Search found 57 matches
- Tue Mar 05, 2019 7:22 pm
- Forum: Zero Order Reactions
- Topic: Half life
- Replies: 5
- Views: 532
Re: Half life
just for the 1st order reactions
- Tue Mar 05, 2019 7:19 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Delta n
- Replies: 7
- Views: 1228
Re: Delta n
Destiny Diaz 4D wrote:so to find delta n you would take the moles from products subtracted from moles from reactants?
yes i think so?
- Tue Mar 05, 2019 7:18 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Determining Spontaneity
- Replies: 7
- Views: 931
Re: Determining Spontaneity
in general, you shouldn't assume anything in terms of spontaneity since it fluctuates with each reaction
- Tue Mar 05, 2019 7:15 pm
- Forum: First Order Reactions
- Topic: First Order Integrated Law
- Replies: 3
- Views: 331
Re: First Order Integrated Law
Yes they are the same thing.
- Tue Mar 05, 2019 7:14 pm
- Forum: General Rate Laws
- Topic: does k change if rxn is multiplied?
- Replies: 6
- Views: 1469
Re: does k change if rxn is multiplied?
it shouldn't change when rxn is multiplied
- Tue Mar 05, 2019 7:13 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Finding Order for Each Reactant
- Replies: 4
- Views: 503
Re: Finding Order for Each Reactant
it doesn't seem like it should matter but i could easily be wrong
- Thu Feb 21, 2019 1:36 am
- Forum: Van't Hoff Equation
- Topic: ΔSº and ΔHº question
- Replies: 5
- Views: 661
Re: ΔSº and ΔHº question
Free energy is the one that changes and is influenced by temperature
- Thu Feb 21, 2019 1:34 am
- Forum: Balancing Redox Reactions
- Topic: Reducing agents and oxidizing agents
- Replies: 6
- Views: 678
Re: Reducing agents and oxidizing agents
Angela Cong 3C wrote:A simple acronym that helps to remember which is OIL RIG
OIL= Oxidation Is Loss (of electrons)
RIG= Reduction Is Gain (of electrons)
That's a really good way of memorizing it thank you
- Thu Feb 21, 2019 1:32 am
- Forum: Ideal Gases
- Topic: units
- Replies: 15
- Views: 1304
Re: units
I did it too and the people above say it's bc k doesn't have units
- Thu Feb 21, 2019 1:31 am
- Forum: Balancing Redox Reactions
- Topic: Week 7 Homework
- Replies: 15
- Views: 1185
Re: Week 7 Homework
He sent out an email saying thermodynamics and Gibbs free energy should be what we turn in
- Thu Feb 21, 2019 1:30 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: When does delta U equal zero?
- Replies: 17
- Views: 8208
Re: When does delta U equal zero?
When the reaction is isothermal
- Thu Feb 21, 2019 1:29 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reversible Reactions
- Replies: 8
- Views: 1264
Re: Reversible Reactions
Will reversible reactions be on the next test?
- Thu Feb 21, 2019 1:27 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reversible vs irreversible
- Replies: 6
- Views: 932
Re: Reversible vs irreversible
Reversible isn't that necessary to know since they're theoretical.
- Thu Feb 21, 2019 1:26 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isobaric
- Replies: 12
- Views: 1593
Re: Isobaric
What would work most would be w= -pdeltav
- Thu Feb 21, 2019 1:25 am
- Forum: Balancing Redox Reactions
- Topic: H+ vs H3O+
- Replies: 10
- Views: 953
Re: H+ vs H3O+
It's best to use H+ even though it doesn't matter too much
- Fri Feb 01, 2019 10:09 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Surroundings
- Replies: 11
- Views: 893
Re: Surroundings
the surroundings is just a broad concept and depending on what is being talked about the "surroundings" could be infinite to the universe and yet be any small part in the universe as well.
- Fri Feb 01, 2019 10:07 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: closed vs isolated
- Replies: 14
- Views: 996
Re: closed vs isolated
a closed system is capable of influence with outer environments and variables while an isolated system cannot be changed whatsoever.
- Fri Feb 01, 2019 10:04 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Heat vs. Temp
- Replies: 9
- Views: 882
Re: Heat vs. Temp
In short, heat is energy while temperature itself is not and it measures the speed of the molecules moving about.
- Sat Jan 26, 2019 9:50 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: q vs. qp
- Replies: 2
- Views: 153
Re: q vs. qp
They both are essentially the same I believe but q with a p subscript means it's processed under constant pressure like the other person said.
- Sat Jan 26, 2019 9:48 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: states of reactants and products
- Replies: 3
- Views: 356
Re: states of reactants and products
no you do not have to have same states
- Sat Jan 26, 2019 9:43 pm
- Forum: Phase Changes & Related Calculations
- Topic: Due date for Discussion Questions
- Replies: 8
- Views: 807
Re: Due date for Discussion Questions
and last quarter with lavelle the forum posts are due every sunday and I'm sure it is the same for this quarter.
- Sat Jan 19, 2019 6:48 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ignoring solids
- Replies: 6
- Views: 728
Re: ignoring solids
In the end game result for K or Q solids and pure liquids will not affect the results.
- Sat Jan 19, 2019 6:46 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Example in class
- Replies: 5
- Views: 555
Re: Example in class
for the example he gave, he used Q since the equation wasn't at equilibrium
- Sat Jan 19, 2019 6:44 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: How to tell if a chemical is an acid or base?
- Replies: 4
- Views: 666
Re: How to tell if a chemical is an acid or base?
For the most part you will kinda just have to memorize whether or not it is a base or an acid
- Fri Jan 11, 2019 3:18 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic Reactions
- Replies: 9
- Views: 790
Re: Exothermic Reactions
IN the lecture today he wrote/ said
when pressure changes
when k does change
If rxn requires heat (endothermic) while forming product then heating will favor P formation.
If rxn gives off heat (exothermic) while forming product then heating will favor R formation.
hope this helps :)
when pressure changes
when k does change
If rxn requires heat (endothermic) while forming product then heating will favor P formation.
If rxn gives off heat (exothermic) while forming product then heating will favor R formation.
hope this helps :)
- Fri Jan 11, 2019 3:16 pm
- Forum: Ideal Gases
- Topic: Units
- Replies: 19
- Views: 1069
Re: Units
Lavelle said due to the absolute 0 K we use Kelvin like the other people said
- Fri Jan 11, 2019 3:14 pm
- Forum: Ideal Gases
- Topic: What does K represent?
- Replies: 9
- Views: 2389
Re: What does K represent?
K is a constant but it is supposed to stay the same regardless of the different P/R right?
- Sat Dec 08, 2018 5:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: How to find my posts
- Replies: 163
- Views: 160912
Re: How to find my posts
the quick links tab works best for me and it gives you the number of posts you put up and the comments people wrote after you.
- Sat Dec 08, 2018 5:16 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
- Replies: 118
- Views: 20755
Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
this was really helpful and so was the review session thank you!
- Sat Dec 08, 2018 5:15 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 38371
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
this was very helpful thank you!
- Fri Nov 30, 2018 3:46 pm
- Forum: Air Pollution & Acid Rain
- Topic: Acid Rain on the Final
- Replies: 4
- Views: 712
Re: Acid Rain on the Final
It is most likely going to be covered on the final but that is dependent on whether or not we get it covered next week before the test.
- Fri Nov 30, 2018 3:44 pm
- Forum: Lewis Acids & Bases
- Topic: Strength
- Replies: 3
- Views: 333
Re: Strength
The easier it is to dissociate into H+ and OH-, the weaker the acid or base is.
- Fri Nov 30, 2018 3:39 pm
- Forum: General Science Questions
- Topic: Final Review
- Replies: 4
- Views: 680
Re: Final Review
It mainly depends on what you believe you need most help in. If you understand all of the topics and just want to concrete your knowledge go to the one you are most confident in to see if you missed anything. Go to the step ups if you are struggling with a topic too.
- Fri Nov 23, 2018 5:51 pm
- Forum: Sigma & Pi Bonds
- Topic: Drawing bonds
- Replies: 3
- Views: 356
Re: Drawing bonds
I mean it is possible he would put it on but I'd refer to the outlines for test 3 he put up.
- Fri Nov 23, 2018 5:49 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Position of atoms in Trigonal Planar
- Replies: 4
- Views: 377
Re: Position of atoms in Trigonal Planar
This applies to the angles?
- Tue Nov 20, 2018 6:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Thanksgiving Wednesday Class
- Replies: 19
- Views: 1360
Re: Thanksgiving Wednesday Class
Chem_Mod wrote:All discussions will happen on Wednesday as usual.
All students should turn in homework for week 8 and 9 during week 9 discussion. This means you need 14 homework problems next week.
So for this weeks discussion we do not need to turn in week 8 homework?
- Sat Nov 17, 2018 4:03 am
- Forum: Hybridization
- Topic: Test 3
- Replies: 5
- Views: 717
Re: Test 3
I think it is just the molecular shapes and structure from those outlines
- Sat Nov 17, 2018 4:01 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR- Polar vs Nonpolar
- Replies: 5
- Views: 244
Re: VSEPR- Polar vs Nonpolar
are there any more exceptions to the rule of polar and nonpolar with the vespr?
- Sat Nov 17, 2018 3:59 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma and Pi Bonds
- Replies: 2
- Views: 251
Re: Sigma and Pi Bonds
double bonds = one pi bond + one sigma bond
triple bonds = one sigma bond + two pi bonds
this is all i know
triple bonds = one sigma bond + two pi bonds
this is all i know
- Fri Nov 09, 2018 9:21 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T-Shape
- Replies: 6
- Views: 772
Re: T-Shape
When we put the angles being 90 and 120 it is mainly a ballpark answer unless you calculated it being on the dot. it is around 90 or slightly less than 90.
- Fri Nov 09, 2018 9:19 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW for discussion
- Replies: 9
- Views: 1008
Re: HW for discussion
I am sure you can due the easier ones on outline 4 since we went over shapes and angles too.
- Fri Nov 09, 2018 9:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape
- Replies: 4
- Views: 256
Re: Molecular Shape
is there any other challenging molecule someone can provide as an example to help further help with my knowledge on how the shapes and angles work?
- Fri Nov 02, 2018 12:26 am
- Forum: Octet Exceptions
- Topic: octet rule exceptions?
- Replies: 5
- Views: 753
Re: octet rule exceptions?
Is there a way to figure out which ones are allowed to contradict the octet rule or is it all of the ones from 3 and down.??
- Fri Nov 02, 2018 12:19 am
- Forum: Resonance Structures
- Topic: Tricks for Resonance Structures
- Replies: 5
- Views: 872
Tricks for Resonance Structures
Are there any simple tricks to seeing how many resonance structures there could be for a single compound? What about for the resonance structures with formal charge that is not 0, would we have to include all the structures or do we exclude a certain number of formal charge when making resonance str...
- Fri Nov 02, 2018 12:14 am
- Forum: Lewis Structures
- Topic: Drawing Lewis Structures
- Replies: 14
- Views: 1980
Re: Drawing Lewis Structures
If the angles are determined by something we haven't gone over will we be tested and graded on specificity of our structures with those angles or will it not matter as much for this midterm.
- Thu Oct 25, 2018 11:48 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration Exceptions [ENDORSED]
- Replies: 3
- Views: 488
Re: Electron Configuration Exceptions [ENDORSED]
It has something to do with the stability of the element and how it likes a specific configuration. The sublevels when they are completely filled are more stable than those that are partially filled. Sorry this is a kind of convoluted explanation but it is the only one I have. I hope more people can...
- Thu Oct 25, 2018 11:42 pm
- Forum: Einstein Equation
- Topic: Units
- Replies: 6
- Views: 893
Re: Units
What equation do you mean? is there a specific equation you are referring to? The test requires you to answer with correct units and sig figs. I do not believe that they give you the units.
- Thu Oct 25, 2018 11:36 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Exam
- Replies: 2
- Views: 230
Re: Exam
You have to know its function and how it can be applied.
- Thu Oct 18, 2018 11:47 pm
- Forum: Properties of Light
- Topic: calculating wavelength
- Replies: 10
- Views: 1115
Re: calculating wavelength
Dr. Lavelle mentioned that E = hv can only be used for light. However, De Broglie's equation of lambda=h/p can only be used for objects with "rest" mass and velocity. "Rest" mass basically means anything that has mass when stationary. why is rest in quotes.. is there a significa...
- Thu Oct 18, 2018 11:28 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: angular nodes
- Replies: 1
- Views: 216
angular nodes
Why is it that when you have an angular node the wave function changes sign?
- Thu Oct 18, 2018 11:21 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electron Configuratin
- Replies: 5
- Views: 399
Re: Electron Configuratin
I would think it is due to the s orbitals having lower energy, but this is a very good question. Now that I think about it I do not understand it either...
- Thu Oct 11, 2018 10:48 pm
- Forum: Properties of Light
- Topic: How light behaves
- Replies: 8
- Views: 522
How light behaves
I cannot conceptualize light being both photon (PACKETS) of energy and wavelengths. I find it difficult to exercise this into equations when I do not understand how it can be both and have one number. Please explain and possibly use equations in your explanation if possible. If not that is okay, any...
- Thu Oct 11, 2018 10:26 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: H-Atom
- Replies: 1
- Views: 144
H-Atom
In the atomic spectra model, the hydrogen atoms are ideally in a vacuum and then there comes a white light going through it. This makes the hydrogen excited and this is where I get foggy. Does the hydrogen become an isotope giving off an electron into the air and then coming back together after the ...
- Thu Oct 11, 2018 10:11 pm
- Forum: Photoelectric Effect
- Topic: Confused conceptually with photoelectric effect
- Replies: 3
- Views: 213
Confused conceptually with photoelectric effect
I do not understand when Lavelle spoke on the length of the wavelength and how it ejects electrons. Please advice since the reading makes it only slightly less confusing. I get how the shorter the wavelength is it will eject more electrons, but I do not understand how. Thank you.
- Wed Oct 03, 2018 11:00 pm
- Forum: Balancing Chemical Reactions
- Topic: Extensive v. Intensive Property [ENDORSED]
- Replies: 6
- Views: 2489
Extensive v. Intensive Property [ENDORSED]
I am not sure I understand the complete difference between Extensive v. Intensive Property. Please send as many examples as possible.
- Wed Oct 03, 2018 10:32 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Question G23
- Replies: 3
- Views: 235
Re: Question G23
For most of the problems in the set, you need to just start by changing the mass to moles. In this problem add to get the total number of moles of ions after and then divide over the volume given. After that you will get the molarity. :)
- Wed Oct 03, 2018 10:24 pm
- Forum: Balancing Chemical Reactions
- Topic: Concept Question for #M15
- Replies: 2
- Views: 230
Concept Question for #M15
When doing stoichiometry (7.55molCl2)*(2mol AlCl3/3mol Cl2) = 5.03 mol AlCl3 -- the limiting reactant I know how to get to the answer, but I am confused conceptually as to why when you already have the mol for AlCl3 and the stoichiometric coefficient being 2.. why do we need to do more towards it to...