Thu Jan 16, 2020 4:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Help on 5.35
- Replies: 5
- Views: 217
Re: Help on 5.35
Selena Yu 1H wrote:It says in the problem that compound A decomposes into compounds B and C. So the chemical equation would be A (g) --> B (g) + C (g)
The answer key says the chemical equation is 2A (g) --> B (g) + 2C (g)
- Thu Jan 16, 2020 4:49 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 6B.9
- Replies: 3
- Views: 225
6B.9
For 6B.9 i and ii, I keep getting different answers from the answer key. For i), I do the negative log of 1.50 and get the pH to be -0.176, [OH-] to be 6.67x10^-15, and pOH to be 14.17. This doesn't match the textbook that says pH = 0.176, [OH-] = 1.50x10^-14, and pOH = 13.824. I just don't know wha...
- Wed Jan 15, 2020 11:32 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Help on 5.35
- Replies: 5
- Views: 217
Help on 5.35
I'm not understanding how to find the chemical equation on 5.35. Can someone help me explain?
Thanks
Thanks
- Wed Jan 15, 2020 9:31 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Help on 5I.17
- Replies: 1
- Views: 88
Help on 5I.17
After I do the ICE table and try to calculate the equilibrium constant, I'm having trouble. For Kc, I have written Kc = (2x)^2/(0.114-x)^2 = 1.00 x 10^-5. I originally did this by multiplying it out and then doing quadratic equation. I got an answer, x = 7.52 x 10^-4 but the answer key did a differe...
- Wed Jan 15, 2020 9:25 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When to use Kc or Kp
- Replies: 2
- Views: 79
Re: When to use Kc or Kp
Kc can also be used for gas problems. It just depends on the units the equilibrium concentrations are in. If its in atm or bars, you would use Kp because it's based on partial pressure. But sometimes gas concentrations can be in molarity too, which would be given in mol/L where you can use Kc to cal...
- Sun Jan 12, 2020 5:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units for K
- Replies: 21
- Views: 591
Re: Units for K
No because K is a constant. We use brackets around equilibrium concentration. The brackets indicate molar concentration so we omit actual units.
- Sun Jan 12, 2020 5:39 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Difference between Kc/Kp and Q
- Replies: 2
- Views: 104
Re: Difference between Kc/Kp and Q
Kc is typically used for molar concentrations for aqueous and gasses. Kp is used for gas equilibrium when we use partial pressure (which will typically be indicated by equilibrium concentration in bars or atm). Q stands for the reaction quotient. On its own, it doesn't mean much. To use it, we compa...
- Sun Jan 12, 2020 4:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Help on 5H.3
- Replies: 1
- Views: 128
Help on 5H.3
Can someone help me explain how 5H.3 works?
Thanks
Thanks
- Sun Jan 12, 2020 4:28 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 1 date
- Replies: 4
- Views: 244
Re: Test 1 date
Starts on Tuesday, 1/21, and will be in your discussion.
- Sun Jan 12, 2020 3:55 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units for Kc and Kp
- Replies: 3
- Views: 104
Units for Kc and Kp
I understand that when we calculate Kc, we omit the units and put brackets instead to indicate molar concentration. However, is it the same rule for when we calculate Kp? Do parentheses indicate gas concentration so therefore we don't need to put units like bars or atms?
Thanks
Thanks
- Sat Dec 07, 2019 11:45 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Explanation on a Part of the Notes
- Replies: 2
- Views: 115
Explanation on a Part of the Notes
Can someone explain to me a section of the notes? It was when he asked "Q2: A biological acid, HA, has pKa = 4.22. What's the Ka value of the acid?" I don't understand the part after that says "Is the acid neutral or negatively charged at pH 6?" and the little section under it. T...
- Sat Dec 07, 2019 10:59 pm
- Forum: Bronsted Acids & Bases
- Topic: List of Strong/Weak Acids/Bases
- Replies: 2
- Views: 316
List of Strong/Weak Acids/Bases
I tried looking for a list on Dr. Lavelle's website but I can't find it. Can someone tell me what are the strong and weak acids and bases that we need to know for the class. Thanks!
- Sat Dec 07, 2019 6:35 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: EDTA 6 Bonding Sites
- Replies: 1
- Views: 475
EDTA 6 Bonding Sites
I don't completely understand why EDTA 4- has 6 bonding sites. I understand that there is 2 from the 2 nitrogen atoms which each has a lone pair. However, there are 4 double bonded oxygen atoms with 2 lone pairs each and 2 single bonded oxygens with 3 lone pairs each. Why is it that the single bonde...
- Thu Dec 05, 2019 12:34 am
- Forum: Biological Examples
- Topic: Biological Significance
- Replies: 2
- Views: 173
Re: Biological Significance
Our notes mention cisplantin for chemotherapy, myoglobin/hemoglobin for oxygen transportion in blood cells, chromium to assist insulin, iron for myoglobin/hemoglobin, cobalt for vitamin B12, and Mn, Ni, Cu, Zn for enzyme function.
- Thu Dec 05, 2019 12:29 am
- Forum: Bronsted Acids & Bases
- Topic: Strong Bases
- Replies: 3
- Views: 263
Re: Strong Bases
Oxides and hydroxides with group 1 and 2 elements. Also, metal oxides react with water to form strong bases.
- Thu Dec 05, 2019 12:28 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Equilibrium sign?
- Replies: 3
- Views: 188
Re: Equilibrium sign?
You would typically use it for weak acids and bases because the ions wouldn't completely dissociate and thus, an equilibrium is formed. A strong acid or base in water would completely dissociate, which is when you would use an arrow.
- Thu Dec 05, 2019 12:26 am
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Ice tables
- Replies: 3
- Views: 193
Re: Ice tables
No. That will be 14B.
- Thu Dec 05, 2019 12:24 am
- Forum: DeBroglie Equation
- Topic: Quantum Help
- Replies: 5
- Views: 496
Re: Quantum Help
I typically start off by writing all of the variables the problem gives me. For example, if it gives me wavelength = 900 nm. Then, I write the variable the problem is asking for, so like energy = ? for example. Lastly, I write out all the equations that contains the variables (like wavelength and en...
- Sun Dec 01, 2019 8:33 pm
- Forum: Bronsted Acids & Bases
- Topic: For J. 9., when do we separate H+ from the acid?
- Replies: 2
- Views: 150
For J. 9., when do we separate H+ from the acid?
J. 9. says: Identify the salt that is produced from the acid–base neutralization reaction between (a) potassium hydroxide and acetic acid, CH 3 COOH; (b) ammonia and phosphoric acid; (c) calcium hydroxide and bromous acid; (d) sodium hydroxide and hydrosulfuric acid, H2S (both H atoms react). Write ...
- Sun Dec 01, 2019 8:31 pm
- Forum: Bronsted Acids & Bases
- Topic: Explanation for J. 17.
- Replies: 1
- Views: 177
Explanation for J. 17.
Can someone help me explain how to do 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.
Thanks!
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.
Thanks!
- Fri Nov 29, 2019 5:06 pm
- Forum: Naming
- Topic: New Naming Rules or Old Ones?
- Replies: 1
- Views: 101
New Naming Rules or Old Ones?
Did Dr. Lavelle ask us to use the new naming rules or it doesn't matter? For example, cyano (old) vs cyanido (new). Thanks
- Fri Nov 29, 2019 3:48 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: Test 2: Number of Hydrogen Bonding Sites Question
- Replies: 3
- Views: 351
Test 2: Number of Hydrogen Bonding Sites Question
I've been hearing mixed answers. What's the correct number of H-bonding sites and what's the explanation? Thanks
- Fri Nov 29, 2019 3:45 pm
- Forum: Bronsted Acids & Bases
- Topic: Difference between Bronsted and Lewis
- Replies: 2
- Views: 156
Difference between Bronsted and Lewis
What's the difference between a Bronsted acid/base and a Lewis acid/base? It seems that they're opposite of each other but that's making me confused. Thanks
- Fri Nov 29, 2019 3:40 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: pH vs. pOH
- Replies: 17
- Views: 2272
Re: pH vs. pOH
To add onto Mingdah, pH and pOH have an inverse relationship.
- Fri Nov 29, 2019 3:39 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pH scale
- Replies: 4
- Views: 299
Re: pH scale
It could but I think all that we should know will stay in between 1 and 14.
- Tue Nov 26, 2019 7:21 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Summary for Naming Coordination Compounds
- Replies: 3
- Views: 237
Summary for Naming Coordination Compounds
I am extremely confused while reading the notes for naming coordination compounds. Is anyone able to give me a brief summary to help me better understand the rules?
Thanks
Thanks
- Fri Nov 22, 2019 1:54 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape and Polarity
- Replies: 5
- Views: 320
Re: Molecular Shape and Polarity
If you're talking about a molecule like CHCl3, it's polar. However, the polarity of it doesn't affect the fact that its tetrahedral and all bond angles are 109.5 degrees. The only time bond angles/shape is affected would be due to lone pairs.
- Fri Nov 22, 2019 1:53 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: QUiz 2
- Replies: 2
- Views: 180
Re: QUiz 2
I think the most significant thing we need to know about ion-ion forces is that its the strongest IMF. But I believe the test will mainly focus around dipole-dipole, LDF, and H-bonds.
- Fri Nov 22, 2019 1:51 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: Hydrogen Bonding Atoms
- Replies: 6
- Views: 283
Re: Hydrogen Bonding Atoms
I believe hydrogen can form H-bonds with any N, O, F that have lone pairs regardless of whether it's already attached to a hydrogen or not.
- Fri Nov 22, 2019 1:49 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: london forces
- Replies: 9
- Views: 446
Re: london forces
The one with the bigger molar mass (and more electrons). It allows for more interactions which increases the London Dispersion Force.
- Fri Nov 22, 2019 1:47 am
- Forum: Sigma & Pi Bonds
- Topic: significance
- Replies: 2
- Views: 160
Re: significance
Sigma bonds allow for the molecule to rotate while pi bonds don't allow it to rotate because they are side by side. Like Lavelle showed in class, if you put 3 EXPO markers in between your two pointer fingers and twist, two markers would fall (pi) while one marker remains in place (sigma).
- Sat Nov 16, 2019 6:20 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Long pairs
- Replies: 3
- Views: 194
Re: Long pairs
Lone pairs create a strong electron-electron repulsion which pushes all other atoms closer to together. For example, if you had a trigonal pyramidal with a lone pair at the top, it would push the atoms that are part of the structure closer together, creating a smaller bond angle between the atoms.
- Sat Nov 16, 2019 6:17 pm
- Forum: Bond Lengths & Energies
- Topic: Quiz for Next week dashes/wedges
- Replies: 11
- Views: 590
Re: Quiz for Next week dashes/wedges
Even if there is, it's easy to remember that wedges mean the bond is towards you and dashes are pointing away from you.
- Sat Nov 16, 2019 6:15 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge vs Octet Rule
- Replies: 12
- Views: 732
Re: Formal Charge vs Octet Rule
Just treat drawing Lewis structures for molecules as drawing a normal Lewis structure. Afterwards, go onto VSEPR.
- Sat Nov 16, 2019 6:13 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.5 c)
- Replies: 3
- Views: 177
Re: 3F.5 c)
You are correct in that they both have London forces. However, CHI3 has stronger London forces because it has more electrons than CHF3, therefore stronger London forces.
- Sat Nov 16, 2019 6:11 pm
- Forum: Octet Exceptions
- Topic: Octet expansion
- Replies: 6
- Views: 528
Re: Octet expansion
I think the most important thing we need to know is that the atoms C, N, O, F must fulfill the octet rule. Any other atoms can either have an expanded octet (or don't fulfill the octet rule at all).
- Mon Nov 04, 2019 11:17 pm
- Forum: Bond Lengths & Energies
- Topic: Midterm
- Replies: 8
- Views: 457
Re: Midterm
8 but it's likely that there'll be different parts to each questions such as a. b. c. etc.
- Mon Nov 04, 2019 11:12 pm
- Forum: Photoelectric Effect
- Topic: Details about the photoelectric experiment
- Replies: 3
- Views: 256
Re: Details about the photoelectric experiment
I highly doubt it. Just know about the concepts that came to light (haha) about the photoelectric experiment (ex. particle-like properties.)
- Mon Nov 04, 2019 11:10 pm
- Forum: SI Units, Unit Conversions
- Topic: Unit Conversion
- Replies: 2
- Views: 238
Re: Unit Conversion
You can put it in any unit you want unless the question specifies what unit it wants your answer to be in.
- Mon Nov 04, 2019 11:09 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability Periodic Trend
- Replies: 5
- Views: 147
Re: Polarizability Periodic Trend
The smaller radius and highly charged cations have the strongest polarizability.
For anions, larger atomic radius and less electronegativity are more highly polarizable.
For anions, larger atomic radius and less electronegativity are more highly polarizable.
- Mon Nov 04, 2019 11:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Class Wed 11/6
- Replies: 3
- Views: 126
Re: Class Wed 11/6
I'm in the 12:00 pm lecture. Dr. Lavelle said that we won't be having any class this Wednesday. He just forgot to tell the other lectures.
- Sat Nov 02, 2019 5:27 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Ionic Character in Covalent Molecules and Vice-Versa
- Replies: 2
- Views: 248
Ionic Character in Covalent Molecules and Vice-Versa
Hi, I'm getting confused on the difference between ionic character in covalent molecules and covalent character in ionic molecules. Based on my notes, it seems like for both types of molecules, the ionic/covalent character is that electrons are unevenly distributed. For example of ionic character in...
- Thu Oct 31, 2019 4:17 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Which orbital would contain the highest ionization energy?
- Replies: 3
- Views: 206
Re: Which orbital would contain the highest ionization energy?
Orbitals don't necessarily have to do with the ionization energy levels. Just know the periodic table trend for ionization energy: The further right you go in a row, the higher the ionization energy is. The further down you go in a column, the lower the ionization energy.
- Thu Oct 31, 2019 4:09 pm
- Forum: Student Social/Study Group
- Topic: Video Module For New Material
- Replies: 4
- Views: 209
Re: Video Module For New Material
He told me that there are no more video modules for the topics after Heisenberg. He said the best way to get something similar to the video modules was to use Sapling Learning.
- Thu Oct 31, 2019 4:07 pm
- Forum: Lewis Structures
- Topic: Question 2A9
- Replies: 4
- Views: 287
Re: Question 2A9
The 2+ charge means that 2 electrons are removed. The outermost/highest energy electrons are usually the first to go, thus the removal of the 2 4s electrons.
- Thu Oct 31, 2019 4:06 pm
- Forum: Ionic & Covalent Bonds
- Topic: Lewis structure
- Replies: 3
- Views: 163
Re: Lewis structure
The atom that goes in the middle is the one with the lowest ionization energy. You can figure that out using the periodic table trends for ionization energy. The further right you go in a row, the higher the ionization energy is. The further down you go in a column, the lower the ionization energy. ...
- Thu Oct 31, 2019 4:02 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge equation
- Replies: 9
- Views: 197
Re: Formal Charge equation
I think you should just stick with the one Dr. Lavelle gave us. The problem probably wouldn't give you bond length in the first place so you couldn't figure out the formal charge with the equation your TA gave you.
- Tue Oct 22, 2019 9:06 pm
- Forum: General Science Questions
- Topic: Units
- Replies: 4
- Views: 234
Re: Units
velocity: m/s
threshold energy: J or kg. m^2. s^-2
Planck's constant: 6.626 x 10^-34 Js or kg.m^2. s^-1
frequency: Hz or s^-1
threshold energy: J or kg. m^2. s^-2
Planck's constant: 6.626 x 10^-34 Js or kg.m^2. s^-1
frequency: Hz or s^-1
- Tue Oct 22, 2019 8:58 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homewrok
- Replies: 2
- Views: 145
Re: Homewrok
One question.
- Tue Oct 22, 2019 8:57 pm
- Forum: Properties of Electrons
- Topic: Electron with wavelike/particle like properties?
- Replies: 1
- Views: 186
Re: Electron with wavelike/particle like properties?
Depending on the different experiments that have been done, we can determine whether an light acts like a particle or wave depending on the situation. Particle-like property: This can refer to the Photoelectric experiment. So basically, if we shoot light at a piece of metal, it has to surpass the th...
- Tue Oct 22, 2019 8:47 pm
- Forum: Photoelectric Effect
- Topic: Work Function?
- Replies: 7
- Views: 508
Re: Work Function?
Work function is the threshold energy. It basically means that its the minimum energy needed from the light source to shoot off an electron.
- Tue Oct 22, 2019 8:46 pm
- Forum: Trends in The Periodic Table
- Topic: 1F. 21
- Replies: 2
- Views: 140
1F. 21
Hi,
F. 21.: 1F.21 Identify the following elements as metals, nonmetals, or
metalloids: (a) lead; (b) sulfur; (c) zinc; (d) silicon; (e) antimony;
(f) cadmium.
Will we have to know the answer for elements like antimony or cadmium?
Thanks
F. 21.: 1F.21 Identify the following elements as metals, nonmetals, or
metalloids: (a) lead; (b) sulfur; (c) zinc; (d) silicon; (e) antimony;
(f) cadmium.
Will we have to know the answer for elements like antimony or cadmium?
Thanks