## Search found 115 matches

Tue Mar 10, 2020 2:52 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Eqn, K2>K1
Replies: 3
Views: 37

### Re: Arrhenius Eqn, K2>K1

If the temperature increases, that means that T2 will be larger. You've essentially answered your own question, because if T2 is larger, the right side ispositive, meaning the left must be positive as well. For this to occur, the value inside ln must be greater than 0. Therefore k2 must be larger th...
Tue Mar 10, 2020 2:49 pm
Forum: Second Order Reactions
Topic: [A] v. Time
Replies: 16
Views: 172

### Re: [A] v. Time

It would be linear, confirming that it is a 2nd order rxn.
Tue Mar 10, 2020 2:47 pm
Forum: Environment, Ozone, CFCs
Topic: NO3
Replies: 4
Views: 55

### NO3

Why isn't NO3 included in the overall equation for O2 ---> ozone if it is used as a reactant?
Tue Mar 10, 2020 2:46 pm
Forum: *Enzyme Kinetics
Topic: K and Catalyst
Replies: 3
Views: 71

### K and Catalyst

will the presence of a catalyst effect the equilibrium constant, K?
Tue Mar 10, 2020 2:45 pm
Forum: Second Order Reactions
Topic: determining order
Replies: 9
Views: 110

### Re: determining order

Plot the initial concentrations as 1/c, ln(c), and just c. Whichever one gives a linear plot is the correct order.
Fri Mar 06, 2020 6:55 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalyst
Replies: 2
Views: 29

### Catalyst

Would adding a catalyst to a reaction change the value of K?
Fri Mar 06, 2020 6:42 pm
Forum: Zero Order Reactions
Topic: Differential v Integrated rate law
Replies: 3
Views: 40

### Differential v Integrated rate law

What is implied when we say that an integrated rate law depends on time? Could the differential not be written as a function of time?
Fri Mar 06, 2020 6:37 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: k' vs k'
Replies: 3
Views: 331

### Re: k' vs k'

not related, just same notation
Mon Mar 02, 2020 3:42 pm
Forum: Balancing Redox Reactions
Topic: 6K.3- part d
Replies: 1
Views: 42

### 6K.3- part d

Reaction of chlorine in water:
Cl2(g) ¡ HClO(aq) 1 Cl2(g)

How do I balance this?
Mon Mar 02, 2020 11:12 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: test 2 topics
Replies: 11
Views: 83

### Re: test 2 topics

All of thermo that wasn't covered on the midterm and ll of electrochemistry
Mon Mar 02, 2020 11:11 am
Forum: Balancing Redox Reactions
Topic: Oxidation/Reduction
Replies: 17
Views: 219

### Oxidation/Reduction

When being asked what Reactant is Oxidized/Reduced, Do we consider the whole molecule or just the atom?
Mon Mar 02, 2020 11:07 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: Order
Replies: 5
Views: 62

### Order

Could someone give be an actual definition of reaction order?
Mon Mar 02, 2020 11:06 am
Forum: Van't Hoff Equation
Topic: Test
Replies: 1
Views: 46

### Test

How much of thermodynamics will be on test 2?
Mon Mar 02, 2020 11:03 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics in Test 2?
Replies: 13
Views: 116

### Re: Kinetics in Test 2?

Kinetics will not be on test 2
Fri Feb 21, 2020 1:37 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8019
Views: 1404000

### Re: Post All Chemistry Jokes Here

Not a joke but it belongs here: What's the name of the absolute banger of a song Lavelle threw on after lecture today?
Fri Feb 21, 2020 1:35 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E
Replies: 5
Views: 34

### E

If electron flow is spontaneous, what will the sign of E be?
Fri Feb 21, 2020 1:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 5
Views: 47

### Re: salt bridge

Salt bridges are more of a conceptual thing. I doubt we'll be asked to do any calculations regarding them.
Fri Feb 21, 2020 1:32 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E v E(standard)
Replies: 4
Views: 39

### E v E(standard)

Could someone explain the difference between E and E(standard)?
Fri Feb 21, 2020 1:30 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Finding Gibbs free energy with K
Replies: 3
Views: 49

### Re: Finding Gibbs free energy with K

Simply look up the value of R for the units being used
Fri Feb 21, 2020 1:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrode
Replies: 4
Views: 43

### Re: Electrode

The Platinum electrode isn't reduced or oxidized, It is simply used as a pathway for the electrons to enter solution (and reduce FE3+, with respect to the example in class.
Tue Feb 11, 2020 9:18 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8019
Views: 1404000

### Re: Post All Chemistry Jokes Here

An atom of U can be oriented in one state, but in the USA, U can be 4 states at once.
Tue Feb 11, 2020 10:36 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: state property
Replies: 4
Views: 46

### Re: state property

Yes. The path required to get to a value doesn't matter with G, so it is a state property. This is why you can perform a Hess's Law-type problem with an equation given G values.
Tue Feb 11, 2020 10:35 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard enthalpy of formation oxygen
Replies: 1
Views: 27

### Re: Standard enthalpy of formation oxygen

Because O2 is the most stable for of oxygen, so it forms without an input of energy.
Tue Feb 11, 2020 10:35 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure equilibrium problems
Replies: 2
Views: 33

### Re: Partial Pressure equilibrium problems

Yes, use partial pressures in an ICE table and use them for the K expression afterwards.
Tue Feb 11, 2020 10:33 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: when is U = 3/2 nRT of an ideal gas true?
Replies: 1
Views: 25

### Re: when is U = 3/2 nRT of an ideal gas true?

I believe this has to do with molecular shape/structure. Don't worry about it for the midterm, you will be given molar heat capacities.
Tue Feb 11, 2020 10:32 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: entropy of irreversible path
Replies: 2
Views: 35

### Re: entropy of irreversible path

Use (Delta)S = nR(V2/V1)
Thu Feb 06, 2020 9:19 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Irreversible v Reversible
Replies: 4
Views: 52

### Irreversible v Reversible

Could someone explain wha reversible and irreversible mean?
Thu Feb 06, 2020 9:16 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: Degeneracy
Replies: 1
Views: 14

### Degeneracy

will we be asked to calculate degeneracy on the midterm?
Thu Feb 06, 2020 9:15 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: calculating entropy
Replies: 4
Views: 53

### calculating entropy

why is the change in entropy sometimes equal to (-deltaH/T)? in other words, what does the - imply?
Thu Feb 06, 2020 9:12 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: molar heat capacity
Replies: 2
Views: 38

### molar heat capacity

why is molar heat capacity sometimes given as a specific value for a compound but sometimes (3/5)R or (3/2)R??
Thu Feb 06, 2020 9:10 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeters
Replies: 17
Views: 365

### Calorimeters

is a bomb calorimeter constant V or P??
Wed Jan 29, 2020 3:31 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: homework question 4A.3
Replies: 6
Views: 63

### Re: homework question 4A.3

Wouldn't using -P mean the system lost energy? Lavelle said this in lecture today but the solutions manual says that the system has work done on it.
Tue Jan 28, 2020 9:11 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard enthalpy of formation
Replies: 3
Views: 26

### Re: Standard enthalpy of formation

Because graphite is the lowest energy arrangement of pure carbon molecules
Tue Jan 28, 2020 9:07 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reaction enthalpy
Replies: 14
Views: 91

### Re: reaction enthalpy

Forming a bond is a favorable/lower energy state for atoms to be in, so that energy is released. Consider the chart we looked at in 14A-- two atoms decreased in their energies as they became closer, the lowest energy being when they formed a bond; however, when they got any closer, the energy skyroc...
Tue Jan 28, 2020 9:04 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4A and B
Replies: 2
Views: 32

### 4A and B

I started doing homework in the thermo section and was faced with a bunch of problems referring to work, delta U, and heat capacity problems that didn't use moles or grams. We haven't gone over any of this in class, so should I read the textbook to understand this or will we be talking about it this...
Tue Jan 28, 2020 9:00 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Heat Supplied to a system
Replies: 6
Views: 80

### Re: Heat Supplied to a system

Simply use q=g(Csp)T for both copper and water and add the two values together. This will give you total heat.
Tue Jan 28, 2020 8:58 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 11
Views: 68

### Re: Bond Enthalpies

Because each bond enthalpy AVERAGES can be found on a table. The bond enthalpy of a specific bond depends on the molecule it is in (electrons may be shared unequally). Therefore, using average bond enthalpies will provide an inaccurate value.
Wed Jan 22, 2020 11:26 am
Forum: Phase Changes & Related Calculations
Topic: Exo/endo definition
Replies: 3
Views: 41

### Exo/endo definition

I’ve often heard the terms “endergonic” and “exergonic” instead of exothermic and endothermic. Is there a difference?
Tue Jan 21, 2020 12:16 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing K
Replies: 13
Views: 111

### Changing K

Which factors can actually change K in a reaction? I'm fairly sure temperature will, however I'm getting mixed messages about pressure having an effect as well.
Tue Jan 21, 2020 12:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: partial pressure vs concentrations
Replies: 3
Views: 17

### Re: partial pressure vs concentrations

Usually the problem will ask for final partial pressures or concentrations, so it depends on the context. However using either one works as long as you are consistent with Kc vs. Kp
Tue Jan 21, 2020 12:12 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 6.23 Buffer Solutions
Replies: 2
Views: 39

### Re: 6.23 Buffer Solutions

We only learned to calculate the pH of buffer solutions and didn't go into how they actually resist changes in pH. I don't think its part of the 14B curriculum and certainly wouldn't worry about it for the upcoming test.
Tue Jan 21, 2020 12:11 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: units for pressure
Replies: 5
Views: 249

### Re: units for pressure

Usually if a question asks for pressure as an answer, I will specify which units to use. However if it does not, make sure your gas constant (R) corresponds to the correct units (which are given to us during tests on the equation sheet).
Tue Jan 21, 2020 12:08 pm
Forum: Ideal Gases
Topic: Topics for Test 1
Replies: 17
Views: 205

### Re: Topics for Test 1

I'd recommend going through all the homework problems s on the syllabus, as the test will be very similar. You don't necessarily have to work them all out, but reading through the questions and corresponding solutions will help you locate any knowledge gaps.
Mon Jan 13, 2020 4:11 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Excess Reactant in Le Chatelier's Principle
Replies: 6
Views: 78

### Re: Excess Reactant in Le Chatelier's Principle

This is a good point, but when dealing with equilibrium concentrations, assume the other reactants/products are in excess
Mon Jan 13, 2020 4:09 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Quotient Units
Replies: 10
Views: 60

### Re: Reaction Quotient Units

Q is a ratio, therefore it doesn't have units, just like K.
Mon Jan 13, 2020 4:08 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH range
Replies: 4
Views: 108

### Re: pH range

Yes, however it is very uncommon
Mon Jan 13, 2020 4:07 pm
Forum: Ideal Gases
Topic: Kc and Kp
Replies: 5
Views: 50

### Re: Kc and Kp

One is measuring based on concentration and the other by pressure. They both represent the same thing because they are simply a ration between chemical compounds, not values with units.
Mon Jan 13, 2020 4:05 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier
Replies: 3
Views: 37

### Re: Le Chatelier

Increasing the total pressure of the system will cause equilibrium to shift to the side with fewer moles
Sat Jan 11, 2020 6:45 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pure Substance
Replies: 5
Views: 40

### Re: Pure Substance

Activity is equal to 1 in order to not change any values
Sat Jan 11, 2020 6:44 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for K
Replies: 10
Views: 84

### Re: Units for K

K is a ration, so all units cancel
Sat Jan 11, 2020 6:20 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Which Constant to use
Replies: 4
Views: 61

### Re: Which Constant to use

Convert all the pressures from the start
Sat Jan 11, 2020 6:19 am
Forum: Ideal Gases
Topic: Solids and Liquids [ENDORSED]
Replies: 10
Views: 108

### Solids and Liquids[ENDORSED]

Why exactly aren't solids and liquids included in equilibrium expressions?
Sat Jan 11, 2020 6:17 am
Forum: Ideal Gases
Topic: textbook [ENDORSED]
Replies: 2
Views: 33

### textbook[ENDORSED]

Will we still be using the 7th edition in 14b?
Thu Dec 05, 2019 4:09 pm
Forum: Naming
Topic: water and coord. compounds
Replies: 1
Views: 41

### Re: water and coord. compounds

aqua refers to water being within the coordination sphere and actually covalent bonded to the central atom. Hydrated refers to water molecules being attracted to the ion.
Thu Dec 05, 2019 4:07 pm
Forum: Bronsted Acids & Bases
Topic: 6c 17
Replies: 2
Views: 49

### Re: 6c 17

I think this problem wanted you to refer to a table of K values, because they're two very different compounds. So base your answer off that.
Thu Dec 05, 2019 4:06 pm
Forum: *Titrations & Titration Calculations
Topic: Wednesday Lecture
Replies: 3
Views: 135

### Re: Wednesday Lecture

Understand the process. Aka, why certain solutions of equal acidic/basic properties can still have a pH not equal to 7. Also what Ka/Kb values represent, and how they decrease as protons are removed from polyphonic acids.
Thu Dec 05, 2019 4:04 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Calculating Acidity and Basicity Constants
Replies: 1
Views: 35

### Re: Calculating Acidity and Basicity Constants

We'd be given Kb or Ka values. the "p" just tells us to take the -log of the Ka/Kb. As far as actually calculating them, I don't think so (unless we're given the concentrations of A, H, and AH, in which case its simple algebra).
Thu Dec 05, 2019 4:03 pm
Forum: Lewis Acids & Bases
Topic: 6A13b
Replies: 2
Views: 48

### Re: 6A13b

Yes. Boron often draws an electron pair when it already has 3 bonds. Also, the 3 Fs are very electronegative and will delocalize this negative charge. Because it's accepting a lone pair, it's a Lewis Acid.
Mon Nov 25, 2019 6:03 pm
Forum: General Science Questions
Topic: Coordination Compounds
Replies: 7
Views: 157

### Coordination Compounds

Should we memorize the specific compounds Dr. Lavelle mentioned in class and their functions?
Mon Nov 25, 2019 5:57 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Nonmental Oxides as Acids
Replies: 4
Views: 62

### Nonmental Oxides as Acids

I understand how Oxides like CO2 and SO2 react with water to for acids, so would we consider CO2/SO2 an acid in a reaction that creates the acid?
i.e. H20 + CO2 = H2CO3.... is CO2 an acid?
Mon Nov 25, 2019 5:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2.27b
Replies: 4
Views: 60

### Re: 2.27b

Still consider the electron as a region of electron density, but understand the shape will be somewhat different. A single electron will not exert as much force on surrounding atoms as a lone pair. For example, NO2+ has a bent shape with an O-N-O bond angle of greater than 120 as opposed to less than.
Mon Nov 25, 2019 5:51 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: determining if polydentate
Replies: 3
Views: 58

### Re: determining if polydentate

Polydentate refers to a ligand forming multiple bonds with the central atom. If a Ligand has multiple sites that can bond (Polar regions, lone pairs etc..) it is said to be polydentate
Mon Nov 25, 2019 5:49 pm
Forum: Naming
Topic: OH2 naming
Replies: 4
Views: 45

### Re: OH2 naming

if it is (OH)2 then hydroxyl. (OH2) would be hydro
Mon Nov 18, 2019 3:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test
Replies: 2
Views: 51

### Test

For the test this week, should we know the VSEPR shapes mentioned in the textbook but not class (ie. AX2E, T-shaped, Square pyramidal)
Mon Nov 18, 2019 3:18 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: Ion-Ion
Replies: 1
Views: 25

### Ion-Ion

aren't ion-ion IM forces and ionic bonds essentially the same thing?
Mon Nov 18, 2019 3:17 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- induced dipole
Replies: 2
Views: 25

### Dipole- induced dipole

Are dipole-induced dipole forces always between separate compounds (one polar and one non-polar)?
Mon Nov 18, 2019 3:16 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: H-Bonds
Replies: 1
Views: 30

### H-Bonds

If we are asked to identify the types of molecular forces compounds may exert on each other and the compound has Hydrogen bonds, should we also say Dipole-Dipole (Because an h-bond is a strong dipole-dipole interaction)?
Mon Nov 18, 2019 3:15 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: IM Forces
Replies: 3
Views: 45

### IM Forces

Do all compounds have London Forces no matter what?
Wed Nov 13, 2019 10:42 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: H-bonding & Dipole-Dipole (Problem 3F.1)
Replies: 4
Views: 64

### Re: H-bonding & Dipole-Dipole (Problem 3F.1)

Yes- think of Hydrogen bonds as especially strong dipole-dipole interactions
Wed Nov 13, 2019 10:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR usage
Replies: 5
Views: 47

### Re: VSEPR usage

Yes indeed. The shape of a molecule can determine the strength of intermolecular forces between compounds.
Wed Nov 13, 2019 10:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR formula
Replies: 1
Views: 31

### Re: VSEPR formula

Yes- most likely Friday
Wed Nov 13, 2019 10:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles Exceptions
Replies: 6
Views: 54

### Re: Bond Angles Exceptions

When all 4 atoms coming off the center atom aren't the same. Ex.) CH4 vs CH3Cl.
Mon Nov 11, 2019 4:12 pm
Forum: Dipole Moments
Topic: Van Der Waals Interaction
Replies: 2
Views: 42

### Re: Van Der Waals Interaction

A different definition from Lavelle's I used in High school- A Van Der Wall Interaction (London Forces) results from instantaneous (shot lasting) dipoles created by the random movement of electrons in atoms or molecules. The larger an atom or molecule, the more electrons, so the more likely for inst...
Wed Nov 06, 2019 11:38 am
Forum: Electronegativity
Topic: Website
Replies: 3
Views: 98

### Website

I can't log into Dr. Lavelle's website. I enter my password and it just loads for a second and nothing happens. I don't get any "wrong password" notification or anything. Anybody else having this problem/have a solution?
Tue Nov 05, 2019 5:52 pm
Forum: Electronegativity
Topic: 2D 3 and 5
Replies: 2
Views: 58

### 2D 3 and 5

or 2D) 3 and 5, should we be using the periodic trend to determine electronegativity difference or the given chart? I understand the trend, but there it doesn't always work when comparing atoms close together on the table (the trend isn't perfect).
Tue Nov 05, 2019 4:38 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Midterm
Replies: 6
Views: 201

### Midterm

Is it important to understand all the experiments we discussed in the quantum unit?
Mon Nov 04, 2019 12:09 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Solids
Replies: 2
Views: 66

### Re: Ionic Solids

Ionic bonds involve an anion "giving away" an electron to an anion. So each has an octet and an equal/opposite charge.
Mon Nov 04, 2019 12:07 pm
Forum: Octet Exceptions
Replies: 6
Views: 97

It couldn't hurt to memorize a few common radicals (i.e. the ones we talked about in lecture).
Mon Nov 04, 2019 12:05 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge/Lewis structures
Replies: 5
Views: 101

### Formal Charge/Lewis structures

When drawing Lewis Structures, should we try and make the central atom have a formal charge of zero almost always (Ions, covalent bonds, etc...)?
Mon Nov 04, 2019 12:02 pm
Forum: Coordinate Covalent Bonds
Topic: Dissociation energy
Replies: 3
Views: 173

### Re: Dissociation energy

The presence of unpaired electrons on atoms within a compound result in them repelling from other because of the negative charges working on each other. Consider F2, where each F atom has 6 unpaired electrons. They exert repulsive forces on one another because of the unpaired electrons in their vale...
Mon Nov 04, 2019 11:56 am
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 2
Views: 56

### Midterm

Will we be given an equation sheet for the midterm?
Tue Oct 29, 2019 9:46 pm
Forum: Ionic & Covalent Bonds
Topic: Review mesh
Replies: 2
Views: 49

### Review mesh

Will there be another review session for the fundamentals unit?
Tue Oct 29, 2019 9:45 pm
Forum: Ionic & Covalent Bonds
Topic: Valence e-
Replies: 3
Views: 62

### Valence e-

This is more quantum, but when do we include the d-orbital elements in the valence shell when a question asks how many valence e- a certain element had? I was under the impression you just counted atoms in the largest shell (so only s and p).
Tue Oct 29, 2019 9:43 pm
Forum: Ionic & Covalent Bonds
Topic: Formal Charge
Replies: 2
Views: 30

### Formal Charge

is it more important for an atom to have a low formal charge or an octet?
Tue Oct 29, 2019 9:42 pm
Forum: Lewis Structures
Topic: Lewis Structure structure
Replies: 4
Views: 47

### Re: Lewis Structure structure

Atoms will arrange in the structure that corresponds to low energy, so atoms will try and space out to avoid repulsive positive forces
Mon Oct 28, 2019 10:11 pm
Forum: Ionic & Covalent Bonds
Topic: When is the midterm?
Replies: 5
Views: 69

### When is the midterm?

Can't access the syllabus foe some reason. When is our midterm for 14A?
Thu Oct 24, 2019 3:21 pm
Forum: Resonance Structures
Topic: bond lengths
Replies: 4
Views: 63

### Re: bond lengths

Also remember that this bond isn't actually "rotating" around the atom. Lots of chem textbooks make it out to be like this. Just remember that the bond lengths will be an average.
Thu Oct 24, 2019 3:19 pm
Forum: Electron Configurations for Multi-Electron Atoms
Replies: 18
Views: 171

You won't ever be asked to calculate the actual value of atomic radii. Just know the trends.
Thu Oct 24, 2019 2:48 pm
Forum: Ionic & Covalent Bonds
Topic: octet rule
Replies: 6
Views: 114

### Re: octet rule

Yes, lager elements have larger ionic radii, meaning less interference from the positivity charged nucleus. Even noble gasses, like Xenon, can form up to 6 bonds.
Thu Oct 24, 2019 2:37 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic v.covalent bonds
Replies: 7
Views: 61

### Re: Ionic v.covalent bonds

Generally yes. Just remember that ionic bonds result in "giving away" or "reviewing" electrons and covalent bonds result in sharing electrons
Thu Oct 24, 2019 2:33 pm
Forum: Properties of Electrons
Topic: Anions and Cations
Replies: 4
Views: 77

### Re: Anions and Cations

If it is of the same atom, an anion will have more electrons that a cation, therefore its ionic radius will be larger. So yes
Thu Oct 24, 2019 2:12 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations of ions
Replies: 4
Views: 37

### Electron Configurations of ions

If we are given a cation ion in the d-block, should we remove electrons from the d orbital first or the outermost s-orbital?
Tue Oct 15, 2019 5:04 pm
Forum: Photoelectric Effect
Topic: Photoelectric effect
Replies: 5
Views: 88

### Re: Photoelectric effect

Either you will be told the work function for a specific metal, or you'll be able to calculate it based on the energy values provided. No need to memorize any.
Tue Oct 15, 2019 3:50 pm
Forum: *Shrodinger Equation
Topic: What is Shrodinger's for?
Replies: 6
Views: 80

### Re: What is Shrodinger's for?

Shrodinger's equation is a model for the wave function of an electron. We simply look at it conceptually to understand what orbitals are. Don't worry about any calculations with this equation.
Tue Oct 15, 2019 3:49 pm
Forum: Properties of Light
Topic: What units do we need to use for the Rydberg constant?
Replies: 2
Views: 26

### Re: What units do we need to use for the Rydberg constant?

use m^-1
Mon Oct 14, 2019 6:22 pm
Forum: Properties of Light
Topic: Symbol review
Replies: 3
Views: 44

### Re: Symbol review

Δx = change in position
Mon Oct 14, 2019 6:19 pm
Forum: *Shrodinger Equation
Topic: psi vs psi^2
Replies: 7
Views: 140

### Re: psi vs psi^2

Psi is the height of a wave at any position on a 3D plane (x,y,z). Psi^2 represents the probability of finding an electron at any point (x,y,z). It's a pretty confusing concept that isn't really analyzed further until more advanced chem classes. Don't stress on it to much.
Mon Oct 14, 2019 11:39 am
Forum: Properties of Light
Topic: EM Spectrum
Replies: 1
Views: 10

### EM Spectrum

Should we memorize the EM Spectrum (wavelengths and their corresponding types of radiation) or will it be provided on exams?
Fri Oct 11, 2019 10:43 pm
Forum: Einstein Equation
Topic: Variables in equations
Replies: 4
Views: 89

### Re: Variables in equations

You'll just have to pay attention to the font, because frequency is the greek letter "nu."
Fri Oct 11, 2019 10:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Negative Electrons vs Positive Nucleus
Replies: 2
Views: 69

### Re: Negative Electrons vs Positive Nucleus

Wavelengths of light exhibit specific energy levels that match up with the energy of an electron. Electrons have energy due to their motion. Electrons don't fall into the nucleus because they are moving (this is more physics). The same reason why the earth doesn't fall into the sun.