mol/Ls zero and first
1/mol/Ls second order
Search found 64 matches
- Fri Mar 08, 2019 12:40 pm
- Forum: General Rate Laws
- Topic: Units for Rate Constants
- Replies: 5
- Views: 556
- Fri Mar 08, 2019 12:37 pm
- Forum: Zero Order Reactions
- Topic: General “order” question
- Replies: 6
- Views: 922
Re: General “order” question
Zero order is time vs concentration
First order is time vs ln concentration
Second order is time vs 1/concentration
First order is time vs ln concentration
Second order is time vs 1/concentration
- Fri Mar 08, 2019 12:35 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Unique Rates
- Replies: 3
- Views: 404
Unique Rates
I’m having trouble understanding what a unique rate is. Can someone clarify please?
- Wed Mar 06, 2019 1:58 pm
- Forum: Second Order Reactions
- Topic: Reaction orders
- Replies: 2
- Views: 343
Re: Reaction orders
You'd have to use the experimental data still because coefficients don't determine order
- Wed Mar 06, 2019 1:56 pm
- Forum: Second Order Reactions
- Topic: graph for second order
- Replies: 7
- Views: 795
graph for second order
How does the graph for second order look? Will it ever be exponential, or only linear?
- Wed Mar 06, 2019 1:54 pm
- Forum: First Order Reactions
- Topic: 1/2 life
- Replies: 7
- Views: 802
1/2 life
Does the 1/2 life for first order depend on the initial concentration like it does for zero and second-order reactions?
- Wed Mar 06, 2019 1:51 pm
- Forum: First Order Reactions
- Topic: First Order Reactions
- Replies: 6
- Views: 603
Re: First Order Reactions
I believe it should be a straight line with decreasing slope
- Wed Mar 06, 2019 1:00 pm
- Forum: Van't Hoff Equation
- Topic: Temp Units
- Replies: 11
- Views: 1353
Re: Temp Units
The units must cancel out. K cancels with the other units, so use K.
- Wed Mar 06, 2019 12:58 pm
- Forum: Van't Hoff Equation
- Topic: test 2
- Replies: 7
- Views: 1133
test 2
There was a problem on test 2 asking whether the compound was acidic or basic using K and the other values given. I'm pretty sure we had to use the Van't Hoff equation as well. Does anyone know how to approach this problem?
- Wed Mar 06, 2019 12:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Class Curve
- Replies: 11
- Views: 1785
Re: Class Curve
I am confused on this as well, but I think 50% is the minimum and it goes in increments of 10-20% for the rest of the letter grades.
- Wed Mar 06, 2019 12:50 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Test 2
- Replies: 7
- Views: 838
Re: Test 2
More negative E for reducing and more positive E for oxidizing I believe
- Tue Feb 19, 2019 10:40 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneity
- Replies: 3
- Views: 598
Re: Spontaneity
deltaG must be negative for a spontaneous reaction, so T deltaS must be a positive term to make sure the number subtracted from deltaH in deltaG=deltaH-TdeltaS has deltaH as a large negative number.
- Tue Feb 19, 2019 10:38 pm
- Forum: Student Social/Study Group
- Topic: Test
- Replies: 17
- Views: 1593
Re: Test
I don't think the test will be cumulative because it will mainly focus on Gibb's Free Energy and electrochem, but Lavelle told me you need to know thermodynamics prior to this for the test.
- Tue Feb 19, 2019 10:36 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Test 2
- Replies: 4
- Views: 623
Re: Test 2
There should be a link on the class website saying what is on the test, but it will cover thermodynamics, mainly in chapter 9 of the outline.
- Tue Feb 12, 2019 11:11 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Equations
- Replies: 5
- Views: 898
Re: Equations
I would focus on connecting the equations to each other because they will all be on the equation sheet. Know the main equation for enthalpy and entropy, then focus on manipulating the variables for each when needed. Basically, focus more on when to use what, not memorizing the formula itself.
- Tue Feb 12, 2019 11:07 pm
- Forum: Calculating Work of Expansion
- Topic: Substituting -nrT for -PΔV
- Replies: 4
- Views: 516
Re: Substituting -nrT for -PΔV
n and r are constant if T changes, but r and T are constant if the system is isothermal (same temperature)
- Tue Feb 12, 2019 11:05 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: R constants
- Replies: 40
- Views: 2265
R constants
How do we know which value of R to use because aren't there two values? I know we usually use 8.3145, but when would we use the other value?
- Tue Feb 12, 2019 10:55 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: C
- Replies: 3
- Views: 333
C
What does C represent in the entropy equation for ln of temperature change?
- Tue Feb 12, 2019 10:53 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: Boltzmann Equation
- Replies: 3
- Views: 697
Boltzmann Equation
When do we use the Boltzmann equation? Do questions specifically ask for it. I've been gone for the past week, so I am lost. Thank you.
- Tue Feb 12, 2019 10:42 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Thermodynamics
- Replies: 1
- Views: 243
Thermodynamics
Do we need to memorize the constants like 3/2, 5/2..etc. for tests?
- Wed Jan 30, 2019 4:46 pm
- Forum: Phase Changes & Related Calculations
- Topic: Water phase change graph
- Replies: 6
- Views: 1488
Re: Water phase change graph
the slanted lines are in their own/same state, while the straight lines represent the phase change (sol->liq->gas)
- Wed Jan 30, 2019 4:43 pm
- Forum: Calculating Work of Expansion
- Topic: reversible & irreversible expansion
- Replies: 2
- Views: 278
Re: reversible & irreversible expansion
The irreversible wouldn't be doing the maximum amount of work because the outside pressure was only 1 atm compared to the inside pressure of 2 atm, so this doesn't represent the work against maximum pressure. On the other hand, the reversible pressure is at equilibrium, so it is expanding against th...
- Wed Jan 30, 2019 4:41 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Thermo Test/Midterm
- Replies: 9
- Views: 786
Re: Thermo Test/Midterm
I don't think so, but I'm not sure. I think you have to know the lewis structures on your own.
- Tue Jan 29, 2019 1:10 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: When to use which method for calculating reaction enthalpies
- Replies: 4
- Views: 411
Re: When to use which method for calculating reaction enthalpies
for 8.9, use 8.206e-2Latm/kmol and 8.314J/kmol then convert to kJ and subtract that answer from kJ given.
- Tue Jan 29, 2019 12:56 am
- Forum: Phase Changes & Related Calculations
- Topic: 6th edition problem
- Replies: 2
- Views: 309
6th edition problem
I'm not understanding how to approach problem 8.3 in the 6th edition textbook. I was sick during this lecture, so I am behind on this section and I'm not understanding how 24J is the answer.
- Tue Jan 29, 2019 12:53 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 7
- Views: 690
Re: Bond Enthalpies
Averages are going to be least exact and inaccurate, which is why bond enthalpies is the least accurate way to measure reaction enthalpies.
- Thu Jan 17, 2019 6:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Conjugate base
- Replies: 7
- Views: 729
Re: Conjugate base
acid+base-->conj. base+ conj. acid. The conjugate base is an anion so that will help you identify it.
- Thu Jan 17, 2019 6:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constants
- Replies: 5
- Views: 384
Re: Equilibrium Constants
Kc is specific to concentration while Kp is for gases and partial pressures. Kc can be used for gaseous mixtures I believe, but it's more likely for Kp to be used.
- Mon Jan 14, 2019 8:18 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 11.27
- Replies: 2
- Views: 106
Re: 11.27
Ok that makes sense, thank you!
- Mon Jan 14, 2019 4:24 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 11.27
- Replies: 2
- Views: 106
11.27
I am confused on how to do 6th edition 11.27 and solving for the partial pressure of PCL3 using the given partial pressures. Can someone help please?
- Wed Jan 09, 2019 3:06 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: "lie to the right" vs "shifted to the right"
- Replies: 6
- Views: 1401
Re: "lie to the right" vs "shifted to the right"
There are more products, meaning that the reaction favors the products since products are on the right.
- Wed Jan 09, 2019 3:04 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: What does it mean when a reaction is at equilibrium?
- Replies: 4
- Views: 448
Re: What does it mean when a reaction is at equilibrium?
Q=K, meaning that the forwards and back reaction rates are equal
- Wed Jan 09, 2019 1:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Favoring Products/Reactants
- Replies: 3
- Views: 416
Re: Favoring Products/Reactants
If q is less than k, the reaction moves towards the products. If q is greater than k, the reaction moves towards the reactants. K is just equilibrium.
- Fri Nov 30, 2018 3:42 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted Acid
- Replies: 2
- Views: 223
Re: Bronsted Acid
A bronzed acid must be the proton donor in the chemical equation. It's dissociation determines the strength of the acid.
- Fri Nov 30, 2018 3:41 pm
- Forum: Lewis Acids & Bases
- Topic: Strength
- Replies: 3
- Views: 358
Re: Strength
Strength is determined by the how readily acid/base dissociates into H+ and OH-.
- Fri Nov 30, 2018 3:39 pm
- Forum: Hybridization
- Topic: 2s or s?
- Replies: 7
- Views: 666
Re: 2s or s?
the number in front represents the period the element is in. S is the orbital.
- Sat Nov 24, 2018 10:59 am
- Forum: Hybridization
- Topic: Writing out Hybridization
- Replies: 8
- Views: 600
Re: Writing out Hybridization
I think Dr. Lavelle said either way is acceptable in lecture because it's whatever you prefer.
- Sat Nov 24, 2018 10:57 am
- Forum: Sigma & Pi Bonds
- Topic: Sigma and Pi Bonds
- Replies: 2
- Views: 168
Re: Sigma and Pi Bonds
A sigma bond is a single bond, a double bond is a sigma and pi, a triple is a sigma and 2 pi. Single is the longest, double is medium-length, and triple is the shortest.
- Sat Nov 24, 2018 10:53 am
- Forum: Hybridization
- Topic: hybridization
- Replies: 1
- Views: 203
Re: hybridization
X is the bonds formed and E is the lone pairs
- Wed Nov 14, 2018 9:23 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Strengths
- Replies: 5
- Views: 441
Re: Bond Strengths
I think it's because the electrostatic forces hold ionic bonds together tightly and because they are between metal and nonmetal, while hydrogen bonds consist of hydrogen and an element of a higher electronegativity. Ionic bonds are when electrons are transferred from one element to the other. Hydrog...
- Wed Nov 14, 2018 9:07 pm
- Forum: Lewis Structures
- Topic: Boron Trifluoride
- Replies: 8
- Views: 831
Re: Boron Trifluoride
B, Be, Li, H all exceptions to octet rule because they don't complete valence shell
- Wed Nov 14, 2018 9:06 pm
- Forum: Lewis Structures
- Topic: Expanded Octets
- Replies: 9
- Views: 2840
Re: Expanded Octets
Atoms that can hold electrons in the d-orbital (P3 and below)
- Wed Nov 14, 2018 8:56 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: How are polarity and polarizability different?
- Replies: 3
- Views: 2481
Re: How are polarity and polarizability different?
Polarity: Charge distribution causing polar or nonpolar molecules due to differences in electronegativity
Polarizability: How easily an electron cloud can be distorted
Polarizability: How easily an electron cloud can be distorted
- Wed Nov 14, 2018 8:46 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability
- Replies: 4
- Views: 471
Re: Polarizability
Polarizability is how easy it is to cause distortion to an electron cloud. Anions are highly polarizable because they have more electrons/are larger. Cations are small/less electrons and have high polarizing power, but low polarizability.
- Wed Nov 14, 2018 8:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 8
- Views: 1426
Re: Bond Angles
You just have to know the bond angles from VSEPR, and Dr. Lavelle was saying 360/# of bonds, but that doesn't always work.
- Wed Nov 14, 2018 8:29 pm
- Forum: Lewis Structures
- Topic: Formal Charge
- Replies: 14
- Views: 1317
Re: Formal Charge
Just try to get formal charges to equal zero or match the charge that the molecule is supposed to have.
- Wed Nov 14, 2018 8:26 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Grades
- Replies: 7
- Views: 892
Re: Grades
I believe so because it doesn't specify that you need 50% on any one assignment category, so it would be 250/500 in the course.
- Wed Nov 14, 2018 8:22 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape
- Replies: 6
- Views: 649
Re: Molecular Shape
Lone pairs on the Iodine lead to repulsion making it t-shaped
- Mon Nov 12, 2018 12:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 4.11 6th Edition
- Replies: 1
- Views: 372
Re: 4.11 6th Edition
Trigonal bipyramidal, trigonal bipyramidal, octahedral/square planar, trigonal pyramidal
- Fri Nov 02, 2018 8:45 pm
- Forum: Resonance Structures
- Topic: Determine Number of Resonance Structures
- Replies: 2
- Views: 1628
Re: Determine Number of Resonance Structures
Count the valence electrons you can have for the molecule, determine how many you've used. If you used too many, you create a double/triple bond and it can be on either side of the central element between the other elements that are the same as each other (ex. NO2) (resonance structures). The amount...
- Fri Nov 02, 2018 8:37 pm
- Forum: Trends in The Periodic Table
- Topic: Oxidation Number
- Replies: 1
- Views: 206
Re: Oxidation Number
You determine the valence electrons it needs to lose or gain to reach an octet.
- Fri Nov 02, 2018 8:36 pm
- Forum: Ionic & Covalent Bonds
- Topic: 3.23 6th Edition
- Replies: 3
- Views: 287
Re: 3.23 6th Edition
You have to lose 7 (+7) to reach an octet or gain 1(-1) to reach an octet (electrons).
- Sat Oct 27, 2018 9:14 am
- Forum: Student Social/Study Group
- Topic: Studying
- Replies: 7
- Views: 793
Re: Studying
I would go to the review session talked about in beginning of lecture on Friday/look up the “garlic bread” review topic because it has mock midterm problems. It seems very useful and the review session date should be posted on there soon. https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=157&t...
- Sat Oct 27, 2018 9:13 am
- Forum: Trends in The Periodic Table
- Topic: electron affinity 1F.11
- Replies: 3
- Views: 783
Re: electron affinity 1F.11
Sulfur has higher electron affinity because oxygen electrons experience more repulsion between each other, since the valence shell is held closer to the nucleus. The repulsion causes more energy to be consumed when an electron is introduced than with sulfur due to the repulsion of electrons being im...
- Sat Oct 27, 2018 8:58 am
- Forum: Ionic & Covalent Bonds
- Topic: Ground State
- Replies: 6
- Views: 780
Re: Ground State
Ground state would be the lowest energy state of the atom. So the electron configuration has to show the lowest energy state.
- Mon Oct 22, 2018 12:29 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Coulomb's Law and Effective Nuclear Charge on test
- Replies: 2
- Views: 228
Re: Coulomb's Law and Effective Nuclear Charge on test
I would know these just because we had practice problems on these topics in lecture and in the text. It's better to have a basic understanding.
- Mon Oct 22, 2018 12:27 am
- Forum: *Particle in a Box
- Topic: Midterm
- Replies: 17
- Views: 4262
Re: Midterm
The midterm from last year is also on ccle :)
- Mon Oct 22, 2018 12:26 am
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 2
- Views: 1726
Re: Electron Affinity
If something has a high electron affinity, it means it has a higher ability to attract other electrons. This will in turn make the bond stronger because of the greater pull.
- Mon Oct 22, 2018 12:23 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Wave Functions
- Replies: 4
- Views: 403
Re: Wave Functions
px, py, and pz correlate to the ml=-1,0,+1. px and pz can be either -1 or +1, but pt must be the middle number for the list of ml values is what I understood.
- Mon Oct 22, 2018 12:19 am
- Forum: Einstein Equation
- Topic: Units
- Replies: 17
- Views: 1770
Re: Units
Joule is kgm^2/s^2, but multiplying my 1/s cancels one of the s units, making kgm^2/s
- Mon Oct 22, 2018 12:16 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg equation
- Replies: 2
- Views: 323
Re: Heisenberg equation
h bar is h/2pi, but in uncertainty problems you use deltap*deltax is greater than or equal to h/4pi
- Thu Oct 04, 2018 8:38 pm
- Forum: Significant Figures
- Topic: Significant figures for molar mass
- Replies: 7
- Views: 5299
Re: Significant figures for molar mass
You should definitely use the most accurate molar mass given. I wouldn't worry about sigfigs until the end. Either way with rounding, your answer won't be too far off from the answer you should have, but it is more accurate to use the most digits given on your periodic table for molar mass. It's bes...
- Thu Oct 04, 2018 8:33 pm
- Forum: Significant Figures
- Topic: Determining Sig Figs
- Replies: 6
- Views: 456
Re: Determining Sig Figs
Sigfigs should always match the lowest significant number given in the problem. For example, if a problem has 3.2+4.88=?, your answer should be rounded to two sigfigs.
- Thu Oct 04, 2018 8:28 pm
- Forum: Significant Figures
- Topic: Regarding the Homework
- Replies: 2
- Views: 203
Re: Regarding the Homework
I would personally try to match the sigfigs given in the problem, but you can use however many sigfigs between calculations. Just round at the end :).