Search found 51 matches

by Wayland Leung
Tue Mar 13, 2018 5:04 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalyst vs Intermedaite
Replies: 3
Views: 181

Re: Catalyst vs Intermedaite

Do we put catalysts in the overall rate law or do we leave them out just like we leave intermediates out of the rate law?
by Wayland Leung
Tue Mar 13, 2018 5:03 pm
Forum: First Order Reactions
Topic: Slope of 1st order RXNs
Replies: 9
Views: 428

Re: Slope of 1st order RXNs

The slope would be -k because the amount of reactants is decreasing over time.
by Wayland Leung
Tue Mar 13, 2018 5:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Organic Chem on Final
Replies: 9
Views: 525

Re: Organic Chem on Final

So we would need to know all the functional groups and their line diagrams and how to draw them?
by Wayland Leung
Thu Mar 08, 2018 12:45 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7569
Views: 1011787

Re: Post All Chemistry Jokes Here

:)
by Wayland Leung
Wed Mar 07, 2018 9:47 pm
Forum: General Rate Laws
Topic: Order of reactants [ENDORSED]
Replies: 1
Views: 110

Order of reactants [ENDORSED]

What is useful about knowing the order of the reactants?
by Wayland Leung
Wed Mar 07, 2018 9:25 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Rate Constant K
Replies: 3
Views: 259

Rate Constant K

What are the things that affect the rate constant,k?
by Wayland Leung
Wed Mar 07, 2018 9:24 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Finding the intermediate(s)
Replies: 5
Views: 172

Re: Finding the intermediate(s)

Why do we not include any intermediates in the overall rate law when the intermediates are a part of the slow step?
by Wayland Leung
Tue Feb 27, 2018 11:27 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Units of Reaction Rate
Replies: 7
Views: 303

Re: Units of Reaction Rate

Are there any constants we need to use in this unit?
by Wayland Leung
Tue Feb 27, 2018 11:26 pm
Forum: General Rate Laws
Topic: Will we ever deal with third order reactions?
Replies: 2
Views: 104

Re: Will we ever deal with third order reactions?

I remember lavelle saying we won't need to focus in them because they rarely happen. Only 1st and 2nd and 0th
by Wayland Leung
Tue Feb 27, 2018 11:21 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: What is the order of the reaction? [ENDORSED]
Replies: 4
Views: 186

What is the order of the reaction? [ENDORSED]

What does the "order" of a reaction mean? What is the difference between a first, second, third, or zeroth order reaction?
by Wayland Leung
Mon Feb 19, 2018 7:03 pm
Forum: Balancing Redox Reactions
Topic: Oxidation Numbers
Replies: 6
Views: 253

Re: Oxidation Numbers

Yea O2 has oxidation number of 2- for each oxygen.
by Wayland Leung
Mon Feb 19, 2018 7:02 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.13 c
Replies: 2
Views: 93

Re: 14.13 c

Platinum is added when there is no metal or electrode, it is used because it is chemically inert and rarely reacts. The Cl(aq) is separated because there is a phase change between it and Cl2(g).
by Wayland Leung
Mon Feb 19, 2018 6:58 pm
Forum: Balancing Redox Reactions
Topic: Balanced Redox Reactions
Replies: 2
Views: 122

Re: Balanced Redox Reactions

The water is added to balance out the H+ or H3O+ ions in the reaction. It doesn't matter which side you add water. Water is added to balance out the hydrogens in the reaction. Water is there only for an acidic solution and an aqueous solution.
by Wayland Leung
Tue Feb 13, 2018 5:45 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible
Replies: 4
Views: 197

Re: Reversible

When a system is reversible, it can be implied that the system is at equilibrium so yes the deltaS of the system would equal the negative deltaS of the surroundings.
by Wayland Leung
Tue Feb 13, 2018 5:44 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: What does n represent?
Replies: 2
Views: 163

Re: What does n represent?

n represents the number of moles in the problem. If we are given the mass in grams, we would convert to moles by dividing by the molar mass.
by Wayland Leung
Tue Feb 13, 2018 5:43 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Practice Test, Question 3A
Replies: 2
Views: 106

Re: Practice Test, Question 3A

We would take the given amount of grams and divide by the molar mass of each element to obtain the number of moles of each element then plug it into the equation.
by Wayland Leung
Mon Feb 05, 2018 11:28 pm
Forum: Balancing Redox Reactions
Topic: acronym for reduction
Replies: 5
Views: 276

Re: acronym for reduction

OIL RIG is a good one to memorize the difference between oxidation and reduction. It is an abstract word that is easy to remember.
by Wayland Leung
Mon Feb 05, 2018 11:27 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Determining reduction or oxidation
Replies: 4
Views: 587

Re: Determining reduction or oxidation

In class we also learned the "LEO" acronym, where loss of electrons is oxidation. That could be a easy way to memorize what oxidation is.
by Wayland Leung
Mon Feb 05, 2018 11:24 pm
Forum: Balancing Redox Reactions
Topic: Salt Bridges?
Replies: 6
Views: 165

Re: Salt Bridges?

Is the salt bridge composed of anions or cations?
by Wayland Leung
Thu Feb 01, 2018 8:38 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: The value of Cp
Replies: 8
Views: 340

Re: The value of Cp

So we only use the C value when there is a constant pressure value and use the R constant value when the pressure isnt constant?
by Wayland Leung
Thu Feb 01, 2018 8:36 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Problem 9.13
Replies: 4
Views: 187

Re: Problem 9.13

Yea i was also wondering why the heat capacity wasn't needed. Would we be wrong if we used the heat capacity?
by Wayland Leung
Thu Feb 01, 2018 8:31 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Change of Entropy for V and T
Replies: 2
Views: 116

Re: Change of Entropy for V and T

In the ideal gas law, pressure is the inverse of volume so you flip the pressure values in order to find the change in entropy.
by Wayland Leung
Sat Jan 27, 2018 2:18 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Constant Volume and Constant Pressure
Replies: 3
Views: 345

Re: Constant Volume and Constant Pressure

What equation would we use if the volume or pressure was not constant to find entropy?
by Wayland Leung
Sat Jan 27, 2018 2:15 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Degeneracy
Replies: 3
Views: 122

Re: Degeneracy

What are the equations for degeneracy? In what context would we solve for degeneracy?
by Wayland Leung
Sat Jan 27, 2018 1:26 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy of gas vs liquid vs solid
Replies: 7
Views: 1530

Re: Entropy of gas vs liquid vs solid

What does it mean when there are more possible states a gas can occupy?
by Wayland Leung
Thu Jan 18, 2018 10:47 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant pressure/volume
Replies: 2
Views: 120

Re: Constant pressure/volume

When would we need to use these values of 5/2R and 3/2R? Could you give some context?
by Wayland Leung
Thu Jan 18, 2018 10:45 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeter
Replies: 5
Views: 205

Re: Calorimeter

When would we use the equation q=C (delta)T in a calorimeter problem?
by Wayland Leung
Sun Jan 14, 2018 4:04 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimetry
Replies: 4
Views: 241

Re: Bomb Calorimetry

Are the calculations for coffee cup calorimetry problems different than bomb calorimeter problems? What are the biggest differences, if any?
by Wayland Leung
Sun Jan 14, 2018 4:03 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta H and Delta U
Replies: 3
Views: 102

Re: Delta H and Delta U

How are the equations for delta h and delta u different? Are there differenet variables in each equation?
by Wayland Leung
Sun Jan 14, 2018 4:02 pm
Forum: Phase Changes & Related Calculations
Topic: Endo and Exothermic Ways to Remember
Replies: 28
Views: 2976

Re: Endo and Exothermic Ways to Remember

The Ex- in exothermic is like the ex- in exit, so heat is leaving the system into the surroundings. Once you know that exothermic is when heat leaves the system, that means endothermic is when heat enters or is absorbed by the system.
by Wayland Leung
Sun Dec 03, 2017 4:59 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Why is Kw value typically used at 25 degrees C [ENDORSED]
Replies: 6
Views: 444

Re: Why is Kw value typically used at 25 degrees C [ENDORSED]

Does only changing the temperature affect the Kw value? Does anything else affect the Kw value?
by Wayland Leung
Sun Dec 03, 2017 4:57 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH and pOH
Replies: 10
Views: 450

Re: pH and pOH

If the ph or pOH is 7, is the solution considered neutral, neither acidic nor neutral?
by Wayland Leung
Wed Nov 29, 2017 10:06 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Weaks vs. Strong acids
Replies: 3
Views: 231

Re: Weaks vs. Strong acids

A strong acid completely dissociates when put in water, where the H+ is ionized in the water. A weak acid does not completely ionize in water. Only a small amount of the molecule becomes aqueous in the water. Only a small amount of H+ is ionized.
by Wayland Leung
Wed Nov 29, 2017 10:04 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Weak Bases
Replies: 4
Views: 730

Re: Weak Bases

How do you determine just by looking at a molecule that it is a weak base?
by Wayland Leung
Mon Nov 20, 2017 2:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: KP versus KC
Replies: 3
Views: 209

Re: KP versus KC

They represent the same thing. Normally we would just call it k. It is up to you to figure out if we are trying to find concentrations or pressure. But the equilibrium constant is the same in both cases.
by Wayland Leung
Mon Nov 20, 2017 2:38 pm
Forum: Ideal Gases
Topic: PV=nRT [ENDORSED]
Replies: 4
Views: 242

Re: PV=nRT [ENDORSED]

what are the units for each variable? Are there different units for pressure? How do we convert them to atm?
by Wayland Leung
Sun Nov 12, 2017 4:35 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Isoelectronic [ENDORSED]
Replies: 4
Views: 329

Re: Isoelectronic [ENDORSED]

Are elements isoelectronic if they have the same number of valence electrons but different structure?
by Wayland Leung
Sun Nov 12, 2017 4:17 pm
Forum: Lewis Structures
Topic: Shape
Replies: 5
Views: 237

Re: Shape

I was wondering what the difference between molecular structure and the molecular shape.
by Wayland Leung
Sun Nov 05, 2017 11:28 am
Forum: Octet Exceptions
Topic: Octets
Replies: 8
Views: 478

Re: Octets

Could someone explain why some elements do not need a full octet?
by Wayland Leung
Sun Nov 05, 2017 11:27 am
Forum: Ionic & Covalent Bonds
Topic: How to easily tell between Ionic and Covalent bonds?
Replies: 8
Views: 459

Re: How to easily tell between Ionic and Covalent bonds?

Will the values of electronegativity be given to us if we are asked to compare which elements are more electronegative or which are ionic and covalent bonds?
by Wayland Leung
Sun Oct 29, 2017 10:09 pm
Forum: Ionic & Covalent Bonds
Topic: Study Habits [ENDORSED]
Replies: 8
Views: 489

Re: Study Habits [ENDORSED]

Mr. Andersen videos are very helpful. But Lavelle honestly has the best tools for you to study and succeed in his class. I would recommend doing all the homework problems and going to peer learning sessions to master the material.
by Wayland Leung
Sun Oct 29, 2017 10:06 pm
Forum: Ionic & Covalent Bonds
Topic: Homework 3.5 part c [ENDORSED]
Replies: 3
Views: 235

Homework 3.5 part c [ENDORSED]

What is the ground state electron configuration of Ga^3+?

Could someone please advise?
by Wayland Leung
Mon Oct 23, 2017 2:22 pm
Forum: Trends in The Periodic Table
Topic: 1st and 2nd ionization energy? [ENDORSED]
Replies: 7
Views: 947

Re: 1st and 2nd ionization energy? [ENDORSED]

The ionization energy to remove the second electron of an atom will always be higher than the ionization energy to remove the first electron because the pull from the nucleus gets stronger and stronger as you begin to remove the electron shells.
by Wayland Leung
Mon Oct 23, 2017 2:18 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Chromium and Copper Electron Configuration Exceptions [ENDORSED]
Replies: 5
Views: 501

Re: Chromium and Copper Electron Configuration Exceptions [ENDORSED]

The d-orbitals for Chromium and Copper are only half-filled and fully-filled. Instead of writing Chromium as [Ar]3d^44s^2, you would write the electron configuration as [Ar]3d^54s^1 to fill the d-orbital with five electrons rather than four. The same goes for copper, instead of 9 electrons in the d-...
by Wayland Leung
Sun Oct 15, 2017 11:40 pm
Forum: Photoelectric Effect
Topic: Wavelike properties [ENDORSED]
Replies: 4
Views: 235

Re: Wavelike properties [ENDORSED]

How do we know if the wavelength is measurable? If the answer comes out to be a wavelength of 10^-24, is it measurable?
by Wayland Leung
Sun Oct 15, 2017 4:12 pm
Forum: DeBroglie Equation
Topic: question on how to determine if something has wavelike properties.
Replies: 6
Views: 900

Re: question on how to determine if something has wavelike properties.

I was confused because I remember watching one of Dr. Lavelle's modules and him saying that large objects like baseballs and cars do not have wave-like properties. Only small masses with high velocities have wave-like properties. Could someone please clarify? How do you know if something has measura...
by Wayland Leung
Tue Oct 10, 2017 9:41 pm
Forum: Properties of Electrons
Topic: electrons
Replies: 2
Views: 310

Re: electrons

Due to the conservation of energy, the energy is not irrelevant and just disappear. It may heat up the metal or take another form. Energy is neither created or destroyed.
by Wayland Leung
Tue Oct 10, 2017 9:34 pm
Forum: Einstein Equation
Topic: Where does Planck's Constant Come From
Replies: 5
Views: 383

Re: Where does Planck's Constant Come From

This is a good question as I was wondering the same thing. Based off the reading from the textbook, I can make an educated guess that he conducted an experiment about the photoelectric effect to come up with the constant value. He proposed in his experiment that energy travels in packets.
by Wayland Leung
Thu Oct 05, 2017 3:42 pm
Forum: SI Units, Unit Conversions
Topic: Sig Figs
Replies: 12
Views: 741

Re: Sig Figs

Also, when you are doing the problem, you should keep the number of sig figs the same throughout the work of the problem until you get an answer. Once you have your final answer, you may adjust it accordingly to the number of sig figs in the number specifically listed in the question.
by Wayland Leung
Thu Oct 05, 2017 3:36 pm
Forum: SI Units, Unit Conversions
Topic: Base Units
Replies: 6
Views: 422

Re: Base Units

It really all just depends on the problem and what it asks you to find. If the question is asking for the amount of product that can be prodced in grams, and you end up with moles of the product, you should multiply that amount by the molar mass to get the answer in terms of grams.

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