## Search found 64 matches

Thu Jan 21, 2021 12:36 pm
Forum: Phase Changes & Related Calculations
Topic: Phase changes and state properties
Replies: 2
Views: 9

### Re: Phase changes and state properties

Hi! If enthalpy of fusion is the energy required to melt a solid, and enthalpy of vaporization is the energy required to vaporize a liquid, then adding these two values together will give you the enthalpy for a solid to become vapor (sort of like multiplying the K constants when you combine two part...
Fri Jan 15, 2021 1:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: KA KB predicting trends (outline)
Replies: 6
Views: 30

### Re: KA KB predicting trends (outline)

Hi- there is a trend for these values. Stronger acids have lower pKa and thus a higher Ka. Stronger bases have a lower pKb and a higher Kb. You can compare relative strengths of acids and bases using these values!
Fri Jan 15, 2021 10:30 am
Forum: General Science Questions
Topic: Percent ionization
Replies: 2
Views: 31

### Re: Percent ionization

That looks right to me-- maybe you have a different value that's off?
Thu Jan 14, 2021 9:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling 1 #10
Replies: 3
Views: 54

### Re: Sapling 1 #10

Hi!
I believe your "b" term, 24.24, should be negative. With that, I got X=0.2375 which works out with the initial concentrations :)
Thu Jan 14, 2021 9:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Calculator for exams
Replies: 22
Views: 65

### Re: Calculator for exams

Hi, Last quarter all calculators were allowed (well, regular ones including scientific and graphic calculators like TI-84) so I would assume the same policy will be in place. I also am curious though if we are allowed to use a Quadratic Formula program on our calculators to solve equilibrium express...
Thu Jan 14, 2021 1:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKA, pKB, KA, KB
Replies: 7
Views: 28

### Re: pKA, pKB, KA, KB

A higher Kb means more products in a base's reaction with water, so a higher Kb value (and a lower pKb value) means a stronger base.
Thu Jan 07, 2021 1:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: concentration or partial pressure
Replies: 7
Views: 37

### Re: concentration or partial pressure

Kc is the equilibrium constant based on concentration, and the values given to you are in concentration (mol/L) so you don't have to worry about converting anything to pressure. If they gave you Kp, then you would have to.
Thu Jan 07, 2021 11:02 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium Part 3 Module
Replies: 2
Views: 13

### Re: Chemical Equilibrium Part 3 Module

The equilibrium constant is K=4, in the question :)
Thu Jan 07, 2021 9:29 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Aqueous in Partial Pressure K
Replies: 2
Views: 12

### Re: Aqueous in Partial Pressure K

Hi,
I believe Kp just wouldn't be relevant for a reaction that includes an aqueous compound. You'd only be able to use (and probably would only want to use) Kc. Plus I don't think Dr. Lavelle would test us on that anyway, thankfully ^^
Wed Jan 06, 2021 3:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: solids and liquids in k expression
Replies: 4
Views: 38

### Re: solids and liquids in k expression

Solids and liquids do change in reactions, however their concentration does not, and equilibrium constants are calculated based off of concentration. Solids don't change concentration b/c they have a fixed volume, and liquids/solvents' concentrations don't significantly change enough to include in t...
Wed Jan 06, 2021 3:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Audio-Visual Assessment 2 Question 29
Replies: 2
Views: 17

### Re: Audio-Visual Assessment 2 Question 29

To solve this I first found how much BrCl there is at equilibrium: (1.84x10^-4)*0.183= 3.367x10^-5 Subtracting that from the original amount of BrCl, we find that 1.503X10^-4 moles of the gas reacted and turned into Br2 or Cl2. Because the stoichiometric ratio is 2BrCl to 1Br2 (or Cl2), then half th...
Wed Jan 06, 2021 2:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: True or False?
Replies: 4
Views: 30

### Re: True or False?

Hi, this is true because the more products there are, the more reactants there will be, regardless of which is more than the other. The equilibrium constant is the ratio of products to reactants so if one increases, the other has to increase as well, until the equilibrium ratio is reached again.
Wed Dec 09, 2020 10:16 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: week 10 Sapling Q12
Replies: 2
Views: 30

### Re: week 10 Sapling Q12

Hi, I believe this is because as the amount of oxygens increases, the more evenly a negative charge on the molecule (after H+ is removed) can be distributed amongst the atoms, making the molecules with more Oxygens more stable as anions than the molecules with fewer oxygens. And when the molecule is...
Wed Dec 09, 2020 10:11 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acidity Stronger
Replies: 3
Views: 38

### Re: Acidity Stronger

Hi, I was also confused by this before but I think the general idea is that when comparing two acids and deciding which is more acidic, like you said you first want to compare the bond strength. For example, when comparing the acidity of HCl and HBr, the H-Br bond is longer since Br is bigger than C...
Wed Dec 09, 2020 10:03 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: emitting light and changing energy levels
Replies: 1
Views: 26

### Re: emitting light and changing energy levels

Hi, I think an "excited" electron means one that is already in the "excited" state, as in it is at a higher energy level n than it originally was, before it absorbed any light. So when the excited atom emits light, the electron moves back down to a lower energy level and becomes,...
Mon Dec 07, 2020 1:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Unable to view the lectures
Replies: 12
Views: 112

### Re: Unable to view the lectures

I'm having the same issue! I hope this is something that can get resolved soon because with finals coming up we'll be needing to watch the lectures even more...
Mon Dec 07, 2020 1:41 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pH>pKa deprotonation
Replies: 3
Views: 48

### pH>pKa deprotonation

I understand from today's lecture that when a weak acid is in a solution with greater pH, it will deprotonate because it is more acidic than the solution it is in. However I thought that a characteristic of weak acids was that they only somewhat deprotonate/ionize in solution... Does the pH have to ...
Thu Dec 03, 2020 4:40 pm
Forum: Naming
Topic: Formula Order
Replies: 4
Views: 42

### Formula Order

I noticed that the textbook says when writing a coordination compound formula from a name, the chemical symbols should be written in alphabetical order, but it also says that the answer to 9C.5(d) is Na[Fe(OH2)2(C2O4)2] where OH2 is written before C2O4. Also an example Dr. L gave in his lecture was ...
Wed Dec 02, 2020 2:59 pm
Forum: Bronsted Acids & Bases
Topic: Molarity and Strong Acid Ionization
Replies: 3
Views: 34

### Re: Molarity and Strong Acid Ionization

Hi! In order to determine pH, we have to determine the concentration of H+ ions, which acids dissociate into (as well as some other anion). Because strong acids are characterized by releasing a lot of H+ ions, strong acids break apart very easily in water (since the pull of the dipole of the water m...
Wed Dec 02, 2020 2:47 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Formation Constant (Kf)
Replies: 1
Views: 30

### Re: Formation Constant (Kf)

Hi!
Dr. Lavelle said that in 14A we will only be learning about pH calculations for strong acids and bases, which only involves something like 1 mol acid= 1 mol H+ + 1 mol X-, so we won't have to do calculations involving the equilibrium constant K (since that's only needed for weak acids/bases).
Wed Dec 02, 2020 12:01 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Hcl and H20 Equillibrium
Replies: 1
Views: 14

### Re: Hcl and H20 Equillibrium

Hi, I think maybe you meant that there was an equilibrium pointing towards H3O+ in the reaction with HCl and H2O. This is because in the chemical reaction HCl(aq) + H2O <-> H3O+(aq) + Cl- , HCl is considered a strong acid, which means it dissociates/ionizes a lot when it's put in water (because it h...
Wed Dec 02, 2020 11:20 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids
Replies: 8
Views: 67

### Re: Strength of Acids

Hi, you're right that HBr is a stronger acid than HCl, because it has a weaker bond so it dissociates more easily, causing it to give off more H+ ions in the solution. In the scheme of all acids though, I think both HBr and HCl are considered strong.
Wed Dec 02, 2020 11:17 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm 1 and 2 Review
Replies: 8
Views: 86

### Re: Midterm 1 and 2 Review

Hi, I don't think we're allowed to view our exams but if you go to any TA's office hours they can view your test and tell you which questions you got wrong!
Fri Nov 27, 2020 2:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: OClO
Replies: 1
Views: 30

### Re: OClO

Hi,
If you are talking about (ClO2)- the ion, I believe this is a bent shape with a tetrahedral arrangement. The regions of electron density determine arrangement (4 regions=tetrahedral) however because there are two lone pairs, the “formula” is X2E2 so the actual shape would be bent.
Fri Nov 27, 2020 2:07 pm
Forum: Hybridization
Topic: Drawing hybridization Aufbau Diagrams
Replies: 1
Views: 24

### Re: Drawing hybridization Aufbau Diagrams

Hi, I believe we only move some electrons to the higher p-orbital when the hybridization doesn’t involve all three p-orbitals. For example, with sp3 hybridized orbitals, all three p-orbitals are at the same energy level as the s-orbital so there would be no electrons in the regular p-orbital. In the...
Tue Nov 24, 2020 11:18 pm
Forum: Administrative Questions and Class Announcements
Replies: 1
Views: 49

Hi, I saw earlier in the quarter from Dr. Lavelle that the class is curved, so there isn’t a certain point range for each grade. It just depends on how well everyone does and the grades are distributed so that only a few students get A’s and D’s and more students get more average grades. Unfortunate...
Tue Nov 24, 2020 11:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling hw 8 #12
Replies: 6
Views: 72

### Re: Sapling hw 8 #12

Hi,
This questions just combining concepts we learned back at the beginning of the quarter with what we’re learning now! So yes, convert grams to moles and find the mole ratios to figure out the empirical formula of the molecule.
Tue Nov 24, 2020 4:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Scores
Replies: 9
Views: 95

### Re: Midterm 2 Scores

I scored exactly one point higher... so maybe a bit of progress? Haha
Will Dr. Lavelle announce the score distribution?
Wed Nov 18, 2020 4:12 pm
Forum: Lewis Structures
Topic: Ionic Lewis Structures
Replies: 2
Views: 27

### Re: Ionic Lewis Structures

Hi! You can recognize these as ionic compounds because out of their two components, one is a cation and one is an anion. For example, with ammonium chloride, ammonium is a cation since its formula is NH4+ and chloride is an anion since its formula is Cl-. Unfortunately you kind of have to know the f...
Wed Nov 18, 2020 3:57 pm
Forum: Lewis Structures
Replies: 4
Views: 46

Hi, and yes! Since bonds or lone pairs both have to have two electrons, all molecules that aren't radicals have to have an even number of electrons.
Tue Nov 17, 2020 6:59 pm
Forum: Bond Lengths & Energies
Topic: IMF vs. Intramolecular Forces
Replies: 7
Views: 55

### Re: IMF vs. Intramolecular Forces

I would guess by "strength of the molecule" it is referring to intramolecular forces. I think if it was referring to IMF it would be more explicit, because the strength of the molecule on its own doesn't really mean anything in terms of how strongly the molecules are attracted to one anoth...
Tue Nov 17, 2020 6:54 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures for Long Molecules
Replies: 2
Views: 14

### Re: Drawing Lewis Structures for Long Molecules

To draw this molecule, you just have to look at the formula they give us. With a lot of molecules, like ClONO2, they can tell you the structure just in the ordering of the atoms. With ClONO2, you have a central O atom with a Cl and N attached to it, and the other two O atoms are attached to the N. I...
Tue Nov 17, 2020 6:46 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Hybridization
Replies: 1
Views: 7

### Re: Hybridization

We have not gone over it, so no! I don't think Dr. L is mean enough to do that haha
Wed Nov 11, 2020 9:16 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Textbook 2A #5
Replies: 1
Views: 14

### Re: Textbook 2A #5

Hi! The copper atom is one of those examples where the full d orbital is lower energy and “preferred” over the full s orbital, like in the case of chromium. So, regular copper has 1 electron in the 4s-orbital and 10 electrons in the 3d-orbital. When an electron is removed, it’s removed from the oute...
Wed Nov 11, 2020 11:16 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: HCl4 and CCl4
Replies: 1
Views: 32

### Re: HCl4 and CCl4

Hi! I think you might mean CCl4 and CH4 (rather than HCl4). You are correct in that CCl4 has stronger Intermolecular forces (induced dipole-induced dipole interactions) because it has a lot more electrons. With more electrons, the molecule is bigger and “holds onto” its electrons less tightly than i...
Wed Nov 11, 2020 10:28 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing ground-state e- configurations
Replies: 3
Views: 30

### Re: Writing ground-state e- configurations

Hi! I believe we would get full points for writing it either way (unless specified) but the second way with the noble gas usually just takes less time so I think that way is better. Also, when looking at atoms bonding, we really only care about the valence electrons so writing out the e- configurati...
Wed Nov 11, 2020 10:20 am
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Community Points [ENDORSED]
Replies: 4
Views: 369

### Re: Chemistry Community Points[ENDORSED]

Yes, I’m sure that would still count for participation points (considering even posting on the chemistry jokes board counts :)
Tue Nov 10, 2020 8:12 pm
Forum: Coordinate Covalent Bonds
Topic: General Question on Coordinate Covalent Bonds
Replies: 8
Views: 81

### Re: General Question on Coordinate Covalent Bonds

Hi! I don’t think there’s an exact way to know if a bond is a coordinate covalent bond just from looking at it, but I can imagine that if you have a good idea of some common Lewis acids and bases (H+, NH3, etc) you might be able to know that a molecule was a result of these other molecules bonding. ...
Thu Nov 05, 2020 8:51 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: degenerate orbitals/electrons
Replies: 2
Views: 32

### Re: degenerate orbitals/electrons

Hi, "Degenerate" in our class so far has been used to refer to orbitals, and it means that they have the same energy. Not every orbital has the same energy but in some cases, like in single-electron atoms, different subshells of the same principal energy level are degenerate (eg, the 2s an...
Thu Nov 05, 2020 8:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: sapling problem
Replies: 3
Views: 49

### 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 t...
Thu Nov 05, 2020 8:36 pm
Forum: Ionic & Covalent Bonds
Topic: Polyatomics ions
Replies: 4
Views: 17

### Re: Polyatomics ions

Hi! The atoms within the molecules themselves are covalently bonded, however the molecule overall is an ion because it has that extra charge that would attract it to other (oppositely charged) ions.
Thu Nov 05, 2020 2:57 pm
Forum: Ionic & Covalent Bonds
Topic: section 2A
Replies: 1
Views: 22

### Re: section 2A

Hi! I believe the electron configuration is [Xe]4f 14 5d 10 6s 2 the f-subshell does contain 14 electrons (if you think about the fact that l=3, then there are seven possible values for m l , thus 14 electrons in all). I think that Lanthanum and Actinium are part of the d-block elements, so that is ...
Thu Nov 05, 2020 2:20 pm
Forum: Quantum Numbers and The H-Atom
Topic: ml and number of possible electrons
Replies: 6
Views: 51

### Re: ml and number of possible electrons

Yes, you're right. Every orbital (with three quantum numbers) has the "space" for two electrons, these electrons just must have opposite spins. I must admit I also don't completely understand exactly why there are two and only two electrons per orbital, but it seems to make sense when you ...
Sat Oct 31, 2020 2:03 pm
Forum: Properties of Electrons
Topic: How to find number of electrons
Replies: 8
Views: 86

### Re: How to find number of electrons

Hi! I believe you'd find this by first finding the energy per photon (of the radiation shining on the metal), using a frequency or wavelength given in the problem. Then in order to find the amount of photons, you would use the total energy given and divide that by the energy per photon. Assuming tha...
Wed Oct 28, 2020 5:49 pm
Forum: Trends in The Periodic Table
Topic: effective nuclear charge
Replies: 2
Views: 36

### Re: effective nuclear charge

The nuclear charge of an atom is the total of its protons, so for example Helium's nuclear charge is +2. The effective nuclear charge only applies to outer electrons, and it is the nuclear charge or pull on those electrons. Because of electron shielding, outer electrons (in multi-electron atoms) don...
Wed Oct 28, 2020 4:01 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Sapling Question
Replies: 4
Views: 75

### Re: Sapling Question

Hi! So, whatever the value for n is, the value for ℓ can be anything from 0 up to n-1. mℓ can take on any value from -ℓ to +ℓ. And every set of three quantum numbers applies to two electrons (as in, every orbital mℓ holds 2 electrons). For the first problem, n=3, ℓ can either be 0, 1, or 2. If ℓ is ...
Tue Oct 27, 2020 10:36 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra: Post-Module Survey
Replies: 2
Views: 23

### Re: Atomic Spectra: Post-Module Survey

This is actually because n 2 means the initial energy and n 1 means the final energy level. I was also confused at first because it might seem to make more sense that n 2 = the "second" energy level but now I just think about it in terms of, 2 is further from the nucleus and 1 is closer to...
Tue Oct 27, 2020 10:28 pm
Forum: DeBroglie Equation
Topic: Book Problem B21
Replies: 3
Views: 23

### Re: Book Problem B21

Hi,
it seems like you did everything correctly but I noticed you converted oz to grams- don't forget that the standard unit for plugging into equations is Kilograms. That should give you the correct answer!
Tue Oct 20, 2020 5:45 pm
Forum: General Science Questions
Topic: Rydberg Formula
Replies: 6
Views: 61

### Re: Rydberg Formula

Use the value 3.29x10^15 Hz for Rydberg's formula when using the equation v=R[1/n12-1/n22]. I noticed that the equation you used was "1/λ = RZ^2(1/n1^2 - 1/n2^2) and so maybe for that equation, R is different (though I've never seen that equation so I don't exactly know where it comes from). Bu...
Tue Oct 20, 2020 1:36 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.23 on Homework
Replies: 3
Views: 45

### Re: 1D.23 on Homework

Hi! So these quantum numbers signify an orbital that an electron can be in. Each energy level, also called a "shell," has a certain amount of "subshells" and then within those subshells are individual orbitals. n is the symbol for the energy level or shell and it can have any val...
Tue Oct 20, 2020 1:25 pm
Forum: General Science Questions
Topic: Rydberg Formula
Replies: 6
Views: 61

### Re: Rydberg Formula

Hi, you're right! That's how I solved this equation. Using v=R[1/n 1 2 -1/n 2 2 ], I first input n 1 =5 with n 2 =6, and then I input n 1 =1 with n 2 =6. I initially kept getting this question wrong, but I realized it was because of a mistake with the Sig Figs that Sapling used... the only way it ac...
Mon Oct 19, 2020 2:12 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Sapling week 2/3 question 8
Replies: 3
Views: 37

### Re: Sapling week 2/3 question 8

So for this question, because the wavelength is 656 nm, we know that the light is in the visible region, and on the emission/absorption spectrum for hydrogen, the spectral lines of the visible region (aka Balmer series) are a result of energy released from an electron that jumped from some n to n=2....
Mon Oct 19, 2020 1:59 pm
Forum: Properties of Electrons
Topic: Electrons and Losing Energy
Replies: 2
Views: 29

### Re: Electrons and Losing Energy

Electrons lose energy when they get closer to the nucleus because when an electron falls from some n to a lower n (energy level), it has to release the energy that it initially absorbed. Electrons only move to higher energy levels when they've absorbed electromagnetic radiation, so the only way for ...
Thu Oct 15, 2020 5:42 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Textbook Problem 1B.27
Replies: 1
Views: 28

### Textbook Problem 1B.27

I don't know if this is more of a question or a warning, but when I was working out problem 1B.27 I noticed that in order to get the correct answer, you have to insert 5.0 m/s for Δv, however the question states that the speed of the object is 5.00 ± 5.0 m/s... and that should mean that Δv is 10 m/s...
Wed Oct 14, 2020 6:14 pm
Forum: Quantum Numbers and The H-Atom
Topic: Sapling Q. 5
Replies: 2
Views: 57

### Re: Sapling Q. 5

Hi, I kept getting this question wrong but it turns out that it was just the sig figs that were incorrect! With the question, not us :( The question only gives one value, n=6, so I put both of my final answers with one sig fig, but it counted my second nm answer as incorrect until I input it with 2 ...
Wed Oct 14, 2020 2:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1.A.15 on Homework
Replies: 6
Views: 48

### Re: 1.A.15 on Homework

I was also confused about this question because I did get n=1 and n=3, but the textbook answer says "n1=1 to n2=3 making it sound like the electron moved from n=1 to n=3...
Tue Oct 13, 2020 5:24 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Post-Module number 20
Replies: 2
Views: 70

### Re: Heisenberg Post-Module number 20

The uncertainty equation for Kinetic Energy is the same as the one for kinetic energy, just with the uncertainty symbol in front of the variables that you are uncertain about: ΔE(k)=1/2m(Δv)^2 So if you have the uncertainty for velocity (which you can find with Δp=ΔV*m), then you can find the uncert...
Tue Oct 13, 2020 5:17 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Post-Assessment #29 for Atom Spectroscopy
Replies: 3
Views: 28

### Re: Post-Assessment #29 for Atom Spectroscopy

For this question I first used the equation c=λv to figure out what the frequency the radiation is with the wavelength given, and then used E=hv to calculate the energy per photon for that frequency. In order to find how many photons are generated in total, you just need to divide the 11 total Joule...
Mon Oct 12, 2020 7:37 pm
Forum: Student Social/Study Group
Topic: Clarification on buying an external webcam
Replies: 5
Views: 78

### Re: Clarification on buying an external webcam

I also got this, it seems we will need to get one but I think it's best to wait for your next discussion section to ask your TA about it before you actually spend the money
Wed Oct 07, 2020 12:04 am
Forum: Empirical & Molecular Formulas
Topic: Audio Visual Topic Video Question
Replies: 6
Views: 43

### Re: Audio Visual Topic Video Question

It works because no matter how large or small of a sample of something you take, the percent composition of its components will always be the same. And what matters when finding empirical formula is the ratio of each component, not the actual amount of each element in the sample. So if you have the ...
Tue Oct 06, 2020 11:53 pm
Forum: Photoelectric Effect
Topic: Which one of following is not describing the photoelectric effect?
Replies: 3
Views: 42

### Re: Which one of following is not describing the photoelectric effect?

Other people please correct me if I’m wrong but I believe the correct answer is D, c= λv, because although the equation is true (the speed of light equals wavelength times frequency), it doesn’t describe the “photoelectric effect,” it just describes the relationship of frequency and wavelength in li...
Tue Oct 06, 2020 9:35 pm
Forum: Quantum Numbers and The H-Atom
Topic: Atomic Spectra Post-Module Assessment #42
Replies: 2
Views: 36

### Re: Atomic Spectra Post-Module Assessment #42

Maybe the equation you’re missing is E(n)=(-hR/n^2) This equation gives you the energy of an electron in a certain energy level (n) so if you input the E value you get from this equation into the delta E equation you gave (deltaE(n)=E(n=4)-E(n=x)) you will find the correct energy value. E=hv applies...
Mon Oct 05, 2020 9:06 pm
Forum: Limiting Reactant Calculations
Topic: Calculating Maximum Mass
Replies: 3
Views: 71

### Re: Calculating Maximum Mass

Calculate the maximum mass of copper(II) hydroxide that can be formed when 2.00 g of sodium hydroxide is added to 80.0 mL of 0.500 M Cu(No3)2 (aq). First, I'd write out the equation. 2NaOH + Cu(NO3)2 --> Cu(OH)2 + 2NaNO3 Then calculate the moles of the reactants 2.00g of sodium hydroxide (mm 22.99+1...
Mon Oct 05, 2020 3:50 pm
Forum: Empirical & Molecular Formulas
Topic: Percent comp calculations
Replies: 5
Views: 79

### Re: Percent comp calculations

Seems like the explanation was given already but as an example, with butane C4H10, you would first find the total mass using the molar mass of each element in it: 4(12.01)+10(1.01) = 58.14 grams (because the molar mass of carbon is 12.01 g/mol and the molar mass of Hydrogen is 1.01 g/mol). Then take...