Search found 103 matches

by 105335337
Mon Mar 09, 2020 2:16 pm
Forum: Environment, Ozone, CFCs
Topic: Catalysts and angular dependence
Replies: 2
Views: 51

Re: Catalysts and angular dependence

While that does make sense, Dr. Lavelle said that it just lowers the value of Ea and the equation, so I am unsure.
by 105335337
Mon Mar 09, 2020 2:16 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Microscopic Reversibility
Replies: 3
Views: 47

Re: Microscopic Reversibility

Microscopic reversibility means if you do the forward process of a reaction mechanism, you will have A & B as your intermediate. If you do the reverse process of the reaction mechanism, you will still have A & B. Microscopic reversibility is when the intermediates are the same for both forwa...
by 105335337
Mon Mar 09, 2020 2:14 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Identifying Catalysts
Replies: 6
Views: 62

Re: Identifying Catalysts

We identify a catalyst by this method:

Look for a reactant that is used and then reformed (taking it out of the overall reaction). This is what a catalyst is. It is originally there and used, but then reformed at a later stage.
by 105335337
Mon Mar 09, 2020 2:13 pm
Forum: General Rate Laws
Topic: general questions
Replies: 3
Views: 63

Re: general questions

Yes this is correct, however the rate laws are always positive, that's why the - is included within the reactants.
by 105335337
Mon Mar 09, 2020 2:12 pm
Forum: General Rate Laws
Topic: Graphs of rate laws
Replies: 8
Views: 74

Re: Graphs of rate laws

If you graph [R] v time & get a straight line: zero order

if you graph ln[R] v time & get a straight line: first order

if you graph 1/[R] v time & get a straight line: second order
by 105335337
Mon Mar 09, 2020 2:11 pm
Forum: *Enzyme Kinetics
Topic: Lecture 3/6
Replies: 2
Views: 82

Re: Lecture 3/6

We covered Ahrenniu's equation, which can be found within the book.
by 105335337
Mon Mar 09, 2020 2:11 pm
Forum: General Rate Laws
Topic: integrated rate law vs general
Replies: 8
Views: 125

Re: integrated rate law vs general

Integrated rate law is the rate within a time period so you can see the rate at that time, but the general rate law is just the rate vs the conc. of reactants.
by 105335337
Mon Mar 09, 2020 2:10 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Kelvin or Celsius?
Replies: 47
Views: 981

Re: Kelvin or Celsius?

You use Kelvin because you must match the units within the R (gas constant) which uses kelvin.
by 105335337
Mon Mar 09, 2020 2:09 pm
Forum: General Science Questions
Topic: Who makes the Final
Replies: 23
Views: 383

Re: Who makes the Final

Lavelle makes the final.
by 105335337
Mon Mar 09, 2020 2:09 pm
Forum: Biological Examples
Topic: Catalysts
Replies: 6
Views: 80

Re: Catalysts

NO is the only catalyst and O2 is simply just a reactant because it is not reformed in the products.
by 105335337
Mon Mar 09, 2020 2:08 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Steady-State Approach
Replies: 4
Views: 46

Re: Steady-State Approach

It won't be covered on the final. He did say there are some homework questions on it, but it is not going to be tested.
by 105335337
Tue Feb 25, 2020 2:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: standard potential of a redox reaction
Replies: 3
Views: 46

Re: standard potential of a redox reaction

E Is an intensive property, so you do not multiply the E value when the equation is multiplied.
by 105335337
Tue Feb 25, 2020 2:16 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: identifying strong reducing/oxidizing agents
Replies: 3
Views: 66

Re: identifying strong reducing/oxidizing agents

If they are highly positive, they are a strong reducer. If they are highly negative, it is a strong oxidizer.
by 105335337
Tue Feb 25, 2020 2:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Concentration Cells
Replies: 2
Views: 46

Re: Concentration Cells

Salt bridges cannot be used because since it is the same molecules on both sides, the salt bridge wouldn't move anything. Porous disks allows for the higher concentration to diffuse into the lower.
by 105335337
Tue Feb 25, 2020 2:10 pm
Forum: Balancing Redox Reactions
Topic: Which equation do we flip?
Replies: 6
Views: 80

Re: Which equation do we flip?

You flip the equation that is being oxidized. For a galvanic cell, the E has to be positive, so whichever will make it positive.
by 105335337
Tue Feb 25, 2020 2:09 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Midterm question Q3B
Replies: 2
Views: 114

Re: Midterm question Q3B

For this question, delta H will be the largest for the most moles because its J/mol. Delta H impacts delta T, so B, which has the most moles, is the correct answer.
by 105335337
Mon Feb 17, 2020 11:17 pm
Forum: Administrative Questions and Class Announcements
Topic: HW7
Replies: 14
Views: 134

Re: HW7

The end of thermodynamics to electrochemistry is perfectly fine for the homework!
by 105335337
Mon Feb 17, 2020 11:15 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Van't Hoff
Replies: 6
Views: 62

Re: Van't Hoff

When using this equation, it assumes that the pressure / volume is constant.
by 105335337
Mon Feb 17, 2020 11:14 pm
Forum: Van't Hoff Equation
Topic: When to Use Vant Hoff
Replies: 5
Views: 74

Re: When to Use Vant Hoff

This equation is used when you have a reaction at two different temperatures with two different k values. It is used to solve for T2/K2 or T1/K1
by 105335337
Mon Feb 17, 2020 11:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Is this course curved?
Replies: 7
Views: 164

Re: Is this course curved?

While the final exams are not curved, I do believe that at the very end, it depends on whether or not the top person did in the class to determine the grade of everyone else.
by 105335337
Mon Feb 17, 2020 11:11 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: G vs G knot
Replies: 15
Views: 113

Re: G vs G knot

G Knot is for when the things are at standard state in the world. G is just the G at that specific states.
by 105335337
Mon Feb 10, 2020 2:18 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: S=kB*lnw equation
Replies: 4
Views: 505

Re: S=kB*lnw equation

Yes, it is given on the formula sheet. It is the Blotzman constant.
by 105335337
Mon Feb 10, 2020 2:17 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Intensive vs. Extensive
Replies: 15
Views: 324

Re: Intensive vs. Extensive

Intensive properties do not rely on the quantity of matter while extensive properties due depend on the quantity of matter.
by 105335337
Mon Feb 10, 2020 2:17 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: Using Cv and Cp
Replies: 4
Views: 53

Re: Using Cv and Cp

Constant volume uses Cv and Constant pressure uses Cp. Cv is normally used though.
by 105335337
Mon Feb 10, 2020 2:16 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal delta H
Replies: 2
Views: 20

Re: Isothermal delta H

Nope, Delta H is always equal to q, but q is not always equal to Delta H. Therefore, Delta H is only equal to q when p is constant.
by 105335337
Mon Feb 10, 2020 2:15 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous delta G
Replies: 7
Views: 66

Re: Spontaneous delta G

WE set delta G to zero in the practice problem because by setting it to 0, it gave us the minimum temperature needed to make the reaction spontaneous, therefore answering the question.
by 105335337
Mon Feb 03, 2020 11:30 pm
Forum: Phase Changes & Related Calculations
Topic: -w vs w
Replies: 15
Views: 154

Re: -w vs w

When w is positive, work is being done on the system & when w is negative. the system is doing work. For example, today the system pushed the piston outwards, doing work on the system, making w negative.
by 105335337
Mon Feb 03, 2020 11:29 pm
Forum: Calculating Work of Expansion
Topic: Integrals
Replies: 2
Views: 30

Re: Integrals

You just need to know that if pressure is constant, the integral results in P (delta)T & if pressure is not it results in nrtln(v2/v1).
by 105335337
Mon Feb 03, 2020 11:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity
Replies: 3
Views: 29

Re: Heat capacity

Heat capacity is the amount of heat required to raise 1g of substance up by one temperature.
by 105335337
Mon Feb 03, 2020 11:27 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated// Energy
Replies: 11
Views: 103

Re: Isolated// Energy

For the system as a whole, there cannot be an exchange in energy because its isolated so the energy is constant.
by 105335337
Mon Feb 03, 2020 11:27 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: endo vs exo
Replies: 8
Views: 43

Re: endo vs exo

Breaking a bond requires energy to overcome the bond strength while forming a bond requires energy to be released.
by 105335337
Tue Jan 28, 2020 2:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Best Method of the 3 Given?
Replies: 7
Views: 57

Re: Best Method of the 3 Given?

The normal method would be Method 1. It has the exact enthalpies and would give you the right answer. When doing bond enthalpies, its different because each molecules would have different and its jut an average. So method 1/3 are the best.
by 105335337
Tue Jan 28, 2020 2:27 pm
Forum: Phase Changes & Related Calculations
Topic: Change in Temperature
Replies: 10
Views: 51

Re: Change in Temperature

Yes, temperature is a factor that changes the equilibrium constant. For example, if temperature increases in a reaction, the equilibrium constant will change.
by 105335337
Tue Jan 28, 2020 2:26 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Test 2
Replies: 7
Views: 79

Re: Test 2

Test 2 will only cover the information that comes after the midterm and up until test 2!
by 105335337
Tue Jan 28, 2020 2:25 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Adding Enthalpies
Replies: 5
Views: 36

Re: Adding Enthalpies

No, instead of multiplying, you add the enthalpies together. If its reverse, you just switch the sign of the enthalpy, and if you double it, you double enthalpy! Hope this helps.
by 105335337
Tue Jan 28, 2020 2:24 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 11
Views: 134

Re: Hess's Law

In multi-step reactions, the enthalpies are able to be added together because enthalpy is a state function (meaning the path to get there doesn't matter, its just the value). So you need to just add the enthalpies together.
by 105335337
Sun Jan 19, 2020 1:57 pm
Forum: Ideal Gases
Topic: ICE Table
Replies: 11
Views: 201

Re: ICE Table

You use an ice table to calculate the concentrations of all molecules in a reaction at equilibrium. You set up the table with Initial, Change, Equilibrium going vertical and the molecules involved in the equilibrium constant going horizontally. You list the initials, the changes, and then the equili...
by 105335337
Sun Jan 19, 2020 1:55 pm
Forum: Ideal Gases
Topic: R Constant
Replies: 7
Views: 52

Re: R Constant

R is the universal gas constant and has the units of the other variables (L, atm, etc...)
by 105335337
Sun Jan 19, 2020 1:54 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure
Replies: 5
Views: 43

Re: Pressure

It depends on which side of the equation has more moles of gas. If the reactants have more moles of gas and pressure is increased, the reaction will shift to the right to lower the pressure and re-reach equilibrium.
by 105335337
Sun Jan 19, 2020 1:53 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Quadratic Equation
Replies: 8
Views: 79

Re: Quadratic Equation

We use the quadratic equation in terms of chemical equilibrium when we are estimating the equilibrium point of a reaction through an ICE Table. If we are unable to use the "x is small" approximation, you must then use the quadratic equation to solve for x.
by 105335337
Sun Jan 19, 2020 1:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic vs. exothermic
Replies: 5
Views: 44

Re: Endothermic vs. exothermic

In an endothermic reaction, heat is technically considered a reactant because it takes heat to cause the reaction to occur.. So I we add more reactant, it will force equilibrium to shift to the right, creating more product.
by 105335337
Mon Jan 13, 2020 12:30 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction shifts right or left?
Replies: 14
Views: 213

Re: Reaction shifts right or left?

Yes. Exactly that. If the reaction is shifted to the left, more reactants are created and if the reaction is shifted to the right, more products are formed.
by 105335337
Mon Jan 13, 2020 12:29 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Change in Pressure
Replies: 6
Views: 34

Re: Change in Pressure

When the pressure is decreased, the reaction will proceed in the direction that has more moles of gas because it will want to increase the pressure to re-reach equilibrium.
by 105335337
Mon Jan 13, 2020 12:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for K
Replies: 21
Views: 214

Re: Units for K

K has no units as hen you do all the calculations, the units cancel out. Furthermore, this is because K is just a constant.
by 105335337
Mon Jan 13, 2020 12:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc
Replies: 5
Views: 45

Re: Kc

Solids & liquids are excluded when solving for Kc. Only gases and aqueous solutions are included.
by 105335337
Mon Jan 13, 2020 12:26 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q=K
Replies: 14
Views: 131

Re: Q=K

Q is just the system quotient at any time. If q ends up equaling K that means that the reaction is at equilibrium. If K>Q the forward reaction is favored & if K<Q then the backwards reaction is favored.
by 105335337
Thu Jan 09, 2020 10:05 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G3
Replies: 8
Views: 64

Re: 5G3

Yes. All gases should be included in the equilibrium constant.
by 105335337
Thu Jan 09, 2020 10:03 am
Forum: Ideal Gases
Topic: K and Q
Replies: 13
Views: 115

Re: K and Q

If the question asks you to solve for the equilibrium constant, that is when you use Kc. If the question asks you to determine whether the reaction is at equilibrium or will proceed forwards/backwards, that's when you compare Kc to Q
by 105335337
Thu Jan 09, 2020 10:02 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Changing Kc [ENDORSED]
Replies: 4
Views: 62

Re: Changing Kc [ENDORSED]

A change in pressure & or volume results in a change in the opposite. These just cause the reaction to go forward or backward and then eventually re-reach equilibrium. Temperature causes the molecules to speed up while nothing else is changing, causing more of them to hit each other.
by 105335337
Thu Jan 09, 2020 10:01 am
Forum: Ideal Gases
Topic: Understanding Q
Replies: 19
Views: 177

Re: Understanding Q

Yes. Q and Kc are solved the completely same way. Q is just to tell if the reaction is at equilibrium or not.
by 105335337
Thu Jan 09, 2020 10:00 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: units of K
Replies: 10
Views: 90

Re: units of K

There are no units for K as the units tend to cancel out.
by 105335337
Sun Dec 08, 2019 9:49 am
Forum: Biological Examples
Topic: Formulas for acid rain
Replies: 2
Views: 99

Re: Formulas for acid rain

H20 + CO2 -> H2CO3
by 105335337
Tue Dec 03, 2019 12:47 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: dipole dipole
Replies: 7
Views: 90

Re: dipole dipole

Yes. Dipole-Dipole IMFs means that both of the molecules have a dipole moment.
by 105335337
Tue Dec 03, 2019 12:42 pm
Forum: Hybridization
Topic: Triple Bond Hybridization
Replies: 4
Views: 45

Re: Triple Bond Hybridization

A triple bond has a hybridization of sp because the central atom (which will have one triple bond and one other area of electron density) creates two areas of electron density, which has the hybridization of sp.
by 105335337
Tue Dec 03, 2019 12:39 pm
Forum: *Particle in a Box
Topic: Hydrogen Atom
Replies: 7
Views: 332

Re: Hydrogen Atom

When a hydrogen absorbs, the energy is positive because it is adding it to the molecule, requiring energy.
by 105335337
Tue Dec 03, 2019 12:38 pm
Forum: Dipole Moments
Topic: Melting points
Replies: 15
Views: 394

Re: Melting points

A double bond has nothing to do with melting point because melting point has to do with intermolecular forces rather than molecular bonds.
by 105335337
Tue Dec 03, 2019 12:31 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pKa vs Ka
Replies: 6
Views: 64

Re: pKa vs Ka

Ka is the disassociation factor while pKa is the pH of the Ka factor. For example. If an acid has a pKa of 1.0x10^-7, the pKa will be 7.
by 105335337
Mon Nov 25, 2019 11:15 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Cis and Trans
Replies: 6
Views: 115

Re: Cis and Trans

Cis & Trans relate to when the same molecule just has different bonding sites for outer elements. Trans is when they are diagonal and Cis is when they are on the same side. This is extremely important to biological compounds as it can totally change the function because shape is influenced. Howe...
by 105335337
Mon Nov 25, 2019 11:14 am
Forum: Administrative Questions and Class Announcements
Topic: Week 9 Homework
Replies: 2
Views: 61

Re: Week 9 Homework

Week 9 homework is on Coordination and Biological Compounds & the beginning of Acids/Bases.
by 105335337
Mon Nov 25, 2019 11:12 am
Forum: Bond Lengths & Energies
Topic: Hydrogen Bonding and Dispersion
Replies: 5
Views: 161

Re: Hydrogen Bonding and Dispersion

Dispersion occurs between two non polar molecules. When two non polar molecules get close into contact, the electrons will cause an induced-dipole onto both molecules, making one side positive and one slightly negative. This yields them to be attracted to each other, creating LDF aka dispersion. H b...
by 105335337
Mon Nov 25, 2019 11:10 am
Forum: Hybridization
Topic: Sigma and Pi Bonds
Replies: 5
Views: 50

Re: Sigma and Pi Bonds

Sigma bonds can be rotated amongst their axises & orbitals, while pi bongs cannot. Sigma bonds are always formed first before the pi bonds, signifying why a single bond only has one sigma bond and no pi bonds. However with double and triple bonds, there is only one sigma bond and two pi bonds.
by 105335337
Mon Nov 25, 2019 11:08 am
Forum: Sigma & Pi Bonds
Topic: Pi Bonding
Replies: 6
Views: 88

Re: Pi Bonding

S orbitals are the only orbital that are unable to form pi bonds because they can rotate no matter what due to the spherical structure. P/d/f orbitals can form pi bonds because they can form double and triple bonds. Therefore, yes, f orbitals can contain pi bonds.
by 105335337
Sun Nov 17, 2019 5:44 pm
Forum: Electronegativity
Topic: Bond type for FeO2?
Replies: 3
Views: 159

Re: Bond type for FeO2?

Officially, FeO2 is considered a polar covalent bond. However, it shows extreme ionic character due to the electronegativity difference (~1.6).
by 105335337
Sun Nov 17, 2019 5:43 pm
Forum: Hybridization
Topic: test 2
Replies: 8
Views: 97

Re: test 2

Hybridization is not on the test, but the pi and sigma bonds will be discussed about in a small section of lecture on Monday. They will be on the test.
by 105335337
Sun Nov 17, 2019 5:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar molecules
Replies: 2
Views: 34

Re: Polar molecules

An electrostatic potential is just a synonym of electric field. Electric fields contain both positive and negative parts. Therefore, a polar molecule, which has both positive and negative side, will be attracted to an electric field.
by 105335337
Sun Nov 17, 2019 5:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Radicals for VSEPR
Replies: 3
Views: 52

Re: Radicals for VSEPR

Dr. Lavelle said that Radicals (meaning the lone electron that is not in a lone pair) counts as one area of electron density. Due to this, in VSEPR Theory, one electron is equivalent to a double bond and a single bond and a lone pair.
by 105335337
Sun Nov 17, 2019 5:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 2
Replies: 19
Views: 282

Re: Test 2

While the bond angles and shape do not have to be drawn correctly (because you can tell the shape based on bonding pairs / lone pairs), it would be extremely helpful to draw them as close as possible. If the question specifically asks for the lewis structure, then it does need to be drawn correctly.
by 105335337
Tue Nov 12, 2019 1:57 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2 Review Sessions?
Replies: 6
Views: 108

Re: Test 2 Review Sessions?

Dr Lavelle has not released them. He will most likely release the dates & times for them around a week prior to the test. Watch out as they will be coming soon!
by 105335337
Tue Nov 12, 2019 1:56 pm
Forum: Dipole Moments
Topic: Temporary Dipoles
Replies: 5
Views: 79

Re: Temporary Dipoles

A temporary dipole is a dipole created by a non polar molecule. For example N3 which has two Nitrogen atoms triple bonded to each other (both with one lone pair) can create a temporary dipole on itself do to electron dispersion. The e- will not always be completely stable, so sometimes one of the N'...
by 105335337
Tue Nov 12, 2019 1:54 pm
Forum: Lewis Structures
Topic: Exceptions
Replies: 5
Views: 73

Re: Exceptions

Some examples include: I, Xe, S, etc...
by 105335337
Tue Nov 12, 2019 1:54 pm
Forum: DeBroglie Equation
Topic: When to Use
Replies: 8
Views: 189

Re: When to Use

The equation is used at any time you are asked the wavelength of a particle with mass. Whether it is a baseball or neutron, both contain mass and follow the De Bregolie equation.
by 105335337
Tue Nov 12, 2019 1:53 pm
Forum: Student Social/Study Group
Topic: Test 2
Replies: 7
Views: 134

Re: Test 2

Personally, I believe that the test will cover two more topics: Molecular Structure/Shape & Coordination Compounds & their biological importance, But I do not know. We will have to wait and see. It will not cover any topics that were on the midterm though.
by 105335337
Tue Nov 05, 2019 3:44 pm
Forum: Ionic & Covalent Bonds
Topic: molecular polarity
Replies: 3
Views: 70

Re: molecular polarity

The reason that CO is more polar than BO is due to the electronegativity difference between both elements. CO has a great electronegativity difference, so it is more polar than BO.
by 105335337
Tue Nov 05, 2019 3:43 pm
Forum: Resonance Structures
Topic: 2C.5 c
Replies: 1
Views: 42

Re: 2C.5 c

The resonance structure is the same exact structure, but the double bond with the O and N is just placed with the second oxygen attached to the [N]
by 105335337
Tue Nov 05, 2019 3:41 pm
Forum: Properties of Electrons
Topic: Multi-electron atom
Replies: 2
Views: 127

Re: Multi-electron atom

Some factors impacting the energy of electron in a multi-electron atom are:

Electron-Electron repulsion
Shielding
Penetration
Zeff
by 105335337
Tue Nov 05, 2019 3:40 pm
Forum: Ionic & Covalent Bonds
Topic: 2D.3
Replies: 3
Views: 72

Re: 2D.3

We would not need to memorize this. You find out the ionic character through the electronegativity difference. The difference between c is 1.39, and typically, anything equal to or less than 1.5 is determined to have more covalent character.
by 105335337
Tue Nov 05, 2019 3:39 pm
Forum: Lewis Structures
Topic: 2C3.c
Replies: 1
Views: 37

Re: 2C3.c

Hello! This is kind of something that you have to get the hang of, but you can tell that the H is going to be attached to the Cl because of how the molecular formula is formatted. HCl, a common known molecule, is together. If the H was attached to the central atom, then the Cl would have probably be...
by 105335337
Mon Oct 28, 2019 1:20 pm
Forum: Bond Lengths & Energies
Topic: Single bond vs double bond
Replies: 14
Views: 287

Re: Single bond vs double bond

These are the lengths of both bonds. The double bond is shorter than the single bond because double bonds are stronger, holding the two atoms closer together, decreasing the distance.
by 105335337
Mon Oct 28, 2019 1:19 pm
Forum: Photoelectric Effect
Topic: kinetic energy
Replies: 6
Views: 103

Re: kinetic energy

The kinetic energy equation will be supplied, but you should know how to use it and what the results means.
by 105335337
Mon Oct 28, 2019 1:19 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Multi-electron atoms
Replies: 6
Views: 82

Re: Multi-electron atoms

Nodal planes are where the electron density is zero. This means that there are absolutely no electrons there.
by 105335337
Mon Oct 28, 2019 1:18 pm
Forum: Trends in The Periodic Table
Topic: reactivity
Replies: 3
Views: 41

Re: reactivity

S-block elements tend to be a lot more reactive than p-block due to their ability to remove electrons with ease. This allows them to share them with other elements, making them really reactive, while p-blocks do not like to lose electrons, making their reactivity much lower.
by 105335337
Mon Oct 28, 2019 1:17 pm
Forum: Ionic & Covalent Bonds
Topic: Electron configuration for ions
Replies: 2
Views: 18

Re: Electron configuration for ions

5s2 would lose an electron first because it is considered the furthest one out. 4d10 is not part of valence electrons once you have 5s2.
by 105335337
Mon Oct 21, 2019 11:53 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Spin
Replies: 5
Views: 80

Re: Electron Spin

There are only two electron spins. One is going clockwise and the other is counter clockwise. Two electrons paired by Hund's Rule will have opposite spins.
by 105335337
Mon Oct 21, 2019 11:52 am
Forum: Quantum Numbers and The H-Atom
Topic: Spin and orbitals
Replies: 4
Views: 48

Re: Spin and orbitals

The reason we fill up all the parallel electrons first is a) because of electron-electron repulsion and b) an atom wants to be the most stable. If you fill up pairs first, the atom will not be as stable as it would be when filling up separate parallel electrons.
by 105335337
Mon Oct 21, 2019 11:51 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: S and P orbital
Replies: 3
Views: 43

Re: S and P orbital

The only reason that we move an electron from s to d is because the energy difference is not as large, but it makes the atom more stable that way. By removing an atom from the s and moving it to the p orbital, the energy difference would be much larger and the end product would be more unstable than...
by 105335337
Mon Oct 21, 2019 11:50 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: how to prepare
Replies: 22
Views: 260

Re: how to prepare

Attend step-up sessions, but also do not over extend your mind. Study a little day by day until you are understanding it more and more. By this, you will soon be very prepared! Good Luck!
by 105335337
Mon Oct 21, 2019 11:49 am
Forum: Significant Figures
Topic: Sig Figs on Tests
Replies: 24
Views: 1113

Re: Sig Figs on Tests

To decide how many sig figs you need to use on the test, look at the problem and see which number has the lowest amount of sig figs. Your answer will have the same as that. Furthermore, some TA's are lenient when grading. Ask them what they think.
by 105335337
Thu Oct 17, 2019 11:38 pm
Forum: Properties of Electrons
Topic: parallel spins
Replies: 3
Views: 65

Re: parallel spins

When they have parallel spins, they repulse each other because they both are negatively charged. Kind of like how to south sides of magnets repel each other.
by 105335337
Thu Oct 17, 2019 11:25 pm
Forum: Properties of Electrons
Topic: effective nuclear charge
Replies: 5
Views: 67

Re: effective nuclear charge

Effective Nuclear Charge is really important for ionization energies too. If an element has a higher ENC, then the nucleus will hold onto electrons harder, requiring more energy to remove them
by 105335337
Thu Oct 17, 2019 10:52 pm
Forum: Einstein Equation
Topic: unit of energy
Replies: 7
Views: 581

Re: unit of energy

keV is an interesting unit. 1 keV is about 1.602x10-19 J.
by 105335337
Thu Oct 17, 2019 10:51 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Value
Replies: 8
Views: 91

Re: Uncertainty Value

The uncertainty value is 0.2 because you add .1 and subtract .1 from the given value, giving a total uncertainty value of 0.2.
by 105335337
Thu Oct 17, 2019 10:51 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Value
Replies: 8
Views: 91

Re: Uncertainty Value

The uncertainty value is 0.2 because you add .1 and subtract .1 from the given value, giving a total uncertainty value of 0.2.
by 105335337
Thu Oct 17, 2019 10:48 pm
Forum: Properties of Light
Topic: What are the units of hertz
Replies: 41
Views: 471

Re: What are the units of hertz

The unit for Hz, which is a frequency is s^-1. However, it means cycles per second.
by 105335337
Thu Oct 10, 2019 9:31 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Conserved in Chem Rxn
Replies: 5
Views: 252

Re: Conserved in Chem Rxn

The following are conserved:
Mass
Atoms
Electrons
Protons

All must be conserved in order to have a complete chemical reaction.
by 105335337
Thu Oct 10, 2019 9:29 am
Forum: Properties of Light
Topic: Speed of Light constant
Replies: 7
Views: 52

Re: Speed of Light constant

3.00 x 10^8 is acceptable to use in almost all cases since we do not need the specificity that the actual number implies. In a case where any said number could change the result and have a large effect, then you would use the 2.9 value, but we do not have that in this class.
by 105335337
Thu Oct 10, 2019 9:28 am
Forum: Significant Figures
Topic: Are we allowed to round when showing work?
Replies: 7
Views: 125

Re: Are we allowed to round when showing work?

Within your work, follow the sig figs, but when using your calculator, do not cut off the rest of the numbers. It will seriously skew your results.
by 105335337
Thu Oct 10, 2019 9:26 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Electron energy: is it related to physics concepts?
Replies: 1
Views: 53

Re: Electron energy: is it related to physics concepts?

These concepts, to my knowledge, are not related. The reason that were reminded of those two equations were because as the variable -> infinity, the result of the equation -> 0. While the two concepts are similar, they are not related. Just a coincidence.
by 105335337
Thu Oct 10, 2019 9:24 am
Forum: Properties of Electrons
Topic: Rydberg formula clarification
Replies: 3
Views: 60

Re: Rydberg formula clarification

The Rydberg formula does not give the best explanation for its own use, however, it is one specific scenario. If you are given an electron that jumps from one level to another, and you are told to find the frequency, you can find it easily with that equation.
by 105335337
Thu Oct 03, 2019 2:11 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: States of Matter
Replies: 9
Views: 301

Re: States of Matter

As of right now, they do not matter as much, but in the future they will matter a lot. They are really telling, especially when we get into deeper chemical equations. It is also super helpful for when we do lab and see what state of matter we need to expect.
by 105335337
Thu Oct 03, 2019 2:08 pm
Forum: Limiting Reactant Calculations
Topic: Basic Question
Replies: 11
Views: 169

Re: Basic Question

There can only be one or zero limiting reactants. If there were two limiting reactants, both would be in perfect amounts, or perfect proportions, fully completing both amounts of reactants. Therefore, there can only be one. When there is no limiting reactant, it is known as a complete reaction.

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