Search found 63 matches

by Jordan Young 2J
Mon Jan 20, 2020 6:22 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: definition of a buffer
Replies: 5
Views: 22

Re: definition of a buffer

A buffer has a weak acid/base and its conjugate so that it can thus resist a chance in pH. You want to have large enough concentrations of both so that it can react if an acid or base is added to the solution
by Jordan Young 2J
Mon Jan 20, 2020 6:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE tables
Replies: 5
Views: 9

Re: ICE tables

If you need to find the equilibrium concentration of a reactant of product or need to use the equilibrium concentration in a calculation you generally will need an ICE table. Also if you have to find the pH of the solution given the concentration of reactant, you will also most likely need an ICE ta...
by Jordan Young 2J
Tue Jan 14, 2020 3:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Table
Replies: 8
Views: 38

Re: ICE Table

Yes you can. You just have to make sure that all of the values in your ICE tables have the same units (initial, change, and equilibrium) and that if you are going to calculate a Kc or Kp value, that you convert to the proper units.
by Jordan Young 2J
Tue Jan 14, 2020 2:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G.1 d homework
Replies: 1
Views: 14

Re: 5G.1 d homework

Yes the statement would be true because if you start with a higher concentration of reactants, you will end up with a higher equilibrium concentration of products since the K stays the same.
by Jordan Young 2J
Mon Jan 13, 2020 11:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A21
Replies: 2
Views: 19

Re: 6A21

Temperature just has an affect on the K constant. So in this case, at that temperature, the equilibrium constant Kw is equal to 2.1*10^-14 instead of 1*10^-14 which is Kw at 25 degrees Celsius. From the question you know that the concentration of H3O equals the concentration of OH- because it is a s...
by Jordan Young 2J
Mon Jan 13, 2020 8:59 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: equilibrium constants and inputs
Replies: 4
Views: 21

Re: equilibrium constants and inputs

Solids don't have concentrations because it doesn't make sense for it to have one. Liquids/solvents in reaction generally do not change much in terms of concentration so we assume that the value stays the same and will be on both sides of the reaction so it has no effect on the equilibrium constant.
by Jordan Young 2J
Mon Jan 13, 2020 4:23 pm
Forum: Ideal Gases
Topic: Solids and liquids
Replies: 4
Views: 35

Re: Solids and liquids

Solids don't have concentrations because it doesn't make sense for solids to have a concentration. The concentration of liquids (which are usually solvents) don't change that much during a reaction so it is therefore not included in the equilibrium expression.
by Jordan Young 2J
Wed Jan 08, 2020 5:40 pm
Forum: Ideal Gases
Topic: Units for Pressure
Replies: 6
Views: 41

Re: Units for Pressure

It doesn't matter which unit you use, but you have to make sure the R constant value/units corresponds with that pressure unit to make sure that units cancel.
by Jordan Young 2J
Wed Jan 08, 2020 5:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How to find stability based off of equilibrium concentrations
Replies: 2
Views: 25

Re: How to find stability based off of equilibrium concentrations

I haven't done the exact problem yet but if you know the equilibrium concentrations of dichloride and chlorine or difluorine and fluorine, the one with the higher equilibrium concentration is more stable because the reactions proceeds to the more stable molecules.
by Jordan Young 2J
Wed Jan 08, 2020 4:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Writing K expression with or without aq?
Replies: 5
Views: 29

Re: Writing K expression with or without aq?

You do include molecules that are in an aqueous solution (aq)
by Jordan Young 2J
Wed Jan 08, 2020 12:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Kp vs Kc
Replies: 9
Views: 43

Re: K vs Kp vs Kc

K is general term for the equilibrium constant of products over reactants. Kp means that the values in the equilibrium constant are the partial pressures of usually gases. Kc means that the values in the equilibrium constant are concentrations of aqueous solutions
by Jordan Young 2J
Wed Jan 08, 2020 12:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Increasing the concentration of products?
Replies: 3
Views: 15

Re: Increasing the concentration of products?

Increasing the concentration of the products will cause the reaction to proceed towards the reactants in order to reach equilibrium
by Jordan Young 2J
Tue Dec 03, 2019 5:22 pm
Forum: Lewis Acids & Bases
Topic: Cations and Anions
Replies: 3
Views: 23

Re: Cations and Anions

I don't think so because the cations and anions of strong acids and bases are stable so they won't act as acids or bases (ex: Cl- from the dissociation HCl is a stable ion)
by Jordan Young 2J
Tue Dec 03, 2019 5:13 pm
Forum: Lewis Acids & Bases
Topic: Textbook 6C.17
Replies: 1
Views: 32

Re: Textbook 6C.17

I think it is because HBrO is a weak acid, which makes BrO- a relatively stronger base than morphine. It also may have to do with nitrogen on the morphine, but I'm not 100% sure.
by Jordan Young 2J
Tue Dec 03, 2019 4:57 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra
Replies: 3
Views: 40

Re: Atomic Spectra

Firstly, you would the equation En= -hR/n^2 and the equation △E = Ef-Ei where Ef is for the final state/energy level of the atom and Ei is the initial state where the atom started. Once you find the change in energy, you can use E=hv to find the frequency as the change in energy is the energy of the...
by Jordan Young 2J
Tue Dec 03, 2019 4:24 pm
Forum: Biological Examples
Topic: Hydrogen Bonding sites
Replies: 8
Views: 46

Re: Hydrogen Bonding sites

Each lone pair on an oxygen, nitrogen, or fluorine is a potential hydrogen bonding site and each hydrogen that is attached to an oxygen, nitrogen, or fluorine is a potential hydrogen bonding site. For example, water has 4 hydrogen bonding sites (2 lone pairs on oxygen and 2 hydrogens attached to the...
by Jordan Young 2J
Tue Dec 03, 2019 4:21 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating pH for weak Acids
Replies: 3
Views: 21

Re: Calculating pH for weak Acids

I think for 14A we only need to know how to calculate pH for strong acids as they 100% dissociate so calculated the pH is straight forward if you're given the concentration. You would just use the pH formula of -log [H30]
by Jordan Young 2J
Mon Nov 25, 2019 4:05 pm
Forum: Bronsted Acids & Bases
Topic: Weak vs Strong Acid/Bases
Replies: 3
Views: 28

Re: Weak vs Strong Acid/Bases

I believe you can tell if an acid or base is strong based on the K value, but we haven't learned this. I think we just have to know the main strong acids (HI, HCl, HBr, HClO4, HClO3, etc.) and main strong bases (NaOH, KOH, etc.). The rest are weak that don't 100% deprotonate/protonate. Also, I think...
by Jordan Young 2J
Mon Nov 25, 2019 3:50 pm
Forum: Naming
Topic: 9C.3 D
Replies: 3
Views: 39

Re: 9C.3 D

I think that when it comes to the ligands in the coordination complex, the order doesn't matter as much. I think it matters more in actual name.
by Jordan Young 2J
Mon Nov 25, 2019 3:41 pm
Forum: Naming
Topic: Focus 9C.3
Replies: 4
Views: 23

Re: Focus 9C.3

The Roman Numeral (III) is for the chromate. There are 3 K so that the charge is neutral. The 6 CN have a total of a 6- charge, the Cr has a 3+ charge, and since each K has a 1- charge, there are 3 of them to make the coordination compound neutral.
by Jordan Young 2J
Mon Nov 25, 2019 3:39 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 9C.5
Replies: 1
Views: 30

9C.5

The question asks which of the following ligands can be polydentate? CO3 2- was said to be mono or bidentate and oxalate was said to be bidentate. For CO3 2-, why can it be mono or bidentate? For oxalate, where are the two places that the ligand can bind to the central metal? Is it the two oxygens t...
by Jordan Young 2J
Mon Nov 25, 2019 2:19 pm
Forum: Bronsted Acids & Bases
Topic: Memorizing the Bronsted Acids and Bases
Replies: 4
Views: 37

Re: Memorizing the Bronsted Acids and Bases

I think it will be helpful at least to know the common ones such as HCl, HBr, and NaOH because I don't think we will be told if the acid or base is strong and weak unless it's one we haven't talked about.
by Jordan Young 2J
Tue Nov 19, 2019 3:25 pm
Forum: Hybridization
Topic: Sigma and Pi Bond Practice Problems
Replies: 1
Views: 28

Re: Sigma and Pi Bond Practice Problems

I'm pretty sure 2F.3 is about figuring out the number of sigma and pi bonds!
by Jordan Young 2J
Tue Nov 19, 2019 3:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw Shape
Replies: 12
Views: 76

Seesaw Shape

For atoms that have a seesaw molecular shape, I know that you select one of the equatorial angles to be the lone pair. So does that mean that the bond angles for seesaw shaped molecules is 90 degrees, 180 degrees, and <120 degrees? If not, what are the bond angles for a seesaw shaped molecule?
by Jordan Young 2J
Tue Nov 19, 2019 2:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Question 2F3 part b
Replies: 3
Views: 29

Re: Question 2F3 part b

Daria Azizad 1K wrote:I think that both the structure w/ two double bonds and the structure w/ one double bond and one single bond are acceptable, so they are just giving answers for both.

But wouldn't the structure with one double bond and one single bond not be ideal because it doesn't minimize formal charge?
by Jordan Young 2J
Tue Nov 19, 2019 2:23 pm
Forum: Hybridization
Topic: Degenerate Orbitals
Replies: 1
Views: 22

Re: Degenerate Orbitals

Yes because when we hybridize orbitals, all of the orbitals become the same level energy, instead of separated by s,p, and d, so they are degenerate.
by Jordan Young 2J
Wed Nov 13, 2019 3:27 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground state?
Replies: 6
Views: 60

Re: Ground state?

I think ground state refers to the lowest possible energy state of an atom or ion which means that there are no excited electrons in the atom or ion. Charge doesn't impact whether electrons are excited or not so that is why ions have a ground state electron configuration. The ground state configurat...
by Jordan Young 2J
Wed Nov 13, 2019 3:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape
Replies: 8
Views: 40

Re: Shape

Yeah, for the ones we learned today, they all had no lone pairs on the central atom. But there are different shapes when the central atom has lone pairs, which we will probably learn soon.
by Jordan Young 2J
Wed Nov 13, 2019 2:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Answers
Replies: 10
Views: 103

Re: Midterm Answers

Yeah there is. It's on his website under Exam Information and its called "Midterm Solutions". Its on the right hand side if you scroll down.
by Jordan Young 2J
Wed Nov 13, 2019 2:10 pm
Forum: *Particle in a Box
Topic: Principle quantum number
Replies: 2
Views: 28

Re: Principle quantum number

The principle quantum number is which shell the electron is in. This is determined by which period the electron of the atom is in. Period 1 has a quantum number of 1, period 2 has a quantum number of 2, etc. For example, an electron is the 2s shell has a principle quantum number of 2.
by Jordan Young 2J
Wed Nov 13, 2019 2:07 pm
Forum: DeBroglie Equation
Topic: Use
Replies: 2
Views: 33

Re: Use

The Debroglie equation is used to calculate values for things with a mass (ex: electron, but not a photon). The equation is wavelength = h/mv where h is Planck's constant, m is mass in kg, and and v if speed in m/s.
by Jordan Young 2J
Tue Nov 05, 2019 5:16 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: van der Waals radius
Replies: 1
Views: 40

Re: van der Waals radius

Van der Waals are an example of intermolecular forces and during lecture he said it won't be on the midterm.
by Jordan Young 2J
Tue Nov 05, 2019 5:03 pm
Forum: Trends in The Periodic Table
Topic: Why does having more polar ions create more covalent character?
Replies: 2
Views: 29

Re: Why does having more polar ions create more covalent character?

A more highly polarizable anion means that the anion's electrons are more likely to be pulled towards the cation because the anion has a relatively low electronegativity. So the bond is considered more covalent because electrons are being distorted and pulled away. A greater difference in electroneg...
by Jordan Young 2J
Tue Nov 05, 2019 4:45 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Midterm
Replies: 6
Views: 85

Re: Midterm

I feel like we won't be asked about the specific experiment, but a lot of the experiments relate to concepts or equations that we learned in class like the Photoelectric Experiment and Photoelectric Effect so I think it would be good to know how the concepts and equations were derived from the exper...
by Jordan Young 2J
Tue Nov 05, 2019 4:43 pm
Forum: Ionic & Covalent Bonds
Topic: 2D.9
Replies: 3
Views: 30

Re: 2D.9

It's because Be 2+ has a smaller atomic radius so its polarizing power is greater because of more effective nuclear charge so its electronegativity/pulling power is higher than Sr 2+
by Jordan Young 2J
Tue Nov 05, 2019 4:40 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.25
Replies: 2
Views: 38

Re: 1E.25

It just means to give the configuration for the outer most shell of electrons (valence electrons) as opposed to the entire electron configuration, in which you would start with 1s2 2s2 etc. Another way of thinking about it is that the valence electron configuration is the configuration from the last...
by Jordan Young 2J
Fri Nov 01, 2019 11:13 pm
Forum: Sigma & Pi Bonds
Topic: Significance of sigma and pi bonds
Replies: 4
Views: 34

Re: Significance of sigma and pi bonds

They have to do with double and triple bonds and how many of each are a sigma or pi bond, but I don't think we need to know this for the midterm because we haven't talked about it in class.
by Jordan Young 2J
Fri Nov 01, 2019 11:03 pm
Forum: Bond Lengths & Energies
Topic: Test?
Replies: 8
Views: 98

Re: Test?

The last slide of the lecture we had today won't be on the midterm. Bond lengths and energies will probably be on the midterm. The values with either be given to you and you have to use them in a question or you'll have to understand the concept of them to answer a question.
by Jordan Young 2J
Fri Nov 01, 2019 10:52 pm
Forum: Trends in The Periodic Table
Topic: Periodic Table & Formulas
Replies: 2
Views: 20

Re: Periodic Table & Formulas

I'm pretty sure it will be the same table! On the midterm review packet, it said to use the Constants and Equations sheet on his website, which I think is similar or exactly the same as the first test.
by Jordan Young 2J
Fri Nov 01, 2019 10:37 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: manipulating equations
Replies: 3
Views: 32

Re: manipulating equations

I don't think you need to show every single step, but I think it might be good so you don't mess up and your units match up. However, I don't think it's absolute necessary to show every step to manipulate an equation, as long as you manipulate it correctly.
by Jordan Young 2J
Fri Nov 01, 2019 6:09 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charges
Replies: 4
Views: 29

Re: Formal Charges

Formal charge is used to determine which resonance structure is "best" or the most stable. By calculating the formal charge, you can determine which resonance structure is most likely to occur. Ideally, you want the higher electronegative atoms to have the negative charges and you want to ...
by Jordan Young 2J
Sun Oct 27, 2019 11:50 pm
Forum: Trends in The Periodic Table
Topic: Shielding and Electron Replusion
Replies: 3
Views: 35

Re: Shielding and Electron Replusion

They are related in a sense. Shielding is when electrons in a lower energy level "shield" electrons in an outer energy level causing them to be less attracted or "pulled" by the nucleus. The example Dr. Lavelle gave in class was your friend blocking you from the heat of a fire by...
by Jordan Young 2J
Thu Oct 24, 2019 6:04 pm
Forum: Octet Exceptions
Topic: Octet exception examples
Replies: 9
Views: 89

Re: Octet exception examples

Boron also is an exception at times and there are some elements in the periodic table that can hold more than 8 electrons, but I think we'll talk about these in class at some point.
by Jordan Young 2J
Thu Oct 24, 2019 4:21 pm
Forum: Trends in The Periodic Table
Topic: Calculated vs Observed Value
Replies: 6
Views: 38

Re: Calculated vs Observed Value

I think it means that electronegativity is value that is calculated through a formula based on other values, whereas other values such as IE, electron affinity, and atomic radius are already found and don't require a formula for calculation.
by Jordan Young 2J
Thu Oct 24, 2019 3:18 pm
Forum: Trends in The Periodic Table
Topic: Which element is stronger in IE?
Replies: 2
Views: 26

Re: Which element is stronger in IE?

Yes, Na has a lower first ionization energy than Mg because of the fact that it has a weaker nuclear pull because it has less protons. Then if both lose one electron, Na+ has a much higher ionization energy than Mg+ because it now has a noble gas electron configuration
by Jordan Young 2J
Thu Oct 24, 2019 2:16 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations of ions
Replies: 4
Views: 22

Re: Electron Configurations of ions

You would remove from the 4s state first and then from the 3d because the 4s becomes higher in energy once the 3d orbital starts being filled.
by Jordan Young 2J
Tue Oct 15, 2019 2:30 pm
Forum: DeBroglie Equation
Topic: De Broglie Wavelength
Replies: 7
Views: 49

Re: De Broglie Wavelength

I think it just means to use the De Broglie equation because the De Broglie equation is derived from the equations E=pc, c= wavelength*frequency, and E=hv which we have learned before. However, this equation only works for any particle with a rest mass, momentum, and wavelength so if it asks for the...
by Jordan Young 2J
Tue Oct 15, 2019 2:25 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: #20 Post Module
Replies: 3
Views: 25

Re: #20 Post Module

I think you need to multiply the kinetic energy value you found by Avogadro's number to get the energy per mole of electrons, but I'm not 100% sure.
by Jordan Young 2J
Tue Oct 15, 2019 2:20 pm
Forum: Properties of Electrons
Topic: Angstrom Conversion
Replies: 12
Views: 102

Re: Angstrom Conversion

1 Angstrom is equal to 10^-10m so if you have a wavelength, for example, you can convert it from meters to angstroms with that conversion factor.
by Jordan Young 2J
Tue Oct 15, 2019 1:40 pm
Forum: Properties of Light
Topic: Question 1A.5
Replies: 4
Views: 42

Re: Question 1A.5

Yes, you write them in order from least to greatest amount of energy
by Jordan Young 2J
Tue Oct 15, 2019 1:30 pm
Forum: Properties of Light
Topic: Relationships
Replies: 3
Views: 45

Re: Relationships

Photons are particles of light and they do have energy, which you can calculate using the equation E=h*v. And thus, light is a source of energy.
by Jordan Young 2J
Thu Oct 10, 2019 2:45 pm
Forum: Significant Figures
Topic: Conflicting Sig Fig Advice
Replies: 3
Views: 59

Re: Conflicting Sig Fig Advice

For me, I think it's better to round for sig figs at the end of the problem because if you round as you are calculating, your answer is more likely to be more off than if you just round at the end of the problem. Generally, if you are fairly close in terms of sig figs and rounding I think you'll be ...
by Jordan Young 2J
Thu Oct 10, 2019 2:34 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg vs Balmer Series
Replies: 2
Views: 47

Re: Rydberg vs Balmer Series

Rydberg is the constant R and it's equal to 3.29x10e-15 Hz. You use this constant in the E= -hR/n^2. The Lyman and Balmer Series are just names for the spectral lines for atomic spectrum for a H atom. Balmer is the visible section and Lyman is the UV section.
by Jordan Young 2J
Wed Oct 09, 2019 3:02 pm
Forum: Properties of Light
Topic: Kinetic Energy
Replies: 2
Views: 39

Kinetic Energy

Why does the kinetic energy stay the same, in the photoelectric effect, even with a higher intensity of light?
by Jordan Young 2J
Wed Oct 09, 2019 2:56 pm
Forum: Properties of Light
Topic: High Intensity
Replies: 5
Views: 52

High Intensity

When discussing the photoelectric effect, is "high intensity" the same as "increasing the number of photons"? Are they synonymous? If so, does higher intensity just mean more/brighter light?
by Jordan Young 2J
Wed Oct 09, 2019 2:47 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Positive/ Negative regarding E
Replies: 3
Views: 33

Re: Positive/ Negative regarding E

The E that you plug into E=hv is the energy for the photon emitted which is why it is positive. The E you find from the problem was the energy of the electron when it moved from n=4 to n=2 which is negative because the energy decreased. The values are equal because the law of conservation of energy,...
by Jordan Young 2J
Tue Oct 01, 2019 10:09 pm
Forum: Significant Figures
Topic: Rounding
Replies: 3
Views: 40

Re: Rounding

Yes you're right. Mr. Lavelle's website says that you round to the nearest even digit if the last number if 5 so you are correct for rounding 1.65 to 1.6 and 1.35 to 1.4
by Jordan Young 2J
Tue Oct 01, 2019 2:42 pm
Forum: Significant Figures
Topic: Could someone please clarify about Sig Figs?
Replies: 4
Views: 49

Re: Could someone please clarify about Sig Figs?

There is also a document on Mr. Lavelle's website called "Everything you wanted to know about Sig Fig" if you want more clarification, but I think the above replies explains it pretty well. Zeros are only significant if they are between two numbers (ex: 705) or at the end of a number with ...
by Jordan Young 2J
Tue Oct 01, 2019 2:30 pm
Forum: SI Units, Unit Conversions
Topic: Homework for Week 1
Replies: 16
Views: 257

Re: Homework for Week 1

The first five homework problems from the textbook are due this Friday (Oct 4th) in lecture. And then starting next week, the five homework problems are due during our discussion sections each week. The five online posts on Chemistry Community are due by Sunday (Oct 6th) and then it's five every week.
by Jordan Young 2J
Tue Oct 01, 2019 2:26 pm
Forum: Balancing Chemical Reactions
Topic: States of Matter in a Chemical Equation [ENDORSED]
Replies: 11
Views: 102

Re: States of Matter in a Chemical Equation [ENDORSED]

It doesn't affect the equation itself but it may be good to know so you can visualize the experiment and sometimes elements change states if you have multiple equations that are linked together. Also, as we learn more it may be important when we expand balancing equations into greater concepts that ...
by Jordan Young 2J
Tue Oct 01, 2019 2:18 pm
Forum: Limiting Reactant Calculations
Topic: M11 limiting reactant
Replies: 2
Views: 30

Re: M11 limiting reactant

When I calculated it, I got that O2 was the limiting reactant in the first equation. I converted both masses to moles and I got 0.9314 moles of P4 and 0.180 moles of O2 and since the molar ratio is 1:3, O2 is the limiting reactant. You can also calculate further to the moles of product produced to c...
by Jordan Young 2J
Tue Oct 01, 2019 2:07 pm
Forum: Balancing Chemical Reactions
Topic: Question L.35 [ENDORSED]
Replies: 6
Views: 89

Re: Question L.35 [ENDORSED]

I got 3FeBr2 + 3Na2CO3 = 6NaBr + 3CO2 + Fe3O4 for balancing the equation. I started with the Fe and then did the Br and then the Na and then the C and O.

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