Search found 68 matches

by KHowe_1D
Sun Jan 26, 2020 3:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE
Replies: 14
Views: 35

Re: ICE

You use an ICE table to solve for concentrations so usually you will be given K.
by KHowe_1D
Sun Jan 26, 2020 3:33 pm
Forum: Phase Changes & Related Calculations
Topic: Standard State
Replies: 2
Views: 14

Re: Standard State

No the standard state depends on the element is the state at which the element is the most stable.
by KHowe_1D
Sun Jan 26, 2020 3:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ice box approximation
Replies: 9
Views: 40

Re: ice box approximation

when x is less than 10^-3 it can be assumed to be small and disregarded from the denominator.
by KHowe_1D
Sun Jan 26, 2020 3:18 pm
Forum: Ideal Gases
Topic: pressure
Replies: 9
Views: 34

Re: pressure

partial pressure is the pressure of each individual gas and total pressure is the pressure of the entire system.
by KHowe_1D
Sun Jan 26, 2020 3:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Temperature (K)
Replies: 4
Views: 10

Re: Temperature (K)

K changes because temperature affects the rate at which the reaction occurs.
by KHowe_1D
Sun Jan 19, 2020 5:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework problem 5.I.15
Replies: 4
Views: 14

Re: Homework problem 5.I.15

I don't think you get marked off for not using an ice table as long as you get the right answer. However I recall Lavelle gives partial credit for correct procedures so if you did use the ice table but got the answer wrong, you would probably get partial credit.
by KHowe_1D
Sun Jan 19, 2020 2:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Change in Amount of P/R?
Replies: 2
Views: 11

Re: Change in Amount of P/R?

K will not change if you add more reactants or products because it is the concentration at equilibrium however Q may change because Q is the reaction quotient that can be calculated at any point during the reaction.
by KHowe_1D
Sun Jan 19, 2020 2:52 pm
Forum: General Science Questions
Topic: Proton and Electron attraction
Replies: 5
Views: 22

Re: Proton and Electron attraction

Protons and electrons have opposite charges (Proton + and electron -) so they attract each other.
by KHowe_1D
Sun Jan 19, 2020 2:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Test 1
Replies: 6
Views: 22

Re: Test 1

The topics covered will be acids and bases as well as equilibrium.

I find the best way to study for Lavelle's tests are to do the practice problems because some of the questions are directly out of the homework problems.
by KHowe_1D
Sun Jan 19, 2020 2:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc from K
Replies: 3
Views: 15

Kc from K

Question 5.H.5 from the homework asks
Evaluate Kc for each of the following equilibria from the value of K:
(a) 2NOCl(g) ∆2NO(g)1Cl2(g),K51.831022 at500K
(b) CaCO3(s) ∆ CaO(s) 1 CO2(g), K 5 167 at 1073 K


Is K different from Kc? and how do you calculate K from Kc?
by KHowe_1D
Sat Jan 11, 2020 3:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure
Replies: 7
Views: 22

Re: Partial Pressure

Yes partial pressure is only used for gases with the units of atm.
by KHowe_1D
Sat Jan 11, 2020 3:41 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction quotient
Replies: 8
Views: 26

Re: Reaction quotient

They have different values because K is only at equilibrium and Q can be calculated at any time during the reaction.
by KHowe_1D
Sat Jan 11, 2020 3:38 pm
Forum: Ideal Gases
Topic: Solids and Liquids [ENDORSED]
Replies: 10
Views: 62

Re: Solids and Liquids [ENDORSED]

They aren't calculated in equilibrium expressions because they are considered pure substances which don't affect the equilibrium concentration.
by KHowe_1D
Sat Jan 11, 2020 3:33 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q
Replies: 10
Views: 30

Re: Q

Yes I believe Q can be applied to both concentration and partial pressure.
by KHowe_1D
Sat Jan 11, 2020 3:29 pm
Forum: Ideal Gases
Topic: K vs Q [ENDORSED]
Replies: 7
Views: 42

Re: K vs Q [ENDORSED]

The difference between K and Q is K is the concentration at equilibrium and Q is the reaction quotient which is calculated the same as K and can be calculated at any time during the reaction.
by KHowe_1D
Sun Dec 08, 2019 3:34 pm
Forum: Naming
Topic: Naming
Replies: 7
Views: 44

Re: Naming

You would use those when the ligand already has a prefix so for example en has a prefix already so if it was (en)2 it would be bisethylenediamine.
by KHowe_1D
Sun Dec 08, 2019 3:32 pm
Forum: Significant Figures
Topic: pH sig figs
Replies: 9
Views: 59

Re: pH sig figs

Sig figs for pH will be the same as doing sig figs for any other question! If you are given a concentration to calculate pH with 3 sig figs then your answer should have 3 sig figs.
by KHowe_1D
Sun Dec 08, 2019 3:31 pm
Forum: Properties of Light
Topic: Speed of Light
Replies: 7
Views: 71

Re: Speed of Light

the units for c are in meters per second.
by KHowe_1D
Sun Dec 08, 2019 3:30 pm
Forum: Identifying Acidic & Basic Salts
Topic: salt solutions
Replies: 6
Views: 40

Re: salt solutions

You need to know how a salt can affect the pH of a solution whether it is making it more basic or acidic.
by KHowe_1D
Sun Dec 08, 2019 3:29 pm
Forum: Sigma & Pi Bonds
Topic: Sigma Vs Pi
Replies: 10
Views: 63

Re: Sigma Vs Pi

sigma bonds are the first bonds to form and can rotate. pi bonds are double and triple bonds and cannot rotate.
by KHowe_1D
Sun Dec 01, 2019 12:15 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Midterm Problem
Replies: 4
Views: 39

Re: Midterm Problem

When it asks you to do the Calcium ion it is referring to the most common ion which would be Ca2+. This is apparent when referencing the periodic table because this would be the most stable Calcium ion.
by KHowe_1D
Sun Dec 01, 2019 12:06 pm
Forum: Amphoteric Compounds
Topic: Identifying Them?
Replies: 12
Views: 61

Re: Identifying Them?

An amphoteric compound can both accept and donate protons/hydrogen atoms.
by KHowe_1D
Sun Dec 01, 2019 12:05 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids - Example from Lecture
Replies: 6
Views: 34

Re: Strength of Acids - Example from Lecture

It is because chlorine has a higher electronegativity than Hydrogen.
by KHowe_1D
Sun Dec 01, 2019 12:03 pm
Forum: Lewis Acids & Bases
Topic: Proton acceptor and proton donor?
Replies: 33
Views: 133

Re: Proton acceptor and proton donor?

Acids are the proton donors while bases are the proton acceptors.
by KHowe_1D
Sun Dec 01, 2019 12:02 pm
Forum: Polyprotic Acids & Bases
Topic: Polyprotic Acid Reactions- Loss of Proton(s)?
Replies: 2
Views: 18

Re: Polyprotic Acid Reactions- Loss of Proton(s)?

Only one proton is lost per reaction so over several reactions, multiple protons can be lost.
by KHowe_1D
Sun Nov 24, 2019 4:38 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted vs Lewis acids
Replies: 5
Views: 26

Re: Bronsted vs Lewis acids

Lewis acids accept electron while bronsted give electrons.
by KHowe_1D
Sat Nov 23, 2019 1:53 pm
Forum: Biological Examples
Topic: Histidine
Replies: 2
Views: 25

Re: Histidine

After a little googling, I believe it is an amino acid that helps the molecule stabilize after oxidation.
by KHowe_1D
Sat Nov 23, 2019 1:26 pm
Forum: Lewis Acids & Bases
Topic: Week 9 Homework
Replies: 5
Views: 36

Re: Week 9 Homework

We are on Outline 5 so we are doing section 9C for the homework.
by KHowe_1D
Sat Nov 23, 2019 1:24 pm
Forum: Lewis Acids & Bases
Topic: Acid and Base Consumption in Humans
Replies: 2
Views: 40

Acid and Base Consumption in Humans

Why is it that humans can consume (and enjoy consuming) relatively acidic things but can't consume most bases? It it like this for most species?
by KHowe_1D
Sat Nov 23, 2019 1:19 pm
Forum: Biological Examples
Topic: Example of a Cage like Molecule
Replies: 2
Views: 22

Re: Example of a Cage like Molecule

I believe an example in class was myoglobin (FeN4) which is what builds up hemoglobin in the blood.
by KHowe_1D
Sun Nov 17, 2019 10:52 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: Intermolecular Forces and Boiling/Melting Points
Replies: 3
Views: 14

Re: Intermolecular Forces and Boiling/Melting Points

Stronger bonds lead to higher boiling/melting points because it takes more energy to break this bonds.

Weaker bonds are easier to break and therefore will have a lower boiling and melting point.
by KHowe_1D
Sun Nov 17, 2019 10:50 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent or Angular
Replies: 13
Views: 94

Re: Bent or Angular

I would refer to the bond as angular because it is the more formal way of referring to the bond.

Either should be fine but to be safe, I would refer to it as angular as stated in the textbook.
by KHowe_1D
Sun Nov 17, 2019 10:47 am
Forum: Formal Charge and Oxidation Numbers
Topic: Calculating formal charge
Replies: 8
Views: 45

Re: Calculating formal charge

It doesn't matter what atom you start with because you are finding the individual charges for each atom. To find the charge of the molecule you would add up the charges of each individual atom.

The most favorable formal charge is zero because it means the molecule is stable.
by KHowe_1D
Sun Nov 17, 2019 10:39 am
Forum: Student Social/Study Group
Topic: Test 2 Topics
Replies: 3
Views: 44

Re: Test 2 Topics

Everything not covered on the midterm will be on the test. This includes dipole moments and the shapes/structures that we are doing now. I'm not sure what else though.
by KHowe_1D
Sun Nov 17, 2019 10:37 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Shapes We Are Expected to Know
Replies: 6
Views: 38

Re: Shapes We Are Expected to Know

I would assume that we need to know the shapes that are gone over in lecture.
by KHowe_1D
Sat Nov 09, 2019 11:19 am
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 18
Views: 109

Re: Resonance Structures

Resonance structures are the different ways the bonds can be done on the same molecule.

For example if there is a double bond on 3 oxygens and a single bond on 1 oxygen, the resonance structure would be the different positions of the single and double bonds on the molecule.
by KHowe_1D
Sat Nov 09, 2019 11:12 am
Forum: Quantum Numbers and The H-Atom
Topic: Quantum numbers
Replies: 12
Views: 99

Re: Quantum numbers

The angular momentum quantum number is l which is 0 to n-1
by KHowe_1D
Sat Nov 09, 2019 10:50 am
Forum: Ionic & Covalent Bonds
Topic: Covalent character and ionic character
Replies: 5
Views: 28

Re: Covalent character and ionic character

Covalent character is where atoms or molecules share electrons and ionic character is when electrons are "transferred" from one atom to another.
by KHowe_1D
Sat Nov 09, 2019 10:49 am
Forum: Ionic & Covalent Bonds
Topic: C, N, O, and F
Replies: 13
Views: 92

Re: C, N, O, and F

Yes they will follow the octet rule even if that makes the formal change not equal to 0 because having 8 electrons in the outer shell is where an atom is most stable.
by KHowe_1D
Sun Nov 03, 2019 4:14 pm
Forum: Lewis Structures
Topic: Lewis structure
Replies: 3
Views: 28

Re: Lewis structure

Yes some of the elements can use the d orbital which can help reach the formal charge of zero.
by KHowe_1D
Sun Nov 03, 2019 3:55 pm
Forum: Ionic & Covalent Bonds
Topic: Electron Configuration
Replies: 7
Views: 37

Re: Electron Configuration

Yes you should always try to have a half-filled or completely full orbital because it is more stable.
by KHowe_1D
Sun Nov 03, 2019 3:51 pm
Forum: Ionic & Covalent Bonds
Topic: middle atom
Replies: 13
Views: 60

Re: middle atom

Most of the time, the central atom is the atom that can form the most bonds with other atoms.
by KHowe_1D
Sun Nov 03, 2019 3:44 pm
Forum: Bond Lengths & Energies
Topic: Strength of Bonds
Replies: 16
Views: 61

Re: Strength of Bonds

Shorter bonds are stronger than longer bonds.
by KHowe_1D
Sun Nov 03, 2019 3:41 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 5
Views: 32

Re: Formal Charge

You want to calculate the formal charge to ensure that you have the most stable molecule.
by KHowe_1D
Sun Oct 27, 2019 6:18 pm
Forum: Lewis Structures
Topic: Octet Rule
Replies: 7
Views: 57

Re: Octet Rule

Helium probably wouldn't bond with other elements because it is already stable as a noble gas. Noble gasses are known not to react with other elements.
by KHowe_1D
Sun Oct 27, 2019 6:16 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Using periodic table to find configurations?
Replies: 3
Views: 24

Re: Using periodic table to find configurations?

Yes it can tell you the electron configuration. The number indicates how many electrons the element has. You can find the orbitals/subshells by looking at what group and period the element is in.
by KHowe_1D
Sun Oct 27, 2019 5:41 pm
Forum: Lewis Structures
Topic: Lone pair
Replies: 8
Views: 36

Re: Lone pair

A lone pair is a pair of electrons not bonding two elements together.
by KHowe_1D
Sun Oct 27, 2019 5:33 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions to Electron Configuration
Replies: 7
Views: 38

Re: Exceptions to Electron Configuration

Cu and Cr are the only exceptions because the half full and full d shell is more stable than a full 4s shell.
by KHowe_1D
Sun Oct 27, 2019 4:41 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions
Replies: 2
Views: 16

Re: Exceptions

They are the exceptions because a full d orbital and a partially full 4s shell is more stable than an almost full d orbital and a full 4s shell.
by KHowe_1D
Sun Oct 20, 2019 1:46 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ordering of s and d orbitals
Replies: 4
Views: 44

Re: Ordering of s and d orbitals

I was taught the same thing in high school but I think that it was because it was easier to remember.

Dr. Lavelle said that the 3d was written before the 4s because the 3d subshell has less energy than the 4s subshell.
by KHowe_1D
Sun Oct 20, 2019 12:55 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Short Hand
Replies: 11
Views: 62

Re: Short Hand

You pick the noble gas before the element. Those are the ones on the far right of the periodic table. These are chosen because they have filled electron shells.
by KHowe_1D
Sun Oct 20, 2019 12:54 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Nodal Planes
Replies: 1
Views: 15

Re: Nodal Planes

A nodal plane is an area where the probability of finding an electron is zero. It relates to electron distribution because you know that electrons are not within the nodal planes.
by KHowe_1D
Sun Oct 20, 2019 12:51 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: writing electron configurations
Replies: 4
Views: 34

Re: writing electron configurations

There are two electron in the first s shell so you have 1s^2 In the second s shell you also have 2 electrons so you have 2s^2 The p shell can hold 6 electrons in its 3 orbitals but since carbon only has 6 total electrons there is one in 2px and one in 2py. The x and the y indicate which orbitals are...
by KHowe_1D
Tue Oct 15, 2019 5:29 pm
Forum: DeBroglie Equation
Topic: HW 1b.15 part c
Replies: 2
Views: 21

Re: HW 1b.15 part c

I believe in this case the answers would be similar with c=frequency*wavelength being 12*10^-9m and frequency=hc/E being 9*10^-9m. However I believe you're supposed to use the frequency=hc/E because the E is factoring in the given velocity (when calculating for kinetic energy) which isn't being fact...
by KHowe_1D
Sun Oct 13, 2019 12:22 pm
Forum: Properties of Electrons
Topic: wave properties of electrons
Replies: 5
Views: 25

Re: wave properties of electrons

Constructive interference is when waves are in sync with each other and produce a larger amplitude.

Destructive interference is when they waves are out of sync resulting in a smaller amplitude.
by KHowe_1D
Sun Oct 13, 2019 12:18 pm
Forum: Properties of Electrons
Topic: Diffraction Patterns
Replies: 3
Views: 27

Re: Diffraction Patterns

This example shows diffraction patterns because the x ray is being or split when it goes through a crystal. The beam is going to enter at one angle, and exit at another.
by KHowe_1D
Fri Oct 11, 2019 2:41 pm
Forum: Properties of Light
Topic: Using the Rydberg Equation in HW 1A.15
Replies: 4
Views: 38

Re: Using the Rydberg Equation in HW 1A.15

I'm not entirely sure either. But I think you could just plug in values for n. I'm not sure if there is a more efficient way of doing this.
by KHowe_1D
Fri Oct 11, 2019 2:38 pm
Forum: Significant Figures
Topic: Sig Figs in Answer
Replies: 8
Views: 83

Re: Sig Figs in Answer

If you weren't given ANY numbers to work with, I would simply round to 3 decimals. That's what I normally do. But remember not to round until the final answer.

There are a few resources that are on the website that include the rules for sig figs.
by KHowe_1D
Fri Oct 11, 2019 2:33 pm
Forum: Properties of Light
Topic: Amplitude
Replies: 12
Views: 98

Re: Amplitude

Amplitude is just how high and low the wave goes but this isn't present in the equations we were given in class. I don't think it is as important as wavelength and frequency in this class. From physics, the amplitude could be calculated using sine, but I don't think we are going to use that in this ...
by KHowe_1D
Sat Oct 05, 2019 2:32 pm
Forum: Photoelectric Effect
Topic: 1B.15 part a
Replies: 1
Views: 37

Re: 1B.15 part a

I used the Broglie relationship because you just need to mass of an electron (which is provided in the book) to calculate the answer.

I modeled my work after the example 1B.4
by KHowe_1D
Sat Oct 05, 2019 2:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 2 Homework Problems [ENDORSED]
Replies: 67
Views: 1641

Re: Week 2 Homework Problems [ENDORSED]

He didn't specify but that is what we covered in the last 2 lectures so I have been doing problems from the Quantum World homework. EDIT: An email was just sent out and it stated: "Since students want to focus on the high school review topics for test 1 they can hand in homework #2 covering rev...
by KHowe_1D
Sat Oct 05, 2019 2:10 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg equation [ENDORSED]
Replies: 73
Views: 1636

Rydberg equation [ENDORSED]

What exactly is the Rydberg equation and how do you know when to use it?
by KHowe_1D
Thu Oct 03, 2019 4:06 pm
Forum: General Science Questions
Topic: Naming compounds
Replies: 6
Views: 69

Re: Naming compounds

My TA said that for the first test we should know a few basic ones but most chemical formulas will be provided.
by KHowe_1D
Thu Oct 03, 2019 4:04 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals F: The Determination of Composition Question #5
Replies: 2
Views: 36

Re: Fundamentals F: The Determination of Composition Question #5

You have to find the mass composition of each substance.

First you find the total molar mass.

Then you take the molar mass of each substance and divide it by the molar mass. Multiply by 100% to get each percentage.
by KHowe_1D
Tue Oct 01, 2019 4:29 pm
Forum: SI Units, Unit Conversions
Topic: Textbook
Replies: 7
Views: 76

Re: Textbook

As many have said. You don't need to bring your textbook but I would read the sections or prior to class so you know what to expect for the lecture. I mainly just use my book for the homework and reference when I need a more in depth explanation.
by KHowe_1D
Tue Oct 01, 2019 4:25 pm
Forum: Balancing Chemical Reactions
Topic: States of Matter in a Chemical Equation [ENDORSED]
Replies: 11
Views: 103

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

Like Jordan said, even if it won't affect the results of your chemical equation you should add them to get into the habit for future, more complex chemical reactions. It also helps me understand how the reactions are occurring and how the molecules interact.
by KHowe_1D
Tue Oct 01, 2019 4:15 pm
Forum: Molarity, Solutions, Dilutions
Topic: Conversion for the example dilution problem done in class on Monday
Replies: 2
Views: 40

Re: Conversion for the example dilution problem done in class on Monday

Dr. Lavelle said unless the question specified units, it doesn't matter as long as your answer is right. He only converted it to mL because that is what you would use in a lab setting.

Go to advanced search