Search found 97 matches
- Sat Mar 13, 2021 8:03 pm
- Forum: First Order Reactions
- Topic: Half Life Unit
- Replies: 38
- Views: 1427
Re: Half Life Unit
I think the units used really just depends on the context of the question, though most of it has been in seconds
- Sat Mar 13, 2021 8:00 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated Systems
- Replies: 15
- Views: 786
Re: Isolated Systems
A perfect isolated system is theoretical since there is always some kind of exchange with surroundings.
- Sun Mar 07, 2021 11:48 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: What was your favorite chem topic?
- Replies: 137
- Views: 8621
Re: What was your favorite chem topic?
Molecular structure was my favorite, and I actually found naming compounds just as fun for some reason.
- Sun Mar 07, 2021 11:43 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: K value
- Replies: 20
- Views: 794
Re: K value
Since K is just a proportionality constant, it must be positive then
- Sun Mar 07, 2021 11:19 pm
- Forum: Zero Order Reactions
- Topic: Overall order of the reaction
- Replies: 45
- Views: 1741
Re: Overall order of the reaction
By summing the individual orders, you can find the overall order of the reaction
- Sun Mar 07, 2021 11:12 pm
- Forum: General Rate Laws
- Topic: Rate Constant
- Replies: 31
- Views: 1135
Re: Rate Constant
Changing the temp changes the rate constant.
- Sun Mar 07, 2021 11:11 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Instantaneous Rate
- Replies: 41
- Views: 2095
Re: Instantaneous Rate
Instantaneous rate decreases as time goes and will approach 0 at equilibrium.
- Sun Feb 28, 2021 11:22 pm
- Forum: Balancing Redox Reactions
- Topic: Full molecule in half reactions?
- Replies: 8
- Views: 468
Re: Full molecule in half reactions?
I had the same molecule in my HW. I used the entire thing when writing my half-reactions.
- Sun Feb 28, 2021 11:18 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in ∆G = -nFE
- Replies: 80
- Views: 3824
Re: n in ∆G = -nFE
n is the moles of electrons being transferred. You can figure it out thru balancing your half-reactions and then the complete reaction
- Sun Feb 28, 2021 8:50 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: What is Potential?
- Replies: 14
- Views: 568
Re: What is Potential?
It measures the likelihood of a species gaining e-, or being reduced
- Sun Feb 28, 2021 8:43 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: E vs E naught
- Replies: 36
- Views: 1538
Re: E vs E naught
Like from thermodynamics, the naught just means under standard conditions
- Sun Feb 28, 2021 8:41 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode/Cathode
- Replies: 45
- Views: 1427
Re: Anode/Cathode
The anode should always be to the left of the salt bridge, and cathode to the right.
- Sun Feb 21, 2021 10:14 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: State function?
- Replies: 36
- Views: 1276
Re: State function?
Cell potential depends on the system's path, so it cant be a state function.
- Sun Feb 21, 2021 10:13 pm
- Forum: Balancing Redox Reactions
- Topic: coefficients for oxidation number
- Replies: 22
- Views: 4708
Re: coefficients for oxidation number
Coefficients are used for balancing the equation and do not affect oxidation numbers
- Sun Feb 21, 2021 10:11 pm
- Forum: Balancing Redox Reactions
- Topic: Cell/battery
- Replies: 26
- Views: 840
Re: Cell/battery
Cell and battery can be used interchangeably.
- Sun Feb 21, 2021 10:10 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: qrev
- Replies: 27
- Views: 1502
Re: qrev
Q is heat, and rev means for a reversible process.
- Sun Feb 21, 2021 10:09 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Cv and Cp
- Replies: 14
- Views: 2313
Re: Cv and Cp
The formula for this is Cv = Cp - R
- Sun Feb 14, 2021 7:13 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Sapling 3
- Replies: 13
- Views: 543
Re: Sapling 3
When delta H is positive, heat is being absorbed to break bonds. Since bonds are broken, molecules are free to occupy more possible positions. So if delta H is positive, delta S must be positive. When delta H is negative, it's exothermic, bonds are being formed. Molecules are a lot more rigid the mo...
- Sun Feb 14, 2021 7:04 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Entropy trends from 4H
- Replies: 8
- Views: 505
Re: Entropy trends from 4H
Larger molecules have a higher combination of possible states, so a higher entropy. Molecules that are not rigid are not confined in a particular position (like a gas), so they can occupy a wider range of positions
- Sun Feb 14, 2021 6:56 pm
- Forum: Calculating Work of Expansion
- Topic: irreversible vs reversible
- Replies: 14
- Views: 653
Re: irreversible vs reversible
If the question states or implies the process is very, very slow it's reversible. If the process happens quickly, it's irreversible.
- Sun Feb 14, 2021 6:52 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: qrev vs q
- Replies: 8
- Views: 441
Re: qrev vs q
qrev specifies isothermal/reversible expansion. q is a general expression of heat
- Sun Feb 14, 2021 6:50 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Closed vs Isolated System
- Replies: 30
- Views: 1225
Re: Closed vs Isolated System
Closed systems can exchange energy with its surroundings. Isolated systems are insulated, and cannot exchange energy.
- Sun Feb 07, 2021 11:47 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Work
- Replies: 39
- Views: 1395
Re: Work
If the system is doing work, its negative.
- Sun Feb 07, 2021 11:43 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: R Constant
- Replies: 91
- Views: 5223
Re: R Constant
I always write my units down even though it is tedious. Keep track of them to cancel out stuff to determine what constant R to use.
- Sun Feb 07, 2021 11:41 pm
- Forum: Calculating Work of Expansion
- Topic: Sapling week 3/4 #15
- Replies: 9
- Views: 502
Re: Sapling week 3/4 #15
Convert NaN3 to moles to find the amount of moles of N2 produced. Plug it in to the formula V=nRT/P, converting T into kelvin. Delta V would just be what you got for V in this case. Plug it into w=-P x delta V and you got your answer
- Sun Feb 07, 2021 8:34 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Can heat capacities be negative?
- Replies: 52
- Views: 13523
Re: Can heat capacities be negative?
Heat capacity is the heat required to raise temp, so it's always positive, not to be confused with enthalpies which can be +/-
- Sun Feb 07, 2021 8:30 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: External Pressure
- Replies: 32
- Views: 968
Re: External Pressure
External pressure is some outside force pushing against the system, internal is the system pushing against something.
- Sun Feb 07, 2021 8:29 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: deltaU
- Replies: 29
- Views: 792
Re: deltaU
It is the change in internal energy of a system, which equals q + w
- Sun Jan 31, 2021 11:51 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: State Function
- Replies: 22
- Views: 711
Re: State Function
It's because work depends on work and distance.
- Sun Jan 31, 2021 9:33 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Exothermic vs Extothermic
- Replies: 13
- Views: 405
Re: Exothermic vs Extothermic
To answer your last question, an exothermic reaction releases heat into the surroundings, which explains the temp increase, just like a hand warmer
- Sun Jan 31, 2021 9:30 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Diatomic molecules standard enthalpy of formation
- Replies: 22
- Views: 1200
Re: Diatomic molecules standard enthalpy of formation
Since diatomic models are likely in the most stable, natural form, the standard enthalpy will be 0.
- Sun Jan 31, 2021 9:29 pm
- Forum: Phase Changes & Related Calculations
- Topic: Define Phase Change
- Replies: 78
- Views: 4914
Re: Define Phase Change
Phase change is a change in state, like from liquid state to solid state.
- Sun Jan 24, 2021 8:45 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: X Approximations
- Replies: 23
- Views: 781
Re: X Approximations
Ka and Kb has to be negligible, so generally < 10^-14 to omit x. Hopefully your approximation is valid if the percent ionization is <5%, otherwise you gotta do more work
- Sun Jan 24, 2021 8:35 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Ice Tables
- Replies: 28
- Views: 960
Re: Ice Tables
For the basic ones, usually reactants is -x and products is +x, and coefficients depend on the stoichiometric coefficients. But for the more complex ones, you would need to know which side is more favorable to determine which side is -x and +x. So you gotta figure out if Q>k or Q<k.
- Sun Jan 24, 2021 6:01 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Difference between K and Kc
- Replies: 13
- Views: 607
Re: Difference between K and Kc
Kc specifically refers to concentration, like Kp refers to pressure.
- Sun Jan 24, 2021 5:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: How to find the H+ from pH
- Replies: 12
- Views: 469
Re: How to find the H+ from pH
pH = -log[H+], so simple algebra will get you the concentration 10^-pH = [H+]
- Sun Jan 24, 2021 5:57 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Ka correlation to strength of an acid
- Replies: 30
- Views: 2137
Re: Ka correlation to strength of an acid
A strong acid would have a high dissociation value, Ka
- Sun Jan 17, 2021 8:28 pm
- Forum: Phase Changes & Related Calculations
- Topic: Determining Stronger Acids
- Replies: 18
- Views: 657
Re: Determining Stronger Acids
If I recall from last quarter, the smaller the pKa, the stronger the acid.
- Sun Jan 17, 2021 8:27 pm
- Forum: Ideal Gases
- Topic: Kc vs. Kp
- Replies: 71
- Views: 2311
Re: Kc vs. Kp
Kc and Kp are calculated pretty much the same, the only difference you need to know is Kp is used for pressure.
- Sun Jan 17, 2021 8:12 pm
- Forum: Ideal Gases
- Topic: reversing reactions
- Replies: 83
- Views: 4846
Re: reversing reactions
In a reverse reaction, you take the reciprical, so 1/K
- Sun Jan 17, 2021 6:05 pm
- Forum: Ideal Gases
- Topic: Inverse Kc [ENDORSED]
- Replies: 41
- Views: 1900
Re: Inverse Kc [ENDORSED]
So you should be using the inverse for a reverse reaction!
- Sun Jan 17, 2021 6:04 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure Rule
- Replies: 29
- Views: 1314
Re: Pressure Rule
I believe solids and liquids don't count, only gases.
- Sun Jan 10, 2021 11:09 pm
- Forum: Ideal Gases
- Topic: value of R
- Replies: 24
- Views: 976
Re: value of R
R depends on the units used.
- Sun Jan 10, 2021 11:07 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: H2O
- Replies: 44
- Views: 1898
Re: H2O
Include it only when it's in a gaseous state.
- Sun Jan 10, 2021 11:05 pm
- Forum: Ideal Gases
- Topic: Units of Temperature
- Replies: 82
- Views: 3356
Re: Units of Temperature
The unit of temperature should be in Kelvin.
- Sun Jan 10, 2021 11:03 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K Favors Products or Reactants
- Replies: 20
- Views: 573
Re: K Favors Products or Reactants
Large K is above 10^3, and a small K is below 10^3.
- Sun Jan 10, 2021 11:00 pm
- Forum: Ideal Gases
- Topic: T variable in pv=nrt [ENDORSED]
- Replies: 38
- Views: 1548
Re: T variable in pv=nrt [ENDORSED]
Most of the time it is in Kelvin.
- Wed Dec 16, 2020 11:52 pm
- Forum: Naming
- Topic: Latin names
- Replies: 10
- Views: 664
Re: Latin names
If you don't know the Latin name, I think something like ironate is acceptable.
- Wed Dec 16, 2020 11:51 pm
- Forum: Student Social/Study Group
- Topic: Winter Break Plans
- Replies: 45
- Views: 1929
Re: Winter Break Plans
Sleep in, maybe brush up on acids and bases
- Fri Dec 11, 2020 11:36 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: What are electron donating groups?
- Replies: 3
- Views: 164
Re: What are electron donating groups?
Hey, to help you out a lil more, I found this neat video to determine e- donating groups and e- withdrawing groups!
https://www.youtube.com/watch?v=yEc6ov904S4
https://www.youtube.com/watch?v=yEc6ov904S4
- Wed Dec 09, 2020 11:53 pm
- Forum: Naming
- Topic: Textbook 9C.3 part c
- Replies: 1
- Views: 46
Textbook 9C.3 part c
Write the formula for tetraamminediaquacobalt(III) bromide
The answer for this [Co(NH3)4(OH2)2]Br3. I got the cation part, but I don't get how come the answer has 3 bromide. Can someone please explain?
The answer for this [Co(NH3)4(OH2)2]Br3. I got the cation part, but I don't get how come the answer has 3 bromide. Can someone please explain?
- Wed Dec 09, 2020 12:29 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Sapling Q #1
- Replies: 7
- Views: 313
Sapling Q #1
For Q1 of this week Sapling suggests that we memorize the strong acids and bases to rule out the weak ones. I suck at memorization and I'm better at understanding things conceptually. So, can some conceptually explain the answers to Q1 or do I really just need to memorize strong acids and bases?
- Sun Dec 06, 2020 5:50 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Textbook 1A.15
- Replies: 4
- Views: 292
Re: Textbook 1A.15
Since a wavelength of 102.6 nm is in the ultraviolet region, it would be in the Lyman series and thus have a value of n=1 for the final energy level. You would also have to find the frequency using the equation c=(wavelength)(frequency), and then use the Rydberg formula to find the value for the in...
- Sun Dec 06, 2020 5:44 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Textbook 1A.15
- Replies: 4
- Views: 292
Re: Textbook 1A.15
Varsha Ravi 2C wrote:Using 102.6nm, you should be able to figure out whether it's in the Balmer or Lyman series, which should tell you n(final). Using that value, you can work backwards and find the initial value.
So it's Lyman, n=1 is the final n level then?
- Sun Dec 06, 2020 5:42 pm
- Forum: Trends in The Periodic Table
- Topic: Focus 1 Exercise 13
- Replies: 3
- Views: 230
Re: Focus 1 Exercise 13
I believe that the reason why it's different for oxygen is because it's the first element in which the electrons are paired in the p-orbitals (nitrogen has 3 unpaired electrons, fluorine has 2 paired 1 unpaired). Because of this, it has a slightly lower ionization energy than nitrogen despite being...
- Sun Dec 06, 2020 5:37 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Textbook 1A.15
- Replies: 4
- Views: 292
Textbook 1A.15
Q: In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line.
How do I start this question?
How do I start this question?
- Sun Dec 06, 2020 5:30 pm
- Forum: Trends in The Periodic Table
- Topic: Focus 1 Exercise 13
- Replies: 3
- Views: 230
Focus 1 Exercise 13
Q: Ionization energies usually increase on going from left to right across the periodic table. The ionization energy for oxygen, however, is lower than that of either nitrogen or fluorine. Explain this anomaly.
I don't know where to begin thinking. Does anyone know how to explain this?
I don't know where to begin thinking. Does anyone know how to explain this?
- Sun Nov 29, 2020 4:57 pm
- Forum: Sigma & Pi Bonds
- Topic: Sapling Q #16
- Replies: 14
- Views: 847
Sapling Q #16
Which of the species contains a delocalized pi bond? HCN, O3, H2O, [CO3]2-
How do I approach this? What does it mean to be delocalized?
How do I approach this? What does it mean to be delocalized?
- Sun Nov 29, 2020 4:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: sigma vs pi bonds
- Replies: 33
- Views: 1989
Re: sigma vs pi bonds
A single bond is one sigma, double is sigma + pi, and triple is sigma + 2 pi. If you recall, the more bonds the shorter the distance btwn two atoms, so the stronger the bond.
- Sun Nov 29, 2020 4:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Tetrahedral vs Trigonal Pyramidal Structure
- Replies: 4
- Views: 735
Re: Tetrahedral vs Trigonal Pyramidal Structure
To answer your question about multiple names, in a way, yes. For example, for a central atom with 3 bonds and 1 lone pair, the electron domain geometry is tetrahedral, but the actual molecular geometry is trigonal pyramidal.
- Sun Nov 29, 2020 4:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone pairs and geometry
- Replies: 4
- Views: 238
Re: Lone pairs and geometry
I can sort of see what you guys mean. Can someone explain square pyramidal and square planar so I can better understand this?
- Sun Nov 29, 2020 3:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone pairs and geometry
- Replies: 4
- Views: 238
Lone pairs and geometry
why is it for molecular geometries like the T-shape the two lone pairs of e- are on the same plane? why can't one lone pair be equatorial and the other be axial? And for the see-saw, why is the lone-pair axial and not equatorial? hope what I'm saying makes sense.
- Sun Nov 22, 2020 5:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pair E-
- Replies: 47
- Views: 1806
Re: Lone Pair E-
Just to reiterate for the 20th time, yes, e- pairs are counted. E- repulsion can influence shape.
- Sun Nov 22, 2020 5:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Memorizing Shape Names
- Replies: 12
- Views: 537
Re: Memorizing Shape Names
For memorizing these shapes, just grind quizlet. Or just make some educated guess on a mc question.
- Sun Nov 22, 2020 4:50 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Character
- Replies: 33
- Views: 1430
Re: Covalent Character
Smaller EN difference, greater the covalent character. If I don't have a chart of exact EN values, I use what I know about periodic table trends to guesstimate
- Sun Nov 22, 2020 4:45 pm
- Forum: Lewis Structures
- Topic: Textbook Q 2.C.5
- Replies: 3
- Views: 133
Re: Textbook Q 2.C.5
Emam Healy 2K wrote:I had this same question. I think that O is more electronegative than Cl, and so it has a higher electron pulling power and really wants the full octet. Since O is more electronegative than Cl, it can handle having the negative formal charge.
Oh I see, that makes sense. Thank you!
- Wed Nov 18, 2020 11:28 pm
- Forum: Lewis Structures
- Topic: Textbook Q 2.C.5
- Replies: 3
- Views: 133
Textbook Q 2.C.5
The question asks to draw the lewis structure of ClO, chlorine monoxide. So the structure I drew has a single bond between the two, Cl with 3 pairs of electrons and O with 2 pairs and a lone electron. Both have a formal charge of 0. Though on the answer key, the structure shows that Cl has 2 pairs a...
- Sun Nov 15, 2020 4:48 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Sapling week 5 & 6 #5
- Replies: 20
- Views: 725
Re: Sapling week 5 & 6 #5
So C's FC is -2. This makes sense because this cancels the other charges, giving an overall charge of 0
- Sun Nov 15, 2020 4:39 pm
- Forum: Dipole Moments
- Topic: Dipole Questions
- Replies: 2
- Views: 84
Re: Dipole Questions
Hey, thank you for clarifying, makes a lot more sense
- Sat Nov 14, 2020 8:01 pm
- Forum: Dipole Moments
- Topic: Dipole Questions
- Replies: 2
- Views: 84
Dipole Questions
Can it be said that all molecules can be involved in dipole-induced dipole interactions? And do permanent dipoles always exist between two different atoms, even if the electronegativity difference is slight?
- Sat Nov 14, 2020 7:43 pm
- Forum: Electronegativity
- Topic: Determining Permanent Dipole
- Replies: 3
- Views: 675
Re: Determining Permanent Dipole
Check electronegativity. Like for H-F the F is definitely pulling H's e- towards it, creating a permanent dipole moment. Dipole-induced dipole occurs when for non-polar. A dipole needs to be create, hence induced. A polar molecule can influence the e- of a non-polar molecular. It can slightly attrac...
- Sat Nov 14, 2020 7:31 pm
- Forum: Dipole Moments
- Topic: H-Bond acceptor
- Replies: 9
- Views: 400
Re: H-Bond acceptor
Just like above, a partial charge is needed, and a there has to be an available lone pair as well
- Sun Nov 08, 2020 9:01 pm
- Forum: Octet Exceptions
- Topic: Expanded Octets
- Replies: 6
- Views: 147
Expanded Octets
I believe in one of Dr. Lavelle's lectures he drew something that had beyond 8e-. My HS chem teacher always said that everything must fulfill the octet rule, so this is pretty new to me. Can someone clarify in detail why some elements disobey the octet rule
- Sun Nov 08, 2020 8:53 pm
- Forum: Trends in The Periodic Table
- Topic: Tips for learning the trends in the Periodic table
- Replies: 11
- Views: 632
Re: Tips for learning the trends in the Periodic table
Personally, I would find it best to understand why the trends occur rather than memorize. I make sure to watch Dr. Lavelle's lectures again and other videos when needed. Then explain it to yourself out loud why elements are placed where they are. It takes a lot of time but it's best for my fish brai...
- Sat Nov 07, 2020 8:02 pm
- Forum: Trends in The Periodic Table
- Topic: Easy Way to Remember Trends
- Replies: 5
- Views: 507
Re: Easy Way to Remember Trends
I guess for memorizing the diatomic elements in the table a good acronym is "have no fear of ice cold beer" (H, N, F, O, I, Cl, Br)
For other trends, I think it would be better to know why the reason those trends occur rather than memorize, if you catch what I'm saying
For other trends, I think it would be better to know why the reason those trends occur rather than memorize, if you catch what I'm saying
- Sat Nov 07, 2020 7:58 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: sapling problem
- Replies: 3
- Views: 163
Re: sapling problem
Hi, I believe when it says "ample" bond character it means it somewhat has that bond character, as opposed to the other options which say the bonds have an "overwhelming" bond character of some type. The bond lengths that they tell us are found within the molecule are mostly in ...
- Sat Nov 07, 2020 7:51 pm
- Forum: Naming
- Topic: Formulas based on names
- Replies: 8
- Views: 1364
Re: Formulas based on names
Honestly I would memorize all the essentials because some questions on the textbook only give the nomenclature. Find a quizlet to save you stress in the future.
- Sat Oct 31, 2020 7:28 pm
- Forum: Photoelectric Effect
- Topic: Lyman Series
- Replies: 30
- Views: 1134
Re: Lyman Series
Lyman series is always n=1 but not always n(final)=1. It's UV light too
- Sat Oct 31, 2020 7:26 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Clarification on ml quantum number
- Replies: 7
- Views: 353
Re: Clarification on ml quantum number
Angular momentum and orientation
- Mon Oct 26, 2020 10:08 am
- Forum: Empirical & Molecular Formulas
- Topic: Finding Mass % Composition
- Replies: 4
- Views: 331
Re: Finding Mass % Composition
What do you mean by "using g/mol"? It seems like you're taking moles and turning it into grams if you're multiplying by g/mol (probably a molar mass?). What would you do if you had gram sample? Like a 1.00 g sample has 0.112 grams of H and 0.888 grams of O, and you wanted to find the empi...
- Mon Oct 26, 2020 9:48 am
- Forum: Empirical & Molecular Formulas
- Topic: Finding Mass % Composition
- Replies: 4
- Views: 331
Finding Mass % Composition
So everytime there is a mass % comp question, I always just find each % using g/mol instead of converting everything to just grams first. I still get the right answer this way. It saves time and reduces the chances of a calc error, in my opinion. I'm wondering if there is any scenario where converti...
- Sun Oct 25, 2020 6:33 pm
- Forum: Properties of Light
- Topic: 1A.3 Textbook problem
- Replies: 4
- Views: 186
Re: 1A.3 Textbook problem
So it can't be D because a decrease in frequency results in a decrease in energy. It can't be A because the speed is constant for all waves. It can't be B because frequency and wavelength have an inverse relationship. I think it's C because when frequency decreases, wavelength increases, and so the ...
- Sun Oct 25, 2020 6:22 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: When n= infinity, the energy required = 0
- Replies: 4
- Views: 604
Re: When n= infinity, the energy required = 0
As n approaches infinity, or as n gets bigger and bigger, E gets closer and closer to 0.
- Sat Oct 24, 2020 10:32 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg’s Constant
- Replies: 6
- Views: 310
Re: Rydberg’s Constant
Yup. How I think about it is that when its absorption, the electron takes in energy and jumps levels. So the lowest energy level must be the initial whether that be n=1 or something else When the electron emits a wave, it must fall energy levels due to conservation of energy. So the initial in emiss...
- Sat Oct 24, 2020 10:24 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Electron Transition Series
- Replies: 2
- Views: 191
Re: Electron Transition Series
Yeah, I think it's important to know the Lyman and Balmer series at least, I'm not sure about the other series. You may be given just the wavelength in a question, so knowing what part of the spectrum the wave is part of will help you find out n initial and n final.
- Fri Oct 23, 2020 8:21 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Wording of Problems
- Replies: 4
- Views: 123
Re: Wording of Problems
Combustion implies burning with oxygen present
- Fri Oct 23, 2020 8:09 pm
- Forum: Einstein Equation
- Topic: Sapling Q. 6
- Replies: 7
- Views: 370
Re: Sapling Q. 6
I calculated the wl in meters, and you got those right. But you just got the conversion wrong. When converting m to nm, you don't divide by 10^9 (what you did), you multiply the number in meters by 10^9. Intuitively, you should have a bigger number in nm than in m. Hope this resolves it
- Sun Oct 18, 2020 7:18 pm
- Forum: Properties of Electrons
- Topic: "hR" graph label
- Replies: 1
- Views: 88
Re: "hR" graph label
negative bc e- is bound to the nucleus, h is planck's constant and R is Rydberg constant. Fractions x -hR determine amt of energy required for the electron to jump, diff elements have different requirements
- Sun Oct 18, 2020 7:10 pm
- Forum: Properties of Electrons
- Topic: Light Emission
- Replies: 4
- Views: 572
Re: Light Emission
Yeah, an electron has to be hit with a certain color of light when for it to move up a certain energy level. This certain color of light has a certain energy level. The color is then emitted when the electron falls back down energy levels, because we needa respect that law of conservation. Different...
- Sun Oct 18, 2020 7:02 pm
- Forum: Properties of Electrons
- Topic: Mass conservation in atomic spectra experiments?
- Replies: 2
- Views: 68
Re: Mass conservation in atomic spectra experiments?
I think the law of conservation of energy mostly applies to this case instead, not conservation of mass. Like when an excited electron falls back down, it releases energy = sum of the initial level - final level, no more no less
- Fri Oct 16, 2020 8:02 pm
- Forum: Properties of Light
- Topic: Textbook Excercise A1.3
- Replies: 3
- Views: 101
Re: Textbook Excercise A1.3
Yo all EM radiation travels at the same speed, not a. Wavelength and frequency are inversely related, not b. Energy would decrease if frequency decreases, not d. Nice job on elimination I'm not really sure but how I tried to justify that it's c I thought about drawing wide squiggly lines (low freque...
- Fri Oct 16, 2020 7:25 pm
- Forum: Properties of Light
- Topic: Balmer and Lyman series
- Replies: 7
- Views: 272
Re: Balmer and Lyman series
Yeah, the Balmer series just means when an excited e- goes to n=1 and Lyman series is n=2. I guess you can tell which series the electron will be a part of if you find out what delta E is
- Sun Oct 11, 2020 4:41 pm
- Forum: SI Units, Unit Conversions
- Topic: Unit Conversion Tips
- Replies: 5
- Views: 267
Re: Unit Conversion Tips
Setup the fractions so you can cancel units out
- Sun Oct 11, 2020 2:40 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Solution Volume
- Replies: 2
- Views: 454
Solution Volume
Hello, I'm not sure how I should start approaching this question. A student prepared a solution of sodium carbonate by adding 2.111 g of the solid to a 250.0-mL volumetric flask and adding water to the mark. Some of this solution was transferred to a buret. What volume of solution should the student...
- Sat Oct 10, 2020 5:06 pm
- Forum: Significant Figures
- Topic: Mantissa in Logarithms
- Replies: 6
- Views: 282
Re: Mantissa in Logarithms
Ahh, I see. This will probably help when we eventually use logarithms in our calculations. Guess I shouldn't brush this off
- Fri Oct 09, 2020 7:42 pm
- Forum: Significant Figures
- Topic: Mantissa in Logarithms
- Replies: 6
- Views: 282
Re: Mantissa in Logarithms
The page doesn't give much info about the application of mantissa and characteristics haha. It just looks like some simple algebraic manipulations without getting anything new out of it. Maybe it's a way to clarify the amt of SF in the scientific notation of an exponent/logarithmic function of fract...
- Fri Oct 09, 2020 3:34 pm
- Forum: Significant Figures
- Topic: Mantissa in Logarithms
- Replies: 6
- Views: 282
Re: Mantissa in Logarithms
Brooo I've never seen the word Mantissa in my life. I'm trying to understand this too. On YT, several of the videos are not even in English though. Where did you even find this image, because it seems to me that knowing mantissa and characteristic is important if you have no access to a calculator a...