## Search found 65 matches

Sat Mar 16, 2019 4:24 pm
Forum: Balancing Redox Reactions
Topic: multiplying half reactions [ENDORSED]
Replies: 4
Views: 830

### Re: multiplying half reactions[ENDORSED]

you don't multiply cell potential, only the coefficients in the half reaction
Thu Mar 14, 2019 12:41 pm
Forum: Experimental Details
Topic: Collision Theory
Replies: 8
Views: 546

### Collision Theory

What exactly do we have to know about collision theory for the final?
Thu Mar 14, 2019 12:37 pm
Forum: Second Order Reactions
Topic: solving for time elapsed
Replies: 1
Views: 118

### Re: solving for time elapsed

find k using the half life equation then use integrated rate law equation for a second life reaction. Ainitial should be 1 and Afinal should be 1/16
Sun Mar 10, 2019 9:16 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Formulas
Replies: 6
Views: 265

### Re: Formulas

usually look for the unknown the question is asking for and list out the values they give you to know which equation to use.
Sun Mar 10, 2019 9:15 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: K Value
Replies: 7
Views: 354

### Re: K Value

most problems don't assign points for sig figs because they're appointed for something else, but with as many points that are on the final, I wouldn't be surprised if they count for something.
Sun Mar 10, 2019 9:10 pm
Forum: First Order Reactions
Topic: Half life of 1st-Order Reaction
Replies: 2
Views: 159

### Re: Half life of 1st-Order Reaction

because half life of any quantity of a first order reaction is the same, it'll take the same time to halve no matter how much it started with
Sun Mar 10, 2019 8:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: What does K say about stability?
Replies: 5
Views: 752

### Re: What does K say about stability?

The higher the K the lower the stability of the reactants and higher the stability of the products
Sun Mar 10, 2019 8:37 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 6
Views: 305

### Re: Catalysts

Catalysts don't actually make the reaction slower or faster, what it does is it offers an alternate pathway in which the activation energy is lower, thereby making the reaction proceed more completely with a given energy.
Sun Mar 10, 2019 8:34 pm
Forum: Balancing Redox Reactions
Topic: Acidic Solutions
Replies: 7
Views: 365

### Re: Acidic Solutions

what do we do when the reaction isn't acidic. add oh- instead?
Sun Mar 10, 2019 8:29 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Final Material
Replies: 4
Views: 168

### Re: Final Material

he has also put a homework question on every test i believe
Sun Mar 10, 2019 8:28 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 2
Replies: 12
Views: 481

### Re: Test 2

a negative gibbs free energy means it is spontaneous, unlike a negative entropy which means its nonspontaneous
Sun Mar 10, 2019 8:27 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram
Replies: 6
Views: 214

### Re: Cell diagram

there must be a solid in the reaction so if there isn't one we add Pt(s) in place
Wed Feb 27, 2019 6:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 4.37 c
Replies: 1
Views: 103

### 4.37 c

Why is Q listed with both Pressures on top and both concentrations on the bottom on the solution manual? I thought Q was Products over reactants?
Wed Feb 20, 2019 5:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Deprotonation
Replies: 3
Views: 157

### Re: Deprotonation

this is because the ka of that reaction relates to h3po4 losing it's first electron and ka2 is h3po4 losing its second electron or h2po4- losing an electron
Wed Feb 20, 2019 5:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Deprotonation
Replies: 3
Views: 157

### Re: Deprotonation

deprotonation is losing an electron, so ka2 would be losing two electrons
Wed Feb 20, 2019 4:25 pm
Forum: General Science Questions
Topic: Midterm
Replies: 5
Views: 487

### Re: Midterm

it's the second deprotonation of h3po4
the first would include h2po4- in the product, the second will include hpo4^2- in the product
Wed Feb 20, 2019 3:18 pm
Forum: Administrative Questions and Class Announcements
Topic: midterm
Replies: 2
Views: 167

### midterm

does anyone know when we'll get our midterms back?
Tue Feb 19, 2019 10:41 am
Forum: Phase Changes & Related Calculations
Topic: #10 on Hotdog
Replies: 3
Views: 400

### Re: #10 on Hotdog

thank you!!
Tue Feb 12, 2019 2:58 pm
Forum: Phase Changes & Related Calculations
Topic: #10 on Hotdog
Replies: 3
Views: 400

### #10 on Hotdog

10. Michael asks me for water with no ice at a dining hall. Just to spite him, I measure 25.0 g of ice at 0.00 oC and drop it into 265 mL of water at 25.0 oC. What is the final temperature of the water? i know we set qice=-qwater and from that i got a T of 296.91K. Now to find the final answer do I ...
Tue Feb 12, 2019 2:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
Replies: 49
Views: 4028

### Re: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!

with a corresponding q=-11.45kj?
Tue Feb 12, 2019 2:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
Replies: 49
Views: 4028

### Re: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!

I also got that the other part of w=9.12 from w=-pdv. so i got a total of 11.45kj or 1.145x10^5j for w. is this correct?
Tue Feb 12, 2019 2:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
Replies: 49
Views: 4028

### Re: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!

what was the full answer for w on #6? I got that part of it is 2.33KJ from the w=-nrtln(v2/v1)
Wed Jan 30, 2019 3:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Replies: 3
Views: 161

skipping around is kinda necessary for the homework
Wed Jan 30, 2019 3:07 pm
Forum: Phase Changes & Related Calculations
Topic: Week 4 Homework
Replies: 12
Views: 584

### Re: Week 4 Homework

i would stick to outline 3, but the homework kinda requires you to read because we haven't gone over too much in lecture so far
Wed Jan 30, 2019 3:06 pm
Forum: Phase Changes & Related Calculations
Topic: J vs. kJ
Replies: 9
Views: 360

### Re: J vs. kJ

J is the SI unit, but if the rest of the problem is worked out in kJ then probably use that. on tests they'll probably specify
Wed Jan 30, 2019 3:05 pm
Forum: Phase Changes & Related Calculations
Topic: Test #1
Replies: 11
Views: 444

### Re: Test #1

yes, we usually get our tests back exactly a week after we take them
Wed Jan 30, 2019 3:03 pm
Forum: Phase Changes & Related Calculations
Topic: Water phase change graph
Replies: 6
Views: 300

### Re: Water phase change graph

the horizontal lines represent the phase change and the length of the line represents the energy added over time
Wed Jan 30, 2019 3:02 pm
Forum: Calculating Work of Expansion
Topic: Units for Work
Replies: 6
Views: 297

### Re: Units for Work

^^ but yes, we will mostly be using SI units which includes joules
Wed Jan 23, 2019 8:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition, 12.69
Replies: 3
Views: 195

### Re: 6th edition, 12.69

^^divide kw by the kb for nh3 and you'll get the ka for nh4+
Wed Jan 23, 2019 1:22 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Exothermic and endothermic
Replies: 3
Views: 245

### Re: Exothermic and endothermic

an exothermic reaction gives off energy as heat for ex. and has a low activation energy, an endothermic reaction requires more energy and will take it from the surroundings
Wed Jan 23, 2019 9:57 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5% Rule
Replies: 3
Views: 104

### Re: 5% Rule

you can know it's okay to use it if the K is below 10^-3!
Wed Jan 23, 2019 9:55 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas
Replies: 2
Views: 98

### Re: Inert Gas

inert gases are just basically saying noble gasses
Tue Jan 22, 2019 3:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka and Kb
Replies: 3
Views: 146

### Re: Ka and Kb

the same goes for Kb and Bases!
Tue Jan 22, 2019 3:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka and Kb
Replies: 3
Views: 146

### Re: Ka and Kb

Ka reflects how much the acid will disassociate in reaction so a high Ka(higher than 1000) will indicate it being a strong acid and a low Ka(lower than .001) will indicate it being a weak acid.
Tue Jan 22, 2019 3:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework for Week 3
Replies: 5
Views: 301

### Re: Homework for Week 3

Acid's and bases will probably be preferable, but in preparation for the test I'm sure you can do a mixture without it being an issue
Wed Dec 05, 2018 10:04 pm
Forum: Naming
Topic: Oxidation Numbers
Replies: 3
Views: 151

### Re: Oxidation Numbers

yeah i think so because oxidation is a process that takes electrons away, leaving the elements with positive charges
Wed Dec 05, 2018 9:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar or nonpolar
Replies: 4
Views: 204

### Re: Polar or nonpolar

it's a tetrahedral shape so i don't think the angles would allow for the dipole moments to cancel out
Tue Dec 04, 2018 1:29 pm
Forum: Administrative Questions and Class Announcements
Replies: 8
Views: 499

becca_vandyke_4b wrote:Are we going to get the same equation sheet for the final thats been on the tests? Trying to figure out if I need to memorize any equations.

yeah we're probably gonna get the same equation sheet
Tue Dec 04, 2018 11:47 am
Forum: Lewis Acids & Bases
Topic: KBr
Replies: 5
Views: 224

### Re: KBr

"KBr dissociates into K+ and Br-. Br- reacts to make HBr, a strong acid. Since Br- is the conjugate base of HBr, it is weak. K+ is also weak so the two weak components sort of offset and have no real effect on the pH, making it neutral."
Mon Dec 03, 2018 12:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw
Replies: 13
Views: 735

### Re: Seesaw

I think less than 180 is also acceptable if you're considering the angle created by the top, middle, and bottom atoms in this structure
Mon Dec 03, 2018 12:09 pm
Forum: Administrative Questions and Class Announcements
Replies: 10
Views: 560

The class isn't based on a curve of our own class, but all the classes before us. This means that he has taken the averages from previous classes and uses them as a guideline for how grades should be set
Mon Dec 03, 2018 12:06 pm
Forum: Naming
Topic: Naming the Shape
Replies: 6
Views: 288

### Re: Naming the Shape

using the lewis formula can be helpful!
Mon Nov 26, 2018 1:26 pm
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 4
Views: 188

### Re: Dipole Moments

They tell us about the charge separation in a molecule, the larger the difference in electronegativities of bonded atoms, the larger the dipole moment.
Wed Nov 14, 2018 6:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bent structure? also, intermolecular interactions
Replies: 3
Views: 114

### Re: bent structure? also, intermolecular interactions

The bent shape occurs when there are three total atoms with a lone pair or 2 on the central atom such as on H2O
Wed Nov 14, 2018 6:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Angular Shape
Replies: 4
Views: 230

### Re: Angular Shape

Yeah that's basically it. An example is H2O where there's two lone pairs on oxygen which pushes down the Hydrogen atoms to make room
Wed Nov 14, 2018 2:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Octet Rule
Replies: 6
Views: 397

### Re: Octet Rule

Sulfur, phosphorus, silicon, and chlorine are common examples of elements that form an expanded octet which means they can have more than the usual 8.
Wed Nov 14, 2018 2:22 pm
Forum: Student Social/Study Group
Topic: Test 3
Replies: 6
Views: 608

### Re: Test 3

this is what Dr. Lavelle posted:
"Test 3 covers: End of Bonding from 3.12 (6 Ed.) and from 2D (7 Ed.); and all of Molecular Shape and Structure (see Syllabus and Outlines for details)."
Wed Nov 14, 2018 2:20 pm
Forum: Resonance Structures
Topic: Formal Charge
Replies: 13
Views: 810

### Re: Formal Charge

It should also be noted that certain atoms like Carbon almost always need to have a formal charge of zero to maintain it's stability
Tue Nov 13, 2018 7:01 pm
Forum: Octet Exceptions
Topic: octet exceptions
Replies: 2
Views: 166

### Re: octet exceptions

some exceptions to the octet rule can be found in the 3rd period in the p block because they have an unoccupied d block that lets them expand past the octet rule
Tue Nov 13, 2018 2:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Thanksgiving Wednesday
Replies: 9
Views: 477

### Re: Thanksgiving Wednesday

Does anybody know how we will turn in homework for Week 8 if we have discussion on Thurs/Fri? Dr. Lavelle said "Hand in homework for Weeks 8 and 9 in Week 9. Therefore in Week 9 discussion section hand in 14 homework problems. These will be excellent preparation for Test 3 during Week 9. Test ...
Tue Nov 13, 2018 2:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs. NonPolar
Replies: 5
Views: 253

### Re: Polar vs. NonPolar

It is also important to note that molecular structure plays an important role in polarity. For example, C02 would be expected to be a polar molecule, since the difference in electronegativity of C and O is large. However, the two O's are on either side of the C, giving it a linear shape. Due to thi...
Tue Nov 13, 2018 2:18 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 4
Views: 246

### Re: Formal Charge

octet rule is the first thing we consider, so as long as you keep in mind exceptions to the octet rule, then you should do octet rule first and check formal charges after.
Tue Nov 13, 2018 2:14 pm
Forum: Octet Exceptions
Topic: Exceptions
Replies: 10
Views: 781

### Re: Exceptions

some exceptions to the octet rule can be found in the 3rd period in the p block because they have an unoccupied d block
Sun Nov 04, 2018 9:10 am
Forum: Ionic & Covalent Bonds
Topic: covalent bonds
Replies: 2
Views: 154

### Re: covalent bonds

Nonmetals typically have much higher ionization energies which makes them less likely to lose electrons and become cations
Sun Nov 04, 2018 9:07 am
Forum: Lewis Structures
Topic: Triangle Bond?
Replies: 2
Views: 126

### Re: Triangle Bond?

The outside oxygen atoms both connect to the central oxygen with one double bond and one single bond, but they aren't connected to each other
Sun Nov 04, 2018 9:06 am
Forum: Lewis Structures
Topic: Triangle Bond?
Replies: 2
Views: 126

### Re: Triangle Bond?

The lewis structure for O3 bent, but not triangular
Thu Oct 25, 2018 10:31 pm
Forum: Properties of Electrons
Topic: Electron Energy
Replies: 3
Views: 278

### Re: Electron Energy

it is absorbing energy
Thu Oct 25, 2018 10:29 pm
Forum: Properties of Electrons
Topic: Degeneracy
Replies: 11
Views: 668

### Re: Degeneracy

"electron orbitals that have the same energy levels are called degenerate orbitals. ... For example, p orbitals consist of three degenerate orbitals that all have exactly the same energy level."
Thu Oct 25, 2018 10:25 pm
Forum: Properties of Electrons
Replies: 2
Views: 107

### Re: Textbook reading Test 2

No, not everything in chapter two will be tested on this one
Wed Oct 17, 2018 9:15 pm
Forum: Properties of Light
Replies: 3
Views: 188

the slope of the wave decreases which in turn decreases the extent of change in the electric field
Wed Oct 17, 2018 9:13 pm
Forum: Properties of Light
Topic: Test 2 [ENDORSED]
Replies: 15
Views: 590

### Re: Test 2[ENDORSED]

this is also what i heard
Wed Oct 17, 2018 9:11 pm
Forum: Properties of Light
Topic: Wave/particles
Replies: 5
Views: 220

### Re: Wave/particles

yeah they have both properties seemingly at the same time
Wed Oct 10, 2018 8:42 pm
Forum: Significant Figures
Topic: Test 1
Replies: 3
Views: 327

### Re: Test 1

I don't think things like M=moles/liters will be given though!
Wed Oct 10, 2018 8:40 pm
Forum: Administrative Questions and Class Announcements
Topic: How to list Chem_Mod posts
Replies: 18
Views: 40137

### Re: How to list Chem_Mod posts

Thank you!!
Wed Oct 10, 2018 8:40 pm
Forum: Limiting Reactant Calculations
Topic: Question M11
Replies: 2
Views: 253

### Re: Question M11

Yes! and in the reaction that creates p4o10 from p4o6 and o2, o2 will be the limiting reactant.