Search found 60 matches
- Sat Mar 16, 2019 8:12 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Lyndon #16
- Replies: 1
- Views: 245
Re: Lyndon #16
The Arrhenius equation is usually k=Ae^(-Ea/RT). If you ln both sides you would get lnk=lnA- Ea/RT. This allows you to figure out the graph since it is in y=mx+b form. 1/T would be the x axis, lnk would be the y axis, and m would be -Ea/R. Therefore, it would be a straight line with a negative slope.
- Sat Mar 16, 2019 8:11 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: lnA
- Replies: 2
- Views: 335
Re: lnA
The Arrhenius equation is usually k=Ae^(-Ea/RT). If you ln both sides you would get lnk=lnA- Ea/RT. This allows you to get a better view of the graph since it is in y=mx+b form. 1/T would be the x axis, lnk would be the y axis, and m would be -Ea/R.
- Sat Mar 16, 2019 8:09 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Collision model
- Replies: 3
- Views: 344
Re: Collision model
If you are referring to Lyndon's packet, he is referring to the number of molecules that need to collide at a certain orientation and activation energy based on the order of the reaction. If the reaction was 3rd order then that would mean 3 molecules would have to collide in a certain orientation an...
- Sat Mar 09, 2019 10:17 pm
- Forum: First Order Reactions
- Topic: Possiility
- Replies: 2
- Views: 318
Re: Possiility
It's possible if 2 of the reactants are in zero order and one of them is in first order.
- Sat Mar 09, 2019 10:10 pm
- Forum: Second Order Reactions
- Topic: Final
- Replies: 32
- Views: 2423
Re: Final
The final will be cumulative and cover everything from weeks 1-10.
- Sat Mar 09, 2019 10:04 pm
- Forum: Second Order Reactions
- Topic: Determining the Order of a Reaction
- Replies: 3
- Views: 478
Re: Determining the Order of a Reaction
The overall order of the reaction can be found by adding all of the exponential factors of each reactant. For example, if Rate=k[H][C], then it would be a second order reaction since each reactant only has a 1 in their exponent
- Sat Mar 02, 2019 7:09 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: E˚ vs E
- Replies: 13
- Views: 15677
Re: E˚ vs E
E˚ is under standard conditions such as 1 atm and 298 K while E is under any other condition.
- Sat Mar 02, 2019 7:06 pm
- Forum: Ideal Gases
- Topic: pV=nRT
- Replies: 12
- Views: 2125
Re: pV=nRT
PV=NRT is a very versatile equation. You can use it for questions that want you to find a missing variable in the equation after plugging everything in.
- Sat Mar 02, 2019 7:05 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: finding DeltaG
- Replies: 6
- Views: 672
Re: finding DeltaG
Delta G can be found in many ways. Its just depends on what the question gives you. For example if it gave the delta H, delta S, and Temperature, you would use Delta G= DeltaH- TDeltaS
- Sat Feb 23, 2019 7:36 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free Energy for Molecules in their Natural States
- Replies: 1
- Views: 238
Re: Gibbs Free Energy for Molecules in their Natural States
Elements in their natural state have 0 Gibbs free energy.
- Sat Feb 23, 2019 7:29 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Homework
- Replies: 3
- Views: 386
Re: Homework
Yes, due to your Discussion section. Same as always
- Sat Feb 23, 2019 7:11 pm
- Forum: Balancing Redox Reactions
- Topic: Standard Cell Potential
- Replies: 3
- Views: 404
Re: Standard Cell Potential
He said that it's better to do it the other way since it provides a better understanding of what's going on. Also, it's less confusing.
- Sat Feb 16, 2019 11:59 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 3rd Law of Thermodynamics
- Replies: 2
- Views: 291
Re: 3rd Law of Thermodynamics
Entropy units are usually J/k
- Sat Feb 16, 2019 11:57 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Heating Curve
- Replies: 3
- Views: 576
Re: Heating Curve
you would need to add the phase change and then the how much entropy it took to raise the temperature. so Delta s = q/t + Delta s= nCln(T2/T1). Don't forget to change temperature to kelvin.
- Sat Feb 16, 2019 11:32 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Signs for entropy
- Replies: 5
- Views: 494
Re: Signs for entropy
A positive delta H is for endothermic reactions which will absorb heat and also increase entropy. A negative Delta h is for exothermic reactions which will entropy to decrease since heat is released
- Fri Feb 08, 2019 8:08 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Energy
- Replies: 5
- Views: 762
Re: Energy
An isolated system does not allow matter or energy to be exchanged so it will be at equilibrium.
- Fri Feb 08, 2019 8:05 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Thermos
- Replies: 4
- Views: 550
Re: Thermos
Closed systems allow energy to be exchanged with the surroundings. A thermos, therefore, keeps the liquid inside from interacting with its surroundings and does not allow matter to escape either so it is isolated.
- Fri Feb 08, 2019 8:02 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Midterm [ENDORSED]
- Replies: 49
- Views: 4917
Re: Midterm [ENDORSED]
I recommend doing all the homework problems, review the problems that your TA went over, and go over your notes. Also, review session are an amazing way of covering all topics in a short period of time.
- Fri Feb 01, 2019 11:26 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Enthalpy
- Replies: 6
- Views: 584
Re: Enthalpy
In order to break bonds, you need a input of heat so thats why delta h is positive (endothermic)
- Fri Feb 01, 2019 11:07 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Extensive
- Replies: 4
- Views: 456
Re: Extensive
Enthalpy, Volume, Temperature, Pressure are all state properties since it doesn't matter how the substance was prepared while extensive properties focus on how much matter there is
- Fri Feb 01, 2019 10:56 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Surroundings
- Replies: 11
- Views: 949
Re: Surroundings
Surroundings can be broad as the universe or limited to a container
- Thu Jan 24, 2019 6:42 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Le Chateliers Priniciple
- Replies: 9
- Views: 938
Re: Le Chateliers Priniciple
Decreasing volume means an increase in pressure which would shift to the side with less moles of gas.
- Thu Jan 24, 2019 6:41 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure
- Replies: 7
- Views: 674
Re: Pressure
Just look at gases when dealing with pressure.
- Thu Jan 24, 2019 6:39 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Test 1
- Replies: 9
- Views: 778
Re: Test 1
The quadratic formula will also be given.
- Thu Jan 17, 2019 5:54 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Conjugate base
- Replies: 7
- Views: 729
Re: Conjugate base
If an acid is strong, the conjugate base will be weak and vice versa.
- Thu Jan 17, 2019 5:53 pm
- Forum: Ideal Gases
- Topic: Reaction Quotient
- Replies: 6
- Views: 429
Re: Reaction Quotient
Since solids and liquids concentrations will not change, they will be eventually canceled out. Therefore, they are not included.
- Thu Jan 17, 2019 5:43 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: K and Q [ENDORSED]
- Replies: 7
- Views: 698
Re: K and Q [ENDORSED]
If Q, the reaction quotient, is greater than K, then the reaction will favor the reactants but if Q is smaller than K than the reaction will favor the products
- Wed Jan 09, 2019 3:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Partial Pressure of Gas
- Replies: 1
- Views: 87
Re: Equilibrium Partial Pressure of Gas
The units cancel out
- Wed Jan 09, 2019 3:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Gibbs Free Energy
- Replies: 4
- Views: 438
Re: Gibbs Free Energy
Dr. Lavelle has not covered thermodynamics yet so right now just focus on equilibrium
- Wed Jan 09, 2019 3:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Initial Concentration
- Replies: 3
- Views: 299
Re: Initial Concentration
yes you can assume that
- Fri Dec 07, 2018 11:40 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate
- Replies: 3
- Views: 195
Re: Polydentate
If there are multiple polydentates, make sure to use bis(2), tris(3), etc.
- Fri Dec 07, 2018 11:38 am
- Forum: Naming
- Topic: Naming Coordination Compounds
- Replies: 3
- Views: 388
Re: Naming Coordination Compounds
The best way to memorize them is to just do practice problems and you will start getting used to eat transition metal.
- Fri Dec 07, 2018 11:21 am
- Forum: Naming
- Topic: cyano vs cyanido
- Replies: 3
- Views: 446
Re: cyano vs cyanido
During my Discussion, my TA (Ben) said that either would be acceptable.
- Sat Dec 01, 2018 9:29 pm
- Forum: Naming
- Topic: Oxidation State
- Replies: 4
- Views: 355
Re: Oxidation State
You have the to know the oxidation numbers of most of the molecule and match the total charge of the molecule in the end.
- Sat Dec 01, 2018 9:28 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: oxidation numbers for ligands
- Replies: 2
- Views: 397
Re: oxidation numbers for ligands
In order to find oxidation numbers you have know the oxidation numbers of at least most of the molecule and then match the charge of the molecule.
- Sat Dec 01, 2018 9:26 pm
- Forum: Naming
- Topic: With Respect to the Final
- Replies: 9
- Views: 985
Re: With Respect to the Final
You should probably be familiar with both for the final. I'm not too sure what it would entail, but try practicing both
- Sat Nov 24, 2018 10:47 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 3
- Replies: 10
- Views: 1034
Re: Test 3
A little bit from outline 3, but all of outline 4 so make sure to study them.
- Sat Nov 24, 2018 10:46 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Position of atoms in Trigonal Planar
- Replies: 4
- Views: 403
Re: Position of atoms in Trigonal Planar
The orientation of a shape doesn't really matter on the test since Professor Lavelle doesn't expect us to draw the shape. He only wants to know the Lewis structures of molecules and find the shape from that.
- Sat Nov 24, 2018 10:42 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Drawing Structures on Test
- Replies: 11
- Views: 994
Re: Drawing Structures on Test
Professor Lavelle said we only need to draw the lewis structures and identify the shape. We would never need to draw the shape;
- Sat Nov 17, 2018 6:46 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 16
- Views: 1228
Re: Bond Angles
You just need to memorize them. There are a lot of good practice problems that help you memorize the angles in the book.
- Sat Nov 17, 2018 6:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 3
- Replies: 19
- Views: 1394
Re: Test 3
You should memorize it. Doing the practice problems in the book will help you memorize them.
- Sat Nov 17, 2018 6:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E.29
- Replies: 2
- Views: 259
Re: 2E.29
You should draw the lewis structures to get a better understanding of what you are looking for.
- Thu Nov 08, 2018 9:42 pm
- Forum: Lewis Structures
- Topic: Formal charges
- Replies: 15
- Views: 1303
Re: Formal charges
No you don't need to write formal charges, but it'll help you determine whether or not there is a resonance of a more stable structure.
- Thu Nov 08, 2018 9:38 pm
- Forum: Lewis Structures
- Topic: Placement of Elements?
- Replies: 5
- Views: 606
Re: Placement of Elements?
We haven't learned the structures yet, but placement will matter soon.
- Thu Nov 08, 2018 9:35 pm
- Forum: Ionic & Covalent Bonds
- Topic: Strength of Bonds?
- Replies: 5
- Views: 680
Re: Strength of Bonds?
Ionic bonds have oppositely charged ions that create a coulombic attraction while covalent bonds only share electrons
- Thu Nov 01, 2018 11:27 am
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal CHarge
- Replies: 5
- Views: 500
Re: Formal CHarge
Each atom has its own formal charge. You will need to to check the formal charge of each of them in order to find the stability of the whole molecule.
- Thu Nov 01, 2018 11:24 am
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 8
- Views: 978
Re: Resonance
A double bond is stronger than a single bond but single bonds are longer than double bonds.
- Thu Nov 01, 2018 11:23 am
- Forum: Ionic & Covalent Bonds
- Topic: Removing the second electron
- Replies: 8
- Views: 691
Re: Removing the second electron
Since there are fewer electrons in the outer shell, each electron has a stronger attractive force. This causes it to be harder to remove.
- Fri Oct 26, 2018 11:42 am
- Forum: Photoelectric Effect
- Topic: Test 2
- Replies: 16
- Views: 1183
Re: Test 2
Test 2 will only go up to what was covered on last Friday which was the quantum numbers.
- Fri Oct 26, 2018 11:35 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Value of Delta X
- Replies: 9
- Views: 1098
Re: Value of Delta X
Delta X is usually the diameter in meters. If it is given in radius you should use that in meters.
- Fri Oct 26, 2018 11:25 am
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy
- Replies: 6
- Views: 1725
Re: Ionization Energy
Sulfur has less ionization energy than oxygen since its valence electrons are at a higher orbital and since the distance is farther, it would be easier to remove an electron due to shielding.
- Thu Oct 18, 2018 2:59 pm
- Forum: Einstein Equation
- Topic: Photons and E=hv
- Replies: 5
- Views: 879
Re: Photons and E=hv
You have to multiply it by Avogadro's number which is 6.022 x 10^23. This will give you the number of photons
- Thu Oct 18, 2018 2:54 pm
- Forum: Properties of Light
- Topic: Tip for frequency equation
- Replies: 4
- Views: 381
Re: Tip for frequency equation
Thank you! I was always confused with the order of the equation.
- Thu Oct 18, 2018 2:51 pm
- Forum: Properties of Light
- Topic: Test 2 [ENDORSED]
- Replies: 15
- Views: 1268
Re: Test 2 [ENDORSED]
Everything that is listed for Quantum World on the syllabus will be tested.
- Tue Oct 09, 2018 2:37 pm
- Forum: Empirical & Molecular Formulas
- Topic: Polyatomic Ions and Naming
- Replies: 3
- Views: 738
Re: Polyatomic Ions and Naming
You will get better throughout the year as you do more problems, so need to stress about it too much. You always can search up common ions to memorize if you are feeling worried.
- Tue Oct 09, 2018 2:31 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Question G13 (Sixth Edition)
- Replies: 3
- Views: 424
Re: Question G13 (Sixth Edition)
You first have to use the M1V1= M2V2 equation in order to get M2. After calculating for M2 (Molarity of NH4NO3), multiply that by 0.1 L (100 ml, given in the problem) in order to get the moles of NH4NO3. Since there are 2 moles of N for every 1 mol of NH4NO3, multiply the mols of NH4NO3 by 2 and you...
- Tue Oct 09, 2018 2:25 pm
- Forum: Limiting Reactant Calculations
- Topic: Test 1 Question
- Replies: 5
- Views: 681
Re: Test 1 Question
Don't forget about the modules on Professor Lavelle's website. Also, my TA said the test will be around 8 questions with subsections.
- Wed Oct 03, 2018 11:21 pm
- Forum: Significant Figures
- Topic: Sig Figs... when to round?
- Replies: 7
- Views: 885
Re: Sig Figs... when to round?
I think you should maintain your rounding to the lowest number of sig figs that is given in the problem. For example, if the problem says there are 5.43 grams of Carbon and that is the lowest number of sig figs given in the problem, then your calculations should have 3 sig figs too.
- Wed Oct 03, 2018 11:19 pm
- Forum: Significant Figures
- Topic: Rounding off/sig figs during steps of a calculation
- Replies: 4
- Views: 415
Re: Rounding off/sig figs during steps of a calculation
You should probably round off to the lowest number sig figs that is given in the problem. So if the problem says that there is 4.56 grams of carbon, you should round off to 3 sig figs.
- Tue Oct 02, 2018 12:03 am
- Forum: Balancing Chemical Reactions
- Topic: States of Atoms
- Replies: 7
- Views: 503
Re: States of Atoms
You probably should make an educated guess so that if you are wrong you can learn from your mistakes. Someone asked today in class if we needed to memorize the states of molecules and Dr. Lavelle said that as the year goes on, we will be more familiar with them.