Search found 99 matches
- Sat Mar 14, 2020 10:23 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram
- Replies: 11
- Views: 701
Re: Cell Diagram
Yes, if we only have (aq) or (g) at one side and no electrode told.
- Sat Mar 14, 2020 10:19 am
- Forum: Balancing Redox Reactions
- Topic: Oxidation number
- Replies: 12
- Views: 1097
Re: Oxidation number
So what is the difference between oxidation number and the charge the atom carries?
- Sat Mar 14, 2020 10:18 am
- Forum: Balancing Redox Reactions
- Topic: Half Reactions
- Replies: 15
- Views: 756
Re: Half Reactions
The problem would probably tell you whether the solution is acidic or basic. But you always add H2O when balancing oxygen.
- Sat Mar 14, 2020 10:04 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: intermediates
- Replies: 8
- Views: 523
Re: intermediates
It is first formed as a product and then a reactant in the reaction.
- Sat Mar 14, 2020 10:02 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: kinetics vs. thermodynamics
- Replies: 23
- Views: 1160
Re: kinetics vs. thermodynamics
So if a product forms when the temperature is high, it is controlled by thermodynamics; if another product forms when the temperature is low, it is controlled by kinetics since it has a relatively low activation ennergy.
- Sat Mar 07, 2020 1:43 pm
- Forum: Experimental Details
- Topic: determining order of reaction
- Replies: 6
- Views: 627
Re: determining order of reaction
Usually, graphs of k and t will be given for a reaction for us to find out its order.
- Sat Mar 07, 2020 1:39 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Inert electrode
- Replies: 9
- Views: 520
Re: Inert electrode
When you only have a solution and gas at one side of the cell.
- Sat Mar 07, 2020 1:38 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: finding n in G=-nFE
- Replies: 15
- Views: 953
Re: finding n in G=-nFE
After you balance the redox reaction, the number of electrons in the overall reaction is n.
- Sat Mar 07, 2020 1:36 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Rate-Limiting Step
- Replies: 5
- Views: 328
Re: Rate-Limiting Step
It is either given in the problem, or it matches the rate law.
- Sat Mar 07, 2020 1:35 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Calculating ln Q
- Replies: 20
- Views: 1387
Re: Calculating ln Q
Q is the reaction quotient. When we are using the Nernst Equation in a concentration cell, we should try to make lnQ negative.
- Sun Mar 01, 2020 5:04 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 10
- Views: 465
Re: Salt Bridge
It allows for a complete electric circuit by letting the ions and the charge that they carry to move.
- Sun Mar 01, 2020 5:02 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Where to find Ecell values
- Replies: 15
- Views: 794
Re: Where to find Ecell values
Appendix 2B. I googled one table for Ecell values but calculations based on those were not the same as the solution manual.
- Sun Mar 01, 2020 4:58 pm
- Forum: Balancing Redox Reactions
- Topic: H+ or H2O
- Replies: 9
- Views: 565
Re: H+ or H2O
You balance the oxygen first by adding water and then you balance H+ if it is an acidic environment.
- Sun Mar 01, 2020 4:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cells
- Replies: 6
- Views: 407
Re: Galvanic Cells
Yes, it is. Because it is spontaneous, so delta G is negative for it.
- Sun Mar 01, 2020 4:54 pm
- Forum: Balancing Redox Reactions
- Topic: Reducing/Oxidizing Agents
- Replies: 13
- Views: 598
Re: Reducing/Oxidizing Agents
A reducing agent is a reactant that gives electrons (increase its oxidation number) during the reaction, while an oxidizing agent is the reactant which gains electrons during the reaction.
- Sat Feb 22, 2020 10:32 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cells
- Replies: 8
- Views: 436
Re: Galvanic Cells
It uses chemical energy in redox reactions to produce electricity.
- Sat Feb 22, 2020 10:31 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nerst Equation
- Replies: 10
- Views: 994
Re: Nerst Equation
No, but you can see it on the equation sheet.
- Sat Feb 22, 2020 10:29 am
- Forum: Balancing Redox Reactions
- Topic: Charge of oxygen
- Replies: 15
- Views: 687
Re: Charge of oxygen
The oxidation number of oxygen would probably always be 2.
- Sat Feb 22, 2020 10:28 am
- Forum: Identifying Acidic & Basic Salts
- Topic: Midterm 3C
- Replies: 9
- Views: 779
Re: Midterm 3C
Yes, because when it dissolves, the NH4+ ions in water can donate a proton, so it can lower the pH.
- Sat Feb 22, 2020 10:24 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Adding Inert Gas
- Replies: 20
- Views: 1017
Re: Adding Inert Gas
It has no effect because adding an inert gas would not change the concentration/partial pressure of the reactants and products.
- Sat Feb 15, 2020 3:56 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: P1/P2
- Replies: 10
- Views: 1129
Re: P1/P2
Because in the ideal gas law, P and V are inversely proportionate to each other.
- Sat Feb 15, 2020 3:53 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta G and spontaneity
- Replies: 4
- Views: 293
Re: Delta G and spontaneity
Yes, because when delta G is negative, it tends to release energy when proceeding to the products, and vice versa.
- Sat Feb 15, 2020 3:51 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Meaning of q=-w
- Replies: 14
- Views: 2221
Re: Meaning of q=-w
Usually, in an isothermally reversible gas expansion, the work done by the heat equals the heat it received.
- Sat Feb 15, 2020 3:50 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard Enthalpies of Formation
- Replies: 10
- Views: 509
Re: Standard Enthalpies of Formation
delta H naught is 0 when the element is in its most stable form.
- Sat Feb 15, 2020 3:49 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Joules or KJ?
- Replies: 14
- Views: 2486
Re: Joules or KJ?
Most of the time J.
- Sat Feb 08, 2020 11:59 am
- Forum: General Science Questions
- Topic: Midterm
- Replies: 17
- Views: 889
Re: Midterm
The pizza rolls review sheet can be super helpful.
- Sat Feb 08, 2020 11:56 am
- Forum: Ideal Gases
- Topic: Temperature
- Replies: 17
- Views: 689
Re: Temperature
Most of the time yes, because you have to cancel the units in the gas constant R. But when you are calculation the difference between temperatures, for example, in the equation involving heat capacity, you don't have to worry about that.
- Sat Feb 08, 2020 11:53 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Spontaneous vs Nonspontaneous
- Replies: 4
- Views: 167
Re: Spontaneous vs Nonspontaneous
It depends on the sign of delta G. If delta G is negative, the forward reaction can occur spontaneously.
- Sat Feb 08, 2020 11:48 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy of a combustion reaction?
- Replies: 7
- Views: 371
Re: Enthalpy of a combustion reaction?
It is usually negative because heat is released during the combustion process.
- Sat Feb 08, 2020 11:47 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Closed Systems
- Replies: 13
- Views: 626
Re: Closed Systems
Probably temperature, volume, and pressure since we can only change the "energy" part of the system.
- Sat Feb 01, 2020 3:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Discussion
- Replies: 8
- Views: 250
Re: Discussion
No, but we have to hand in the homework. The practise questions in the discussion are usually helpful.
- Sat Feb 01, 2020 3:35 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated vs Closed [ENDORSED]
- Replies: 34
- Views: 3984
Re: Isolated vs Closed [ENDORSED]
Yes, it is isolated in an ideal situation because we can neither exchange substance nor energy with the surrounding.
- Sat Feb 01, 2020 3:29 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Material
- Replies: 13
- Views: 634
Re: Midterm Material
There is a review sheet and some sessions provided by the UAs, which is super useful for midterms and finals.
- Sat Feb 01, 2020 3:27 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: reaction enthalpy
- Replies: 14
- Views: 436
Re: reaction enthalpy
It requires energy to break a bond, so the change in energy should be positive. When a bond form, the system indeed goes more stable, with less energy, so it releases energy, and the enthalpy should be negative.
- Sat Feb 01, 2020 3:24 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes
- Replies: 17
- Views: 642
Re: Phase Changes
Yes, during phase change, the temperature remains constant, but latent heat is released or absorbed.
- Sat Jan 25, 2020 3:56 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heat vs. Enthalpy
- Replies: 6
- Views: 141
Re: Heat vs. Enthalpy
Enthalpy is the change of heat in a chemical reaction, while heat is a more general term.
- Sat Jan 25, 2020 3:53 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: sign changes in bond enthalpy
- Replies: 5
- Views: 129
Re: sign changes in bond enthalpy
Energy is required when we break a bond, so the sign should be positive. When bonds form, it releases energy, and so the sign should be negative.
- Sat Jan 25, 2020 3:52 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Percent Ionization
- Replies: 12
- Views: 491
Re: Percent Ionization
It should be the final ionized acid/base divided by the initial concentration of the acid/base.
- Sat Jan 25, 2020 3:50 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Grading of Tests
- Replies: 18
- Views: 643
Re: Grading of Tests
Yes, we can get partial credit.
- Sat Jan 25, 2020 3:19 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam Burn
- Replies: 6
- Views: 191
Re: Steam Burn
When the steam hits your art, it releases its latent heat because it is changing its phase from a gas to a liquid.
- Sun Jan 19, 2020 10:26 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Quadratic Equation
- Replies: 8
- Views: 340
Re: Quadratic Equation
When the equilibrium constant is 10^-3 or greater, we should use the quadratic equation.
- Sun Jan 19, 2020 10:23 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE Tables
- Replies: 13
- Views: 407
Re: ICE Tables
Is it the same reason that we do not include it when we are calculating the equilibrium constant?
- Sun Jan 19, 2020 10:20 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q < K
- Replies: 16
- Views: 763
Re: Q < K
Yes, it is. The product side is favoured.
- Sun Jan 19, 2020 10:19 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: pKa
- Replies: 13
- Views: 429
Re: pKa
The stronger an acid, the smaller the pka.
- Sun Jan 19, 2020 10:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Q
- Replies: 14
- Views: 284
Re: K vs Q
k is a constant and is used as a standard that we can compare with. Q is what we can calculate based on the data we've got.
- Sat Jan 11, 2020 2:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Change in k
- Replies: 11
- Views: 469
Re: Change in k
K is a constant and if anything of the environment changes, such as the temperature, the system adjusts to the changes, resulting in the constant k.
- Sat Jan 11, 2020 2:48 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Table 5G.2
- Replies: 5
- Views: 124
Re: Table 5G.2
We can use the Kc in this table if the question asks us to solve for concentrations of gases in the reaction, such as question 5.39.
- Sat Jan 11, 2020 2:45 pm
- Forum: Ideal Gases
- Topic: Topics on Test 1
- Replies: 37
- Views: 1194
Re: Topics on Test 1
Probably outline1 and ouline2.
- Sat Jan 11, 2020 2:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: using Kp vs Kc
- Replies: 13
- Views: 1490
Re: using Kp vs Kc
In fact, you can use both. Table 5G.2 shows an example of how Kc works for gas reactions.
- Sat Jan 11, 2020 2:39 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic and endothermic reactions
- Replies: 4
- Views: 113
Re: Exothermic and endothermic reactions
We can see the exothermic reaction as a reaction with "heat" as a product. Thus if we increase temperature of the system, we are indeed increasing the "concentration" of heat (product), so the reaction goes to the left. It works the same as in an endothermic reaction. We simply s...
- Thu Dec 05, 2019 1:00 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: London disperson
- Replies: 6
- Views: 258
Re: London disperson
Yes, because the electrons in all the molecules have a chance to move to a place where a dipole appears.
- Thu Dec 05, 2019 12:58 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxolate Chelate
- Replies: 6
- Views: 325
Re: Oxolate Chelate
No, chelates can form at least BIdentate.
- Thu Dec 05, 2019 12:57 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: ICE tables
- Replies: 3
- Views: 249
Re: ICE tables
We need to know the basic calculation of the concentration of titration for a strong acid and a strong base, plus the situation of the equivalence point involving a weak base and a strong acid, or a strong base and a weak acid.
- Thu Dec 05, 2019 12:51 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelate
- Replies: 5
- Views: 339
Re: Chelate
A few examples of biological importance we covered in class are necessary to know, at least.
- Thu Dec 05, 2019 12:43 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric vs Amphiprotic
- Replies: 9
- Views: 518
Re: Amphoteric vs Amphiprotic
polyprotic means an acid can give more than one proton and its conjugate base can accept more than one proton.
- Wed Nov 27, 2019 7:13 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test #2 handback
- Replies: 11
- Views: 663
Re: Test #2 handback
Are we going to get them on week 10?
- Wed Nov 27, 2019 6:47 pm
- Forum: Student Social/Study Group
- Topic: Grades
- Replies: 18
- Views: 1049
Re: Grades
Will we be curved based on the performance of the whole class?
- Wed Nov 27, 2019 6:41 pm
- Forum: Hybridization
- Topic: Sigma and Pi Bonds
- Replies: 21
- Views: 915
Re: Sigma and Pi Bonds
Single bond: sigma bond
Double bond: one sigma bond+one pi bond
Triple bond: one sigma bond+two pi bonds
Double bond: one sigma bond+one pi bond
Triple bond: one sigma bond+two pi bonds
- Wed Nov 27, 2019 6:39 pm
- Forum: Conjugate Acids & Bases
- Topic: strength of an acid and its conjugate base
- Replies: 3
- Views: 226
strength of an acid and its conjugate base
Is it true that a relatively weak acid has a stronger conjugate base and a relatively weak base has a stronger acid?
Re: 9C.3
The order you put your ligand doesn't. The order seems only easier to name, instead.
- Sun Nov 24, 2019 3:34 pm
- Forum: Naming
- Topic: Final Format
- Replies: 6
- Views: 328
Re: Final Format
More questions cover topics from the beginning of this quarter, with a focus after the midterm, on the molecular shape, bonding, acids and base.
- Sun Nov 24, 2019 3:32 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent Shape
- Replies: 31
- Views: 2750
Re: Bent Shape
one or two, which also decide the bond angle.
- Sun Nov 24, 2019 3:30 pm
- Forum: Dipole Moments
- Topic: Melting points
- Replies: 15
- Views: 1249
Re: Melting points
The bond strength of a double bond is talking about "INTRA" molecular force, while the melting point is related to "INTER" molecular force.
- Sun Nov 24, 2019 3:27 pm
- Forum: Biological Examples
- Topic: Heme complex
- Replies: 8
- Views: 603
Re: Heme complex
I think on a test, we would be asked to identify which transition metal is bound to which ligand at least, and describe why this is important for all living things?
- Sun Nov 24, 2019 3:22 pm
- Forum: Student Social/Study Group
- Topic: Any tips on how to catch up in this class?
- Replies: 16
- Views: 891
Re: Any tips on how to catch up in this class?
Professor Lavelle has posted some outlines/learning outcomes on his class website. Read through them and find some videos online to catch up. Those videos online are good learning materials because they are more focused and test problem oriented. Good luck.
- Wed Nov 13, 2019 7:54 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Linear VSEPR model
- Replies: 21
- Views: 1199
Re: Linear VSEPR model
That would be a bent shape. I believe we'll talk about this in a few days.
- Wed Nov 13, 2019 7:53 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR model angles
- Replies: 7
- Views: 363
Re: VSEPR model angles
Yes, they are always popular test materials.
- Wed Nov 13, 2019 7:52 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Class grading
- Replies: 12
- Views: 726
Re: Class grading
For this midterm, I don't think he would curve, either.
- Wed Nov 13, 2019 7:50 pm
- Forum: Dipole Moments
- Topic: Hydrogen bonds
- Replies: 17
- Views: 678
Re: Hydrogen bonds
Only with O, F and N because they have the highest electronegativity.
- Wed Nov 13, 2019 7:49 pm
- Forum: Properties of Light
- Topic: Midterm Solution Q2.A
- Replies: 2
- Views: 176
Re: Midterm Solution Q2.A
Question2 tests your knowledge of the photoelectric effect, which indicates that light can be viewed as particles. The first thing you need to do is to convert 492 KJ for a mole of light particles to the work function of a single light particle.
- Fri Nov 08, 2019 10:35 am
- Forum: Octet Exceptions
- Topic: elements in 3p block
- Replies: 8
- Views: 483
Re: elements in 3p block
Their n=3, which indicates that they are able to have 3d orbitals.
- Fri Nov 08, 2019 10:34 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Formal Charge
- Replies: 9
- Views: 1390
Re: Formal Charge
After checking the formal charge, we also prefer structures that have -1 on the more electronegative atoms.
- Fri Nov 08, 2019 10:33 am
- Forum: Dipole Moments
- Topic: Drawing Unpaired Electrons
- Replies: 7
- Views: 295
Re: Drawing Unpaired Electrons
Yes, always include all the electrons in the structure.
- Fri Nov 08, 2019 10:31 am
- Forum: Lewis Structures
- Topic: Midterm grades
- Replies: 26
- Views: 1306
Re: Midterm grades
Like Test1 which is also graded by the TAs, it should take one week.
- Fri Nov 08, 2019 10:30 am
- Forum: Dipole Moments
- Topic: How do i know if a molecule has a dipole moment?
- Replies: 7
- Views: 354
Re: How do i know if a molecule has a dipole moment?
A symmetric molecule usually does not have a dipole moment, but if it is asymmetric, check the difference in electronegativity, so you can find out its dipole moment.
- Fri Nov 08, 2019 10:28 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarisability vs Polarizing Power
- Replies: 15
- Views: 1043
Re: Polarisability vs Polarizing Power
Polarizing power describes the power of a cation to distort an anion, and polarisability is the property of how easy an anion is distorted.
- Fri Nov 08, 2019 10:25 am
- Forum: General Science Questions
- Topic: Test 2
- Replies: 20
- Views: 763
Re: Test 2
It should cover materials started from "bond strength" and "molecular shape", just after the midterm.
- Fri Nov 08, 2019 10:24 am
- Forum: Octet Exceptions
- Topic: Lewis Acids and Bases?
- Replies: 11
- Views: 483
Re: Lewis Acids and Bases?
Lewis Acids are electron acceptors and Lewis Bases are electron donors.
- Sun Oct 27, 2019 1:09 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy
- Replies: 9
- Views: 360
Re: Ionization Energy
A positive sign means taking energy into the system or the system needs energy to so some certain activity. The negative sign means the system releases energy or loses energy during activity.
- Sun Oct 27, 2019 1:06 pm
- Forum: Ionic & Covalent Bonds
- Topic: Midterm Topics Covered
- Replies: 7
- Views: 338
Re: Midterm Topics Covered
I think it would cover the Quantum World all the way to the start of molecular shape, for we still have one week before the midterm.
- Sun Oct 27, 2019 1:02 pm
- Forum: Lewis Structures
- Topic: Drawing the structure
- Replies: 7
- Views: 375
Re: Drawing the structure
Yes, it is a Lewis structure and P is able to extend the octet because it is in the d-block.
- Sun Oct 27, 2019 1:00 pm
- Forum: Trends in The Periodic Table
- Topic: Exceptions in the trends
- Replies: 4
- Views: 275
Exceptions in the trends
Hi, what are some examples of exceptions in the periodic trends, such as the radii of oxygen and nitrogen do not fit the trend?
- Sun Oct 27, 2019 12:57 pm
- Forum: Lewis Structures
- Topic: Expanded Octet
- Replies: 6
- Views: 178
Re: Expanded Octet
Elements that have d-orbitals are able to fit more than 8 valence electrons, so they can expand the Octet.
- Sun Oct 20, 2019 8:16 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: s-, p-, d- ,f- orbitals
- Replies: 10
- Views: 441
Re: s-, p-, d- ,f- orbitals
n=2, (principle quantum number, shell); l=1, (subshell is p); x describes the axis of the orbital.
- Sun Oct 20, 2019 8:14 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals
- Replies: 8
- Views: 249
Re: Orbitals
So for Cr, 5 electrons in 5 3d orbitals and 1 electron in 4s has lower energy than 4 electrons in 3d, and 2 electron in 4s.
- Sun Oct 20, 2019 8:05 pm
- Forum: *Shrodinger Equation
- Topic: Schrodinger for exam
- Replies: 20
- Views: 780
Re: Schrodinger for exam
I think we only need to understand the relationship between Schrodinger's equation and quantum numbers. After all, the emphasis of Focus 1 (Quantum World) is still on the model of electrons and properties of light.
- Sun Oct 20, 2019 8:01 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Advice for studying
- Replies: 92
- Views: 6216
Re: Advice for studying
Do every homework question and read concepts on the text bool as well. Tne syllabus says 1/8 of the homework questions are likely to be on the exams as well, so we should definitely pay attention to those questions.
- Sun Oct 20, 2019 7:58 pm
- Forum: Properties of Light
- Topic: MidTerms and Finals
- Replies: 11
- Views: 367
Re: MidTerms and Finals
I think the midterm is in the evening, lasting for 2 hours, so it is unlikely on a discussion session. For the final, it won't be in the lecture or the discussion.
- Sun Oct 13, 2019 1:14 pm
- Forum: Photoelectric Effect
- Topic: Frequency vs Energy per Photon
- Replies: 4
- Views: 112
Re: Frequency vs Energy per Photon
Increasing the number of photons means increasing the intensity of light, counterintuitively. Only when the energy of each photon is sufficient, can it remove a electron. One photon is responsible for removing an electron, so it is the energy (frequency) counts, not the number of photons.
- Sun Oct 13, 2019 1:03 pm
- Forum: Photoelectric Effect
- Topic: 1B.9
- Replies: 2
- Views: 121
Re: 1B.9
For this question, first calculate the total energy the lamp produced in 2 seconds. Then use E=hc/\lambda[/tex] to calculate the energy of a single violet photon. Divide the first result (total energy) with your result in the second step (energy of a single photon), should give to the answer to the ...
- Sun Oct 13, 2019 12:53 pm
- Forum: Properties of Light
- Topic: 1A.11
- Replies: 3
- Views: 226
Re: 1A.11
For this question, try to think of the the lower energy level of these groups of lines. For example, for the Lyman series, these lines show the lower energy level of the transition of an electron from different energy levels is n=1, while for Balmer, it is n=2.
- Sun Oct 13, 2019 12:49 pm
- Forum: DeBroglie Equation
- Topic: DeBroglie Equation
- Replies: 9
- Views: 344
Re: DeBroglie Equation
Considering the DeBroglie equation, which needs you to calculate the momentum=mv, the light does not have a mass, so you can't use this equation for light.
- Wed Oct 09, 2019 8:06 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Typical wavelength for spectrum
- Replies: 2
- Views: 105
Typical wavelength for spectrum
Hi, why is the UV light a typical experiment tool to conduct atomic spectroscopy? I know it has great energy and can probably excite electrons, but why do we usually use this wavelength of light to conduct related experiments? Thank you.
- Sat Oct 05, 2019 3:32 pm
- Forum: Balancing Chemical Reactions
- Topic: Fractions in Balancing Equations
- Replies: 11
- Views: 12846
Re: Fractions in Balancing Equations
After you finish balancing the chemical equations, always remember to convert fractions into integrals because fractions should never appear in chemical equations to the definition of stoichiometric coefficients.
- Sat Oct 05, 2019 3:28 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Converting Before or After?
- Replies: 10
- Views: 539
Re: Converting Before or After?
It would be easier and clearer to do all the converting after you solve the question and do the correct the calculations, and if you can cancel the units and cut it to a reasonable/desired unit, the answer would probably be right.
- Sat Oct 05, 2019 3:24 pm
- Forum: Properties of Light
- Topic: Classical Mechanics vs. Quantum Mechanics
- Replies: 4
- Views: 88
Re: Classical Mechanics vs. Quantum Mechanics
Hi, so in a classical mechanics, we see things and explain the reasons behind them in a macro scale, and as a result, our measurement is continuous. In a quantum mechanics, or a situation for micro things, everything is so small that we can only use discrete numbers to describe a transition. Try to ...
- Sat Oct 05, 2019 3:17 pm
- Forum: Significant Figures
- Topic: Question about significant figures and rounding a number
- Replies: 4
- Views: 303
Re: Question about significant figures and rounding a number
Thank you for the replying. I saw the textbook said that when we rounded numbers with stuff like 0.75, we should round it to the nearest even number, so 0.8(+0.5), but for 0.65, it should be rounded to 0.6(-0.5). Is this right?
- Tue Oct 01, 2019 3:50 pm
- Forum: Significant Figures
- Topic: Question about significant figures and rounding a number
- Replies: 4
- Views: 303
Question about significant figures and rounding a number
Hi, I have a question about rounding numbers to its nearest integral, tenth, or hundredth, etc, and how the significant figure can effect that. For example, how to round 5.454545 and 5.55555 and make them each have 1,2,3 or 4 significant figures? Thank you.
- Mon Sep 30, 2019 9:46 pm
- Forum: Limiting Reactant Calculations
- Topic: Methods of identifying Limiting Reactants
- Replies: 5
- Views: 764
Re: Methods of identifying Limiting Reactants
Hi Baoying, calculating the limiting reactant can be a tough task because the evidence we use to prove which reactant is limited is indeed the balanced chemical equations with their stoichiometric coefficients. Therefore, you either calculate the moles of each reactant to find the limiting one as th...