Search found 103 matches
- Sun Mar 14, 2021 9:18 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: ΔU
- Replies: 9
- Views: 603
Re: ΔU
deltaU = 0 in isothermal reactions.
- Sun Mar 14, 2021 9:16 am
- Forum: Calculating Work of Expansion
- Topic: W= -PDeltaV
- Replies: 15
- Views: 1826
Re: W= -PDeltaV
Yes, this equation can only be used for irreversible expansion, where pressure is constant.
- Sun Mar 14, 2021 9:11 am
- Forum: Van't Hoff Equation
- Topic: Delta H naught VS delta H
- Replies: 28
- Views: 2330
Re: Delta H naught VS delta H
The "naught" is used to indicate standard conditions, so delta H naught would be change in enthalpy under standard conditions, while delta H is just change in enthalpy in general.
- Sun Mar 14, 2021 9:09 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Which R to use
- Replies: 42
- Views: 2860
Re: Which R to use
Hi for that you would use the 8.314 value. When you're not sure, I would take a look at the units when solving for the problem to see which R constant best fits your calculations.
- Sun Mar 14, 2021 9:06 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Temperature of Standard Conditions
- Replies: 5
- Views: 460
Re: Temperature of Standard Conditions
Yes for standard conditions, temperature would be 25C or 298 K.
- Sun Mar 14, 2021 4:31 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Determining slow step
- Replies: 5
- Views: 397
Re: Determining slow step
I think normally they would tell you the slow step, but if not you can calculate each step's reaction rate and compare to determine the slow step and its rate.
- Sun Mar 14, 2021 4:29 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: About k
- Replies: 26
- Views: 2735
Re: About k
k (lowercase) refers to the rate of reaction, so a large k value will indicate a fast reaction rate.
- Sun Mar 14, 2021 4:28 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: determining order [ENDORSED]
- Replies: 7
- Views: 592
Re: determining order [ENDORSED]
Yes it's possible since you can look at patterns in the experiment table and see how the reaction rate changes as concentrations change, and from there you can determine the order.
- Sun Mar 14, 2021 4:25 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Slowest step
- Replies: 38
- Views: 1376
Re: Slowest step
The slowest step determines the rate of reaction since the reaction is only complete once the slowest step is finished.
- Sun Mar 14, 2021 3:21 am
- Forum: Balancing Redox Reactions
- Topic: Sapling week 7/8 #18
- Replies: 25
- Views: 4782
Re: Sapling week 7/8 #18
Thanks! It was really helpful!
- Sun Mar 14, 2021 3:20 am
- Forum: Balancing Redox Reactions
- Topic: Acidic and Basic Redox Reactions
- Replies: 7
- Views: 570
Re: Acidic and Basic Redox Reactions
Yes these look correct and is a really good summary!
- Sun Mar 14, 2021 3:18 am
- Forum: Balancing Redox Reactions
- Topic: Studying for finals?
- Replies: 47
- Views: 1993
Re: Studying for finals?
For me, I would go through the textbook problems and also read the sapling explanations.
- Sun Mar 14, 2021 3:18 am
- Forum: Balancing Redox Reactions
- Topic: Exercise 6K Question 3
- Replies: 4
- Views: 330
Re: Exercise 6K Question 3
Thanks for the explanations! I was also a bit confused on these parts as well, they really helped!
- Sun Mar 14, 2021 3:12 am
- Forum: Balancing Redox Reactions
- Topic: oxidation numbers
- Replies: 9
- Views: 614
Re: oxidation numbers
Thanks! I was also a little confused too.
- Tue Mar 09, 2021 5:14 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Does phase matter in Hess's Law?
- Replies: 21
- Views: 1848
Re: Does phase matter in Hess's Law?
Yes phases do matter in Hess's Law since the change from one phase to another phase involves releasing/absorbing energy.
- Tue Mar 09, 2021 5:12 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy vs Entropy
- Replies: 39
- Views: 3002
Re: Enthalpy vs Entropy
Enthalpy refers to the heat released/absorbed in the system, while Entropy refers to the disorder of the system.
- Tue Mar 09, 2021 5:09 am
- Forum: Phase Changes & Related Calculations
- Topic: Voltage difference
- Replies: 9
- Views: 772
Re: Voltage difference
Hi, E(max) refers to the maximum voltage difference.
- Tue Mar 09, 2021 5:04 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated Systems
- Replies: 15
- Views: 770
Re: Isolated Systems
If I'm not wrong, the concept of an isolated system is theoretical since no matter what there will always at least some exchange of energy.
- Tue Mar 09, 2021 5:01 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Free Energy
- Replies: 49
- Views: 1882
Re: Free Energy
Hi, state functions are not dependent on the path taken to achieve the final state (meaning only the initial and final state are important), and free energy is an example.
- Tue Mar 09, 2021 4:58 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Open vs closed
- Replies: 31
- Views: 2755
Re: Open vs closed
An open system allows for the exchange of matter and energy between the system and the surroundings, a closed system only allows for the exchange of energy, while an isolated system does not allow for either to occur. Hope this helps!
- Tue Mar 09, 2021 4:57 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: q and w for an Isolated System
- Replies: 19
- Views: 3273
Re: q and w for an Isolated System
Yes, in an isolated system q and w would both be 0, since no energy is exchanged between the surrounding and the system.
- Tue Mar 09, 2021 4:55 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Is thermal mugs an example of an isolated system?
- Replies: 38
- Views: 1895
Re: Is thermal mugs an example of an isolated system?
Yes, if the mug cap is sealed then the thermal mug would be an example of an isolated system.
- Tue Mar 09, 2021 4:54 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated System
- Replies: 5
- Views: 408
Re: Isolated System
Hi! Dr. Lavelle did talk about isolated systems in one of his lectures, but an isolated system is essentially a system where no heat/energy or matter is exchanged with its surroundings.
- Tue Mar 09, 2021 4:52 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Adding a gas
- Replies: 26
- Views: 1002
Re: Adding a gas
Since Argon is a noble gas, it will have no effect on the reaction.
- Tue Mar 09, 2021 4:50 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q Calculations
- Replies: 21
- Views: 931
Re: Q Calculations
Yes normally the units for Q would be mol/L
- Mon Mar 01, 2021 6:24 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: isobaric
- Replies: 20
- Views: 1121
Re: isobaric
Isobaric refers to a system under constant pressure.
- Mon Mar 01, 2021 6:23 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: State property
- Replies: 47
- Views: 3470
Re: State property
Hi, state properties don't take into account the path taken to achieve the final value. So, work and heat aren't state properties since they do take into account the path.
- Mon Mar 01, 2021 6:20 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Sign of work
- Replies: 17
- Views: 740
Re: Sign of work
Hi, if work is being done on the system then work will be positive. Meanwhile, if work is being done by the system then work will be negative.
- Mon Mar 01, 2021 6:18 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: work
- Replies: 21
- Views: 860
Re: work
Actually it's the opposite!
- Mon Mar 01, 2021 6:18 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Useful Summary of Thermodynamic Definitions
- Replies: 55
- Views: 18344
Re: Useful Summary of Thermodynamic Definitions
Thanks for the summary!
- Mon Mar 01, 2021 6:17 am
- Forum: Calculating Work of Expansion
- Topic: R constant of an Ideal Gas
- Replies: 16
- Views: 720
Re: R constant of an Ideal Gas
Hi! For me I would look at the units for the R constants given and see which R value's units best fit the equation you are using.
- Mon Mar 01, 2021 6:15 am
- Forum: Calculating Work of Expansion
- Topic: Work sign
- Replies: 46
- Views: 1893
Re: Work sign
Hi! A negative sign would indicate that work is being done by the system, while a positive sign would indicate work is being done on the system.
- Mon Mar 01, 2021 6:14 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Log or ln
- Replies: 22
- Views: 1522
Re: Log or ln
They give different values so I don't think they can be used interchangeably.
- Mon Mar 01, 2021 6:13 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Sapling 10
- Replies: 9
- Views: 423
Re: Sapling 10
Hi, if I'm not wrong I think you would have to look up the standard reduction potentials in the given table.
- Mon Mar 01, 2021 6:11 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in ∆G = -nFE
- Replies: 80
- Views: 3802
Re: n in ∆G = -nFE
Hi, n actually refers to the number of mol of electrons being transferred, which you can find through a balanced reaction.
- Mon Mar 01, 2021 6:09 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Gibbs free energy
- Replies: 18
- Views: 996
Re: Gibbs free energy
Hi! Standard Gibbs free energy is found under standard constant conditions for pressure, temperature, etc. while Gibbs free energy is calculated under different conditions (not fixed).
- Mon Mar 01, 2021 6:07 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Tables
- Replies: 36
- Views: 1589
Re: ICE Tables
Hi! Like everyone else said, the x-values are determined by the coefficients.
- Mon Mar 01, 2021 6:05 am
- Forum: Ideal Gases
- Topic: Chem BL
- Replies: 107
- Views: 7116
Re: Chem BL
Hey! I'm taking Chem 14BL in the spring and 14C in the fall.
- Mon Mar 01, 2021 5:49 am
- Forum: Ideal Gases
- Topic: K and Q
- Replies: 57
- Views: 3060
Re: K and Q
They have different values since Q is the ratio between products and reactants at any point in the reaction, while K is while at equilibrium.
- Mon Mar 01, 2021 5:44 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Sapling Week 7/8 #15
- Replies: 6
- Views: 352
Re: Sapling Week 7/8 #15
Since solids aren't counted when solving for Q, you'd only use [Mg2+] and [Sn2+].
- Mon Mar 01, 2021 5:38 am
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox
- Replies: 16
- Views: 827
Re: Balancing Redox
You can calculate the number of electrons to put on each side by finding the charges present on each side, and you would add electrons to each side accordingly to balance the charge for the overall equation. Hope this helps!
- Sun Feb 14, 2021 10:25 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Sapling Learning Week 5 and 6 Homework Question 7
- Replies: 4
- Views: 1425
Re: Sapling Learning Week 5 and 6 Homework Question 7
Also thank you so much this was really helpful!
- Sun Feb 07, 2021 3:58 am
- Forum: Phase Changes & Related Calculations
- Topic: when to assume x is insignificant
- Replies: 86
- Views: 6385
Re: when to assume x is insignificant
I believe that Lavelle said during lecture that if the equilibrium constant is below 10^-4 (to be on the safe side), you can assume x as insignificant.
- Sun Feb 07, 2021 3:56 am
- Forum: Phase Changes & Related Calculations
- Topic: Define Phase Change
- Replies: 78
- Views: 4902
Re: Define Phase Change
Hi! Phase change is essentially the change between the phases of solid, liquid, and gas. Hope this helps!
- Sun Feb 07, 2021 3:54 am
- Forum: Phase Changes & Related Calculations
- Topic: Why does steam cause severe burns?
- Replies: 22
- Views: 1626
Re: Why does steam cause severe burns?
The reason why steam causes severe burns is because of the high temperature of water vapor and also since the water vapor condenses on the skin, even more energy is released in the form of heat due to the change of water from vapor phase to liquid phase.
- Sun Feb 07, 2021 3:51 am
- Forum: Phase Changes & Related Calculations
- Topic: Boiling water
- Replies: 25
- Views: 2761
Re: Boiling water
When water boils, hydrogen bonds between water molecules are broken, which results in water vapor. The hydrogen bonds between water molecules are the reason why water boils at such a high temperature. Hope this helps!
- Sun Feb 07, 2021 3:49 am
- Forum: Phase Changes & Related Calculations
- Topic: Endothermic vs exothermic
- Replies: 24
- Views: 1637
Re: Endothermic vs exothermic
Water condensing on a surface is exothermic because the water changes from vapor phase to liquid phase, meaning that energy is lost. Hope this helps!
- Sun Feb 07, 2021 3:47 am
- Forum: Phase Changes & Related Calculations
- Topic: Vapor vs gas
- Replies: 121
- Views: 8894
Re: Vapor vs gas
Yeah, if I'm not wrong vapor and gas refer to the same thing.
- Sun Feb 07, 2021 3:46 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Strong Acids/Bases
- Replies: 19
- Views: 1281
Re: Strong Acids/Bases
Thanks everyone! I also wasn't sure which strong acids and bases to memorize, but the response and charts were really helpful.
- Sun Feb 07, 2021 3:43 am
- Forum: Ideal Gases
- Topic: Exo vs Endothermic
- Replies: 40
- Views: 2252
Re: Exo vs Endothermic
A general rule is that breaking bonds takes energy while forming bonds release energy. So in this case, the reaction would be exothermic since bonds are formed.
- Sat Dec 12, 2020 6:50 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: HBrO2 vs HClO2
- Replies: 7
- Views: 980
HBrO2 vs HClO2
Hi! So I know that HBr is stronger than HCl because of the longer H - Br bond, but how come HBrO2 is weaker acid than HClO2?
- Thu Dec 10, 2020 9:50 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric Oxides
- Replies: 2
- Views: 595
Re: Amphoteric Oxides
Since the diagonal band of amphoteric oxides really closely correlates to the metalloids on the periodic table, I'd say mainly focus on that. Also looking at the molecule's net charge also helps too.
- Thu Dec 10, 2020 9:47 pm
- Forum: DeBroglie Equation
- Topic: De broglie equation versus E=hv
- Replies: 10
- Views: 740
Re: De broglie equation versus E=hv
I believe the debroglie's equation is for objects with mass, while E = hv can be only used for photons.
- Sun Dec 06, 2020 9:26 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 Dispersion
- Replies: 33
- Views: 1672
Re: London Dispersion
Hi London Dispersion forces exist in all molecules! However, molecules bigger in size will have stronger London dispersion forces compared to a smaller molecule.
- Sun Dec 06, 2020 9:24 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Does pH indicate strength of an acid?
- Replies: 26
- Views: 2360
Re: Does pH indicate strength of an acid?
Yes, those things are the same things because the pH scale is used to indicate acidity. Low pH will indicate it is an acid, and that is a result of the higher concentration of H+ ions when dissolved in water. Hope this helps!
- Sun Dec 06, 2020 9:19 pm
- Forum: Ionic & Covalent Bonds
- Topic: lone pairs -polar molecule
- Replies: 15
- Views: 1167
Re: lone pairs -polar molecule
Hi, I wouldn't assume that if a molecule has lone pairs it would be polar, since for example diatomic molecules do have lone pairs but are nonpolar because the dipole moments cancel out.
- Sun Dec 06, 2020 9:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: Polar and Nonpolar
- Replies: 37
- Views: 1676
Re: Polar and Nonpolar
Hi, what I normally do is that I draw out the 3D structure of the molecule and seeing if the dipole moments cancel out.
- Sun Dec 06, 2020 9:15 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 16
- Views: 785
Re: Electron Affinity
Hi, when two elements on the periodic table are next to each other, the element on the right would have a higher electron affinity because electron affinity increases across a period from left to right
- Sun Dec 06, 2020 9:11 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Silver Electron Configuration
- Replies: 9
- Views: 2703
Re: Silver Electron Configuration
Hi, I think silver's electron configuration is [Kr] 4d10 5s1 because it's more stable since the d-orbital is completely occupied. Hope this helps!
- Sun Dec 06, 2020 9:08 pm
- Forum: *Black Body Radiation
- Topic: Understanding Black Body Radiation
- Replies: 8
- Views: 666
Re: Understanding Black Body Radiation
Hi, if I'm not wrong a black body is a theoretical "body" that absorbs all wavelengths of EM radiation, and black body radiation is the radiation that it emits. Hope this helps!
- Sun Dec 06, 2020 9:06 pm
- Forum: Properties of Light
- Topic: Photoelectric Effect
- Replies: 14
- Views: 808
Re: Photoelectric Effect
Yes E(excess) is equal to the kinetic energy, because that's the energy in "excess" after the minimum energy required to eject an electron is reached if that makes sense. Hope this helps!
- Sun Dec 06, 2020 9:03 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: d orbitals
- Replies: 11
- Views: 1540
Re: d orbitals
Yeah you are correct! It doesn't matter if it's s-, p-, d-, or f- each orbital will have a max of 2 electrons. And if we look at the d-block of the periodic table, we can count that there are 10 electrons total in the d subshell, with a total of 5 orbitals. Hope this helps!
- Sun Dec 06, 2020 8:59 pm
- Forum: Properties of Electrons
- Topic: intensity vs energy
- Replies: 29
- Views: 3168
Re: intensity vs energy
This should be false, because on the quantum level an increase in intensity means an increase in the number of photons, while an increase in energy increases the actual energy of each photon itself. Hope this helps!
- Sun Dec 06, 2020 8:57 pm
- Forum: Properties of Light
- Topic: Is c always the speed of light?
- Replies: 92
- Views: 4923
Re: Is c always the speed of light?
Yeah I believe c will always be the speed of light!
- Sun Dec 06, 2020 8:55 pm
- Forum: Significant Figures
- Topic: When should I start looking at sig figs?
- Replies: 31
- Views: 1382
Re: When should I start looking at sig figs?
Hi, I normally don't round to the number of sig figs need until the final answer. Hope that helps!
- Sun Dec 06, 2020 8:54 pm
- Forum: SI Units, Unit Conversions
- Topic: How to memorize prefixes
- Replies: 36
- Views: 3444
Re: How to memorize prefixes
Hi, mnemonics are definitely a great way to memorize these prefixes and constant repetition (although takes time) works well too!
- Sun Dec 06, 2020 8:51 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: How to find coordination number.
- Replies: 10
- Views: 2950
Re: How to find coordination number.
Hi, you can find the coordination by counting the number of bonds connected to the central metal atom. Hope that helps!
- Sun Dec 06, 2020 8:47 pm
- Forum: Naming
- Topic: "(en)" Sapling
- Replies: 19
- Views: 856
Re: "(en)" Sapling
Hi, (en) is short for the bidentate molecule ethylenediamine. Hope that helps!
- Tue Dec 01, 2020 9:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Delocalized vs localized
- Replies: 12
- Views: 644
Re: Delocalized vs localized
If I'm not wrong, delocalized electrons are electrons not associated with only one atom, meaning that they are not fixed in a certain position.
- Tue Dec 01, 2020 9:34 pm
- Forum: Hybridization
- Topic: How to find the hybridization
- Replies: 14
- Views: 681
Re: How to find the hybridization
^^ I'm also a bit confused about the differences between unhybridized orbitals and hybridized orbitals (John's question). If anyone can help explain that would be great!
- Tue Dec 01, 2020 9:29 pm
- Forum: Hybridization
- Topic: How to find the hybridization
- Replies: 14
- Views: 681
Re: How to find the hybridization
Hi, you would just count the regions of electron density (numbers of atoms bonded to + lone pairs) and it will correspond to a hybridization, like 2 to sp, 3 to sp^3, and so on.
- Tue Dec 01, 2020 9:26 pm
- Forum: Hybridization
- Topic: How to simply determine hybridization
- Replies: 27
- Views: 10488
Re: How to simply determine hybridization
Hi, so you can determine hybridization by counting the regions of electron density (so counting number of atoms bonded and lone pairs), and from there you can correspond to it to the hybridization like counting 2 would correspond to sp, 3 to sp^2, and so on.
- Mon Nov 23, 2020 5:19 pm
- Forum: Electronegativity
- Topic: determining electronegativity
- Replies: 40
- Views: 5552
Re: determining electronegativity
The trend in the periodic table is that electronegativity increases left to right in periods / top to bottom in groups!
- Mon Nov 23, 2020 5:16 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: Vapor pressure
- Replies: 3
- Views: 290
Re: Vapor pressure
Vapor pressure I believe is correlated with evaporation rate (higher vapor pressure indicates higher evaporation rate), so stronger intermolecular forces would result in a lower vapor pressure, since the stronger forces would make it harder for the substance to vaporize.
- Mon Nov 23, 2020 5:05 pm
- Forum: Bond Lengths & Energies
- Topic: Covalent Bond Length
- Replies: 13
- Views: 1366
Re: Covalent Bond Length
Hi, bond length is affected by the atomic radius size, electronegativity, and whether it is a single/double/triple bond.
- Mon Nov 23, 2020 5:03 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Optimal Formal Charge Configuration
- Replies: 3
- Views: 220
Re: Optimal Formal Charge Configuration
Hi, the more electronegative atom should get the negative formal charge and the less electronegative atom should get the positive formal charge, as that would make the molecule more stable.
- Mon Nov 23, 2020 5:00 pm
- Forum: Dipole Moments
- Topic: Polarity
- Replies: 30
- Views: 1264
Re: Polarity
Polar bonds form due to the difference in electronegativities between the atom but these bonds can cancel out due to the orientation of the molecule as a whole.
- Mon Nov 23, 2020 4:54 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidations Numbers
- Replies: 4
- Views: 452
Re: Oxidations Numbers
Thanks for the explanation! He didn't go over it really and I was also stuck on oxidation numbers.
- Mon Nov 23, 2020 4:50 pm
- Forum: Electronegativity
- Topic: How to memorize
- Replies: 6
- Views: 308
Re: How to memorize
I think for this class we dont necessarily need to memorize the actual electronegativity numerical values, but just the trends in electronegativity in elements. So just how electronegativity increases left to right in periods / top to bottom in groups and how electronegativity is generally greater i...
- Mon Nov 23, 2020 4:36 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Best Formal Charge Equations
- Replies: 24
- Views: 1034
Re: Best Formal Charge Equations
Hi, for formal charge I also use the lines/dots way FC = valence electrons - # dots - # bonds/lines since it gives me more of a visual picture that helps me with picturing the charge.
- Mon Nov 23, 2020 4:33 pm
- Forum: Octet Exceptions
- Topic: Expansion for 3s?
- Replies: 4
- Views: 201
Re: Expansion for 3s?
Hi, I'm pretty sure that atoms with 3s valence e- can't expand into 3d for ground state. I think the expanded octet concept mostly applies to the p-orbital if I'm not wrong.
- Sat Nov 14, 2020 10:50 am
- Forum: Resonance Structures
- Topic: Delocalized Electrons
- Replies: 7
- Views: 332
Re: Delocalized Electrons
Hi, delocalized electrons from what I know are electrons that are not just shared between a pair of atoms, but can be found in different positions (resonance).
- Sun Nov 08, 2020 12:49 am
- Forum: Ionic & Covalent Bonds
- Topic: Atomic Radius
- Replies: 38
- Views: 2952
Re: Atomic Radius
Hi, the atomic radius in the top right is related to the complete octet of the elements because as the octet starts to fill up, there are more valence electrons for the protons in the nucleus to interact with, the attraction being stronger.
- Sun Nov 01, 2020 3:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Participation Points [ENDORSED]
- Replies: 62
- Views: 3325
Re: Participation Points [ENDORSED]
I was also wondering the same, thanks for clarifying!
- Sun Nov 01, 2020 3:53 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: wavelength
- Replies: 13
- Views: 534
Re: wavelength
Hi, because wavelength is a measure of the distance between two adjacent points in a wave, wavelength can't be negative. Hope it helps!
- Sun Nov 01, 2020 3:50 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic Radius
- Replies: 30
- Views: 2938
Re: Atomic Radius
Hi, the atomic radius decreases as you go across the period from left to right because of the increase in valence electrons, while it increases when you go down the groups because there's more subshells. Hope this helps!
- Sat Oct 31, 2020 8:49 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Sapling Homework
- Replies: 8
- Views: 283
Re: Sapling Homework
Hi, that electron configuration looks correct but I'd say maybe take out the commas and spaces? You can also try writing the full electron configuration if that doesn't work. Hope you figure it out!
- Sat Oct 31, 2020 8:44 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 4s and 3d
- Replies: 14
- Views: 426
Re: 4s and 3d
Hi, so in this case 3d comes first because the 3d orbital has lower energy when compared to the 4s orbital. Hope this helps! This is one of the main exceptions talked about because it seems out of order.
- Sun Oct 25, 2020 7:12 pm
- Forum: *Black Body Radiation
- Topic: What is Black Body?
- Replies: 53
- Views: 2224
Re: What is Black Body?
Hi, Lavelle went over this briefly during lecture, but essentially black body is a theoretical concept where a material would absorb all forms of wavelengths/frequencies of EM radiation, making it appear "black" (it would be invisible to our eyes).
- Sun Oct 25, 2020 7:08 pm
- Forum: Properties of Light
- Topic: Light spectrum
- Replies: 8
- Views: 258
Re: Light spectrum
Hi, like everyone has said above, because the wavelengths aren't provided on the constants sheet it's a good idea to memorize at least the general order of wavelengths associated with the EM radiation. Probably wouldn't hurt to know the wavelengths outside the visible light spectrum as well.
- Sun Oct 25, 2020 6:06 pm
- Forum: Photoelectric Effect
- Topic: Mass of atoms
- Replies: 18
- Views: 560
Re: Mass of atoms
Hi, when using mass of electrons or protons or whatever you’d be using the standard SI units in the problem so yes, you’ll be using kg. Also Lavelle sent out a constants sheet with all the masses that you’ll be able to use on the exam so no need to memorize them!
- Sun Oct 25, 2020 5:00 pm
- Forum: Properties of Electrons
- Topic: intensity vs energy
- Replies: 29
- Views: 3168
Re: intensity vs energy
Hi, personally I think this statement is false as it doesn’t take into account the different views on light. On the quantum view, increasing the intensity does not increase the energy of the individual protons (you’d have to increase frequency in order to do that)
- Sat Oct 24, 2020 1:07 am
- Forum: DeBroglie Equation
- Topic: Practice Problem
- Replies: 7
- Views: 497
Re: Practice Problem
Hi, just make sure to read the problem very carefully and make note of the units you are working with before you start. For this problem, make sure you convert the mass into kg and convert the final answer wavelength to nm (as the problem asks). Also it's useful to include units while you're solving...
- Fri Oct 23, 2020 11:04 pm
- Forum: Properties of Light
- Topic: Wavelength
- Replies: 14
- Views: 530
Re: Wavelength
Hi, even though the SI units is meters, I normally would convert my final answer to nm. I think when it comes to the final answer, either m or nm should be fine (I don't think you'll be penalized if you use either). It's just that make sure use meters for wavelength while you're solving for the answ...
- Sat Oct 17, 2020 2:17 pm
- Forum: Einstein Equation
- Topic: m vs nm
- Replies: 66
- Views: 3310
Re: m vs nm
Either should be fine as long as the conversions are done correctly, but personally I prefer to use nm in my final answer.
- Sat Oct 17, 2020 2:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Built-in webcams/Equipment request [ENDORSED]
- Replies: 22
- Views: 1467
Re: Built-in webcams/Equipment request [ENDORSED]
Hi, you can just use a second device like a phone or iPad if you have one that you can use to show your workspace. That way you don't have to spend extra money and buy an external separate external webcam!
- Sat Oct 17, 2020 2:08 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 17426
Re: How are you studying?
Hi, personally I find just doing the textbook review questions to be very helpful as well as taking notes on the Audio-Visual Focus-Topics modules + the assessments are very useful too. Good luck!
- Sat Oct 17, 2020 2:04 pm
- Forum: Significant Figures
- Topic: Sig Figs and Constants on Exams
- Replies: 9
- Views: 508
Re: Sig Figs and Constants on Exams
Hi, I think it should be fine to round the constants (just not too much) as long as you keep the proper sig figs for the answer. I don't think it'll make that much of a difference :)
- Sat Oct 10, 2020 2:49 pm
- Forum: Limiting Reactant Calculations
- Topic: Best way to find limiting reactant
- Replies: 5
- Views: 271
Re: Best way to find limiting reactant
Hi! For me personally, I find myself using the first method (the one Lavelle used) much more often because I think it's simpler and easier to understand. But I think just use whatever method works best for you! Both ways lead to the answer, so I think it's just based on personal preference.
- Sat Oct 10, 2020 2:38 pm
- Forum: Significant Figures
- Topic: How many significant figures are in 7.00 x 10^2?
- Replies: 25
- Views: 3469
Re: How many significant figures are in 7.00 x 10^2?
Hi! 700 only has 1 sig fig because there is no decimal but since 7.00 x 10^2 has a decimal with two trailing zeros behind it (zeros behind decimals are considered significant) it would have 3 sig figs.