Search found 60 matches

by Charles Gu 1D
Sat Mar 16, 2019 8:12 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Lyndon #16
Replies: 1
Views: 34

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.
by Charles Gu 1D
Sat Mar 16, 2019 8:11 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: lnA
Replies: 2
Views: 49

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.
by Charles Gu 1D
Sat Mar 16, 2019 8:09 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Collision model
Replies: 3
Views: 46

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...
by Charles Gu 1D
Sat Mar 09, 2019 10:17 pm
Forum: First Order Reactions
Topic: Possiility
Replies: 2
Views: 46

Re: Possiility

It's possible if 2 of the reactants are in zero order and one of them is in first order.
by Charles Gu 1D
Sat Mar 09, 2019 10:10 pm
Forum: Second Order Reactions
Topic: Final
Replies: 30
Views: 430

Re: Final

The final will be cumulative and cover everything from weeks 1-10.
by Charles Gu 1D
Sat Mar 09, 2019 10:04 pm
Forum: Second Order Reactions
Topic: Determining the Order of a Reaction
Replies: 3
Views: 47

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
by Charles Gu 1D
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: 199

Re: E˚ vs E

E˚ is under standard conditions such as 1 atm and 298 K while E is under any other condition.
by Charles Gu 1D
Sat Mar 02, 2019 7:06 pm
Forum: Ideal Gases
Topic: pV=nRT
Replies: 12
Views: 269

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.
by Charles Gu 1D
Sat Mar 02, 2019 7:05 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: finding DeltaG
Replies: 6
Views: 92

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
by Charles Gu 1D
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: 38

Re: Gibbs Free Energy for Molecules in their Natural States

Elements in their natural state have 0 Gibbs free energy.
by Charles Gu 1D
Sat Feb 23, 2019 7:29 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Homework
Replies: 3
Views: 56

Re: Homework

Yes, due to your Discussion section. Same as always
by Charles Gu 1D
Sat Feb 23, 2019 7:11 pm
Forum: Balancing Redox Reactions
Topic: Standard Cell Potential
Replies: 3
Views: 49

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.
by Charles Gu 1D
Sat Feb 16, 2019 11:59 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 3rd Law of Thermodynamics
Replies: 2
Views: 69

Re: 3rd Law of Thermodynamics

Entropy units are usually J/k
by Charles Gu 1D
Sat Feb 16, 2019 11:57 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Heating Curve
Replies: 3
Views: 81

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.
by Charles Gu 1D
Sat Feb 16, 2019 11:32 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Signs for entropy
Replies: 5
Views: 93

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
by Charles Gu 1D
Fri Feb 08, 2019 8:08 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Energy
Replies: 5
Views: 105

Re: Energy

An isolated system does not allow matter or energy to be exchanged so it will be at equilibrium.
by Charles Gu 1D
Fri Feb 08, 2019 8:05 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Thermos
Replies: 4
Views: 70

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.
by Charles Gu 1D
Fri Feb 08, 2019 8:02 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Midterm [ENDORSED]
Replies: 48
Views: 976

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.
by Charles Gu 1D
Fri Feb 01, 2019 11:26 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Enthalpy
Replies: 6
Views: 75

Re: Enthalpy

In order to break bonds, you need a input of heat so thats why delta h is positive (endothermic)
by Charles Gu 1D
Fri Feb 01, 2019 11:07 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Extensive
Replies: 4
Views: 77

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
by Charles Gu 1D
Fri Feb 01, 2019 10:56 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Surroundings
Replies: 11
Views: 124

Re: Surroundings

Surroundings can be broad as the universe or limited to a container
by Charles Gu 1D
Thu Jan 24, 2019 6:42 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Le Chateliers Priniciple
Replies: 9
Views: 199

Re: Le Chateliers Priniciple

Decreasing volume means an increase in pressure which would shift to the side with less moles of gas.
by Charles Gu 1D
Thu Jan 24, 2019 6:41 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure
Replies: 7
Views: 110

Re: Pressure

Just look at gases when dealing with pressure.
by Charles Gu 1D
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: 156

Re: Test 1

The quadratic formula will also be given.
by Charles Gu 1D
Thu Jan 17, 2019 5:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Conjugate base
Replies: 7
Views: 98

Re: Conjugate base

If an acid is strong, the conjugate base will be weak and vice versa.
by Charles Gu 1D
Thu Jan 17, 2019 5:53 pm
Forum: Ideal Gases
Topic: Reaction Quotient
Replies: 6
Views: 92

Re: Reaction Quotient

Since solids and liquids concentrations will not change, they will be eventually canceled out. Therefore, they are not included.
by Charles Gu 1D
Thu Jan 17, 2019 5:43 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: K and Q [ENDORSED]
Replies: 7
Views: 106

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
by Charles Gu 1D
Wed Jan 09, 2019 3:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Gibbs Free Energy
Replies: 4
Views: 102

Re: Gibbs Free Energy

Dr. Lavelle has not covered thermodynamics yet so right now just focus on equilibrium
by Charles Gu 1D
Wed Jan 09, 2019 3:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Initial Concentration
Replies: 3
Views: 37

Re: Initial Concentration

yes you can assume that
by Charles Gu 1D
Fri Dec 07, 2018 11:40 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 39

Re: Polydentate

If there are multiple polydentates, make sure to use bis(2), tris(3), etc.
by Charles Gu 1D
Fri Dec 07, 2018 11:38 am
Forum: Naming
Topic: Naming Coordination Compounds
Replies: 3
Views: 77

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.
by Charles Gu 1D
Fri Dec 07, 2018 11:21 am
Forum: Naming
Topic: cyano vs cyanido
Replies: 3
Views: 58

Re: cyano vs cyanido

During my Discussion, my TA (Ben) said that either would be acceptable.
by Charles Gu 1D
Sat Dec 01, 2018 9:29 pm
Forum: Naming
Topic: Oxidation State
Replies: 4
Views: 58

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.
by Charles Gu 1D
Sat Dec 01, 2018 9:28 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: oxidation numbers for ligands
Replies: 2
Views: 53

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.
by Charles Gu 1D
Sat Dec 01, 2018 9:26 pm
Forum: Naming
Topic: With Respect to the Final
Replies: 9
Views: 172

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
by Charles Gu 1D
Sat Nov 24, 2018 10:47 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 3
Replies: 10
Views: 215

Re: Test 3

A little bit from outline 3, but all of outline 4 so make sure to study them.
by Charles Gu 1D
Sat Nov 24, 2018 10:46 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Position of atoms in Trigonal Planar
Replies: 4
Views: 60

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.
by Charles Gu 1D
Sat Nov 24, 2018 10:42 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing Structures on Test
Replies: 11
Views: 160

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;
by Charles Gu 1D
Sat Nov 17, 2018 6:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 16
Views: 215

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.
by Charles Gu 1D
Sat Nov 17, 2018 6:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 3
Replies: 19
Views: 317

Re: Test 3

You should memorize it. Doing the practice problems in the book will help you memorize them.
by Charles Gu 1D
Sat Nov 17, 2018 6:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.29
Replies: 2
Views: 42

Re: 2E.29

You should draw the lewis structures to get a better understanding of what you are looking for.
by Charles Gu 1D
Thu Nov 08, 2018 9:42 pm
Forum: Lewis Structures
Topic: Formal charges
Replies: 15
Views: 204

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.
by Charles Gu 1D
Thu Nov 08, 2018 9:38 pm
Forum: Lewis Structures
Topic: Placement of Elements?
Replies: 5
Views: 91

Re: Placement of Elements?

We haven't learned the structures yet, but placement will matter soon.
by Charles Gu 1D
Thu Nov 08, 2018 9:35 pm
Forum: Ionic & Covalent Bonds
Topic: Strength of Bonds?
Replies: 5
Views: 149

Re: Strength of Bonds?

Ionic bonds have oppositely charged ions that create a coulombic attraction while covalent bonds only share electrons
by Charles Gu 1D
Thu Nov 01, 2018 11:27 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal CHarge
Replies: 5
Views: 136

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.
by Charles Gu 1D
Thu Nov 01, 2018 11:24 am
Forum: Resonance Structures
Topic: Resonance
Replies: 8
Views: 188

Re: Resonance

A double bond is stronger than a single bond but single bonds are longer than double bonds.
by Charles Gu 1D
Thu Nov 01, 2018 11:23 am
Forum: Ionic & Covalent Bonds
Topic: Removing the second electron
Replies: 8
Views: 123

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.
by Charles Gu 1D
Fri Oct 26, 2018 11:42 am
Forum: Photoelectric Effect
Topic: Test 2
Replies: 16
Views: 368

Re: Test 2

Test 2 will only go up to what was covered on last Friday which was the quantum numbers.
by Charles Gu 1D
Fri Oct 26, 2018 11:35 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Value of Delta X
Replies: 8
Views: 237

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.
by Charles Gu 1D
Fri Oct 26, 2018 11:25 am
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 6
Views: 136

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.
by Charles Gu 1D
Thu Oct 18, 2018 2:59 pm
Forum: Einstein Equation
Topic: Photons and E=hv
Replies: 5
Views: 299

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
by Charles Gu 1D
Thu Oct 18, 2018 2:54 pm
Forum: Properties of Light
Topic: Tip for frequency equation
Replies: 4
Views: 90

Re: Tip for frequency equation

Thank you! I was always confused with the order of the equation.
by Charles Gu 1D
Thu Oct 18, 2018 2:51 pm
Forum: Properties of Light
Topic: Test 2 [ENDORSED]
Replies: 15
Views: 262

Re: Test 2 [ENDORSED]

Everything that is listed for Quantum World on the syllabus will be tested.
by Charles Gu 1D
Tue Oct 09, 2018 2:37 pm
Forum: Empirical & Molecular Formulas
Topic: Polyatomic Ions and Naming
Replies: 3
Views: 243

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.
by Charles Gu 1D
Tue Oct 09, 2018 2:31 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question G13 (Sixth Edition)
Replies: 3
Views: 166

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...
by Charles Gu 1D
Tue Oct 09, 2018 2:25 pm
Forum: Limiting Reactant Calculations
Topic: Test 1 Question
Replies: 5
Views: 212

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.
by Charles Gu 1D
Wed Oct 03, 2018 11:21 pm
Forum: Significant Figures
Topic: Sig Figs... when to round?
Replies: 7
Views: 137

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.
by Charles Gu 1D
Wed Oct 03, 2018 11:19 pm
Forum: Significant Figures
Topic: Rounding off/sig figs during steps of a calculation
Replies: 4
Views: 86

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.
by Charles Gu 1D
Tue Oct 02, 2018 12:03 am
Forum: Balancing Chemical Reactions
Topic: States of Atoms
Replies: 7
Views: 118

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.

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