Search found 50 matches
- Sun Mar 17, 2019 9:21 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatlier Principle
- Replies: 10
- Views: 2118
Re: Le Chatlier Principle
Addin a catalyst wouldn't affect the equilibrium, rather it would just speed up the forward and reverse reaction.
- Sun Mar 17, 2019 9:20 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: bomb calorimeter
- Replies: 8
- Views: 1224
Re: bomb calorimeter
Work would be equal to zero, since volume is constant.
- Sun Mar 10, 2019 10:48 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Ideal Gas Constants
- Replies: 4
- Views: 734
Re: Ideal Gas Constants
Only monoatomic constants need to be known.
- Sun Mar 10, 2019 10:45 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Constant Vol.
- Replies: 8
- Views: 1061
Re: Constant Vol.
Yes since if there is no change in pressure, then zero work would be done.
- Sun Mar 10, 2019 10:44 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Final Exam
- Replies: 23
- Views: 1824
Re: Final Exam
The final exam is cumulative, so yes chemical equilibrium will be one the exam.
- Sun Mar 03, 2019 10:03 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Final exam
- Replies: 8
- Views: 941
Re: Final exam
The final exam is on march 17th.
- Sun Mar 03, 2019 10:02 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ignoring x
- Replies: 16
- Views: 3359
Re: ignoring x
You can ignore x when k is less than 1x10^-3
- Sun Mar 03, 2019 10:01 pm
- Forum: Ideal Gases
- Topic: pV=nRT
- Replies: 12
- Views: 2125
Re: pV=nRT
You can use the equation to find any of the variables, so p,V,n and T. R is a constant.
- Sun Feb 24, 2019 6:48 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reversible Reactions
- Replies: 8
- Views: 1325
Re: Reversible Reactions
Any reversible reaction is isothermal, but never assume that any isothermal reaction is reversible.
- Sun Feb 24, 2019 6:47 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Internal energy (U) of an isolated system
- Replies: 17
- Views: 2715
Re: Internal energy (U) of an isolated system
There is no change in energy within a closed system. Since energy can neither leave or enter the system.
- Sun Feb 24, 2019 6:44 pm
- Forum: Ideal Gases
- Topic: Approximations for ICE
- Replies: 20
- Views: 1644
Re: Approximations for ICE
When K is less than 10^-3, you can just approximate. Always remember to prove the approximation using the 5% rule.
- Sun Feb 17, 2019 8:29 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Midterm Grades
- Replies: 35
- Views: 2788
Re: Midterm Grades
I'm guessing week 7 discussion sections.
- Sun Feb 17, 2019 8:27 pm
- Forum: Calculating Work of Expansion
- Topic: Work
- Replies: 8
- Views: 952
Re: Work
I would focus on the ones showed on the constants page that is given each test. Also as mentioned, we don't need to know any of the ones that have derivatives or the integrals, these serve mainly as proofs.
- Sun Feb 17, 2019 8:24 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642609
Re: Post All Chemistry Jokes Here
What do you call an acid with an attitude?
An A-mean-o-acid.
An A-mean-o-acid.
- Sun Feb 10, 2019 6:47 pm
- Forum: Phase Changes & Related Calculations
- Topic: Work equation
- Replies: 4
- Views: 529
Re: Work equation
I would look over the equation worksheet, then list out all the constants that aren't listed there and memorize them.
- Sun Feb 10, 2019 6:45 pm
- Forum: Ideal Gases
- Topic: derivatives and integrals
- Replies: 6
- Views: 1020
Re: derivatives and integrals
When Dr. Lavelle uses derivatives and integrals, it just a way to show how he was able to derive the equations. They are more just used as proofs. Use the equations that are derived.
- Sun Feb 10, 2019 6:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Quiz 1 Number 3c
- Replies: 6
- Views: 670
Re: Quiz 1 Number 3c
It should be in mol/L as it is asking for M or concentration.
- Sun Jan 27, 2019 10:15 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: First row question
- Replies: 3
- Views: 477
Re: First row question
Cations from groups 1 and 2 or cations with just a +1 charge are not large enough to have enough of an effect.
- Sun Jan 27, 2019 10:12 pm
- Forum: Ideal Gases
- Topic: Chemistry Community Posting
- Replies: 7
- Views: 630
Re: Chemistry Community Posting
You should have your three posts done before 11:59 on the Sunday of that week.
- Sun Jan 27, 2019 10:11 pm
- Forum: Ideal Gases
- Topic: pH and pOH
- Replies: 18
- Views: 1965
Re: pH and pOH
Usually the question will ask you to solve for one or the other.
- Sun Jan 13, 2019 10:24 pm
- Forum: Ideal Gases
- Topic: Homework Week 2
- Replies: 10
- Views: 1039
Re: Homework Week 2
From now on, homework will be due whenever your discussion section is.
- Sun Jan 13, 2019 10:22 pm
- Forum: Ideal Gases
- Topic: Denoting brackets/parentheses
- Replies: 9
- Views: 2189
Re: Denoting brackets/parentheses
Brackets are primarily used to denote that the element is in concentration, parentheses are just used for partial pressures.
- Sun Jan 13, 2019 10:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Tables
- Replies: 3
- Views: 373
Re: ICE Tables
If I remember correctly, ICE tables can be used for both concentrations and partial pressures.
- Sun Dec 09, 2018 10:11 am
- Forum: Trends in The Periodic Table
- Topic: 2nd Ionization Energy
- Replies: 2
- Views: 527
Re: 2nd Ionization Energy
I believe we only need to know the trend of 1st ionization energy for the test, since we haven't really talked too much about the 2nd level.
- Sun Dec 09, 2018 10:09 am
- Forum: Dipole Moments
- Topic: Forces Present in molecules
- Replies: 3
- Views: 606
Re: Forces Present in molecules
Vanderwals occur in every molecule, dipole-dipole occurs in polar molecules, and induced-dipole occurs with one polar and non-polar molecule.
- Sun Dec 09, 2018 9:39 am
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 567384
Re: Saying Thank You to Dr. Lavelle
As the quarter comes to a close, I want to thank Dr. Lavelle for providing a fun and interesting learning environment at all times throughout the quarter.
- Sun Dec 02, 2018 10:29 pm
- Forum: Hybridization
- Topic: S Hybridization?
- Replies: 5
- Views: 501
Re: S Hybridization?
Yes, but most of the time it is usually for atoms that are not the central atom within the molecule.
- Sun Dec 02, 2018 10:21 pm
- Forum: Resonance Structures
- Topic: Formal Charge
- Replies: 13
- Views: 1423
Re: Formal Charge
Since it is an ion, the overall FC should not be equal to zero. Ideally, you want the central atom to have an FC=0 and have any charge whether positive or negative on the outer atoms around the central atom.
- Sun Dec 02, 2018 10:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
- Replies: 118
- Views: 21455
Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Thank you so much for providing us with study material :D
- Sun Nov 25, 2018 10:26 pm
- Forum: Trends in The Periodic Table
- Topic: Bond Lenghts
- Replies: 7
- Views: 924
Re: Bond Lenghts
You would need the lewis structure before giving an informed answer about the length of the bonds between atoms of certain elements.
- Sun Nov 25, 2018 10:22 pm
- Forum: Lewis Structures
- Topic: Exceptions to the Octet Rule
- Replies: 5
- Views: 541
Re: Exceptions to the Octet Rule
Period 3 and above elements can have expanded octets, as well the first four elements, H, He, Li, and Be will try to have 2 e- to finish the first shell rather the 8 e- as it is easier to be stable in this way.
- Sun Nov 25, 2018 10:19 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: labeling hybridization
- Replies: 3
- Views: 333
Re: labeling hybridization
You would label hybridization by drawing the three possible ways BF3 can look like. As shown in the image provided labeled B. You would show these are resonate by using the double sided arrows.
- Sun Nov 18, 2018 8:47 pm
- Forum: Bond Lengths & Energies
- Topic: Calculating Bond Length
- Replies: 3
- Views: 466
Re: Calculating Bond Length
We do not need to know the specific length of a bond, we only need to know the trends of bond lengths.
- Sun Nov 18, 2018 8:45 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Length
- Replies: 9
- Views: 1020
Re: Bond Length
how do we know the bond length? is it something we have to look up? We do not need to know the exact bond length, we just need to know the trend of the size of bonds. There was an example of this on the midterm with how we have a double and single bond in resonance, which showed that the actual bon...
- Sun Nov 18, 2018 8:43 pm
- Forum: Dipole Moments
- Topic: Test
- Replies: 15
- Views: 1325
Re: Test
The next test is on week 9 I believe.
- Sun Nov 11, 2018 10:57 pm
- Forum: Properties of Light
- Topic: Test 3
- Replies: 24
- Views: 2216
Re: Test 3
I believe test 3 would be the parts of outline 3 that weren't covered on the midterm and all of outline 4.
- Sun Nov 11, 2018 10:55 pm
- Forum: Limiting Reactant Calculations
- Topic: Chem Community Points
- Replies: 3
- Views: 704
Re: Chem Community Points
You need to post at least three times a week, the deadline being midnight of each sunday.
- Sun Nov 11, 2018 10:54 pm
- Forum: Empirical & Molecular Formulas
- Topic: Midterm
- Replies: 1
- Views: 510
Re: Midterm
You would take the percentage of molar mass of each element so in CO2 you would divide 12.011/(12.011+2*15.999), then multiply by how many grams of the molecule you have, you would do this again for the hydrogen in H2O, once you have these two weights of the elements you are looking for, you would a...
- Sun Nov 04, 2018 10:52 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge on Central Atom
- Replies: 9
- Views: 1582
Re: Formal Charge on Central Atom
As the central atom's FC becomes zero, the more stable the entirety of the molecule becomes.
- Sun Nov 04, 2018 10:49 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic Radius
- Replies: 6
- Views: 1041
Re: Atomic Radius
The basic reason/logic behind it is that as an atom has more electrons, then the radius increases by the shells.
- Sun Nov 04, 2018 10:13 pm
- Forum: Properties of Light
- Topic: Photoelectric Effect
- Replies: 7
- Views: 937
Re: Photoelectric Effect
Yes, because intensity is proportional to electrons ejected.
- Sun Oct 28, 2018 10:21 pm
- Forum: Trends in The Periodic Table
- Topic: Lewis Structures
- Replies: 7
- Views: 727
Re: Lewis Structures
If i remember right, the position of the dots do not matter as long as there are no restrictions such as bonds or e- pairs.
- Sun Oct 28, 2018 10:20 pm
- Forum: Ionic & Covalent Bonds
- Topic: Lewis Dot Structures: Ionization Energy
- Replies: 6
- Views: 768
Re: Lewis Dot Structures: Ionization Energy
The element with the lowest energy means that it can bond with more elements, which is why it is a great starting point in the center.
- Sun Oct 28, 2018 10:19 pm
- Forum: Ionic & Covalent Bonds
- Topic: the Octet rule
- Replies: 21
- Views: 4135
Re: the Octet rule
The only exception to the octet rule are the first four elements, as they will try to only finish the first shell which only needs two e-.
- Sun Oct 21, 2018 11:46 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642609
Re: Post All Chemistry Jokes Here
Q. What do you do with a dead chemist?
A. You Barium.
A. You Barium.
- Sun Oct 21, 2018 11:44 pm
- Forum: Photoelectric Effect
- Topic: Test 2
- Replies: 16
- Views: 1180
Re: Test 2
I believe that each concept will be from the quantum world sections, but you still need to know the basics of from the first test that was given to us.
- Sun Oct 21, 2018 11:42 pm
- Forum: Properties of Light
- Topic: Quantum Equations
- Replies: 3
- Views: 421
Re: Quantum Equations
Usually you can determine which equations you use based on what the question asks and what information is given to you in the problem.
- Thu Oct 04, 2018 11:17 pm
- Forum: SI Units, Unit Conversions
- Topic: Hecto as SI Unit [ENDORSED]
- Replies: 4
- Views: 269
Re: Hecto as SI Unit [ENDORSED]
I believe Dr. Lavelle was showing us formal SI units which are multiples of 3 for brevity's sake, however the hectometer is a SI unit.
- Thu Oct 04, 2018 11:13 pm
- Forum: SI Units, Unit Conversions
- Topic: Exercise E1 (Question regarding unit conversions) [ENDORSED]
- Replies: 3
- Views: 211
Re: Exercise E1 (Question regarding unit conversions) [ENDORSED]
If the question does not specify which units to use, then usually you would stick with the unit that is given, so picometers.
- Thu Oct 04, 2018 11:02 pm
- Forum: Significant Figures
- Topic: Sig Figs
- Replies: 3
- Views: 701
Re: Sig Figs
If I remember correctly, when it comes to a combination of both multiplication/division and addition/subtraction. You would adhere to the addition rule for sig figs.