Search found 108 matches

by rabiasumar2E
Sun Mar 15, 2020 6:05 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 3
Views: 72

Re: Catalysts

A catalyst is first a reactant and is used up, then is a product and is formed.
by rabiasumar2E
Sat Mar 14, 2020 8:45 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Time
Replies: 13
Views: 259

Re: Final Exam Time

The exam starts at 11:15am and is over at 2:45pm! It will most likely close at 2:45pm and submit whatever you had completed on it.
by rabiasumar2E
Sat Mar 14, 2020 2:05 pm
Forum: General Rate Laws
Topic: Rate-determining step
Replies: 7
Views: 127

Re: Rate-determining step

It will probably be given to you in the question!
by rabiasumar2E
Fri Mar 13, 2020 2:52 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Slowest step
Replies: 9
Views: 125

Re: Slowest step

The slow step determines the rate of the full reaction because no matter how fast the other steps are, the reaction is only complete once the slow step has been completed.
by rabiasumar2E
Fri Mar 13, 2020 2:48 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Slow step
Replies: 7
Views: 98

Re: Slow step

There isn't a numerical value that you would use to deduce if it's a slow step or not. It would just be the slowest step out of all of the steps.
by rabiasumar2E
Wed Mar 11, 2020 5:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 3
Views: 56

Re: Test 2

My TA emailed us about where to pick them up! You should get one from yours soon!
by rabiasumar2E
Sun Mar 08, 2020 9:51 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: A
Replies: 8
Views: 51

Re: A

[A]0 represents the initial concentration and [A] represents the concentration of the reactants!
by rabiasumar2E
Sun Mar 08, 2020 9:50 pm
Forum: Administrative Questions and Class Announcements
Topic: TesT 2
Replies: 3
Views: 32

Re: TesT 2

I'm pretty sure you'll get them back during your section this week !
by rabiasumar2E
Sun Mar 08, 2020 3:04 pm
Forum: First Order Reactions
Topic: rate constants
Replies: 19
Views: 248

Re: rate constants

Yes! Rate constants are always positive because concentrations cannot be negative values.
by rabiasumar2E
Sun Mar 08, 2020 2:58 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Adding carbon (gr) to cell diagrams
Replies: 4
Views: 50

Re: Adding carbon (gr) to cell diagrams

Adding carbon graphite isn't as common as adding platinum but it can be written wherever platinum can be written! Writing carbon graphite is equivalent to writing platinum in this circumstance.
by rabiasumar2E
Tue Mar 03, 2020 12:57 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Platinum
Replies: 6
Views: 42

Re: Platinum

You add Pt to your cell diagram when there is no conducting solid in any of your half-reactions.
by rabiasumar2E
Sun Mar 01, 2020 8:50 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: cell diagrams
Replies: 4
Views: 53

Re: cell diagrams

Use Pt in your cell diagram if there is no solid present in the reaction!
by rabiasumar2E
Sun Mar 01, 2020 3:25 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 6
Views: 44

Re: Galvanic Cells

Yes! Galvanic cells are spontaneous and therefore, the E must be positive.
by rabiasumar2E
Sun Mar 01, 2020 3:21 pm
Forum: Zero Order Reactions
Topic: Deriving Equations
Replies: 7
Views: 602

Re: Deriving Equations

I'm sure there are a few that we'll have to derive on our own but I think he'll give us every equation we need to do so with on the equation sheet!
by rabiasumar2E
Sun Mar 01, 2020 3:19 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 11
Views: 89

Re: salt bridge

The purpose of a salt bridge is to maintain charge balance.
by rabiasumar2E
Sat Feb 29, 2020 1:40 pm
Forum: Balancing Redox Reactions
Topic: Reducing/Oxidizing Agents
Replies: 13
Views: 76

Re: Reducing/Oxidizing Agents

Whatever is being oxidized is the reducing agent and whatever is being reduced is the oxidizing agent.
by rabiasumar2E
Sat Feb 29, 2020 1:30 pm
Forum: Balancing Redox Reactions
Topic: Test 2
Replies: 19
Views: 194

Re: Test 2

Test two is going to cover everything from the second page of outline four and all of outline five !
by rabiasumar2E
Sun Feb 23, 2020 7:34 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Half reactions
Replies: 13
Views: 126

Re: Half reactions

Half reactions are the reduction and oxidation reactions that make up a redox reaction.
by rabiasumar2E
Sun Feb 23, 2020 2:18 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 5
Views: 31

Re: salt bridge

The salt bridge allows ion transfer between the two solutions and is used to maintain charge !
by rabiasumar2E
Sun Feb 23, 2020 2:09 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs free energy
Replies: 5
Views: 60

Re: Gibbs free energy

It represents the charge of one mole of electrons.
by rabiasumar2E
Sun Feb 23, 2020 1:55 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: adding/subtracting half-redox rxns
Replies: 4
Views: 57

Re: adding/subtracting half-redox rxns

Since E is an intensive property, it doesn't depend on how many times the reaction occurs and therefore, will never change! H is an extensive property, which is why you can use Hess's Law.
by rabiasumar2E
Sat Feb 22, 2020 8:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: property of E
Replies: 6
Views: 41

Re: property of E

E doesn't change because it's an intensive property! It doesn't depend on how many times the reaction occurs.
by rabiasumar2E
Sun Feb 16, 2020 8:32 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: memorize
Replies: 14
Views: 208

Re: memorize

After taking the midterm, I'm pretty certain he'll provide us with any constants we may need for an exam.
by rabiasumar2E
Sun Feb 16, 2020 8:29 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: S = kblnW explanation
Replies: 4
Views: 48

Re: S = kblnW explanation

S= entropy
kB= boltzmann constant
ln= natural log
W= number of states^(number of atoms or molecules)
by rabiasumar2E
Sun Feb 16, 2020 8:28 pm
Forum: Van't Hoff Equation
Topic: delta s
Replies: 9
Views: 82

Re: delta s

Because standard conditions don't change !
by rabiasumar2E
Sun Feb 16, 2020 8:26 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: S = 0
Replies: 18
Views: 258

Re: S = 0

It's zero in an isothermal reversible reaction.
by rabiasumar2E
Sun Feb 16, 2020 8:17 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous
Replies: 13
Views: 117

Re: Spontaneous

A reaction is spontaneous when delta G is negative!
by rabiasumar2E
Sat Feb 08, 2020 10:53 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: q rev
Replies: 9
Views: 78

Re: q rev

'Rev' just means reversible so q rev is used when calculating the heat for a reversible reaction.
by rabiasumar2E
Sat Feb 08, 2020 10:49 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Units
Replies: 4
Views: 47

Re: Units

The units for change in enthalpy is J/K. And no, the units for temperature will not remain! They'll end up cancelling out.
by rabiasumar2E
Sat Feb 08, 2020 10:46 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy and Pressure
Replies: 3
Views: 30

Re: Entropy and Pressure

Yes! When pressure increases, entropy decreases because volume decreases.
by rabiasumar2E
Mon Feb 03, 2020 5:57 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: ∆U
Replies: 8
Views: 88

Re: ∆U

It represents the change in the internal energy of a system !
by rabiasumar2E
Sun Feb 02, 2020 7:14 pm
Forum: Calculating Work of Expansion
Topic: Two different equations
Replies: 2
Views: 36

Re: Two different equations

The difference between the two work equations is that one includes the integral and one does not. You use the work equation without the integral when pressure is constant.
by rabiasumar2E
Sun Feb 02, 2020 7:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1 #6
Replies: 6
Views: 65

Re: Test 1 #6

It's because HF is actually a weak acid, meaning it doesn't dissociate completely!
by rabiasumar2E
Sat Feb 01, 2020 9:36 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: isolated system
Replies: 13
Views: 105

Re: isolated system

Another example could be hot coffee in a thermos.
by rabiasumar2E
Sat Feb 01, 2020 9:32 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Thermodynamics Outline
Replies: 5
Views: 54

Re: Thermodynamics Outline

I think we probably will end up having to know most if not all of the thermodynamics outline for the midterm.
by rabiasumar2E
Sat Feb 01, 2020 9:30 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy units
Replies: 4
Views: 31

Re: Entropy units

I'm sure you can use kJ/K for entropy if it matches the units of everything else in the problem you are working on but the SI unit for entropy is K/J!
by rabiasumar2E
Sun Jan 26, 2020 1:06 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic reaction
Replies: 18
Views: 243

Re: Exothermic reaction

If a reaction is exothermic, an increase in its temperature will cause the reaction to shift to the left and a decrease in its temperature will cause the reaction to shift to the right!
by rabiasumar2E
Sat Jan 25, 2020 9:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Energy of the reactants
Replies: 6
Views: 47

Re: Energy of the reactants

The energy of the products being higher than the reactants is due to the products absorbing heat from their surroundings, meaning the reaction is an endothermic reaction.
by rabiasumar2E
Sat Jan 25, 2020 7:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Excluding H2O from Ka and Kb
Replies: 5
Views: 45

Re: Excluding H2O from Ka and Kb

Solids and liquids don't affect the value of K, therefore we don't include them in the calculations!
by rabiasumar2E
Sat Jan 25, 2020 7:12 pm
Forum: Phase Changes & Related Calculations
Topic: Reading?
Replies: 5
Views: 64

Re: Reading?

I usually read the sections he has assigned for homework on the outline that we're focusing on in lecture at that time !
by rabiasumar2E
Sat Jan 25, 2020 6:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Different methods
Replies: 4
Views: 31

Re: Different methods

What the question contains will help determine what method you should use!
by rabiasumar2E
Sat Jan 25, 2020 6:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpy of formation
Replies: 4
Views: 23

Re: Standard Enthalpy of formation

The unit for standard enthalpy of formation is kJ/mol!
by rabiasumar2E
Mon Jan 20, 2020 8:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Does order matter?
Replies: 5
Views: 40

Re: Does order matter?

No, as long as the products are in the numerator and the reactants are in the denominator the order of which one you write first does not matter.
by rabiasumar2E
Sun Jan 19, 2020 6:24 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endo vs. Exothermic
Replies: 5
Views: 43

Re: Endo vs. Exothermic

If a reaction requires heat it is endothermic. If a reaction gives off heat it is exothermic.
by rabiasumar2E
Sun Jan 19, 2020 4:40 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Strong Acids/Bases vs. Weak Acids/Bases
Replies: 9
Views: 60

Re: Strong Acids/Bases vs. Weak Acids/Bases

Strong acids and bases dissociate completely whereas weak acids and bases do not. I would just memorize the strong acids/bases to make working out problems a little easier. There is a list of both in the textbook.
by rabiasumar2E
Thu Jan 16, 2020 1:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and liquids
Replies: 3
Views: 20

Re: Solids and liquids

Solids and liquids don't affect the value of K, so we leave them out.
by rabiasumar2E
Tue Jan 14, 2020 5:27 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: HW 5j #5
Replies: 4
Views: 49

Re: HW 5j #5

The answer is no change because the number of moles on both the reactant and product sides are the same.
by rabiasumar2E
Sun Jan 12, 2020 10:53 am
Forum: Ideal Gases
Topic: aqueous elements in eq calculation
Replies: 8
Views: 69

Re: aqueous elements in eq calculation

Aqueous solutions would be included in the equilibrium equation because these effect the value of K but solids and liquids aren't included because they don't affect K in any way.
by rabiasumar2E
Sun Jan 12, 2020 10:46 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Q
Replies: 3
Views: 32

Re: K and Q

Because they don't change the value of K in any way, so you can disregard them while writing the K or Q expression.
by rabiasumar2E
Sun Jan 12, 2020 10:44 am
Forum: Administrative Questions and Class Announcements
Topic: Test Dates
Replies: 3
Views: 54

Re: Test Dates

Test one starts on January 21st and test two starts on February 25th. So, whenever you have ur discussion after or on that date is when you'll have your tests.
by rabiasumar2E
Sun Jan 12, 2020 10:38 am
Forum: Ideal Gases
Topic: Test 1
Replies: 7
Views: 89

Re: Test 1

I'm not exactly sure but maybe a good way to gauge it would be to see how many ideal gas homework problems he's assigned? I would just be as comfortable with ideal gases as I could be to be prepared.
by rabiasumar2E
Sat Jan 11, 2020 1:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K values
Replies: 4
Views: 56

Re: K values

K = 1 is rare because it's not common for reactants and products to have the same stability.
by rabiasumar2E
Sat Dec 07, 2019 1:55 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Electron Configuration
Replies: 3
Views: 111

Re: Electron Configuration

4s would come after 3d!! In high school most of us learned to put the 4s before the 3d since they are in that order on the periodic table, but energy level wise the 4s would come after 3d. To put it simply, whenever you're doing electron configuration, put them in numerical order.
by rabiasumar2E
Sat Dec 07, 2019 1:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand Charges
Replies: 3
Views: 63

Re: Ligand Charges

I would memorize them, which seems like a hassle but honestly the more practice problems you do, the easier it gets to memorize.
by rabiasumar2E
Sat Dec 07, 2019 1:46 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Naming Coordination Compounds on Final
Replies: 2
Views: 57

Re: Naming Coordination Compounds on Final

I would! It's probably the best way to ensure that you can name anything he might give us on the final.
by rabiasumar2E
Thu Dec 05, 2019 10:59 am
Forum: Octet Exceptions
Topic: radicals
Replies: 3
Views: 123

Re: radicals

You always place radicals on the most electronegative atom!
by rabiasumar2E
Thu Dec 05, 2019 10:52 am
Forum: Hybridization
Topic: S Character
Replies: 4
Views: 47

Re: S Character

S character refers to the contribution of the s-orbital in hybridization. For example in a sp2 notation, there would be 33% s character and 66% p character. In a sp3 notation, there would be 25% s character and 75% p character.
by rabiasumar2E
Sun Dec 01, 2019 6:59 pm
Forum: General Science Questions
Topic: Week 10 Classes
Replies: 7
Views: 168

Re: Week 10 Classes

alex_4C wrote:Is our final on the 8th or 9th?


Our final is on the 8th at 11:30am.
by rabiasumar2E
Sun Dec 01, 2019 5:25 pm
Forum: Student Social/Study Group
Topic: final
Replies: 4
Views: 82

Re: final

Honestly everything we've learned in class will most likely make its way on the final in one way or another. I would just look at the outlines from his website and continue to do the hw problems he's provided to try to be well prepared for it.
by rabiasumar2E
Sun Dec 01, 2019 12:34 pm
Forum: Lewis Acids & Bases
Topic: Lewis vs. Bronsted
Replies: 3
Views: 31

Re: Lewis vs. Bronsted

In the book it mentions that when they say 'acid' they are referring to the Brønsted acid so I'm assuming that applies for lecture as well. I think if he were to mention lewis acids/bases he would say 'lewis acid' or 'lewis base'. And I would definitely know how to differentiate the two for the final!
by rabiasumar2E
Sun Dec 01, 2019 11:55 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Strong and Weak Acids
Replies: 7
Views: 94

Re: Strong and Weak Acids

There is a list of strong acids in the book that I would recommend having memorized!
HBr, HCl, HI, HNO3, HClO4, HClO3, H2SO4
by rabiasumar2E
Sun Dec 01, 2019 11:50 am
Forum: Amphoteric Compounds
Topic: Identifying Them?
Replies: 12
Views: 151

Re: Identifying Them?

On the periodic table, there is a diagonal band of amphoteric oxides closely matching the diagonal band of metalloids. You can also tell if it is able to accept and donate hydrogen ions. As for identifying them in a chemical equation, it's not necessarily important to know if it's amphoteric, just w...
by rabiasumar2E
Sat Nov 30, 2019 6:25 pm
Forum: Amphoteric Compounds
Topic: amphoteric oxides
Replies: 3
Views: 45

Re: amphoteric oxides

Yes! All amphoteric compounds are oxides.
by rabiasumar2E
Sat Nov 30, 2019 6:24 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted Acids and Bases
Replies: 3
Views: 40

Re: Bronsted Acids and Bases

Yes water is considered both an acid and a base. Just as the above response says, amphoteric compounds have the characteristic of both. You can find amphoteric oxides on the period table in a diagonal band closely matching the diagonal band of the metalloids.
by rabiasumar2E
Sat Nov 30, 2019 6:19 pm
Forum: Lewis Acids & Bases
Topic: Identifying lewis acids and bases
Replies: 4
Views: 38

Re: Identifying lewis acids and bases

A lewis acid is an electron pair acceptor and a lewis base is an electron pair donor. This differs from Brønsted acids and bases; Brønsted acid is a proton donor and a Brønsted base is a proton acceptor.
by rabiasumar2E
Sun Nov 24, 2019 6:13 pm
Forum: Hybridization
Topic: Strength of sigma vs pi bonds
Replies: 6
Views: 53

Re: Strength of sigma vs pi bonds

Sigma bonds are stronger than pi bonds because they overlap head on and a greater overlap = a stronger bond. Pi bonds overlap from the side therefore their bond is not as strong because the overlap is not as much.
by rabiasumar2E
Sun Nov 24, 2019 6:10 pm
Forum: Hybridization
Topic: bonds
Replies: 2
Views: 45

Re: bonds

A sigma bond is symmetrical with no nodal planes with respect to the internuclear axis but a pi bond has a single nodal plane with respect to the internuclear axis.
by rabiasumar2E
Sun Nov 24, 2019 6:01 pm
Forum: Naming
Topic: Trans and Cis
Replies: 8
Views: 139

Re: Trans and Cis

Yes, so if two of the same atoms are on the same side of the central atom then it is cis- and if they are on opposite sides then it is trans-.
by rabiasumar2E
Sun Nov 17, 2019 3:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs and bond angles
Replies: 4
Views: 38

Re: Lone pairs and bond angles

Yes, a lone pair decreases the bond angles. For example, in NH3 since there is a lone pair the bond angles will be around 107 degrees rather than the 109.5 degrees that shape usually gives.
by rabiasumar2E
Sun Nov 17, 2019 1:13 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: Hydrogen Bonds
Replies: 3
Views: 50

Re: Hydrogen Bonds

Hydrogen bonds are the strongest types of dipole-dipole interactions. Ion-ion are the strongest type of IMF!
by rabiasumar2E
Sun Nov 17, 2019 12:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.21 d
Replies: 2
Views: 31

Re: 2E.21 d

In lecture he mentioned that we aren't expected to know the value of the actual angle and that we should just be able to determine that it would be less than 109.5 degrees.
by rabiasumar2E
Sun Nov 17, 2019 12:56 pm
Forum: Dipole Moments
Topic: ion-dipole moments
Replies: 3
Views: 47

Re: ion-dipole moments

Yes, ion-dipole is stronger than dipole-dipole. The order goes: ion-ion, ion-dipole, dipole-dipole, dipole-induced dipole, induced dipole-induced dipole.
by rabiasumar2E
Thu Nov 14, 2019 2:11 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 12
Views: 127

Re: Polarity

You can look at the difference in electronegativity to figure out if a molecule is polar or look at its shape. If a molecule is symmetric it is non-polar, i.e. CH4 would be non-polar because it's symmetrical. An example of a polar molecule is NH3, which is not symmetric.
by rabiasumar2E
Thu Nov 14, 2019 1:58 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: Polar Vs Nonpolar
Replies: 7
Views: 81

Re: Polar Vs Nonpolar

A polar molecule occurs when the molecule is not symmetric, i.e. when one side has a positive charge and the other side has a negative charge.
by rabiasumar2E
Thu Nov 14, 2019 1:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework 2E.11
Replies: 3
Views: 40

Re: Homework 2E.11

The VSEPR formula is AXnEn.
A: central atom
Xn: number of bonding electrons (electrons connected to central atom)
En: number of lone pairs

Draw the lewis structure and you'll find everything you need for the formula!
by rabiasumar2E
Sun Nov 10, 2019 3:01 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: Test 2
Replies: 6
Views: 85

Re: Test 2

I think test two covers everything we have learned after the first midterm.
by rabiasumar2E
Sun Nov 10, 2019 1:10 pm
Forum: Octet Exceptions
Topic: Octet Exception
Replies: 8
Views: 213

Re: Octet Exception

Any element in and after the third period can have an expanded octet due to them having more than just p-orbitals.
by rabiasumar2E
Sun Nov 10, 2019 11:36 am
Forum: Dipole Moments
Topic: HW this week
Replies: 6
Views: 59

Re: HW this week

I would maybe ask your TA just to be sure. If your discussion session is in the beginning of the week, I'm sure doing problems from chemical bonds is okay.
by rabiasumar2E
Sun Nov 03, 2019 10:26 am
Forum: Lewis Structures
Topic: Lowest Energy
Replies: 2
Views: 40

Re: Lowest Energy

Ideally you want your central atom to have a formal charge of zero or as close as you can get to it. The octet rule can only be broken if that element is able to break it. Elements from period three or higher have d-orbitals, allowing them to accommodate for more electrons. So just make sure that if...
by rabiasumar2E
Sun Nov 03, 2019 10:18 am
Forum: Octet Exceptions
Topic: Octet Exceptions
Replies: 1
Views: 43

Re: Octet Exceptions

Elements in period three or higher have d-orbitals in their valence shell, meaning that they are able to accommodate additional electrons because they have room to do so.
by rabiasumar2E
Sun Nov 03, 2019 10:15 am
Forum: Lewis Structures
Topic: Exceptions to octet rule
Replies: 4
Views: 45

Re: Exceptions to octet rule

In lecture he said that atoms in period 3 or higher can accommodate additional electrons because they have d-orbitals, allowing them room to do so. I think breaking the octet rule is done when trying to draw the lewis structure most accurately with the lowest energy or sometimes just to get the righ...
by rabiasumar2E
Sun Nov 03, 2019 10:09 am
Forum: Bond Lengths & Energies
Topic: Bond Strength
Replies: 6
Views: 58

Re: Bond Strength

When the bond is shorter, the attraction of the electrons to the nucleus becomes stronger. Therefore, a double bond (since it is shorter) will always be stronger than a single bond and a triple bond will always be stronger than a double.
by rabiasumar2E
Sun Nov 03, 2019 8:53 am
Forum: Lewis Structures
Topic: Exceptions to the octet rule
Replies: 3
Views: 51

Re: Exceptions to the octet rule

How do we know how many valence electrons an element with an expanded octet has? How are lone pairs shown in a lewis dot structure? An element will always have the same number of valence electrons whether it has an expanded octet! Cl can have an expanded octet but its number of valence electrons wi...
by rabiasumar2E
Sun Nov 03, 2019 8:50 am
Forum: Octet Exceptions
Topic: Expanded Octets and Formal Charge
Replies: 3
Views: 51

Re: Expanded Octets and Formal Charge

For the most part, the central atom will only have an expanded octet because we are trying to get the formal charge to zero. The point is just to draw the best lewis structure so if your formal charge for the central atom isn't zero and it has an expanded octet, I would try to move somethings around...
by rabiasumar2E
Sun Nov 03, 2019 8:44 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm Format
Replies: 4
Views: 73

Re: Midterm Format

From seeing what Test 1 looked like, I'm pretty sure that the midterm will also be somewhat the same format so I'm assuming all free response.
by rabiasumar2E
Sun Oct 27, 2019 3:42 pm
Forum: Lewis Structures
Topic: Lone pair
Replies: 8
Views: 73

Re: Lone pair

Lone pairs are just electrons that aren't bonded!
by rabiasumar2E
Sun Oct 27, 2019 3:25 pm
Forum: Ionic & Covalent Bonds
Topic: Double and single bond lengths
Replies: 6
Views: 57

Re: Double and single bond lengths

A double is shorter than a single bond because it has more electrons and therefore, attracts to the nucleus more, making it stronger. A triple bond is also shorter than a double bond.
by rabiasumar2E
Sun Oct 27, 2019 3:16 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 5
Views: 89

Re: Formal Charge

We use the formal charge equation to help us find the most stable structure of a molecule.
in FC= V -(L + S/2), V= number of valence electrons, L= number of lone pair electrons, S= number of shared electrons
by rabiasumar2E
Sun Oct 27, 2019 3:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Noble gas electron configurations
Replies: 3
Views: 60

Re: Noble gas electron configurations

I don't want to say that the textbook is wrong but I'm sure that neon's electron configuration is 1s2 2s2 2p6.
by rabiasumar2E
Sun Oct 27, 2019 3:10 pm
Forum: Ionic & Covalent Bonds
Topic: Week 5 HW
Replies: 4
Views: 76

Re: Week 5 HW

I would say chemical bonds since that's what we'll be covering in lecture this week.
by rabiasumar2E
Sun Oct 27, 2019 2:46 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1E.17
Replies: 2
Views: 53

Re: 1E.17

When 4s is not filled, it has lower energy than 3d so it is filled first. But when 3d is filled it is no longer higher in energy, which is why Lavelle wants us to write 4s after 3d. So, when you remove an electron, you would remove it from the closest orbital which would be 4s.
by rabiasumar2E
Fri Oct 25, 2019 12:34 pm
Forum: Lewis Structures
Topic: Formal Charges
Replies: 4
Views: 56

Re: Formal Charges

Say you want to find the formal charge of S in SO4^-2. You have to draw the lewis structure and from there you'll find the the numbers to plug into the formal charge formula. Number of valence electrons for S is 6. 'L' represents any lone pairs it may have and in this case it has 0. 'S' represents s...
by rabiasumar2E
Sun Oct 20, 2019 11:44 am
Forum: Administrative Questions and Class Announcements
Topic: Homework for Week 4
Replies: 1
Views: 31

Re: Homework for Week 4

Yes, since we're still covering this topic in class we can do any five problems from the ones he assigned for the quantum world section.
by rabiasumar2E
Sun Oct 20, 2019 11:35 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electron Configurations
Replies: 3
Views: 21

Re: Writing Electron Configurations

We use those elements because they are noble gasses and aren't reactive, meaning their configuration is complete. 'He' would be 1s2 and 'Ne' would end with 2p6. We use them to help with the configurations of other elements that are further down the periodic table mostly for convenience so we don't h...
by rabiasumar2E
Sat Oct 19, 2019 6:38 pm
Forum: Limiting Reactant Calculations
Topic: Missed this Question on Test1
Replies: 5
Views: 454

Re: Missed this Question on Test1

First I made sure that the equation was balanced. Then I did the following to find out how much of CO2 and H20 was used to make glucose and therefore figure out what the limiting reagent was. 10.0g CO2 (1mol Co2/ 44.011g CO2) (1mol C6H12O6/ 6mol CO2) (180.156g C6H12O6/ 1 mol C6H12O6) = 6.822g 20.0g ...
by rabiasumar2E
Sat Oct 19, 2019 6:38 pm
Forum: Limiting Reactant Calculations
Topic: Missed this Question on Test1
Replies: 5
Views: 454

Re: Missed this Question on Test1

First I made sure that the equation was balanced. Then I did the following to find out how much of CO2 and H20 was used to make glucose and therefore figure out what the limiting reagent was. 10.0g CO2 (1mol Co2/ 44.011g CO2) (1mol C6H12O6/ 6mol CO2) (180.156g C6H12O6/ 1 mol C6H12O6) = 6.822g 20.0g ...
by rabiasumar2E
Sat Oct 19, 2019 6:26 pm
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 4
Views: 69

Re: Schrodinger Equation

I believe we use it to help us find the allowed energy levels in a quantum system.

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