Search found 53 matches
- Mon Mar 15, 2021 12:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: THANK YOU DR LAVELLE!
- Replies: 47
- Views: 7095
Re: THANK YOU DR LAVELLE!
Thank you Dr. Lavelle! You're positive and energetic attitude made zoom university better!
- Thu Mar 11, 2021 11:15 pm
- Forum: Student Social/Study Group
- Topic: STEM Clubs!
- Replies: 7
- Views: 873
Re: STEM Clubs!
Hey! I'm apart of YMAA (youth movement against Alzheimer's) and MEDLIFE EAch are a lot of fun and MEDLIFE has trip every year to Peru to help the communities there!
- Thu Mar 11, 2021 11:12 pm
- Forum: Student Social/Study Group
- Topic: How are y'all doing?
- Replies: 46
- Views: 2997
Re: How are y'all doing?
I try to take a few hours before my classes to eat, shower, and relax. After classes, I work hard until midnight to make sure I feel productive. Usually, I take one day out of the week and do whatever I want as a reward.
- Thu Mar 11, 2021 11:06 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Exo or Endo based on Ea
- Replies: 4
- Views: 1685
Re: Exo or Endo based on Ea
I think it has to do something entropy. The universe prefers disorder so it will make it very difficult to organize reactant molecules into orderly compounds so it has a higher EA. The universe prefers the reverse of an endothermic because it releases energy and increases disorder so it has a lower ...
- Thu Mar 11, 2021 10:58 pm
- Forum: General Rate Laws
- Topic: Rate determining step
- Replies: 38
- Views: 1675
Re: Rate determining step
Here is a way to think about it: a relay team running a race will have the fastest time as their slowest runner. You can also think about it in terms of limiting reagents because the reaction can only produce so much product as there are limiting reactants.
- Thu Mar 11, 2021 10:55 pm
- Forum: Zero Order Reactions
- Topic: Sapling Question week 9/10
- Replies: 18
- Views: 4115
Re: Sapling Question week 9/10
To find the rate constant you must find the order of all the reactants and plug in the values from the table.
- Thu Mar 11, 2021 10:54 pm
- Forum: Balancing Redox Reactions
- Topic: DeltaG = - n F E
- Replies: 3
- Views: 208
Re: DeltaG = - n F E
To use this the cell has to be in standard conditions.
- Sun Mar 07, 2021 7:45 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: average rate
- Replies: 11
- Views: 666
Re: average rate
I believe that the reaction rate for reactants will always be negative because they are converted to products.
- Sun Mar 07, 2021 7:41 pm
- Forum: Student Social/Study Group
- Topic: How do you deal with burnout?
- Replies: 144
- Views: 20661
Re: How do you deal with burnout?
When I burnout it is pretty hard to get back into work mode. So, I promise myself that I will take one day out of the week where I do whatever I want. This usually motivates to continue working during the week.
- Sun Mar 07, 2021 7:38 pm
- Forum: General Rate Laws
- Topic: Multiple Reactants
- Replies: 7
- Views: 404
Re: Multiple Reactants
One thing I remember is that to calculate the overall order of multiple reactants, you add their exponents together. He goes over this towards the end of the lecture on Friday. You can also take a look at the unique average rate for a reaction.
- Sun Mar 07, 2021 7:37 pm
- Forum: Student Social/Study Group
- Topic: Chem Final
- Replies: 13
- Views: 888
Re: Chem Final
I believe it will be 60% new material and the rest is old. At least that's how it is for my other classes.
- Sun Mar 07, 2021 3:05 pm
- Forum: General Rate Laws
- Topic: Why are there negative orders
- Replies: 14
- Views: 743
Why are there negative orders
The book says: "Increasing the concentration of that species, usually a product, slows down the reaction because the species participates in a reverse reaction." Does this have to do with equilibrium? if there is an increase in products, the reaction rate of products will slow down and the...
- Fri Feb 26, 2021 11:07 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Spontaneity and Galvanic Cells
- Replies: 5
- Views: 340
Spontaneity and Galvanic Cells
How do you know when a reaction is spontaneous based on E?
- Fri Feb 26, 2021 10:50 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing out Cell Diagrams
- Replies: 5
- Views: 378
Writing out Cell Diagrams
When do you add a neutral metal to the end of a cathode or anode in a cell diagram? For example, why does the cathode in |Hg|Hg2+||No3-, H_| NO| Pt(s) only have the platinum?
- Fri Feb 26, 2021 9:58 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Half Reactions
- Replies: 2
- Views: 217
Half Reactions
When we are given a reaction such as H+ + OH- --> H2O how do we write the balanced half reactions? Does H+ not have the same charge in each reaction?
- Fri Feb 26, 2021 9:56 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cells solubility equilibrium, Bronsted...
- Replies: 1
- Views: 97
Galvanic Cells solubility equilibrium, Bronsted...
How do we know what kind of galvanic cell to make if it tells us to make one under "solubility equilibirum" or "Bronsted neutralization reaction"? What does it mean?
- Fri Feb 26, 2021 8:27 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Moles in ΔG = -nFE
- Replies: 45
- Views: 4323
Moles in ΔG = -nFE
How do we calculate the number of moles in a cell given a reaction to plug into ΔG?
- Sun Feb 21, 2021 11:10 pm
- Forum: General Science Questions
- Topic: MT 2 grades
- Replies: 34
- Views: 2211
Re: MT 2 grades
I'm pretty sure in about 3 days, at the most, a week.
- Sun Feb 21, 2021 11:09 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Voltage
- Replies: 5
- Views: 332
Re: Voltage
To measure a volt, you use a voltmeter and that has two nodes attached to two ends of the circuit. The difference between those two nodes is the voltage.
- Sun Feb 21, 2021 11:07 pm
- Forum: Balancing Redox Reactions
- Topic: Easy way to remember reduction/oxidazing agents?
- Replies: 10
- Views: 1251
Re: Easy way to remember reduction/oxidazing agents?
I remember it by looking at the charges: if the charge decreased, then I know it gained electrons because they have a negative charge.
- Sun Feb 21, 2021 11:06 pm
- Forum: Student Social/Study Group
- Topic: Fave food
- Replies: 266
- Views: 47897
Re: Fave food
I don't have a favorite food but my favorite meal is pancakes, bacon, and scrambled eggs.
- Sun Feb 21, 2021 11:05 pm
- Forum: Balancing Redox Reactions
- Topic: salt bridge
- Replies: 19
- Views: 796
Re: salt bridge
The purpose of the salt bridge is to keep the solutions neutrally charged.
- Sun Feb 21, 2021 11:03 pm
- Forum: Student Social/Study Group
- Topic: We made it through Midterm 2!
- Replies: 71
- Views: 4895
Re: We made it through Midterm 2!
Congrats! We only have a few more weeks ahead of us! Finish strong!
- Thu Feb 11, 2021 1:14 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Free Energy
- Replies: 49
- Views: 2289
Re: Free Energy
State functions depend on final and initial states.
- Wed Feb 10, 2021 9:42 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: Molecular Structures and Entropy
- Replies: 1
- Views: 63
Molecular Structures and Entropy
How do we determine entropy based on molecular structures? I know degeneracy depends on the number of molecules and the states that they form.
- Wed Feb 10, 2021 8:55 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy vs Entropy
- Replies: 39
- Views: 3352
Re: Enthalpy vs Entropy
Another helpful idea I learned is that entropy is "the chaos in the universe" and we do work (exerting energy) to put it back in order.
- Wed Feb 10, 2021 8:53 pm
- Forum: Calculating Work of Expansion
- Topic: How to Know When to use Cp and Cv
- Replies: 4
- Views: 247
Re: How to Know When to use Cp and Cv
The problem will specify what conditions the reaction occurs and that tells us when to use cp or cv.
- Sat Feb 06, 2021 1:10 pm
- Forum: Ideal Gases
- Topic: Chem BL
- Replies: 107
- Views: 10439
Re: Chem BL
I'm taking chem 14BL right now and it's not too bad. Most of the material we have not gone over in class, however, you should some of this stuff from high school chemistry. Similarly, the professors are very helpful and post explanation of the concepts that we may have not learned.
- Sat Feb 06, 2021 1:09 pm
- Forum: Student Social/Study Group
- Topic: Superbowl Sunday
- Replies: 26
- Views: 1873
Re: Superbowl Sunday
it's going to be an exciting game. I'm rooting for the buccaneers.
- Sat Feb 06, 2021 1:07 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Ideal Gas Expansion
- Replies: 7
- Views: 214
Re: Ideal Gas Expansion
The internal energy doesn't change because initial and final states are the same. (state function)
- Sat Feb 06, 2021 1:04 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling #19
- Replies: 3
- Views: 172
Re: Sapling #19
We learned this in our first lecture discussing Thermodynamics. Usually, you use this equation to find heat capacity, specific heat, moles, or the change in temperature. It is good to remember the q system = -q surroundings and delta U = q + w.
- Sat Feb 06, 2021 1:01 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: sapling 12
- Replies: 5
- Views: 291
Re: sapling 12
You have to find the heat capacity of the calorimeter and then multiply by the delta T of the second compound.
- Sat Feb 06, 2021 1:00 pm
- Forum: Phase Changes & Related Calculations
- Topic: Why does steam cause severe burns?
- Replies: 22
- Views: 1870
Re: Why does steam cause severe burns?
Steam is still heating up after it is evaporated. It still has potential for the molecules to heat up more and disperse farther into the universe.
- Sat Feb 06, 2021 12:58 pm
- Forum: Calculating Work of Expansion
- Topic: Is reversible expansion just theoretical?
- Replies: 11
- Views: 450
Re: Is reversible expansion just theoretical?
Reversible expansion is theoretical because the theory is that all heat can be converted to work, which is not true.
- Mon Feb 01, 2021 12:00 am
- Forum: Phase Changes & Related Calculations
- Topic: Why does steam cause severe burns?
- Replies: 22
- Views: 1870
Re: Why does steam cause severe burns?
Steam is still heating up when it is released as vapor, therefore, it is hotter than boiling water.
- Tue Jan 26, 2021 11:59 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Textbook 4E.9
- Replies: 1
- Views: 135
Textbook 4E.9
Benzene is more stable and less reactive than would be predicted from its Kekulé structures. Use the data in Table 4E.3 to calculate the lowering in molar energy when resonance is allowed between the Kekulé structures of benzene.
How would you solve this problem? What are they asking for?
How would you solve this problem? What are they asking for?
- Mon Jan 25, 2021 10:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Textbook Questions 4D.23
- Replies: 2
- Views: 115
Textbook Questions 4D.23
How would you solve for N2O5?
Calculate the standard enthalpy of formation of dinitrogen pentoxide from the following data:
2NO(g)+O2(g)→2NO2(g). ΔHo=−114.1kJ
4NO2(g)+O2(g)→2N2O5(g)ΔHo=−110.2kJ
and from the standard enthalpy of formation of nitric oxide, NO = +90.25
Calculate the standard enthalpy of formation of dinitrogen pentoxide from the following data:
2NO(g)+O2(g)→2NO2(g). ΔHo=−114.1kJ
4NO2(g)+O2(g)→2N2O5(g)ΔHo=−110.2kJ
and from the standard enthalpy of formation of nitric oxide, NO = +90.25
- Sun Jan 24, 2021 8:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 2 #7
- Replies: 8
- Views: 374
Re: Sapling Week 2 #7
They want to make it clear for us that mixing water and ClO- gives an conjugate acid and base.
- Sun Jan 24, 2021 8:29 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Ice Tables
- Replies: 28
- Views: 1203
Re: Ice Tables
It depends if you are given the initial concentration of the reactants or products: if you're given the concentration of reactants, then products are "+x" and reactants are "-x" and vice versa.
- Thu Jan 21, 2021 11:30 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Polyprotic Acid Problems
- Replies: 3
- Views: 296
Polyprotic Acid Problems
What is the general steps to solving polyprotic acid problems?
- Thu Jan 21, 2021 10:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: How to find pH
- Replies: 3
- Views: 233
How to find pH
If we are given the initial concentration of HA, do we use an ICE box to solve the problem? As in the problem 6D.13: Rank the following solutions in order of increasing pH: (a) 1.0 ×10−5 M HCl(aq);(b) 0.20 MCH3NH3Cl(aq);(c) 0.20 M CH3COOH(aq);(d) 0.20 M C6H5NH2(aq). Justify your ranking.
- Thu Jan 21, 2021 9:37 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ordering from weakest to strongest Acd/base
- Replies: 11
- Views: 607
Ordering from weakest to strongest Acd/base
How do you know when an acid is strong from its Ka and pKa? Same thing for a base.
- Sun Jan 17, 2021 3:52 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle and Pressure
- Replies: 6
- Views: 353
Le Chatelier's Principle and Pressure
Why does a reaction shift towards the reactants when there is an increase in pressure? Is it because they are not dissociated? I read on a website that in a response to an increase in pressure, the reaction will shift to the side with the least amount of moles.
- Sun Jan 17, 2021 3:28 pm
- Forum: Student Social/Study Group
- Topic: Sapling Homework
- Replies: 15
- Views: 947
Re: Sapling Homework
It seems like the homework is due every other week.
- Thu Jan 14, 2021 8:38 pm
- Forum: Ideal Gases
- Topic: Thermodynamics in Equilibirum
- Replies: 6
- Views: 259
Thermodynamics in Equilibirum
Are we supposed to know thermodynamics in equilibrium even though he didn't cover it in lecture?
- Thu Jan 14, 2021 4:52 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Textbook Problem 5I.19
- Replies: 4
- Views: 213
Textbook Problem 5I.19
A reaction mixture that consisted of 0.400 mol H2 and 1.60 mol I2 was introduced into a flask of volume 3.00 L and heated. At equilibrium, 60.0% of the hydrogen gas had reacted. What is the equilibrium constant K for the reaction H2(g)+I2g)⇌2HI(g)at this temperature?' How do I solve the problem? Do ...
- Thu Jan 14, 2021 4:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Stability and Thermodynamics
- Replies: 1
- Views: 62
Stability and Thermodynamics
How do you use thermodynamics to conclude that a reaction is stable?
- Mon Jan 11, 2021 1:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Textbook Problem 5h #3
- Replies: 5
- Views: 273
Textbook Problem 5h #3
Use the information in Table 5G.2 to determine the value of K at 300 K for the reaction 2BrCl(g)+H2(g)⇌Br2(g)+2HCl(g).
Can someone help me with this problem?
Can someone help me with this problem?
- Fri Jan 08, 2021 8:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Question #2 Sapling
- Replies: 2
- Views: 142
Question #2 Sapling
I'm confused on how to solve this problem:
At a certain temperature, 0.660 mol SO3 is placed in a 1.50 L container.
2SO3(g) <--> 2SO2(g)+O2(g)
At equilibrium, 0.120 mol O2 is present. Calculate K.
If anyone can help, I would appreciate it.
At a certain temperature, 0.660 mol SO3 is placed in a 1.50 L container.
2SO3(g) <--> 2SO2(g)+O2(g)
At equilibrium, 0.120 mol O2 is present. Calculate K.
If anyone can help, I would appreciate it.
- Thu Jan 07, 2021 7:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: What is an activity?
- Replies: 9
- Views: 470
Re: What is an activity?
I believe he wrote the equilibrium constant equal to the activity in the first lecture.
- Wed Jan 06, 2021 8:46 pm
- Forum: Ideal Gases
- Topic: Ideal Gas Law Question
- Replies: 11
- Views: 457
Re: Ideal Gas Law Question
Temperature is considered a constant because it is directly proportional to pressure.
- Tue Jan 05, 2021 5:48 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: TB #5H.1
- Replies: 4
- Views: 204
Re: TB #5H.1
I don't have access to the homework yet but I can try and help. For part B, you use the new coefficients in the for equilibrium constant. I believe you should get either the same or a multiple of the original ratio.
- Tue Jan 05, 2021 5:41 pm
- Forum: Ideal Gases
- Topic: Conditions for PV=nRT
- Replies: 5
- Views: 341
Re: Conditions for PV=nRT
Hey! As far as I understand, the conditions are as follows: at constant temperature and pressure, the volume of the gas is proportional to the number of moles. I searched it up to double check and I posted the link.https://www.westfield.ma.edu/PersonalPages/cmasi/gen_chem1/Gases/ideal%20gas%20law/pv...