Search found 88 matches
- Thu Mar 15, 2018 4:08 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 14.13 b
- Replies: 4
- Views: 581
Re: 14.13 b
How would we know that I2 is not conductive?
- Thu Mar 15, 2018 1:09 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: delta s surrounding and system
- Replies: 3
- Views: 4924
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.
- Mon Mar 12, 2018 11:34 pm
- Forum: General Rate Laws
- Topic: graphs
- Replies: 8
- Views: 979
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.
- Mon Mar 12, 2018 10:34 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 15.63
- Replies: 5
- Views: 1292
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.
- Mon Mar 12, 2018 10:21 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 15.63
- Replies: 5
- Views: 1292
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?
- Mon Mar 12, 2018 10:08 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 15.47
- Replies: 4
- Views: 578
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-
- Mon Mar 12, 2018 10:05 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 15.47
- Replies: 3
- Views: 516
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...
- Wed Mar 07, 2018 4:07 pm
- Forum: General Rate Laws
- Topic: Test 3 material
- Replies: 6
- Views: 751
Re: Test 3 material
I don't think it will include the slow and fast reactions.
- Tue Mar 06, 2018 3:50 pm
- Forum: First Order Reactions
- Topic: 15.37
- Replies: 3
- Views: 516
Re: 15.37
Why can we use the mass in this instead of concentration in this problem?
- Tue Mar 06, 2018 12:18 am
- Forum: General Rate Laws
- Topic: Concentration and Rate Relationship
- Replies: 4
- Views: 604
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.
- Tue Mar 06, 2018 12:15 am
- Forum: General Rate Laws
- Topic: Test 3 material
- Replies: 6
- Views: 751
Re: Test 3 material
Does anyone know which homework problem 15.6 would go up to?
- Tue Mar 06, 2018 12:15 am
- Forum: General Rate Laws
- Topic: 15.17
- Replies: 3
- Views: 473
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
- Tue Mar 06, 2018 12:13 am
- Forum: General Rate Laws
- Topic: 15.17
- Replies: 3
- Views: 483
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.
- Thu Mar 01, 2018 11:58 pm
- Forum: General Rate Laws
- Topic: Negative Signs [ENDORSED]
- Replies: 6
- Views: 1032
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...
- Tue Feb 27, 2018 10:54 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Units of Reaction Rate
- Replies: 7
- Views: 923
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.
- Tue Feb 27, 2018 10:14 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Hw 15.1 [ENDORSED]
- Replies: 7
- Views: 1108
Re: Hw 15.1 [ENDORSED]
The rate of N2 would be 1/3 times the rate of H2
- 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: 1085
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
- Tue Feb 27, 2018 10:05 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: 15.3 [ENDORSED]
- Replies: 7
- Views: 874
Re: 15.3 [ENDORSED]
For that same question, what do they mean when they ask for the unique rate of reaction?
- Wed Feb 21, 2018 11:05 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: 14.27
- Replies: 6
- Views: 800
Re: 14.27
I also do not understand why we would need deltaG values to calculate the potential of a half-reaction
- Wed Feb 21, 2018 10:20 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: When writing cell diagrams, how do you know when to include an additional element at the electrode?
- Replies: 5
- Views: 593
- Wed Feb 21, 2018 1:41 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing REDOX reactions
- Replies: 5
- Views: 698
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.
- Wed Feb 21, 2018 1:23 pm
- Forum: Balancing Redox Reactions
- Topic: Writing Half-Reactions
- Replies: 6
- Views: 909
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.
- Wed Feb 21, 2018 1:20 pm
- Forum: Balancing Redox Reactions
- Topic: Finding half reactions
- Replies: 4
- Views: 587
Re: Finding half reactions
I also think that for the test, it would just be given to us in a chart or some form
- Wed Feb 21, 2018 1:19 pm
- Forum: Balancing Redox Reactions
- Topic: redox agent
- Replies: 5
- Views: 693
Re: redox agent
Just think of the opposites, so the oxidizing agent is reduced, while the reducing agent is being oxidized!
- Wed Feb 14, 2018 1:18 pm
- Forum: Calculating Work of Expansion
- Topic: Practice Midterm 4
- Replies: 3
- Views: 520
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
- 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: 431
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).
- Wed Feb 14, 2018 1:03 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reversible
- Replies: 4
- Views: 519
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.
- Tue Feb 13, 2018 12:17 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 9.5
- Replies: 3
- Views: 416
Re: 9.5
So would the signs be the same for entropy as well?
- Mon Feb 12, 2018 1:54 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Van't Hoff Equation
- Replies: 3
- Views: 428
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.
- Mon Feb 12, 2018 1:53 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Arithmetic in 11.19c
- Replies: 2
- Views: 476
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!
lnk = - 130410/(8.314*298.15) = -52.61
k = e^(-52.61)
k = 1.419 * 10^-23
k = 1 * 10^-23
Hopefully this helps!
- Mon Feb 12, 2018 1:48 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 11.111
- Replies: 2
- Views: 348
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
- Mon Feb 12, 2018 1:45 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 11.83
- Replies: 4
- Views: 630
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.
- Fri Feb 09, 2018 2:47 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 9. 43
- Replies: 5
- Views: 612
Re: 9. 43
Yes, I think the heat capacity will usually be given to you.
- Tue Feb 06, 2018 1:34 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: temperature
- Replies: 5
- Views: 587
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.
- 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: 502
Re: 9.13 Equation Confusion
I believe the equation can be used for ideal gases
- Tue Feb 06, 2018 1:28 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: deltaS question
- Replies: 7
- Views: 938
Re: deltaS question
Yes, I believe most of the time, the questions will tell you whether or not it's an ideal gas.
- 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: 630
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.
- Wed Jan 31, 2018 9:53 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Question 9.5
- Replies: 3
- Views: 457
Re: Question 9.5
I believe the signs in the solutions manual are referring to the system itself
- Wed Jan 31, 2018 9:52 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: unit of entropy
- Replies: 11
- Views: 1220
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.
- Wed Jan 31, 2018 7:12 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy and Temperature
- Replies: 3
- Views: 424
Re: Entropy and Temperature
What would the c value be in delta S=n*C*ln(t2/t1)?
- Wed Jan 31, 2018 6:56 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 9.1 [ENDORSED]
- Replies: 3
- Views: 412
Re: 9.1 [ENDORSED]
So the signs would be in reference to the system?
- Wed Jan 31, 2018 6:55 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: DeltaU and DeltaH
- Replies: 4
- Views: 921
Re: DeltaU and DeltaH
What if there were a change in pressure?
- Thu Jan 25, 2018 11:21 pm
- Forum: Calculating Work of Expansion
- Topic: Homework 8.11
- Replies: 8
- Views: 865
Re: Homework 8.11
Yes it did! Thank you!
- 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: 383
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
- 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: 408
Re: 8.75 part b
I also thought that there would be a C=O double bond formed. Can anyone please clarify?
- Wed Jan 24, 2018 4:52 pm
- Forum: Phase Changes & Related Calculations
- Topic: Irreversible and Reversible
- Replies: 7
- Views: 720
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.
- Tue Jan 23, 2018 4:47 pm
- Forum: Calculating Work of Expansion
- Topic: 8.17 Work done by a system
- Replies: 6
- Views: 700
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?
- Tue Jan 23, 2018 3:01 pm
- Forum: Calculating Work of Expansion
- Topic: 8.13- negative signs?
- Replies: 2
- Views: 204
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.
- Tue Jan 23, 2018 2:52 pm
- Forum: Calculating Work of Expansion
- Topic: Homework 8.11
- Replies: 8
- Views: 865
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?
- Tue Jan 23, 2018 2:20 pm
- Forum: Calculating Work of Expansion
- Topic: 8.3
- Replies: 3
- Views: 345
Re: 8.3
Why do we need to multiply the distance, d, to 1L/1000cm^3 to find delta V?
- Mon Jan 22, 2018 12:00 am
- Forum: Phase Changes & Related Calculations
- Topic: Test 1 [ENDORSED]
- Replies: 7
- Views: 966
Re: Test 1 [ENDORSED]
I believe Dr. Lavelle posted the formula sheet similar to what we would be receiving on the test.
- Tue Jan 16, 2018 11:19 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: What does R stand for?
- Replies: 13
- Views: 3389
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.
- Tue Jan 16, 2018 11:17 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: PdeltaV=deltanRT
- Replies: 4
- Views: 6057
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.
- 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: 3090
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.
- Thu Jan 11, 2018 9:19 am
- Forum: Phase Changes & Related Calculations
- Topic: qp=deltaH
- Replies: 8
- Views: 1019
Re: qp=deltaH
Both would probably be acceptable, but it may be best to stick to whatever Dr. Lavelle prefers to use in lecture.
- Thu Jan 11, 2018 9:18 am
- Forum: Phase Changes & Related Calculations
- Topic: chapter 8
- Replies: 6
- Views: 622
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.
- Thu Jan 11, 2018 9:16 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy is a state property
- Replies: 13
- Views: 1883
Re: Enthalpy is a state property
So would heat be a path function?
- Thu Dec 07, 2017 11:38 am
- Forum: Dipole Moments
- Topic: Dipoles: Polar or nonpolar?
- Replies: 2
- Views: 364
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.
- Wed Dec 06, 2017 6:40 pm
- Forum: Lewis Acids & Bases
- Topic: Memorizing Acids and Bases
- Replies: 7
- Views: 896
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.
- Wed Dec 06, 2017 6:34 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Monodentate vs Bidentate etc. [ENDORSED]
- Replies: 7
- Views: 5958
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 ...
- Tue Nov 28, 2017 4:20 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone pairs and naming shape
- Replies: 2
- Views: 272
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.
- Tue Nov 28, 2017 12:42 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 4
- Views: 625
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?
- Tue Nov 28, 2017 12:39 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Electron Arrangement and Molecular Shape
- Replies: 4
- Views: 561
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...
- Wed Nov 22, 2017 8:43 am
- Forum: Naming
- Topic: Ligand Names
- Replies: 6
- Views: 667
Re: Ligand Names
Should we just memorize the names the old way instead of the new naming system?
Re: Naming
Where does the roman numeral III come from? Does it stem from the charge of the chromium?
- Thu Nov 16, 2017 1:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle
- Replies: 7
- Views: 979
Re: Bond Angle
This is because at times, lone pairs may result in more repulsion, thus creating a different bond angle.
- Tue Nov 14, 2017 6:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs and Bond Angle
- Replies: 3
- Views: 484
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?
- Tue Nov 14, 2017 6:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: CO2 vs. H2O
- Replies: 6
- Views: 6691
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.
- Thu Nov 09, 2017 10:53 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Electron Spin Quantum Number [ENDORSED]
- Replies: 12
- Views: 4050
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.
- Thu Nov 09, 2017 10:47 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Resonance Structure
- Replies: 4
- Views: 359
Re: Resonance Structure
Does anyone know if we're expected to list all the possible resonance structures wherever applicable on the midterm?
Thanks
Thanks
- Thu Nov 02, 2017 11:16 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Removing an Electron [ENDORSED]
- Replies: 5
- Views: 829
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?
- 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: 2138
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
- Thu Nov 02, 2017 10:53 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Homework 2.43
- Replies: 4
- Views: 562
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...
- Thu Oct 26, 2017 6:24 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Test 3 [ENDORSED]
- Replies: 7
- Views: 2815
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
- Thu Oct 26, 2017 6:21 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Relation of radius/diameter size to precision
- Replies: 3
- Views: 580
Re: Relation of radius/diameter size to precision
Should we convert all the units to meters or picometers before doing this problem?
- Thu Oct 26, 2017 6:20 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Understadning Heisenberg Indeterminacy Equation
- Replies: 6
- Views: 1375
Re: Understadning Heisenberg Indeterminacy Equation
What is the importance of h/4pi? Where does the 4pi come from?
- Thu Oct 19, 2017 3:40 pm
- Forum: Properties of Light
- Topic: Color of visible light
- Replies: 11
- Views: 1248
Re: Color of visible light
I would just remember that visible light is between 400 nm (violet) and 700 nm (red)
- Tue Oct 17, 2017 3:13 pm
- Forum: Photoelectric Effect
- Topic: Post Mod #28 pt b: conversion units [ENDORSED]
- Replies: 3
- Views: 329
Re: Post Mod #28 pt b: conversion units [ENDORSED]
Just to clarify, do you multiply or divide avogadro's number?
- Tue Oct 17, 2017 2:48 pm
- Forum: Properties of Light
- Topic: Converting Units [ENDORSED]
- Replies: 11
- Views: 1432
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.
- Tue Oct 17, 2017 2:46 pm
- Forum: Properties of Light
- Topic: Lyman and Balmer series.
- Replies: 4
- Views: 472
Re: Lyman and Balmer series.
Should we know the approximate numbers of the different wavelengths?
- Tue Oct 17, 2017 2:45 pm
- Forum: Properties of Light
- Topic: Planck's Constant
- Replies: 10
- Views: 1275
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.
- Fri Oct 13, 2017 6:46 am
- Forum: Einstein Equation
- Topic: Photoelectric Post-Module 29 [ENDORSED]
- Replies: 2
- Views: 392
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?
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?
- Thu Oct 12, 2017 12:37 am
- Forum: Properties of Light
- Topic: Work Functions
- Replies: 4
- Views: 723
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...
- Thu Oct 12, 2017 12:30 am
- Forum: Properties of Light
- Topic: Planck Constant [ENDORSED]
- Replies: 8
- Views: 1494
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.
- Thu Oct 05, 2017 7:37 pm
- Forum: SI Units, Unit Conversions
- Topic: Exercise F11
- Replies: 4
- Views: 375
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.
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.
- Tue Oct 03, 2017 6:46 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G.17 [ENDORSED]
- Replies: 6
- Views: 2019
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.
- Tue Oct 03, 2017 6:42 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G25 homework problem
- Replies: 7
- Views: 827
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?
- Tue Oct 03, 2017 3:08 pm
- Forum: SI Units, Unit Conversions
- Topic: Exercise E1 [ENDORSED]
- Replies: 6
- Views: 1338
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.