## Search found 100 matches

Fri Mar 13, 2020 12:10 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Problem 6N.1 part b
Replies: 4
Views: 97

### Re: Problem 6N.1 part b

Yeah I noticed the same error, I think it's just a mistake.
Fri Mar 13, 2020 12:09 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: F in the equation for standard Gibbs energy
Replies: 4
Views: 89

### Re: F in the equation for standard Gibbs energy

It's Faraday's constant which will be given on the equation sheet.
Fri Mar 13, 2020 12:07 pm
Forum: General Rate Laws
Topic: Average rate vs unique rate
Replies: 4
Views: 67

### Re: Average rate vs unique rate

^^ Unique reaction rates means that it is the same for all reactants and products as opposed to the average reaction rate which can be different for each reactant and product.
Fri Mar 13, 2020 12:01 pm
Forum: General Rate Laws
Topic: Temperature and kinetics
Replies: 5
Views: 69

### Re: Temperature and kinetics

Yes, with higher temperature molecules move faster, therefore creating more kinetic energy.
Fri Mar 13, 2020 11:56 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: A- pre-exponential factor
Replies: 2
Views: 34

### A- pre-exponential factor

I know what A represents however I am confused by how you calculate A?
Sun Mar 08, 2020 8:38 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Cell potential
Replies: 6
Views: 78

### Re: Cell potential

How adding water affects cell potential is dependent on which solution it is diluting. If it is diluting the anode solution, then the overall Q is decreased, decreasing the lnQ expression and therefore increasing cell potential since the [-RTlnQ] term is smaller.
Sun Mar 08, 2020 8:33 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: How to determine Q
Replies: 4
Views: 64

### Re: How to determine Q

^^^ I agree with Tyler, it depends on the reaction given. Through the reaction given you are able to determine which is the product and which is the recatant.
Sun Mar 08, 2020 8:31 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: K
Replies: 5
Views: 70

### Re: K

If the cell potential is positive then it means the products are favored and therefore K>1 due to [producrs]/[reactants].
Sun Mar 08, 2020 8:28 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Diagram
Replies: 16
Views: 202

### Cell Diagram

For cell diagrams, theoretically I know that the reaction on the right is the cathode only if the cell potential is positive but for the purposes of the class, if the cell potential is not given then should one assume the cathode is the reaction on the right?
Thu Mar 05, 2020 12:59 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell potential of water
Replies: 1
Views: 29

### cell potential of water

How do you know which water reduction half reaction to use when looking up the cell potential?
Mon Mar 02, 2020 1:29 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 4
Views: 54

### Re: salt bridge

I am honestly not sure about the former but for the latter, the salt bridge is required so that the electrons continue moving throughout both solutions and keeping the voltage from reaching zero.
Mon Mar 02, 2020 12:54 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: work
Replies: 7
Views: 68

### Re: work

Gibbs free energy is equal to the maximum non expansion work a reaction can do at constant pressure and temperature
Thu Feb 27, 2020 11:50 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: log and ln in Nernst
Replies: 8
Views: 77

### Re: log and ln in Nernst

I believe he emphasized the log equation just because it is more relevant to life science but yeah I don't think it matters as long as you remember the conversion factor
Thu Feb 27, 2020 11:45 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Electrochemical Series
Replies: 2
Views: 42

### Re: Electrochemical Series

yeah I'm pretty sure the table of values will be given
Thu Feb 27, 2020 11:39 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: identifying strong reducing/oxidizing agents
Replies: 3
Views: 65

### Re: identifying strong reducing/oxidizing agents

the higher the number, the stronger the agent
Thu Feb 27, 2020 11:38 am
Forum: Balancing Redox Reactions
Topic: Oxygen's oxidation #
Replies: 6
Views: 73

### Re: Oxygen's oxidation #

^^ if Oxygen is in gas form, it's most stable, (O2) then the charge is zero and if it is in a molecule with another element then it has a charge of 2
Thu Feb 27, 2020 11:30 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Which half reaction is cathode or anode?
Replies: 6
Views: 371

### Re: Which half reaction is cathode or anode?

the cathode is being reduced and the anode is being oxidized; that can be deciphered through the equations given
Thu Feb 27, 2020 11:27 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 3
Views: 32

### Re: Cell Diagrams

the solids act as the electrode and is the thing that allows electron flow to happen from one cell to another
Thu Feb 27, 2020 11:26 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: K and Cell potential
Replies: 3
Views: 42

### Re: K and Cell potential

to be more specific, when Q is less than 1 then the E of the cell is increased because it makes the ln(Q) term in E=E naught -ln(Q) and when Q is more than 1 then E of the cell is decreased
Thu Feb 27, 2020 11:20 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: reducing/oxidizing agents
Replies: 7
Views: 76

### Re: reducing/oxidizing agents

in order to determine whether it is a reducing or oxidizing agent think about what the cell is doing to the other
Thu Feb 13, 2020 11:52 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy Change over the Course of Thermodynamic Processes
Replies: 3
Views: 39

### Re: Entropy Change over the Course of Thermodynamic Processes

Because entropy is a state function you do not need to include the entropies along the way to the final state. The initial and final state are the same so the change is zero.
Thu Feb 13, 2020 11:50 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Delta S
Replies: 6
Views: 66

### Re: Delta S

When talking about that it's important to note what exactly the delta S is for. For reversible reactions the total delta S is zero whereas the delta S of the system is a number and the the delta S of the surroundings is equal and opposite to the delta S of the system.
Thu Feb 13, 2020 11:47 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: deltaSrev/T
Replies: 2
Views: 33

### Re: deltaSrev/T

you usually only use it for phase changes because the temperature is constant
Thu Feb 13, 2020 11:45 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: constant pressure and volume
Replies: 3
Views: 80

### Re: constant pressure and volume

^^ At constant pressure delta H equals q and at constant pressure work equals zero.
Tue Feb 11, 2020 1:10 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Using Cp vs just R or C for ΔS
Replies: 2
Views: 46

### Using Cp vs just R or C for ΔS

When reading a problem how do you know which equation to use for ΔS?
options: ΔS= nRln(V2/V1) vs ΔS= Cln(T2/T1)
I'm having trouble distinguishing which to use based on the information given in problems, any insight will be helpful!
Mon Feb 10, 2020 8:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy Method for Complex molecules [ENDORSED]
Replies: 1
Views: 75

### Bond Enthalpy Method for Complex molecules[ENDORSED]

Will we provided with the molecular structure of more complex molecules or are we expected to be able to deduce them? I am struggling to write the lewis structure for some of the more complex molecules (ex. CH3CH(OH)CH3 from 4E.7 b) and thus use the incorrect bond enthalpies; should I just practice ...
Sun Feb 09, 2020 10:45 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Pizza Rolls 5a
Replies: 4
Views: 91

### Re: Pizza Rolls 5a

Johnathan Smith 1D wrote:Would you happen to know what the answer is because I got an answer that I’m not sure is right?

During the review session I believe they said the answer was delta S =33.0 J/K
Sun Feb 09, 2020 10:43 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Intensive
Replies: 8
Views: 113

### Re: Intensive

entropy is actually an extensive property ( it depends on the mass)
Sun Feb 09, 2020 10:37 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Boltzmann Equation
Replies: 2
Views: 30

### Re: Boltzmann Equation

Yes, the Boltsmann Equation calculates positional entropy using degeneracy (W) and kB (Boltzmann's constant).
Sun Feb 09, 2020 10:36 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Boltzmann Equation
Replies: 2
Views: 28

### Re: Boltzmann Equation

The Joules can be converted to eV.
Sun Feb 09, 2020 10:30 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Types of Entropy Calculations
Replies: 1
Views: 28

### Re: Types of Entropy Calculations

Boltzmann's equation is used for positional/residual entropy which is present in everything but is relatively small.
Sun Feb 02, 2020 4:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 3 Methods
Replies: 3
Views: 49

### Re: 3 Methods

The three methods are Hess's Law, using bond enthalpies, and delta H = Σ delta Hf of products - Σ delta Hf of reactants.
Using the bond enthalpy method is the least accurate so if you can use other methods that's preferred.
Sun Feb 02, 2020 4:04 pm
Forum: Phase Changes & Related Calculations
Topic: Calorimeters
Replies: 8
Views: 57

### Re: Calorimeters

if it's a bomb calorimeter then it is an isolated system
Sun Feb 02, 2020 4:01 pm
Forum: Calculating Work of Expansion
Topic: Work positive or negative
Replies: 5
Views: 58

### Re: Work positive or negative

^^ what they said; if the system is doing work it's negative, if work is being done on the system then it's positive
Sun Feb 02, 2020 3:59 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: entropy?
Replies: 4
Views: 64

### entropy?

why do we need entropy in order to describe the system?
Fri Jan 31, 2020 11:45 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Boltzmann Equation
Replies: 2
Views: 52

### Boltzmann Equation

I am confused on how Avogadro's number becomes involved in the W=2^N equation??
Sat Jan 25, 2020 4:57 pm
Forum: Ideal Gases
Topic: aqueous elements in eq calculation
Replies: 8
Views: 70

### Re: aqueous elements in eq calculation

yes aqueous solutions are included in eq calculations
Sat Jan 25, 2020 4:54 pm
Forum: Ideal Gases
Topic: final exam pickup
Replies: 10
Views: 176

### Re: final exam pickup

final exam pickup is in Young Hall 3034 from 9-5 (although they have an our lunch break at 12)
Sat Jan 25, 2020 4:52 pm
Forum: Ideal Gases
Topic: R Constant
Replies: 18
Views: 249

### Re: R Constant

There are different R constants that have different units so you just pick the R constant that has units matching the other parts (i.e. atm or bar)
Sat Jan 25, 2020 4:49 pm
Forum: Ideal Gases
Topic: 5J.13 and Ideal Gas Law
Replies: 2
Views: 45

### Re: 5J.13 and Ideal Gas Law

There is no need to calculate anything; just compare the two different K values.
Sat Jan 25, 2020 4:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy
Replies: 4
Views: 27

### Re: Bond Enthalpy

^^ bond enthalpy is always positive because by definition the energy is always being put in.
Tue Jan 14, 2020 10:08 pm
Forum: Ideal Gases
Topic: ICE Table
Replies: 11
Views: 194

### Re: ICE Table

An ICE table shows the change in concentrations the reactants and products go through from the beginning of the reaction to the end. I stands for initial, c stands for change, and e stands for equilibrium.
Tue Jan 14, 2020 10:06 pm
Forum: Ideal Gases
Topic: "omitting" the units
Replies: 7
Views: 114

### Re: "omitting" the units

^^as they stated K represents activity which is unitless
Tue Jan 14, 2020 10:03 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing Pressure
Replies: 3
Views: 45

### Re: Changing Pressure

reactants and products have an inversely proportional relationship, so if R goes down, P goes up, if P goes down, R goes up.
Tue Jan 14, 2020 10:01 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Expansion
Replies: 5
Views: 36

### Re: Expansion

^^ as the previous replies stated, expansion would affect Q (the reaction quotient) however it would not affect K because K is a fixed value.
Tue Jan 14, 2020 10:00 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: volume's effect on K
Replies: 7
Views: 64

### Re: volume's effect on K

When volume changes it changes Q (the reaction quotient) however it does not change K because K is a constant of that molecule at that temperature. The only thing that can change K is temperature.
Tue Jan 14, 2020 9:57 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: volume change with inert gas
Replies: 9
Views: 95

### Re: volume change with inert gas

the inert gas doesn't change the physical characteristics of the products and reactants
Tue Jan 14, 2020 9:55 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Kw
Replies: 16
Views: 128

### Re: Kw

Kw is the equilibrium constant.
Tue Jan 14, 2020 9:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acid and Base Equilibrium
Replies: 2
Views: 34

### Re: Acid and Base Equilibrium

Yeah I don't think we've gotten to that part yet. Lavelle will probably go over it in class.
Tue Jan 14, 2020 9:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: equilibrium concentration with gases
Replies: 7
Views: 71

### Re: equilibrium concentration with gases

Yes. Pressure isn't involved in Kc
Tue Jan 14, 2020 9:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.H.3
Replies: 3
Views: 74

### Re: 5.H.3

You have to find the equations in the table that could combine to create 2BrCl + H2 <--> Br2 + 2HCl and then use the K's to find the K of the overall equation. You can use the section 5H. 2 to decide what to do with the K's.
Sun Dec 08, 2019 12:11 am
Forum: Naming
Topic: cisplatin
Replies: 4
Views: 57

### Re: cisplatin

cisplatin is [Pt(NH3)2Cl2] which is a chemotherapy drug. to be specific cisplatin has the Cl on the same side of the molecule so that the 2 Cl's bond with 2 Guanines on a DNA strand to shut down cell division.
Sun Dec 08, 2019 12:08 am
Forum: Naming
Topic: polydentate
Replies: 1
Views: 41

### Re: polydentate

yes
Sun Dec 08, 2019 12:08 am
Forum: Naming
Topic: naming
Replies: 2
Views: 55

### Re: naming

if the overall charge of the coordination complex is not zero (i.e. a negative or positive number) then the end of the metal is changed to -ate. The only special names are iron which turns into ferrate and copper which changes to cupprate.
Sun Dec 08, 2019 12:06 am
Forum: Naming
Topic: Cation vs. Anion Transition Metal
Replies: 3
Views: 113

### Re: Cation vs. Anion Transition Metal

if the overall charge of the coordination complex is not 0 (so positive or negative charge) then -ate is added to the end of the metal ion
Sun Dec 08, 2019 12:04 am
Forum: Naming
Topic: charges on a compound
Replies: 2
Views: 34

### Re: charges on a compound

You'd simply add the charge of the ions together and then make it so that the charge of the metal ion plus the charge of the ions together equal -2.
Sun Dec 08, 2019 12:02 am
Forum: Biological Examples
Topic: EDTA
Replies: 1
Views: 99

### EDTA

For EDTA the formula given by google is C10H16N2O8 but isn't ethylenediamine C2N2H8 so that would make each acetate C2H2O2 but isn't acetate C2H3O2?
Sun Dec 01, 2019 9:15 pm
Forum: Naming
Topic: Water in Coordination Compounds
Replies: 7
Views: 98

### Re: Water in Coordination Compounds

Its just to emphasize that it's the oxygen bonding to the compound.
Sun Dec 01, 2019 9:14 pm
Forum: Naming
Topic: Naming coordination compounds
Replies: 5
Views: 47

### Re: Naming coordination compounds

The charge of the metal ion is determined by counting up the charge of the other elements and then making the charge of the metal ion so that together it's equal to the total charge of the compound.
Sun Dec 01, 2019 9:07 pm
Forum: Naming
Topic: How to Know the Charge of Ions
Replies: 7
Views: 91

### Re: How to Know the Charge of Ions

Yeah unfortunately I think we just need to memorize the charges of the common ions
Sun Dec 01, 2019 9:06 pm
Forum: Naming
Topic: Roman Numeral
Replies: 13
Views: 118

### Re: Roman Numeral

The roman numeral tells you the charge of the metal ion.
Sun Dec 01, 2019 9:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Lone pairs and bonding sites
Replies: 3
Views: 61

### Re: Lone pairs and bonding sites

Yes if it has more than one lone pair (and thus can donate more than one pair of electrons) it is polydentate.
Sun Nov 24, 2019 11:51 pm
Forum: Sigma & Pi Bonds
Topic: Stability of Sigma and Pi Bonds
Replies: 4
Views: 75

### Re: Stability of Sigma and Pi Bonds

In sigma bonds the areas of electron density are overlapping whereas pi bonds only have regions of electron density side by side.
Sun Nov 24, 2019 11:46 pm
Forum: Coordinate Covalent Bonds
Topic: Ch 17 #29
Replies: 2
Views: 540

### Re: Ch 17 #29

They mean the same thing, so either is fine
Sun Nov 24, 2019 11:45 pm
Forum: Coordinate Covalent Bonds
Topic: Difference between coordinate covalent and covalent bond
Replies: 6
Views: 3505

### Re: Difference between coordinate covalent and covalent bond

In a coordinate covalent bond one atom provides both electrons.
Sun Nov 24, 2019 11:44 pm
Forum: Coordinate Covalent Bonds
Topic: Definition
Replies: 5
Views: 171

### Re: Definition

A coordinate covalent bond is when one atom shares both pairs of electrons.
Tue Nov 19, 2019 12:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Bipyramidal
Replies: 1
Views: 29

### Trigonal Bipyramidal

How is a trigonal bipyramidal shape nonpolar? How do the equatorial atoms' pull cancel out if they are angled in non-opposing directions?
Sun Nov 17, 2019 8:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E. 25 Polar molecules
Replies: 1
Views: 43

### 2E. 25 Polar molecules

For part a of 2E. 25 how do you know that the chlorines are next to each other so that they don't cancel out? I know this is similar to the example Lavelle showed in class with the Dichloroethene, where cis was polar and trans was nonpolar but how do you know which lewis structure is the correct one?
Sat Nov 16, 2019 12:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 44

### Re: Bond Angles

if the atom contains lone pairs it may affect the bond angles slightly because they have a stronger repelling force and push the other bonding electrons closer together, distorting the shape slightly.
Sat Nov 16, 2019 12:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent or Angular
Replies: 13
Views: 300

### Re: Bent or Angular

I don't believe it matters as it was referred to as angular in the textbook and Lavelle referred to the shape as bent.
Sat Nov 16, 2019 12:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T Shape
Replies: 7
Views: 87

### Re: T Shape

I would know it just in case
Sat Nov 16, 2019 12:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle with Lone Pairs
Replies: 3
Views: 45

### Re: Bond Angle with Lone Pairs

lone pairs have a greater repelling force, therefore forcing the bonding electrons closer together and therefore decreasing the bond angle slightly
Sat Nov 16, 2019 12:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs and Bond Angles
Replies: 2
Views: 49

### Re: Lone Pairs and Bond Angles

^^^ lone pairs are always stronger than bonding atoms
Tue Nov 05, 2019 11:21 am
Forum: Lewis Structures
Topic: 2B.1 c
Replies: 2
Views: 54

### 2B.1 c

For the molecule ONF, how do you know which molecule should go in the middle? Generally the element with the lowest ionization energy is the central atom but doesn't oxygen have a lower ionization energy because it's more favorable to have 3 electrons in the 2d shell, so why is nitrogen the central ...
Tue Nov 05, 2019 10:58 am
Forum: Resonance Structures
Topic: resonance importance?
Replies: 7
Views: 95

### resonance importance?

I know that a resonant structure lowers the energy of a molecule to make it more stable but I don't really understand why having a mixture of structures help lowers the energy. Any insight would be helpful
Sun Nov 03, 2019 10:05 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.21
Replies: 2
Views: 50

### Re: 1D.21

For reference for l,
l=0 ---> s orbital
l=1 ---> p orbital
l=2 ---> d orbital
l=3 ---> f orbital (we don't really need to know this)
the principal quantum number, n, just needs to be in the front so,
n=5 l=2 ---> 5d
n=1 l=0 ---> 1s
n=6 l=3 ---> 6f
n=2 l=1 ---> 2p
Sun Nov 03, 2019 9:59 pm
Forum: *Shrodinger Equation
Topic: ?
Replies: 2
Views: 170

### Re: ?

ψ describes the system mathematically
Sun Nov 03, 2019 9:56 pm
Forum: Bond Lengths & Energies
Topic: Why Are Double Bonds Shorter
Replies: 16
Views: 524

### Re: Why Are Double Bonds Shorter

^^^ more electrons have more pull and make the bond shorter
Sun Nov 03, 2019 9:54 pm
Forum: Bond Lengths & Energies
Topic: Chemical Bonds
Replies: 4
Views: 65

### Re: Chemical Bonds

^^ atoms become more stable with bonds
Sun Nov 03, 2019 9:52 pm
Forum: Bond Lengths & Energies
Topic: Does bond length have any effects?
Replies: 5
Views: 46

### Re: Does bond length have any effects?

Yes, shorter bonds require more energy to break; double bonds and triple bonds are shorter than single bonds and therefore need more energy to break.
Sun Oct 27, 2019 7:57 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 4
Views: 233

### Re: Formal Charge

In making a lewis dot structure you first think about the octet rule and then adjust the structure to have a better formal charge.
Sun Oct 27, 2019 7:56 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge vs octet rule
Replies: 5
Views: 420

### Re: Formal charge vs octet rule

What people above me said: it is better to be more stable if it is below period 3.
Sun Oct 27, 2019 7:51 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Formula
Replies: 5
Views: 61

### Re: Formal Charge Formula

Shared electrons are the electrons that are represented by the line in a lewis dot structure. Each line counts as 2 electrons.
Sun Oct 27, 2019 7:47 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Central atom
Replies: 8
Views: 145

### Re: Central atom

What the people of above me said :). The center atom's formal charge may not always be zero, if there is a choice between an outer atom with a formal charge of zero and the center atom with zero than it is best to have the center atom with zero.
Sun Oct 27, 2019 7:43 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Lowering Formal Charge
Replies: 6
Views: 108

### Re: Lowering Formal Charge

The goal is to minimize formal charge overall but if it comes down to minimizing the formal charge on one of the outer atoms at the expense of the center atom's formal charge increasing than it's better to have the center atom with the lowest possible formal charge.
Sat Oct 19, 2019 10:43 pm
Forum: Properties of Electrons
Topic: Intensity vs. Energy
Replies: 10
Views: 124

### Re: Intensity vs. Energy

intensity depends on the amplitude of the wavelength and is directly related to the amount of photons while energy is related to if there is enough energy for the electron to be ejected.
Sat Oct 19, 2019 10:39 pm
Forum: Properties of Electrons
Topic: x,y,z for Electrons
Replies: 10
Views: 141

### Re: x,y,z for Electrons

x, y, z, refers to the different planes that electrons are on
Sat Oct 19, 2019 10:34 pm
Forum: Properties of Electrons
Topic: Electron structures
Replies: 2
Views: 52

### Re: Electron structures

^^ what they said. There's no technical rule but people usually just fill it in left to right.
Sat Oct 19, 2019 10:33 pm
Forum: Properties of Electrons
Topic: Aufbau vs Hund's
Replies: 2
Views: 56

### Re: Aufbau vs Hund's

Hund's principle states that every orbital in a subshell will be occupied with one electron before any one orbital is doubly occupied. Whereas Aufbau's principle states that lower energy orbitals fill before higher energy orbitals so that orbitals in the n=1 energy level will fill before the n=2 ene...
Sat Oct 19, 2019 10:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 282
Views: 134677

### Re: Saying Thank You to Dr. Lavelle

Thank you Dr. Lavelle for all of your instruction. Your passion for not only the subject of chemistry but the well-being of your students is palpable. Thank you for applying chemistry principles to a lab setting in order for us to understand the importance of every chemistry concept we learn.
Sun Oct 13, 2019 1:57 pm
Forum: Properties of Light
Topic: e=hv
Replies: 7
Views: 164

### Re: e=hv

Yes it was derived from the photoelectric experiment.
Sun Oct 13, 2019 1:47 pm
Forum: Properties of Light
Topic: difference between Rydberg equation and De Broglie equation
Replies: 5
Views: 128

### Re: difference between Rydberg equation and De Broglie equation

The De Broglie equation is to find the wavelength of matter since all moving objects with rest mass however it only has wavelike properties with an extremely small mass. The Rydberg equation is to calculate the amount of energy released when an electron drops to a lower energy level and works only f...
Sun Oct 13, 2019 1:33 pm
Forum: Properties of Light
Topic: Light intensity and Kinetic Energy
Replies: 7
Views: 118

### Re: Light intensity and Kinetic Energy

When light intensity is increased, there are simply more photons and one photon interacts with a single electron. In order for each photon to have enough energy to eject one electron the wavelength needs to be shorter.
Sun Oct 13, 2019 1:28 pm
Forum: Properties of Light
Topic: Wave Properties of electrons
Replies: 7
Views: 111

### Re: Wave Properties of electrons

Diffraction patterns are how light spreads out when it passes through a small passage. Based on the diffraction patterns there must be waves in phase (constructive) and waves out of phase (destructive interference) where the waves either line up with each other or they don't and they can cancel each...
Sun Oct 13, 2019 1:18 pm
Forum: Properties of Light
Topic: Rydberg constant
Replies: 7
Views: 96

### Re: Rydberg constant

The Rydberg equation works only for the hydrogen spectrum because it was found based on the Hydrogen experiment. A more sophisticated model is needed for a multi-electron problem.
Thu Oct 03, 2019 1:00 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: States of Matter
Replies: 9
Views: 301

### Re: States of Matter

No it doesn't matter.
Thu Oct 03, 2019 12:58 pm
Forum: Significant Figures
Topic: General sig figs question
Replies: 5
Views: 104

### Re: General sig figs question

I'm pretty sure significant figures when adding or subtracting are dictated by the lowest amount of numbers after the decimal.
Ex. 12.5+5.35=17.9
Thu Oct 03, 2019 12:49 pm
Forum: SI Units, Unit Conversions
Topic: Dimensional Analysis Question
Replies: 6
Views: 74

### Re: Dimensional Analysis Question

It's basically just a way to convert units from one to another. For example if you have distance given in yards (ex. 5 yards) you can use dimensional analysis to convert it into feet [i.e. (5 yards)x(3 feet/1 yard)= 15 feet; the yards cancel out and leave you with feet as the final unit].
Thu Oct 03, 2019 12:42 pm
Forum: Significant Figures
Topic: General Rules of Sig Figs with Example Questions
Replies: 4
Views: 97

### Re: General Rules of Sig Figs with Example Questions

The general rule for the number of sig figs for an answer is exactly like what the previous reply said; they are based on the amount of numbers that aren't zero or any zeros that are in between other numbers. For example, 25.7 has three sig figs where as 25.07 has four sig figs. Another rule is that...
Wed Oct 02, 2019 12:10 am
Forum: Significant Figures
Topic: E21b. Sig Figs
Replies: 5
Views: 134

### E21b. Sig Figs

If the given number is 25.92 mg of HF why is the amount of significant figures for the answer 3?