Search found 88 matches

by Adrian Lim 1G
Thu Mar 15, 2018 4:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.13 b
Replies: 4
Views: 131

Re: 14.13 b

How would we know that I2 is not conductive?
by Adrian Lim 1G
Thu Mar 15, 2018 1:09 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: delta s surrounding and system
Replies: 3
Views: 286

Re: delta s surrounding and system

I think usually the signs for delta s in the surroundings and system depend on the reaction itself. I believe the surroundings and the system would essentially be the opposites of each other. As stated above, delta s is basically q/T, so we could determine signs from heat either absorbed or released.
by Adrian Lim 1G
Mon Mar 12, 2018 11:34 pm
Forum: General Rate Laws
Topic: graphs
Replies: 8
Views: 192

Re: graphs

I would know the different graphs; however, if you were to know the different parts of the equation, graphing it shouldn't be too hard but it would probably be wise to know the graphs of the different reactions.
by Adrian Lim 1G
Mon Mar 12, 2018 10:34 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.63
Replies: 5
Views: 138

Re: 15.63

Also, for that question, do you know where the 1.8 from k'/k comes from and the -0.59 comes from at the end? When I plug in my numbers I end up getting something like 1.06 for k'/k, so my numbers are off.
by Adrian Lim 1G
Mon Mar 12, 2018 10:21 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.63
Replies: 5
Views: 138

Re: 15.63

For that equation, do you know if it would matter if we switched k and k' as long as the corresponding temperatures are the same? Would you end up getting the same result?
by Adrian Lim 1G
Mon Mar 12, 2018 10:08 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.47
Replies: 4
Views: 137

Re: 15.47

I'm not too sure why for step 1, it is just written as Cl instead of Cl-. It might be due to balancing charge, but the solutions manual says that the intermediate is the chloride ION, so I would just stick to Cl-
by Adrian Lim 1G
Mon Mar 12, 2018 10:05 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.47
Replies: 3
Views: 106

Re: 15.47

I would first look for the intermediate(s), which is produced and then used up to get the overall reaction. As for the diagrams, I just went from left to right of the molecule, but I don't think it would hurt too much to have the compound written in a slightly different form as long as everything is...
by Adrian Lim 1G
Wed Mar 07, 2018 4:07 pm
Forum: General Rate Laws
Topic: Test 3 material
Replies: 6
Views: 189

Re: Test 3 material

I don't think it will include the slow and fast reactions.
by Adrian Lim 1G
Tue Mar 06, 2018 3:50 pm
Forum: First Order Reactions
Topic: 15.37
Replies: 3
Views: 99

Re: 15.37

Why can we use the mass in this instead of concentration in this problem?
by Adrian Lim 1G
Tue Mar 06, 2018 12:18 am
Forum: General Rate Laws
Topic: Concentration and Rate Relationship
Replies: 4
Views: 132

Re: Concentration and Rate Relationship

For the most part, it would be easier to see the changes if you had the rate of reaction and the corresponding orders. From there, you could just plug in new concentrations to see what kind of effect it would have on the overall rate.
by Adrian Lim 1G
Tue Mar 06, 2018 12:15 am
Forum: General Rate Laws
Topic: Test 3 material
Replies: 6
Views: 189

Re: Test 3 material

Does anyone know which homework problem 15.6 would go up to?
by Adrian Lim 1G
Tue Mar 06, 2018 12:15 am
Forum: General Rate Laws
Topic: 15.17
Replies: 3
Views: 98

Re: 15.17

Because C is independent of the rate, we consider it as zero order. Therefore, we would not include it in our rate of reaction equation
by Adrian Lim 1G
Tue Mar 06, 2018 12:13 am
Forum: General Rate Laws
Topic: 15.17
Replies: 3
Views: 98

Re: 15.17

Because C is essentially zero order, it would be best to leave it off. If you leave it in the rate law, you would need an exponent of a 0 essentially indicating that it is independent of rate. Otherwise, you would probably be marked off for leaving it in.
by Adrian Lim 1G
Thu Mar 01, 2018 11:58 pm
Forum: General Rate Laws
Topic: Negative Signs [ENDORSED]
Replies: 6
Views: 203

Re: Negative Signs [ENDORSED]

We usually want the rate to be a positive number because it might seem unusual for a rate to be a negative number. Thus, when we calculate the rate of a reactant, we usually add the negative sign in front of the change of concentration over change in time. This is because the change in concentration...
by Adrian Lim 1G
Tue Feb 27, 2018 10:54 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Units of Reaction Rate
Replies: 7
Views: 204

Re: Units of Reaction Rate

Yes, you should have units to see which units you need for k. Also, it is wise to always make sure to include units; even if it isn't necessary, it's nice to double check certain terms and values.
by Adrian Lim 1G
Tue Feb 27, 2018 10:14 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Hw 15.1 [ENDORSED]
Replies: 7
Views: 207

Re: Hw 15.1 [ENDORSED]

The rate of N2 would be 1/3 times the rate of H2
by Adrian Lim 1G
Tue Feb 27, 2018 10:06 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Textbook Problems 15.3 and 15.5
Replies: 7
Views: 428

Re: Textbook Problems 15.3 and 15.5

I think the answer in the solutions manual shows the rate of reaction of NO2 in this specific reaction, so it doesn't divide by 2 for part a
by Adrian Lim 1G
Tue Feb 27, 2018 10:05 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: 15.3 [ENDORSED]
Replies: 7
Views: 189

Re: 15.3 [ENDORSED]

For that same question, what do they mean when they ask for the unique rate of reaction?
by Adrian Lim 1G
Wed Feb 21, 2018 11:05 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 14.27
Replies: 6
Views: 187

Re: 14.27

I also do not understand why we would need deltaG values to calculate the potential of a half-reaction
by Adrian Lim 1G
Wed Feb 21, 2018 1:41 pm
Forum: Balancing Redox Reactions
Topic: Balancing REDOX reactions
Replies: 5
Views: 165

Re: Balancing REDOX reactions

You would not need to multiply E by the factor, but if you were to switch the equation, the E would change sign.
by Adrian Lim 1G
Wed Feb 21, 2018 1:23 pm
Forum: Balancing Redox Reactions
Topic: Writing Half-Reactions
Replies: 6
Views: 180

Re: Writing Half-Reactions

I believe it would be better to flip the anode because in a redox reaction, we would add up the two half-reactions, so some terms would need to balance out on both sides.
by Adrian Lim 1G
Wed Feb 21, 2018 1:20 pm
Forum: Balancing Redox Reactions
Topic: Finding half reactions
Replies: 4
Views: 170

Re: Finding half reactions

I also think that for the test, it would just be given to us in a chart or some form
by Adrian Lim 1G
Wed Feb 21, 2018 1:19 pm
Forum: Balancing Redox Reactions
Topic: redox agent
Replies: 5
Views: 127

Re: redox agent

Just think of the opposites, so the oxidizing agent is reduced, while the reducing agent is being oxidized!
by Adrian Lim 1G
Wed Feb 14, 2018 1:18 pm
Forum: Calculating Work of Expansion
Topic: Practice Midterm 4
Replies: 3
Views: 211

Re: Practice Midterm 4

We changed the final temperature during review in order to reflect the fact that the final conditions were exactly the same as the initial conditions
by Adrian Lim 1G
Wed Feb 14, 2018 1:14 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: #4 on practice midterm
Replies: 3
Views: 156

Re: #4 on practice midterm

I believe for reduction of pressure from 8 atm to 1 atm, work would just be 0 because according to w = -Pdeltav, since volume doesn't change, work would just be 0. This step should be done separate from the volume change, however, which can be given by w = -nRTln(V2/V1).
by Adrian Lim 1G
Wed Feb 14, 2018 1:03 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible
Replies: 4
Views: 139

Re: Reversible

I believe if the process is isothermal, meaning there is no change in temperature, then the reversible system would have a delta U = 0.
by Adrian Lim 1G
Tue Feb 13, 2018 12:17 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.5
Replies: 3
Views: 100

Re: 9.5

So would the signs be the same for entropy as well?
by Adrian Lim 1G
Mon Feb 12, 2018 1:54 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Van't Hoff Equation
Replies: 3
Views: 99

Re: Van't Hoff Equation

I would memorize the equation, but it should be pretty simple to derive just in case you forget on the test.
by Adrian Lim 1G
Mon Feb 12, 2018 1:53 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Arithmetic in 11.19c
Replies: 2
Views: 107

Re: Arithmetic in 11.19c

delta G = (-604.03 - 392.36) + 1128.8 = 130.41 kj/mol
lnk = - 130410/(8.314*298.15) = -52.61
k = e^(-52.61)
k = 1.419 * 10^-23
k = 1 * 10^-23
Hopefully this helps!
by Adrian Lim 1G
Mon Feb 12, 2018 1:48 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 11.111
Replies: 2
Views: 107

Re: 11.111

Just as Andres stated, we assume the temperature is 25C because it is in standard state. However, when you plug T into the equations, make sure the temperature is in Kelvin because the unit of R is given in Kelvin
by Adrian Lim 1G
Mon Feb 12, 2018 1:45 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 11.83
Replies: 4
Views: 132

Re: 11.83

For 11.83, we need to find both delta H and delta S in order to use the formula delta G = delta H - T delta S to find delta G. We are not given the delta G, so we would need to find this. Once you find delta G, you can just use the formula delta G = -RTlnK to find K, the equilibrium constant.
by Adrian Lim 1G
Fri Feb 09, 2018 2:47 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9. 43
Replies: 5
Views: 159

Re: 9. 43

Yes, I think the heat capacity will usually be given to you.
by Adrian Lim 1G
Tue Feb 06, 2018 1:34 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: temperature
Replies: 5
Views: 132

Re: temperature

I think it would be best to use 273.15 and then for the final answer just truncate if necessary for the number of sig figs.
by Adrian Lim 1G
Tue Feb 06, 2018 1:32 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.13 Equation Confusion
Replies: 3
Views: 108

Re: 9.13 Equation Confusion

I believe the equation can be used for ideal gases
by Adrian Lim 1G
Tue Feb 06, 2018 1:28 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: deltaS question
Replies: 7
Views: 209

Re: deltaS question

Yes, I believe most of the time, the questions will tell you whether or not it's an ideal gas.
by Adrian Lim 1G
Tue Feb 06, 2018 1:23 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Differing Equations Used For delta S with Change in Temperature
Replies: 3
Views: 123

Re: Differing Equations Used For delta S with Change in Temperature

I think it also depends on the information that you're given. Depending on that information, you can determine which equation to use.
by Adrian Lim 1G
Wed Jan 31, 2018 9:53 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Question 9.5
Replies: 3
Views: 108

Re: Question 9.5

I believe the signs in the solutions manual are referring to the system itself
by Adrian Lim 1G
Wed Jan 31, 2018 9:52 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: unit of entropy
Replies: 11
Views: 276

Re: unit of entropy

The units are J/K, but if you forget, it could be helpful to write out the units and then see which cancel and what you're left with.
by Adrian Lim 1G
Wed Jan 31, 2018 7:12 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy and Temperature
Replies: 3
Views: 108

Re: Entropy and Temperature

What would the c value be in delta S=n*C*ln(t2/t1)?
by Adrian Lim 1G
Wed Jan 31, 2018 6:56 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.1 [ENDORSED]
Replies: 3
Views: 127

Re: 9.1 [ENDORSED]

So the signs would be in reference to the system?
by Adrian Lim 1G
Wed Jan 31, 2018 6:55 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: DeltaU and DeltaH
Replies: 4
Views: 151

Re: DeltaU and DeltaH

What if there were a change in pressure?
by Adrian Lim 1G
Thu Jan 25, 2018 11:21 pm
Forum: Calculating Work of Expansion
Topic: Homework 8.11
Replies: 8
Views: 284

Re: Homework 8.11

Yes it did! Thank you!
by Adrian Lim 1G
Wed Jan 24, 2018 10:26 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.117
Replies: 2
Views: 130

Re: 8.117

The delta H given is for 1 mole of reaction or 3 moles of H2. However, the question is asking for the change for the production of only one mole. Thus, you would have to take the given delta H and divide it by 3
by Adrian Lim 1G
Wed Jan 24, 2018 7:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.75 part b
Replies: 3
Views: 126

Re: 8.75 part b

I also thought that there would be a C=O double bond formed. Can anyone please clarify?
by Adrian Lim 1G
Wed Jan 24, 2018 4:52 pm
Forum: Phase Changes & Related Calculations
Topic: Irreversible and Reversible
Replies: 7
Views: 209

Re: Irreversible and Reversible

On his website, he also said under announcements that there will be no questions on isothermal or reversible expansion on test 1.
by Adrian Lim 1G
Tue Jan 23, 2018 4:47 pm
Forum: Calculating Work of Expansion
Topic: 8.17 Work done by a system
Replies: 6
Views: 207

Re: 8.17 Work done by a system

For 8.17, the solutions manual says delta E is 0 when change is occurring at a constant temperature. is deltaE just the same as deltaU?
by Adrian Lim 1G
Tue Jan 23, 2018 3:01 pm
Forum: Calculating Work of Expansion
Topic: 8.13- negative signs?
Replies: 2
Views: 82

Re: 8.13- negative signs?

Also, the problem says that the surroundings is a cooling system, which means that the surroundings will absorb the heat from the system. Thus, because the system is losing heat, the q in relation to the system would be negative.
by Adrian Lim 1G
Tue Jan 23, 2018 2:52 pm
Forum: Calculating Work of Expansion
Topic: Homework 8.11
Replies: 8
Views: 284

Re: Homework 8.11

In the solutions manual, why is ln (v2/v1) stated as ln (2.4/1.2)? Where does the 2.4 come from?
by Adrian Lim 1G
Tue Jan 23, 2018 2:20 pm
Forum: Calculating Work of Expansion
Topic: 8.3
Replies: 3
Views: 153

Re: 8.3

Why do we need to multiply the distance, d, to 1L/1000cm^3 to find delta V?
by Adrian Lim 1G
Mon Jan 22, 2018 12:00 am
Forum: Phase Changes & Related Calculations
Topic: Test 1 [ENDORSED]
Replies: 7
Views: 293

Re: Test 1 [ENDORSED]

I believe Dr. Lavelle posted the formula sheet similar to what we would be receiving on the test.
by Adrian Lim 1G
Tue Jan 16, 2018 11:19 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: What does R stand for?
Replies: 13
Views: 573

Re: What does R stand for?

Just to clarify, R is the ideal gas constant and its units are given per mole. Thus, when you are using this for q = mcdeltat, make sure the m is amount given in moles so the moles with the c would cancel.
by Adrian Lim 1G
Tue Jan 16, 2018 11:17 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: PdeltaV=deltanRT
Replies: 4
Views: 448

Re: PdeltaV=deltanRT

Like the reply above stated, it's just a different way to calculate work. We can use - delta n R T if we know the net change in moles of the equation in order to find the work.
by Adrian Lim 1G
Tue Jan 16, 2018 11:14 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: When to use C=5/2R or C=3/2R
Replies: 7
Views: 1467

Re: When to use C=5/2R or C=3/2R

R is essentially the gas constant, which is 8.314 J * K^-1 * mol^-1. When we use this constant to find heat (q) with the equation q = m * c * delta t, we need to make sure the m is in moles because the unit of the constant is given per mole.
by Adrian Lim 1G
Thu Jan 11, 2018 9:19 am
Forum: Phase Changes & Related Calculations
Topic: qp=deltaH
Replies: 8
Views: 343

Re: qp=deltaH

Both would probably be acceptable, but it may be best to stick to whatever Dr. Lavelle prefers to use in lecture.
by Adrian Lim 1G
Thu Jan 11, 2018 9:18 am
Forum: Phase Changes & Related Calculations
Topic: chapter 8
Replies: 6
Views: 230

Re: chapter 8

Yes, I don't think he covered the initial homework problems yet, which is probably why he is allowing us to turn in both week 1 and week 2 homework problems during week 2 of discussion.
by Adrian Lim 1G
Thu Jan 11, 2018 9:16 am
Forum: Phase Changes & Related Calculations
Topic: Enthalpy is a state property
Replies: 13
Views: 404

Re: Enthalpy is a state property

So would heat be a path function?
by Adrian Lim 1G
Thu Dec 07, 2017 11:38 am
Forum: Dipole Moments
Topic: Dipoles: Polar or nonpolar?
Replies: 2
Views: 153

Re: Dipoles: Polar or nonpolar?

If there is a net dipole moment, then the molecule is essentially polar. If the dipole moments cancel, this makes the molecule nonpolar.
by Adrian Lim 1G
Wed Dec 06, 2017 6:40 pm
Forum: Lewis Acids & Bases
Topic: Memorizing Acids and Bases
Replies: 7
Views: 281

Re: Memorizing Acids and Bases

We should probably know the common strong and weak acids and bases, but otherwise there are ways we could determine the strength, such as a the presence of higher electronegative elements to offset charge or the length of the bonds.
by Adrian Lim 1G
Wed Dec 06, 2017 6:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Monodentate vs Bidentate etc. [ENDORSED]
Replies: 7
Views: 634

Re: Monodentate vs Bidentate etc. [ENDORSED]

Also, to look at what kind of dentate it would be, you could look for nitrogen. Usually, nitrogen would have a lone pair of elections that would want to form a bond. Also, you could look for atoms that have a negative charge, for those are the ones that would want to form bonds. Otherwise, it would ...
by Adrian Lim 1G
Tue Nov 28, 2017 4:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs and naming shape
Replies: 2
Views: 104

Re: Lone pairs and naming shape

Using lone pairs may also help to write the VESPR type, which can help with naming of the shape. For example, if you had one lone pair on the central atom and three bonded atoms, the VSEPR would be AX3E, and as a result, you can tell the shape from this.
by Adrian Lim 1G
Tue Nov 28, 2017 12:42 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 4
Views: 170

Re: Bond Angles

Do you know if Dr. Lavelle has a chart of all the shapes and bond angles of the different shapes? Also, some angles are a bit confusing, as some may say approximately less than 109, whereas a solution may be more accurate, such as 107.5. Should we know the exact numbers?
by Adrian Lim 1G
Tue Nov 28, 2017 12:39 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron Arrangement and Molecular Shape
Replies: 4
Views: 151

Re: Electron Arrangement and Molecular Shape

For the electron arrangement, you can essentially look at the number of electron densities around the central atom, whereas for the actual shape, you need to just look at the number of atoms surrounding the central atom. However, you need to also be aware of any lone pair electrons, which could resu...
by Adrian Lim 1G
Wed Nov 22, 2017 8:43 am
Forum: Naming
Topic: Ligand Names
Replies: 6
Views: 207

Re: Ligand Names

Should we just memorize the names the old way instead of the new naming system?
by Adrian Lim 1G
Wed Nov 22, 2017 8:41 am
Forum: Naming
Topic: Naming
Replies: 2
Views: 122

Re: Naming

Where does the roman numeral III come from? Does it stem from the charge of the chromium?
by Adrian Lim 1G
Thu Nov 16, 2017 1:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle
Replies: 7
Views: 254

Re: Bond Angle

This is because at times, lone pairs may result in more repulsion, thus creating a different bond angle.
by Adrian Lim 1G
Tue Nov 14, 2017 6:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs and Bond Angle
Replies: 3
Views: 147

Re: Lone Pairs and Bond Angle

Is there a difference between the electron arrangement and the shape of a molecule? How do the electron pairs impact the electron arrangement and how do the electron pairs impact the shape of a molecule?
by Adrian Lim 1G
Tue Nov 14, 2017 6:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: CO2 vs. H2O
Replies: 6
Views: 303

Re: CO2 vs. H2O

H20 has a bent structure, so the dipole moments that move towards the more electronegative oxygen do not cancel out, making H20 polar. However, in CO2, the structure is linear, meaning the dipole moments would end up cancelling out each other, making it non polar.
by Adrian Lim 1G
Thu Nov 09, 2017 10:53 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron Spin Quantum Number [ENDORSED]
Replies: 12
Views: 659

Re: Electron Spin Quantum Number [ENDORSED]

To reiterate, the spin number is +1/2 and -1/2; however, we will not be able to determine which is which at certain times depending on how one draws the spin of the electrons in the orbitals.
by Adrian Lim 1G
Thu Nov 09, 2017 10:47 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance Structure
Replies: 4
Views: 161

Re: Resonance Structure

Does anyone know if we're expected to list all the possible resonance structures wherever applicable on the midterm?

Thanks
by Adrian Lim 1G
Thu Nov 02, 2017 11:16 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Removing an Electron [ENDORSED]
Replies: 5
Views: 254

Re: Removing an Electron [ENDORSED]

What if the electron configuration were 3d^3 4s^2? Would electrons be removed from the s-orbital or the d-orbital?
by Adrian Lim 1G
Thu Nov 02, 2017 10:54 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Determining if an atom is in an excited state
Replies: 2
Views: 184

Re: Determining if an atom is in an excited state

Also, I believe you can look at the different spins on the electron to tell whether it is in an excited state or ground state
by Adrian Lim 1G
Thu Nov 02, 2017 10:53 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 2.43
Replies: 4
Views: 207

Re: Homework 2.43

Hi I just had a follow up question about the second part. Why isn't the electron configuration for Tungsten [Xe] 4f^145 d^5 6s^1? I remember Dr. Lavelle talking about exceptions during a lecture, and one of them included chromium, which would want to have a half full d^5 orbital. Why doesn't Tungste...
by Adrian Lim 1G
Thu Oct 26, 2017 6:24 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Test 3 [ENDORSED]
Replies: 7
Views: 373

Re: Test 3 [ENDORSED]

Jenny, I do not think that chapter 3 would be included in test 3; just 1.6 to the end of Chapter 2
by Adrian Lim 1G
Thu Oct 26, 2017 6:21 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Relation of radius/diameter size to precision
Replies: 3
Views: 175

Re: Relation of radius/diameter size to precision

Should we convert all the units to meters or picometers before doing this problem?
by Adrian Lim 1G
Thu Oct 26, 2017 6:20 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Understadning Heisenberg Indeterminacy Equation
Replies: 6
Views: 314

Re: Understadning Heisenberg Indeterminacy Equation

What is the importance of h/4pi? Where does the 4pi come from?
by Adrian Lim 1G
Thu Oct 19, 2017 3:40 pm
Forum: Properties of Light
Topic: Color of visible light
Replies: 11
Views: 478

Re: Color of visible light

I would just remember that visible light is between 400 nm (violet) and 700 nm (red)
by Adrian Lim 1G
Tue Oct 17, 2017 3:13 pm
Forum: Photoelectric Effect
Topic: Post Mod #28 pt b: conversion units [ENDORSED]
Replies: 3
Views: 168

Re: Post Mod #28 pt b: conversion units [ENDORSED]

Just to clarify, do you multiply or divide avogadro's number?
by Adrian Lim 1G
Tue Oct 17, 2017 2:48 pm
Forum: Properties of Light
Topic: Converting Units [ENDORSED]
Replies: 11
Views: 464

Re: Converting Units [ENDORSED]

It would depend on the problem as all the replies above have stated, but it may be a good idea to see the units of the values that the problem gave and just be consistent with that.
by Adrian Lim 1G
Tue Oct 17, 2017 2:46 pm
Forum: Properties of Light
Topic: Lyman and Balmer series.
Replies: 4
Views: 252

Re: Lyman and Balmer series.

Should we know the approximate numbers of the different wavelengths?
by Adrian Lim 1G
Tue Oct 17, 2017 2:45 pm
Forum: Properties of Light
Topic: Planck's Constant
Replies: 10
Views: 425

Re: Planck's Constant

Planck's constant is a set number for the constant h. It is used in formulas, such as E = hv. It will be given to you on the formula sheet. Just to reiterate the above reply, don't get it confused with p. p stands for momentum and is equal to the mass * velocity.
by Adrian Lim 1G
Fri Oct 13, 2017 6:46 am
Forum: Einstein Equation
Topic: Photoelectric Post-Module 29 [ENDORSED]
Replies: 2
Views: 174

Photoelectric Post-Module 29 [ENDORSED]

Hi,
Does anyone know why the answer the question 29 part b on the photoelectric post-module is not B? They tell us the work function for sodium is 150.6 kj/mol and then asks us how much energy is required to remove an electron from the sodium atom. Wouldn't that just be 150600 J or 1.506 * 10^5?
by Adrian Lim 1G
Thu Oct 12, 2017 12:37 am
Forum: Properties of Light
Topic: Work Functions
Replies: 4
Views: 253

Re: Work Functions

Just to clarify the above response - the energy of the incoming photon - work function = energy of the electron being ejected. Also remember that photons work in packets, meaning one photon needs to have a sufficient amount of energy to eject one electron, also known as the work function. One photon...
by Adrian Lim 1G
Thu Oct 12, 2017 12:30 am
Forum: Properties of Light
Topic: Planck Constant [ENDORSED]
Replies: 8
Views: 366

Re: Planck Constant [ENDORSED]

Yeah since you will probably get the value of the constant on the formula sheet, I would just use the value given. Otherwise, just follow the rounding necessary based off the given values.
by Adrian Lim 1G
Thu Oct 05, 2017 7:37 pm
Forum: SI Units, Unit Conversions
Topic: Exercise F11
Replies: 4
Views: 239

Re: Exercise F11

Hi,
Are you talking about part a with Na, Al, and F? After dividing all three by the smallest, I got 5.9, so I would assume you could round to 6.
by Adrian Lim 1G
Tue Oct 03, 2017 6:46 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.17 [ENDORSED]
Replies: 6
Views: 580

Re: G.17 [ENDORSED]

You have to use the molar mass of CuSO4 5H20 because the question is asking you to find the mass of the whole compound, including the 5H20.
by Adrian Lim 1G
Tue Oct 03, 2017 6:42 pm
Forum: Molarity, Solutions, Dilutions
Topic: G25 homework problem
Replies: 7
Views: 366

Re: G25 homework problem

I also don't understand the problem very well. Do you think it'll be mentioned in the test on Friday?
by Adrian Lim 1G
Tue Oct 03, 2017 3:08 pm
Forum: SI Units, Unit Conversions
Topic: Exercise E1 [ENDORSED]
Replies: 6
Views: 668

Re: Exercise E1 [ENDORSED]

I believe it is okay to leave it in pm as long as you label your units. However, in chemistry, if you were to convert the pm to meters, it would probably be best to write your answer in scientific notation, considering the fact that a picometer is extremely small in comparison to a meter.

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