Search found 86 matches

Sun Jan 24, 2021 5:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong vs weak acids/bases
Replies: 6
Views: 19

Strong vs weak acids/bases

For acid/base equilibrium, do we only have to use ice tables to find the concentrations of the acid/base at equilibrium if the acid or base is weak? Why do we not use ICE tables if the acid or base is strong?
Thanks!
Sun Jan 24, 2021 5:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium concentrations for acids
Replies: 3
Views: 10

Equilibrium concentrations for acids

When you’re finding equilibrium concentrations for an acid, do you always have to use Ka as its equilibrium quotient?
Sun Jan 24, 2021 10:42 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Acids/base equilibrium #5
Replies: 2
Views: 14

Sapling Acids/base equilibrium #5

Hi guys,
I’m having some trouble going through #5 on the acids/base sapling homework. The problem is:
The Kb for an amine is 1.118 * 10-5. What percentage of the amine is protonated if the pH of a solution of the amine is 9.757? Assume that all OH- came from the reaction of B with H2O.
Sun Jan 24, 2021 10:15 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water as a liquid in a reaction
Replies: 4
Views: 8

Water as a liquid in a reaction

If water was a liquid participating in a reaction but not the main solvent, would it still be included in the equilibrium equation for the equilibrium constant?
Sun Jan 24, 2021 10:13 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating equilibrium concentrations
Replies: 3
Views: 6

Calculating equilibrium concentrations

Hi guys! When you’re calculating for equilibrium concentrations using ICE tables, when can you ignore the value of X in the denominator?
Sun Jan 17, 2021 12:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Adding together two equilibrium equations
Replies: 5
Views: 16

Adding together two equilibrium equations

When you add together two equilibrium equations, what happens to the equilibrium constants of the two equations?
Sun Jan 17, 2021 12:50 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q > K, Q< K
Replies: 25
Views: 75

Q > K, Q< K

Can someone explain what happens when Q> K and Q< K?
I’m having a bit of trouble understanding the concept.
Thanks!
Sun Jan 17, 2021 10:15 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #10, WK 1
Replies: 8
Views: 63

Sapling #10, WK 1

Hi guys, I’m having trouble on the final part of #10 in the sapling homework. Can someone guide me through it? The problem is: The reaction N 2 O 4 <—> 2NO 2 is allowed to reach equilibrium in a chloroform solution at 25C. The equilibrium concentrations are 0.373 mol/L N 2 O 4 and 2.04 mol/L NO 2 . ...
Sun Jan 17, 2021 9:58 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Endothermic/exothermic reactions and K
Replies: 11
Views: 28

Endothermic/exothermic reactions and K

For endothermic reactions, how does K change when you add heat. How does K change when you add heat to exothermic reactions? Also, why does K change instead of Q when you add heat to the reaction.
Sun Jan 17, 2021 9:37 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling WK 1, #4
Replies: 3
Views: 23

Sapling WK 1, #4

Hi guys! I’m having a lot of trouble getting started with the chemical equilibrium sapling HW, problem #4. The problem is: At a certain temperature, the given reaction has an equilibrium constant of K p = 329. PCl 3 + Cl 2 <—> PCl 5 PCl 5 is placed in a sealed container at an initial pressure of .07...
Sun Jan 10, 2021 12:34 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing pressure
Replies: 7
Views: 35

Changing pressure

Does changing pressure only cause a change in the reaction when the volume ( thus the concentration) is being changed?
Sun Jan 10, 2021 12:32 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing volume
Replies: 6
Views: 29

Changing volume

For the quick way shown in lecture #3, why does the reaction shift right when the volume decreases and there are more moles of gas on the left?
Sun Jan 10, 2021 9:57 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constant between 10^-3 and 10^3
Replies: 6
Views: 13

Equilibrium constant between 10^-3 and 10^3

If the value of K is in between 10-3 and 103 does equilibrium not sit towards the right or left? Where would we define equilibrium as going towards?
Sun Jan 10, 2021 9:53 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Changing K
Replies: 4
Views: 25

Changing K

Why doesn’t the value of K change when you change the concentration of the reactants or products?
Why does only temperature change K?
Sun Jan 10, 2021 9:31 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Q
Replies: 7
Views: 19

K vs Q

Hi guys!
Do you use Q when you are unsure if the reactants/products are at equilibrium? Do you also use Q if the problem doesn’t explicitly state if the reactants and products have reached equilibrium?
Thanks!
Sat Dec 12, 2020 7:24 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Stronger acids and stability?
Replies: 5
Views: 50

Stronger acids and stability?

Hi guys!
I’ve been a little confused on this but for acids, are stronger acids more or less stable? Would electron withdrawing in an acid make it stable or not?
Thanks!
Fri Dec 11, 2020 7:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Why is CH2Cl2 polar
Replies: 6
Views: 45

Why is CH2Cl2 polar

Why is CH2Cl2 polar?
Can’t the C-Cl dipole bonds be opposite of each other and cancel each other out after having drawn the Lewis structure?
Fri Dec 11, 2020 7:16 pm
Forum: Naming
Topic: Ferrate for iron
Replies: 5
Views: 47

Ferrate for iron

Hi guys! While I was doing the homework I noticed some of the transition metals had different names than their chemical formula, like iron ( which was ferrate when written as part of the chemical formula of a coordination compound). Are there any specific metals we should know that will have differe...
Fri Dec 11, 2020 7:13 pm
Forum: Air Pollution & Acid Rain
Topic: Acid rain
Replies: 1
Views: 57

Acid rain

Hi guys!
Does anyone know what we should specifically know about acid rain? Do we have to understand the chemical formulas for different nonmetal oxides that react with H2O to produce acid rain?
Fri Dec 11, 2020 7:11 pm
Forum: Bronsted Acids & Bases
Topic: Strong bases oxides vs hydroxides
Replies: 4
Views: 58

Strong bases oxides vs hydroxides

Since metal oxides ( with metals being from groups one and two) typically produce two moles of OH- for every oxygen atom they have in their chemical formula, would they be typically stronger than metal hydroxides?
Mon Dec 07, 2020 4:26 pm
Forum: Bronsted Acids & Bases
Topic: Sapling #6 week 10
Replies: 4
Views: 66

Sapling #6 week 10

I was doing the sapling homework and was confused on why HCN is a weak acid instead of being a weak base. Since the nitrogen of HCN has a lone pair, I thought it would be a weak base since it can accept a proton from water. Can someone explain why it is a weak acid instead?
Thanks!
Sun Dec 06, 2020 1:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape and polarity
Replies: 3
Views: 21

Molecular shape and polarity

For molecules with lone pairs of electrons on the central atoms, are they typically polar or nonpolar?
Is there a way to use the shape of molecules with lone pairs on the central atom to determine the polarity of the molecule?
Thanks!
Sun Dec 06, 2020 1:20 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands we should be familiar with?
Replies: 3
Views: 40

Ligands we should be familiar with?

What ligands we should be familiar with or that we should memorize/ know the chemical formula for?
Thanks!
Sun Dec 06, 2020 1:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling Week 7/8 #18
Replies: 1
Views: 30

Sapling Week 7/8 #18

Hi guys! I’ve been having trouble understanding this part of question 18 from the Week 7/8 homework. The question is “ A general formula for molecules of this type is H 2 C(C) x CH 2 , where x is a whole number.” Select the correct statement about the relationship of x to the orientations of the hyd...
Sun Dec 06, 2020 1:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecules with lone pairs
Replies: 5
Views: 64

Molecules with lone pairs

Hi guys!
Why do lone pairs of electrons on molecules occupy more space than bonded electrons?
Mon Nov 30, 2020 4:31 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Sapling #5 for Week 9
Replies: 4
Views: 59

Sapling #5 for Week 9

Hi guys!
I was doing the sapling HW for week 9 and got stuck on #5. What does the “en” in [Cd(en)Br2] mean? Also, how would you find the coordination number for this molecule?
Thanks
Sun Nov 29, 2020 2:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pair vs radical
Replies: 3
Views: 27

Lone pair vs radical

Hi guys!
For a molecule, if it had a single electron unbounded instead of a lone pair of electrons being unbounded, how big of an effect would that have on the molecule’s bond angles.
Sun Nov 29, 2020 2:21 pm
Forum: Administrative Questions and Class Announcements
Topic: sapling
Replies: 4
Views: 57

Re: sapling

Hello!
I don’t think those assignments are worth extra credit. I did them a while back, and they’re just to help you with the basics and getting used to using Sapling.
Sun Nov 29, 2020 10:43 am
Forum: Hybridization
Topic: Lecture #23
Replies: 13
Views: 119

Lecture #23

Hi guys!
I was going over lecture #23 and had something I was a little confused on.
For the molecule Benzene (C6H6)
where is the electron for the un-hybridized p-orbital located? Also, is it delocalized?
Thanks!
Sat Nov 28, 2020 5:37 pm
Forum: Sigma & Pi Bonds
Topic: Delocalized Pi bond
Replies: 6
Views: 51

Delocalized Pi bond

Hi guys!
I’m still a bit confused on this but can someone explain what makes a delocalized pi bond and what makes it different from a regular pi bond?
Sat Nov 28, 2020 5:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling #17
Replies: 2
Views: 25

Sapling #17

Hi guys! I was doing the sapling Homework for week 7/8 and had trouble on number 17. The question is draw the three possible structures of C3H4 and the follow up question to it is to select the choice that contains all of the bond angles that are represented in the structures of C3H4. I was able to ...
Sat Nov 28, 2020 5:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: CH2Cl2
Replies: 7
Views: 55

CH2Cl2

Can someone explain why CH2Cl2 is a polar molecule based on its molecular shape?
Thu Nov 19, 2020 7:40 pm
Forum: Lewis Structures
Topic: Why is SO2 a Lewis acid?
Replies: 2
Views: 45

Why is SO2 a Lewis acid?

Hi guys!
I’m having a lot of trouble understanding why SO2 is a Lewis acid. Sapling says that it’s a molecule with a polar double bond but how does that help it accept more electrons?
Thanks!
Thu Nov 19, 2020 4:25 pm
Forum: Dipole Moments
Topic: Pressures and Points
Replies: 4
Views: 47

Re: Pressures and Points

Hello! The stronger the intermolecular forces between the molecules, the higher the melting and boiling points will be. Vapor pressure refers to the amount of vapor released when a liquid turns into a gas. The more vapor released, the higher the vapor pressure. Weaker intermolecular forces have a hi...
Thu Nov 19, 2020 2:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3d fills before or after 4s?
Replies: 7
Views: 60

Re: 3d fills before or after 4s?

Hello! Cu is part of the exceptions in electron configuration. So its configuration for a neutral atom of Cu is [Ar]3d 10 4s 1 , because it prefers a full d shell. When Cu loses an electron, it will lose its outermost electron. In this case, its outer most electron is in the 4s shell ( since 4s 1 is...
Thu Nov 19, 2020 1:59 pm
Forum: Lewis Structures
Topic: Single electron in a Lewis Structure
Replies: 6
Views: 57

Re: Single electron in a Lewis Structure

Hi! It’s possible for there to be an unpaired electron in a Lewis structure. When it happens the molecule is called a radical, because one of its electrons are unpaired and it’s highly reactive. An unpaired electron in a Lewis structure happens when there is an odd number of valence electrons when y...
Thu Nov 19, 2020 1:57 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: LDF
Replies: 5
Views: 60

LDF

If there are many LDF interactions, can they become stronger than a dipole-dipole interaction?
Thu Nov 19, 2020 1:56 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: Strongest/weakest intermolecular forces
Replies: 6
Views: 87

Strongest/weakest intermolecular forces

Hi guys!
Can someone let me know the order of intermolecular interactions from weakest to strongest?
I get them confused a lot of times.
Thanks!
Wed Nov 18, 2020 10:24 pm
Forum: Ionic & Covalent Bonds
Topic: Nonpolar vs Polar covalent
Replies: 1
Views: 11

Nonpolar vs Polar covalent

Hi guys! So covalent bonds are polar when the electrons are shared unequally and they’re nonpolar when the electrons are shared equally. Usually, how close do the atoms have to be in electronegativity for a bond to be considered nonpolar.
Also, are C-H bonds considered nonpolar?
Thanks!
Sun Nov 15, 2020 10:36 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation number
Replies: 1
Views: 16

Oxidation number

Hi guys! I’ve seen a couple of homework problems on oxidation numbers. Can someone explain what the oxidation number is and how you find it.
Thanks!
Wed Nov 11, 2020 8:13 am
Forum: Quantum Numbers and The H-Atom
Topic: 2s to 2p in a hydrogen atom
Replies: 1
Views: 31

2s to 2p in a hydrogen atom

Hi guys!
For a hydrogen atom, if you were to excite the electron so that it would go from 2s to 2p, would the energy of the electron change?
Thanks!
Tue Nov 10, 2020 7:38 pm
Forum: Resonance Structures
Topic: Resonance structures and stability
Replies: 4
Views: 21

Resonance structures and stability

Hi everyone!
Can someone explain why resonance structures are usually more stable? I’ve been having some trouble understanding this.
Thanks!
Tue Nov 10, 2020 7:36 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum number ms and wave function
Replies: 2
Views: 26

Quantum number ms and wave function

Hi guys!
Do we need to know ms to specify an orbital or do we only need to use the first three quantum numbers to specify the orbital?
Thanks!!
Tue Nov 10, 2020 7:27 pm
Forum: Dipole Moments
Topic: Interactions Between Ions and Molecules
Replies: 7
Views: 57

Re: Interactions Between Ions and Molecules

Ion ion interactions are stronger because ions are fully charged. An example is NaCl, Na has a full +1 charge, and Cl has a full -1 charge. Ions are fully charged because the cation loses its electrons, and the anion gains electrons. These large and opposite charge values create a big attraction. T...
Tue Nov 10, 2020 7:21 pm
Forum: Octet Exceptions
Topic: Radicals, which atoms lacks electron?
Replies: 3
Views: 39

Re: Radicals, which atoms lacks electron?

Hello! For a radical, if an atom has an unpaired valence electron (or 7 electrons instead of 8) then it is a radical. You can tell if the valence electron is unpaired if one of its electrons is alone. So if an atom has or is sharing ( through covalent bonds) 6 electrons and has one additional unpair...
Tue Nov 10, 2020 7:14 pm
Forum: Dipole Moments
Topic: Interactions Between Ions and Molecules
Replies: 7
Views: 57

Re: Interactions Between Ions and Molecules

Ion ion interactions are stronger because ions are fully charged. An example is NaCl, Na has a full +1 charge and Cl has a full -1 charge. Ions are fully charged because the cation loses its electrons and the anion gains electrons. These large and opposite charge values create a big attraction. The ...
Sun Nov 08, 2020 8:02 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charges and stability
Replies: 5
Views: 58

Formal charges and stability

Hi guys! I was working on some formal charge problems and had a quick question. When calculating formal charge, would an molecule with a charge of +2 be more stable if all of that charge was on one atom of the molecule, or would it be more stable if the charge was separated on two atoms, each with a...
Sun Nov 08, 2020 7:38 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizable
Replies: 3
Views: 16

Polarizable

I was watching Dr.Lavelle’s lecture from last Friday. What does polarizable mean and what does it mean for something to be highly polarizable?
Thank you!
Sun Nov 08, 2020 7:13 am
Forum: Lewis Structures
Topic: 2B.11 part C
Replies: 1
Views: 27

2B.11 part C

Hi guys! For problem 2B.part (c) I was wondering how you would know the order of the atoms when drawing the Lewis structure of the molecule. There’s a lot of different atoms in this molecule, and I’m a little confused on how to order them. Here’s the problem: “ Draw the complete Lewis structure of t...
Sun Nov 08, 2020 7:04 am
Forum: Lewis Structures
Topic: 2.B 5 part b
Replies: 1
Views: 12

2.B 5 part b

Hi everyone! For question 2B.5 part b from the textbook, which is “ Draw the Lewis structure of (b) hypobromite ion BrO-“ I was wondering why the structure doesn’t have a double bond instead of the single bond it’s shown to have in the answer key.
Sat Nov 07, 2020 2:42 pm
Forum: Trends in The Periodic Table
Topic: Atomic radius when changing sub- shells
Replies: 4
Views: 19

Atomic radius when changing sub- shells

Does the atomic radius increase when you go from 2s to 2p?
Fri Nov 06, 2020 9:21 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configurations of f state
Replies: 4
Views: 47

Electron configurations of f state

I was working on the homework and some electron configurations had electrons in the f state. Do we have to know how to write electron configurations using the f- orbitals?
Tue Nov 03, 2020 11:19 am
Forum: Lewis Structures
Topic: NO3- example in lecture
Replies: 4
Views: 27

NO3- example in lecture

Hi guys!
I was watching lecture #14 and I noticed that nitrogen was used as the central atom. I thought oxygen was an exception in ionization energies, so it would have a lower ionization energy than nitrogen due to its electron-electron repulsions. Why is nitrogen used as the central atom?
Sun Nov 01, 2020 9:26 pm
Forum: Quantum Numbers and The H-Atom
Topic: ionization energy
Replies: 3
Views: 45

Re: ionization energy

Hello! Oxygen will also have a lower first ionization energy than fluorine because of fluorine’s higher atomic number. Because fluorine has a higher atomic number, it has more protons, thus a higher effective nuclear charge. This positive nuclear charge will attract electrons more, and result in a h...
Sun Nov 01, 2020 9:19 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 8
Views: 52

Re: Electron Configuration

Hello! When there are zero electrons occupying the 3d orbitals, 4s will have a lower energy than 3d. This means that 4s will go after 2p when writing electron configurations. However, when electrons begin to fill the 3d orbitals, then 4s will have the higher energy than 3d. Therefore, 4s will be wri...
Sun Nov 01, 2020 5:24 pm
Forum: Trends in The Periodic Table
Topic: Second ionization energy
Replies: 3
Views: 34

Re: Second ionization energy

Hello! The second ionization energy is higher than the first one because it becomes harder to remove a second electron from an atom after you have already removed the first one. You will need more energy to remove a second electron, thus resulting in a higher second ionization energy. Atoms do not w...
Sat Oct 31, 2020 8:59 pm
Forum: Trends in The Periodic Table
Topic: Ionization energy exceptions
Replies: 1
Views: 28

Ionization energy exceptions

Hi guys! I have a couple of questions about ionization energies. Would there be any other exceptions that we have to know other than oxygen for ionization energy trends? Are there any other exceptions due to electron repulsions for the typical ionization energy trend?
Thanks
Sat Oct 31, 2020 8:58 pm
Forum: Student Social/Study Group
Topic: Halloween!!!
Replies: 54
Views: 332

Re: Halloween!!!

Hi!! Happy Halloween!!
My family and I dressed up and are watching some Halloween themed movies together. We also ordered food tonight and bought some candy!
Sat Oct 31, 2020 8:25 pm
Forum: Trends in The Periodic Table
Replies: 2
Views: 21

Hi everyone!
The atomic radii increases down a group and decreases across a period. I was wondering, which one has a greater effect on the atomic radii? Does going down a group increase the atomic radii more than going across a period would decrease the atomic radii?
Thanks!
Sat Oct 31, 2020 6:46 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configuration 4s and 3d
Replies: 2
Views: 36

Electron configuration 4s and 3d

Hi everyone!
Just to clarify, is the 4s higher than energy than the 3d orbital? It’s energy was mentioned in lecture a couple of times, but I’m a little confused.
Thanks
Sat Oct 31, 2020 6:37 pm
Forum: Quantum Numbers and The H-Atom
Topic: Textbook 1D.13
Replies: 3
Views: 22

Textbook 1D.13

Hi everyone! I need a bit of help on 1D.13 part (a) and part (b). The problem states “(a) How many values of the quantum number l are possible when n=7? (b) How many values of m l are allowed for an electron in a 6d-subshell?”. Does anyone know how to get started on this problem, or any strategies o...
Sun Oct 25, 2020 6:40 pm
Forum: DeBroglie Equation
Topic: Frequency of an object with mass
Replies: 3
Views: 45

Frequency of an object with mass

Hi everyone! We use De Broglie’s equation to find the wavelength of an object with mass. After finding that wavelength, is there any way to convert it into frequency. Can the E = hv equation be used or not since its an equation only for electromagnetic radiation? Is there any other equation that can...
Sun Oct 25, 2020 6:33 pm
Forum: Properties of Light
Topic: 1A.3 Textbook problem
Replies: 4
Views: 39

Re: 1A.3 Textbook problem

Hi! For the elimination process, the answer cannot be A since the speed of radiation will always be equal to the speed of light ( 3 * 10 8 m/s ). The answer cannot be B since wavelength and frequency are inversely proportional, so wavelength will increase when frequency decreases. The answer cannot ...
Sun Oct 25, 2020 6:28 pm
Forum: Photoelectric Effect
Topic: Exercise 1B9
Replies: 2
Views: 28

Re: Exercise 1B9

Hi! They derived that equation by using these two equations: 1. E= hv 2. c = λv you can find what frequency is equal to from the speed of light equation. Rearrange c = λv so that it becomes v = c/λ . Then, you can plug this into the v of the energy of a photon equation. So E = hv will become E = hc/...
Sun Oct 25, 2020 6:23 pm
Forum: Properties of Light
Topic: 1A.9 problem
Replies: 7
Views: 76

Re: 1A.9 problem

Hi! You can convert MHz to Hz by multiplying MHz by 106. So 300 MHz * 106 would be the amount of MHz in Hz.
Fri Oct 23, 2020 7:01 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Problem 1 B.27
Replies: 2
Views: 25

Problem 1 B.27

Hi everyone! I’m having trouble with problem 1 B.27 in the textbook. The problem is “ A bowling ball with a mass 8.00 kg is rolled down a bowling alley lane at 5.00 ± 5.0 m/s . What is the minimum uncertainty in its position?” Can someone help me with the first step of getting started with this prob...
Fri Oct 23, 2020 11:35 am
Forum: DeBroglie Equation
Topic: Light and momentum
Replies: 7
Views: 58

Light and momentum

Hi everyone!
I have a couple of questions about light and De Broglie.
How does light have a momentum if it doesn’t have a mass? Can light be used in the De Broglie equation if its momentum is given, or can it not be used because light doesn’t have a mass?
Thank you!
Fri Oct 23, 2020 11:28 am
Forum: SI Units, Unit Conversions
Topic: SI Conversions
Replies: 11
Views: 82

Re: SI Conversions

I think knowing the SI unit conversions of:
Kilo= 103
Centi=10-2
Milli=10-3
Micro=10-6
Nano=10-9
Angstrom=10-10
Will be very useful for the exam. The other conversions needed ( from eV to Joules, etc..) are on the formula sheet.
Fri Oct 23, 2020 9:18 am
Forum: *Shrodinger Equation
Topic: Wave function
Replies: 8
Views: 97

Wave function

Hi everyone!
I‘m reviewing schrodinger’s equation but I’m having trouble understanding some key parts of the equation What is a wave function and how does it relate to the electron? Also, what does Dr. Lavelle mean by a change in the wave function?
Tue Oct 20, 2020 4:48 pm
Forum: Properties of Electrons
Topic: Wave properties of electrons and diffraction
Replies: 3
Views: 24

Wave properties of electrons and diffraction

Hi everyone!
In the audio visual about the wave properties of electrons, diffraction is mentioned multiple times. I’m a little confused about what diffraction means. What is diffraction and how does it relate to the properties of electrons?
Thank you!
Sun Oct 18, 2020 8:23 pm
Forum: Student Social/Study Group
Topic: Respondus
Replies: 4
Views: 26

Re: Respondus

It’s on CCLE. Go to site info and scroll all the way down to the bottom of the page. There will be a link there allowing you to download respondus.
Sun Oct 18, 2020 4:39 pm
Forum: Quantum Numbers and The H-Atom
Topic: Balmer and Lyman series
Replies: 4
Views: 30

Re: Balmer and Lyman series

Thank you so much! Everything’s a lot clearer now for me.
Sun Oct 18, 2020 4:35 pm
Forum: Quantum Numbers and The H-Atom
Topic: solving 1A #15
Replies: 2
Views: 26

Re: solving 1A #15

Hello! The line will fall into the UV radiation spectrum making it a part of the Lyman series.The wavelengths of the Balmer series are much larger ( around 400-700 nm). What you should do next is find the frequency of atomic hydrogen by plugging in the wavelength into the c = λν. After finding the f...
Sun Oct 18, 2020 4:20 pm
Forum: Quantum Numbers and The H-Atom
Topic: Balmer and Lyman series
Replies: 4
Views: 30

Balmer and Lyman series

Hi everyone! I was reading the textbook Focus 1. A and looking at the definitions of the Balmer series and Lyman series. The textbook says that the “Balmer series consists of the lines with n 1 =2 (and n 2 =3,4,...). The Lyman series is a set of lines in the ultraviolet region of the spectrum with n...
Thu Oct 15, 2020 11:56 am
Forum: Properties of Light
Topic: Electron diffraction
Replies: 5
Views: 48

Electron diffraction

Can someone explain what electron diffraction ( option B) is from Problem 1B.3? Problem 1B.3 in the textbook: From the following list of observations, select the one that best supports the idea that electromagnetic radiation has the properties of particles. Explain your reasoning. A. Black-body radi...
Thu Oct 15, 2020 11:37 am
Forum: Einstein Equation
Topic: Textbook Question 1A.3
Replies: 3
Views: 60

Re: Textbook Question 1A.3

The extent of change refers to the wave’s steepness, or slope. It portrays how much a wave changes over time. The steeper, the higher the extent of change. When you reduce the frequency of a wave, you’re increasing its wavelength. Increasing the wavelength decreases the slope of the wave. Thus, you’...
Thu Oct 15, 2020 7:31 am
Forum: Properties of Light
Topic: Problem 1A.15
Replies: 3
Views: 59

Problem 1A.15

I’m having a lot of trouble getting started with problem 1A.15 from the textbook. The problem is: “ 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 lea...
Wed Oct 14, 2020 7:22 pm
Forum: Properties of Light
Topic: Exercise 1A.7
Replies: 4
Views: 49

Re: Exercise 1A.7

When you divide the speed of light which has units of meters per second (m/s), by hertz which has units of 1/seconds (s^-1 or 1/s), the seconds will cancel out and you’ll be left with meters. To convert the number you have in meters to nanometers, multiply by 10^9.
Tue Oct 13, 2020 9:39 pm
Forum: Photoelectric Effect
Topic: Intensity vs. Frequency of light
Replies: 1
Views: 23

Intensity vs. Frequency of light

Hello everyone! I was watching the photoelectric effect video module and had some questions after watching it.
What’s the difference the intensity of light and its frequency? Also, what happens when you change the intensity of light vs. when you change its frequency? Thank you!
Sun Oct 11, 2020 7:57 pm
Forum: General Science Questions
Topic: Balancing equations
Replies: 17
Views: 156

Re: Balancing equations

Hi! There are different approaches you can take when balancing a chemical equation. There cannot be different answers to a balanced chemical equation. The most simplified form of the balanced chemical equation is its correct form. To balance a chemical equation I first count the number of atoms of e...
Tue Oct 06, 2020 12:05 pm
Forum: Limiting Reactant Calculations
Topic: Sapling #10 Walkthrough
Replies: 6
Views: 69

Re: Sapling #10 Walkthrough

After you find the mass of the 2-butanone, find the number of moles of the 2-butanone by dividing the mass by its molar mass. The molar mass of 2-butanone is 72.1 g/mol. The number of moles of 3-methyl-3-hexanone is equal to the number of moles of the 2-butanone. Using the molar mass of the 3-methyl...
Mon Oct 05, 2020 8:57 pm
Forum: Limiting Reactant Calculations
Topic: M7 (Limiting Reactant Fundamental Exercise)
Replies: 3
Views: 58

Re: M7 (Limiting Reactant Fundamental Exercise)

Hi! Oxide is usually used to name a compound that has an oxygen in it. Since the compound is boron oxide, it has both boron and oxygen in it. Using the periodic table, we see that boron has a charge of 3+ while oxygen has a charge of 2-, so we need 2 borons and 3 oxygens to have a balanced compound....
Mon Oct 05, 2020 5:50 pm
Forum: Student Social/Study Group
Topic: Properties of Light/Quantum Mechanics Audio Visual Modules
Replies: 3
Views: 49

Re: Properties of Light/Quantum Mechanics Audio Visual Modules

I watched the additional videos they were helpful in preparing me for the photoelectric effect and atomic spectra video modules. They review the different properties light has and help transition me into the next topic.
Mon Oct 05, 2020 5:45 pm
Forum: Significant Figures
Topic: Sig Figs
Replies: 11
Views: 119

Re: Sig Figs

I also got 4 sig figs which counts the 3204.
Mon Oct 05, 2020 5:24 pm
Forum: Empirical & Molecular Formulas
Topic: Fundamentals M. 19
Replies: 6
Views: 69

Re: Fundamentals M. 19

^^ I also used N2 gas while doing my calculations. N2 is likely the product since it is diatomic and the form typically found in nature.

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