## Search found 50 matches

Tue Mar 13, 2018 5:50 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Mechanism Steps
Replies: 4
Views: 286

### Re: Reaction Mechanism Steps

Yes we would have to assume that in order to be able to calculate the rate law
Tue Mar 13, 2018 5:43 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Question 15.51
Replies: 8
Views: 518

### Re: Question 15.51

can someone elaborate on what the solutions manual is talking about when we say that the second elementary reaction is fast and it does not affect the reaction order?? the rate law is determined by the slowest elementary step, which is step 1 in this case, so step 2 doesn't have any effect on it be...
Tue Mar 13, 2018 5:35 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Collision Theory
Replies: 1
Views: 144

### Re: Collision Theory

This is section 15.12 of the textbook which is one of the sections that we are responsible for knowing according to the syllabus, but I don't think we have covered it in class
Sat Mar 10, 2018 3:12 pm
Forum: *Enzyme Kinetics
Topic: Chapter 15 [ENDORSED]
Replies: 3
Views: 310

### Re: Chapter 15[ENDORSED]

yes according to the syllabus we are responsible for knowing all of 15.1 to 15.15, except 15.9, for the final
Sat Mar 10, 2018 2:57 pm
Forum: Second Order Reactions
Topic: Units of k for orders above 2nd
Replies: 6
Views: 501

### Re: Units of k for orders above 2nd

Yes I'm pretty sure this will always work, I've never thought about it like this so thanks for the tip!
Sat Mar 10, 2018 2:46 pm
Forum: Second Order Reactions
Topic: 3rd order?
Replies: 7
Views: 766

### Re: 3rd order?

If you don't remember the units for k for certain orders you can always just divide the rate by the concentration. For 3rd order reactions, the units are (M/s)(1/M^3) which simplifies to (1/M^2)s
Sun Mar 04, 2018 4:26 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Quiz 3
Replies: 6
Views: 435

### Re: Quiz 3

yes the only problems we will be tested on are from 15.1-15.6
Sun Mar 04, 2018 4:16 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Reaction
Replies: 6
Views: 381

### Re: Arrhenius Reaction

No but we don't have to worry about these until the final
Sun Mar 04, 2018 4:02 pm
Forum: General Rate Laws
Topic: Rate Law
Replies: 3
Views: 260

### Re: Rate Law

The concentration of reactants is negative so there needs to be a negative sign to cancel it out and make the rate positive
Fri Feb 23, 2018 2:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram [ENDORSED]
Replies: 4
Views: 301

### Re: Cell diagram[ENDORSED]

you use a single line because they are different states
Fri Feb 23, 2018 2:27 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Spontaneous Directions [ENDORSED]
Replies: 7
Views: 565

### Re: Spontaneous Directions[ENDORSED]

standard potential has to be positive for the reaction to be spontaneous
Fri Feb 23, 2018 2:21 pm
Forum: General Rate Laws
Replies: 6
Views: 2355

There will always be a negative sign in front of the reactants in order to make the reaction rate positive
Sun Feb 18, 2018 5:22 pm
Forum: Balancing Redox Reactions
Topic: Bruincast
Replies: 4
Views: 344

### Re: Bruincast

I just checked that link and the class that is bruincasted is not Lavelle's
Sun Feb 18, 2018 4:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: galvanic cells and voltaic cells
Replies: 2
Views: 139

### Re: galvanic cells and voltaic cells

Yes, they are the same
Sun Feb 18, 2018 3:49 pm
Forum: Balancing Redox Reactions
Topic: Test 2
Replies: 5
Views: 280

### Re: Test 2

I think we will be given a chart with half reactions and their cell potentials and then we will have to come up with the reactions for the specific problem and find them on the chart
Sat Feb 10, 2018 7:51 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: When to use + sign
Replies: 11
Views: 549

### Re: When to use + sign

So should we always put a + sign on positive answers for change calculations on tests/exams?
Sat Feb 10, 2018 6:11 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.47 delta S = 0
Replies: 2
Views: 210

### Re: 9.47 delta S = 0

Delta S=0 because the amount of heat lost by the system is equal to the amount of heat gained by the surroundings.
Sat Feb 10, 2018 6:07 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.13
Replies: 4
Views: 231

### Re: 9.13

Yes I think that's what we are supposed to use when it says to assume ideal behavior
Thu Feb 01, 2018 11:31 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Total Enthalpy
Replies: 2
Views: 187

### Re: Total Enthalpy

In a reversible reaction, the change in entropy of the system is the negative of the change in entropy of the surroundings, so the total change is zero
Wed Jan 31, 2018 1:57 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: Box 9.1 Absolute Zero
Replies: 2
Views: 177

### Re: Box 9.1 Absolute Zero

It's not on our review sheet and he hasn't mentioned it in class, so we probably don't need to memorize it.
Wed Jan 31, 2018 1:40 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Homework 9.55
Replies: 2
Views: 175

### Re: Homework 9.55

Yes I think that's what we are supposed to do.
Sun Jan 28, 2018 5:00 pm
Forum: Phase Changes & Related Calculations
Topic: Combustion of liquids
Replies: 4
Views: 360

### Re: Combustion of liquids

It's usually liquid H2O because the temperature of the reactions in our homework problems is stated or assumed to be 25 degrees Celsius
Sun Jan 28, 2018 4:49 pm
Forum: Phase Changes & Related Calculations
Topic: 8.40
Replies: 4
Views: 273

### Re: 8.40

I got that same answer as well
Sat Jan 27, 2018 5:11 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Units for Entropy
Replies: 4
Views: 267

### Re: Units for Entropy

Yeah I think the standard units are just J/K and J/K/mol is used when the question asks for the entropy per mole.
Fri Jan 19, 2018 2:06 pm
Forum: Calculating Work of Expansion
Topic: 8.13
Replies: 2
Views: 96

### Re: 8.13

The cylinder itself is losing energy so the heat is negative
Fri Jan 19, 2018 2:03 pm
Forum: Calculating Work of Expansion
Topic: units for calculating work
Replies: 6
Views: 306

### Re: units for calculating work

atm and liters would probably be the best units since the conversion of L.atm to joules will be given to us on the constants and formulas sheet.
Thu Jan 18, 2018 9:15 pm
Forum: Calculating Work of Expansion
Topic: Question 8.27 Conversion
Replies: 2
Views: 195

### Re: Question 8.27 Conversion

This is the conversion of kPa to atm that we have to use in order to get our answer in joules.
Sun Jan 14, 2018 1:59 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta H and Delta U
Replies: 3
Views: 134

### Re: Delta H and Delta U

Yes this is only true when the pressure and volume are constant
Sun Jan 14, 2018 1:57 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework help on 8.29
Replies: 4
Views: 209

### Re: Homework help on 8.29

So thinking in terms of which one has more bonds is incorrect?
Sun Jan 14, 2018 1:40 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Not a State Property
Replies: 6
Views: 309

### Re: Heat Not a State Property

Heat depends on the path that is taken not just its initial and final state, so it is not a state property
Thu Dec 07, 2017 5:12 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted vs. Lewis
Replies: 4
Views: 357

### Re: Bronsted vs. Lewis

yes, Bronsted acids donate a proton and Bronsted bases accept a proton while Lewis acids accept an electron pair and Lewis bases donate an electron pair.
Thu Dec 07, 2017 5:03 pm
Forum: Hybridization
Topic: Lone Pairs in Hybridization
Replies: 4
Views: 422

### Re: Lone Pairs in Hybridization

lone pairs are included and double/triple bonds are only counted as one area of electron density
Fri Dec 01, 2017 5:00 pm
Forum: Ideal Gases
Topic: Q and K [ENDORSED]
Replies: 35
Views: 1761

### Re: Q and K[ENDORSED]

There is no difference between the formulas, but they calculate different things. K is calculated by using the equilibrium concentrations and Q is calculated by using the concentrations at a different time during the reaction.
Fri Dec 01, 2017 4:56 pm
Forum: Ideal Gases
Topic: Units for the formula
Replies: 4
Views: 495

### Re: Units for the formula

What does the R stand for again?
Wed Nov 22, 2017 6:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs. Angular
Replies: 5
Views: 559

### Re: Bent vs. Angular

Yes, they mean the same thing.
Wed Nov 22, 2017 6:00 pm
Forum: Naming
Topic: 17.29 Cobalt vs. Colbaltate
Replies: 3
Views: 279

### Re: 17.29 Cobalt vs. Colbaltate

We use cobalt in our answer for b and d because there is a positive charge on the complex and we use cobaltate in our answer for c because the complex has a negative charge.
Sat Nov 18, 2017 4:56 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Understanding sigma and pi bonds?
Replies: 8
Views: 437

### Re: Understanding sigma and pi bonds?

why can't pi bonds rotate?
Sat Nov 18, 2017 4:35 pm
Forum: Hybridization
Topic: Hybridization in Carbon
Replies: 3
Views: 192

### Re: Hybridization in Carbon

Any bond (single, double, or triple) only counts as one region of electron density.
Fri Nov 10, 2017 10:54 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Drawing the configuration
Replies: 4
Views: 277

### Re: Drawing the configuration

sofiakrylova3j wrote:So technically we don't know if a certain electron has positive or negative spin?

I don't think so. Unless you are given ms= 1/2 or ms= -1/2 then you know it's spin up or spin down.
Fri Nov 10, 2017 10:44 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Sulfur Dioxide?
Replies: 3
Views: 376

### Re: Sulfur Dioxide?

The two resonance structures can exist because the actual structure is a blend of all three, even though most of the time the sulfur dioxide molecule is in the state of the one with the formal charge of zero.
Fri Nov 03, 2017 7:53 pm
Forum: Ionic & Covalent Bonds
Topic: How to easily tell between Ionic and Covalent bonds?
Replies: 8
Views: 671

### Re: How to easily tell between Ionic and Covalent bonds?

I learned this method in high school too and I think it will work in this class, but it might be better to calculate the electronegativity difference.
Fri Nov 03, 2017 7:48 pm
Forum: Ionic & Covalent Bonds
Topic: Noble Gases
Replies: 6
Views: 574

### Re: Noble Gases

Yes they still can form compounds, but under extreme circumstances.
Fri Oct 27, 2017 9:28 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Px, Py, Pz
Replies: 10
Views: 805

### Re: Px, Py, Pz

I think he might prefer if we write it in the Px, Py, Pz form but I don't think we'll be penalized if we write it the other way
Fri Oct 27, 2017 8:15 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: d and s blocks
Replies: 16
Views: 991

### Re: d and s blocks

the energy of (n)s is greater than (n-1)d so you write the d block before the s block. For example: 3d is written before 4s because the energy of 4s is greater than the energy of 3d
Thu Oct 19, 2017 10:05 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation
Replies: 7
Views: 551

### Re: Rydberg Equation

n1 is always the ending energy level: E(final)-E(initial)
Thu Oct 19, 2017 9:38 pm
Forum: Properties of Light
Topic: Color of visible light
Replies: 11
Views: 806

### Re: Color of visible light

I think the only ones we are expected to remember for now are red(700 nm) and violet(400 nm) and maybe blue(470nm)
Thu Oct 12, 2017 5:47 pm
Forum: Photoelectric Effect
Topic: Energy in kj or j when solving a problem?
Replies: 10
Views: 876

### Re: Energy in kj or j when solving a problem?

Josh Moy 1I wrote:If we have kg or km should we convert to g and m?

If the problem specifically asks you to convert to g or m then you should, but if it doesn't ask you to then I would suggest just keeping the units that you are given in the problem.
Thu Oct 12, 2017 5:14 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module Question 18 [ENDORSED]
Replies: 3
Views: 386

### Re: Photoelectric Effect Module Question 18[ENDORSED]

Yes the question is asking for all the conditions that apply so C and D are both right since the energy of the photon can be equal to or greater than the energy needed to remove the electron.
Thu Oct 05, 2017 8:52 pm
Forum: Limiting Reactant Calculations
Topic: Percent Yield [ENDORSED]
Replies: 5
Views: 1334

### Re: Percent Yield[ENDORSED]

A high percent yield is better because it suggests that there were fewer impurities that occurred during the experiment and can help with the accuracy of calculations.
Thu Oct 05, 2017 8:35 pm
Forum: Empirical & Molecular Formulas
Topic: Problem E5
Replies: 6
Views: 1695

### Re: Problem E5

Yes I got those answers too and I checked them in the solutions manual :)