Search found 52 matches

by lizzygaines1D
Tue Mar 13, 2018 10:26 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate Determining Step
Replies: 2
Views: 83

Re: Rate Determining Step

one of the rates must be the slowest rate.
by lizzygaines1D
Tue Mar 13, 2018 10:22 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Increasing Tempt
Replies: 2
Views: 164

Re: Increasing Tempt

increase in temperature causes an increase in the rate constant (because you T2 is larger so Ea/R(1/T1 - 1/T2) is positive therefore lnK2/k1 is positive.
by lizzygaines1D
Tue Mar 13, 2018 10:19 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Breaking ATP bonds and engergy
Replies: 1
Views: 77

Re: Breaking ATP bonds and engergy

it still requires energy to break ATP down, however you are gaining more energy from the release of P and your new bond is ADP which has less energy, so your net energy is a lot larger than what you supplied.
by lizzygaines1D
Tue Mar 13, 2018 10:15 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Adsorption
Replies: 4
Views: 145

Re: Adsorption

its basically when the reactants sit on the surface of the catalyst.
by lizzygaines1D
Mon Mar 12, 2018 11:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Which form of Nitrogen to Use
Replies: 2
Views: 219

Which form of Nitrogen to Use

In a combustion reaction when you have a nitrogen in the reactant, how do you know which form of nitrogen (NO, NO2 etc) to put in the products to balance it out?
by lizzygaines1D
Mon Mar 12, 2018 12:49 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL
Replies: 9
Views: 458

Re: FINAL

I'm going to assume that if it was covered in class its fair game for the final.
by lizzygaines1D
Mon Mar 12, 2018 12:40 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: NOT doing direct computation?
Replies: 1
Views: 47

NOT doing direct computation?

We do not have to know how to approach reaction mechanisms from a direct computational method right?
by lizzygaines1D
Mon Mar 12, 2018 12:36 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Intermediate
Replies: 6
Views: 135

Intermediate

Can someone clarify how to determine if you have an intermediate or not?
by lizzygaines1D
Mon Mar 12, 2018 12:26 pm
Forum: Biological Examples
Topic: Nitric Oxide Catalyses
Replies: 6
Views: 289

Nitric Oxide Catalyses

For the example in lecture today:
NO+1/2O2---->NO2
NO2---->NO+O
O2+O----->O3
NO is not an intermediate because it is a catalyst. The only way we knew this is because the example was nitric oxide catalyses or is there any other ways to determine which molecule is the catalyst?
by lizzygaines1D
Mon Mar 12, 2018 12:21 pm
Forum: *Enzyme Kinetics
Topic: Catalysts
Replies: 11
Views: 290

Catalysts

Do catalysts speed up both the forward and reverse reaction?
by lizzygaines1D
Sat Mar 10, 2018 10:25 pm
Forum: Second Order Reactions
Topic: the slope
Replies: 12
Views: 383

Re: the slope

Hope this can clarify everything.
by lizzygaines1D
Sat Mar 10, 2018 10:20 pm
Forum: Calculating Work of Expansion
Topic: Work in Irreversible Process
Replies: 1
Views: 70

Work in Irreversible Process

For irreversible processes, potential is lost because the opposing pressure is less than maximum at each stage, but how does this correlate to work not being is maximal value?
by lizzygaines1D
Sat Mar 10, 2018 10:16 pm
Forum: Calculating Work of Expansion
Topic: Midterm Q4A
Replies: 3
Views: 104

Re: Midterm Q4A

yeah just to add on and clarify because this problem was tricky and there was info given that you didn't need. the external pressure never changed throughout the reaction.
by lizzygaines1D
Tue Mar 06, 2018 9:46 pm
Forum: General Rate Laws
Topic: Units for Time
Replies: 2
Views: 65

Units for Time

If you are asked to find the average rate of the reaction of some period of time, (in this case time isn't needed to solve the problem) and no time units are given, what should the time units be? I thought it would be seconds, but in self test 15.2A in the book the rate was given in L^-1 x h^-1.
by lizzygaines1D
Tue Mar 06, 2018 12:48 pm
Forum: First Order Reactions
Topic: Key Words for First Order Reactions Half Life Problems
Replies: 2
Views: 84

Re: Key Words for First Order Reactions Half Life Problems

Usually the question will give you the order, and if it doesn't it should give the units of k. If the units are inverse time units, you'll know its first order etc. etc.
by lizzygaines1D
Tue Mar 06, 2018 12:42 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Which Step is Slower?
Replies: 8
Views: 148

Re: Which Step is Slower?

Okay this clarifies so much. thank you!
by lizzygaines1D
Tue Mar 06, 2018 10:41 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: infinitesimal change
Replies: 3
Views: 207

Re: infinitesimal change

An infinitesimal change is a change over a very very very short period of time, so short, that you can almost consider t as being 0. You'll see this in a reversible process.
by lizzygaines1D
Tue Mar 06, 2018 10:38 am
Forum: General Rate Laws
Topic: When to Use Avg. vs Instantaneous
Replies: 5
Views: 101

Re: When to Use Avg. vs Instantaneous

Okay I asked my TA and yes usually you should use the instantaneous unless told otherwise.
by lizzygaines1D
Mon Mar 05, 2018 1:17 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Assuming Elementary Rxn [ENDORSED]
Replies: 2
Views: 90

Assuming Elementary Rxn [ENDORSED]

Today in lecture for the reaction A+B--->C+D we assumed the reaction is an elementary second order reaction. Why can we assume this and when will you not be able to assume this?
by lizzygaines1D
Mon Mar 05, 2018 1:15 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Which Step is Slower?
Replies: 8
Views: 148

Which Step is Slower?

when going through reaction mechanisms, how can you determine which step is slower?
by lizzygaines1D
Mon Mar 05, 2018 1:11 pm
Forum: General Rate Laws
Topic: When to Use Avg. vs Instantaneous
Replies: 5
Views: 101

When to Use Avg. vs Instantaneous

How would you be able to differentiate between using the unique average rate and the unique instantaneous rate?
by lizzygaines1D
Wed Feb 28, 2018 2:00 pm
Forum: Zero Order Reactions
Topic: Using Half Life with Zero Order
Replies: 2
Views: 91

Using Half Life with Zero Order

In the text book under the half life formula for zero order reactions it says not used. What does that refer to?
by lizzygaines1D
Tue Feb 13, 2018 7:55 pm
Forum: Calculating Work of Expansion
Topic: w in a calorimeter
Replies: 2
Views: 123

w in a calorimeter

is w always 0 in a calorimeter?
by lizzygaines1D
Tue Feb 13, 2018 12:40 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacities of Gases
Replies: 3
Views: 241

Heat Capacities of Gases

Does anyone know if and of the different R values, aka 3/2R or 5/2R will be given on the midterm?
by lizzygaines1D
Mon Feb 12, 2018 9:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.19
Replies: 2
Views: 111

14.19

For the cell Cu(s)/Cu2+(aq)//M2+(aq)/M(s) how do you know that the Cu2+ is the anode and M2+ is the cathode?
by lizzygaines1D
Tue Feb 06, 2018 9:59 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 11.21
Replies: 2
Views: 94

11.21

Calculate the standard Gibbs Free energy for I2(g)--->2I(g) when K=6.8 at 1200 K. So using deltaG=deltaGrxn+RTlnQ, I understand how to solve for everything else, but how would you find Q if you are not given a pressure or anything for the products and reactants?
by lizzygaines1D
Tue Feb 06, 2018 9:27 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 11.19
Replies: 1
Views: 84

11.19

for 11.19 c "calculate the equilibrium constant at 25C for the decomposition of limestone: CaCo3(s)--->CaO(s)+CO2(g)" so using lnk=-deltaG/RT, for finding deltaG, would you use deltaGf for CaCo3 for calcite or aragonite? These values are so close it probably won't affect the answer, but fo...
by lizzygaines1D
Sun Jan 28, 2018 11:46 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Entropy vs. Standard Entropy
Replies: 4
Views: 155

Entropy vs. Standard Entropy

what's the difference is in finding the entropy of vaporization vs the standard entropy of vaporization?
by lizzygaines1D
Sun Jan 28, 2018 5:10 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Self-Test 9.2 B
Replies: 2
Views: 72

Self-Test 9.2 B

the question:
5.5 g of stainless steel is increased from 20 C to 100 C. what is the change in entropy? The specific heat capacity of stainless steel is .51 J/Cxg
Obviously you plug it into Cln(T2/T1), but then you have to multiply by grams? Why do you do this and when do you know when to do this?
by lizzygaines1D
Sun Jan 28, 2018 4:33 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy Equations with Irreversible Paths
Replies: 2
Views: 61

Entropy Equations with Irreversible Paths

The change in entropy equations with constant temperature, or change in volume work for reversible and irreversible changes, but does the equation that accounts for a change in temperature also work for an irreversible change?
by lizzygaines1D
Tue Jan 16, 2018 3:09 pm
Forum: Phase Changes & Related Calculations
Topic: 8.15 b
Replies: 3
Views: 139

Re: 8.15 b

8.15 b asks for when q = 0 which would always be true when no energy is transferred as heat. 8.16 b asks for when w = 0.
by lizzygaines1D
Tue Jan 16, 2018 3:04 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Accounting for Copper in 8.19
Replies: 2
Views: 111

Accounting for Copper in 8.19

For homework problem #19, you are asked how much heat is needed for a 500.0 g copper kettle with 400.0 g of water inside to raise the temp of the water form 22 degrees C to 100 degrees C. I understand using the q=mC x change in temp, but I'm assuming you have to account for the copper kettle absorbi...
by lizzygaines1D
Tue Dec 05, 2017 5:08 pm
Forum: Conjugate Acids & Bases
Topic: Example 12.1 b
Replies: 1
Views: 95

Example 12.1 b

Why is the conjugate acid of O2- OH-? What happened to the second O?
by lizzygaines1D
Tue Dec 05, 2017 3:54 pm
Forum: Bronsted Acids & Bases
Topic: J.11 part c
Replies: 1
Views: 92

J.11 part c

for the reaction 2HI + CaO---->CaI2 + H2O how can you tell that 2HI is the acid and CaO is the base?
by lizzygaines1D
Tue Dec 05, 2017 3:38 pm
Forum: Sigma & Pi Bonds
Topic: Double Bond Being Pi+Pi
Replies: 2
Views: 165

Double Bond Being Pi+Pi

The book that while most times a double bond includes a sigma and pi bond, sometimes it will consist of a pi and pi bond. When does this happen and how are you supposed to know?
by lizzygaines1D
Tue Dec 05, 2017 3:36 pm
Forum: Naming
Topic: Determining Linking Atom
Replies: 2
Views: 101

Determining Linking Atom

For naming purposes, how can you tell which is the linking atom if it's not underlined?
by lizzygaines1D
Tue Dec 05, 2017 3:29 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: CH3COOH
Replies: 3
Views: 292

CH3COOH

in the book it says acetic acid releases one hydrogen ion to water and any other Bronsted base present in the solution. Does that mean if there was more than one base it would donate more than one H, or will it only ever donate the last H?
by lizzygaines1D
Tue Dec 05, 2017 3:16 pm
Forum: Biological Examples
Topic: Lewis Acid/Base?
Replies: 2
Views: 231

Re: Lewis Acid/Base?

to further clarify, if you look at the example HCl+H2O--->H3O+Cl, HCl is your acid because it gives the H to H20 to form H30. H20 is your base because it receives the H from HCl.
by lizzygaines1D
Fri Nov 17, 2017 6:18 pm
Forum: Biological Examples
Topic: Cobalt
Replies: 4
Views: 259

Cobalt

what was the biological function of cobalt? I missed that note in class.
by lizzygaines1D
Fri Nov 17, 2017 6:09 pm
Forum: Naming
Topic: Roman Numeral
Replies: 2
Views: 117

Roman Numeral

for the example in class [Co(NH3)5CL]ClH20 and the name was penta-ammine-chloro-cobalt(II)Chloride Dihydrate, what is the roman numeral (II) for?
by lizzygaines1D
Sun Nov 12, 2017 7:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Where to put the lone pairs?
Replies: 3
Views: 172

Where to put the lone pairs?

So for tetrahedral molecules, you'd place the lone pairs in between the each shared electron pair, but what about a trigonal molecule? I guess I'm confused as to the fact that you're supposed to place lone pairs on opposite ends, but in the book it will show to lone pairs next to each other when its...
by lizzygaines1D
Sun Nov 12, 2017 7:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-shape vs. trigonal
Replies: 2
Views: 170

T-shape vs. trigonal

How can you tell when a molecule is going to be T-shaped vs. whether it will be trigonal pyramidal or planar? Do you have to draw them differently or you can somehow just tell with the formula?
by lizzygaines1D
Sun Nov 05, 2017 12:55 pm
Forum: Lewis Structures
Topic: Lewis Acid/Base vs. Regular Acid/Base
Replies: 1
Views: 81

Lewis Acid/Base vs. Regular Acid/Base

...is there a difference between a Lewis Acid/base vs. a regular acid/base? If so, what is it. Very confused.
by lizzygaines1D
Sun Nov 05, 2017 12:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Which one do I draw?
Replies: 5
Views: 277

Which one do I draw?

How do you know when you're supposed to draw a plain Lewis Structure, or the cool 3-D VSEPR one? Will the instructions tell you? Does it matter?
by lizzygaines1D
Thu Oct 26, 2017 12:54 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: No f- orbital questions? [ENDORSED]
Replies: 4
Views: 245

Re: No f- orbital questions? [ENDORSED]

yes to confirm this our group was told we wouldn't have to know the shape or draw it for this test.
by lizzygaines1D
Thu Oct 26, 2017 12:51 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Week 4 [ENDORSED]
Replies: 5
Views: 310

Re: Week 4 [ENDORSED]

I'm pretty sure Test 3 will cover everything from chapter 1 not covered on the previous test (mainly Heisenberg) and all of chapter 2.
by lizzygaines1D
Fri Oct 20, 2017 3:23 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals and Electron Configuration
Replies: 3
Views: 162

Re: Orbitals and Electron Configuration

basically you are spreading out the electrons until you can pair them all. Aufbau principle tells us that if you have more than one orbital in the subshell, you add a parallel spin to the different orbital. I like to think of it as spreading out the electrons before you pair them all up to get the l...
by lizzygaines1D
Wed Oct 18, 2017 8:29 pm
Forum: DeBroglie Equation
Topic: Difference longest Wavelength and wavelength
Replies: 2
Views: 164

Difference longest Wavelength and wavelength

Sometimes a question will ask you to find the longest possible wavelength, and sometimes you just have to find the wavelength. Either way you use the formula wavelength=CxH/work function. Is this right? If so what's the difference in finding the longest possible wavelength, or just the wavelength?
by lizzygaines1D
Sat Oct 14, 2017 9:24 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: H Equation [ENDORSED]
Replies: 6
Views: 303

Re: H Equation [ENDORSED]

if you were working with a different element, because of the difference in number of electrons, the Rydberg constant would be different.
by lizzygaines1D
Wed Oct 11, 2017 11:49 pm
Forum: Properties of Light
Topic: How to Find Wavelength Given only the velocity? [ENDORSED]
Replies: 2
Views: 183

How to Find Wavelength Given only the velocity? [ENDORSED]

for Homework 1.33 a, the velocity of an electron is 3.6x10^3 km/s and the question asks for the wavelength of the ejected electron? How do you solve this when all you have is velocity?
by lizzygaines1D
Fri Oct 06, 2017 3:27 pm
Forum: Limiting Reactant Calculations
Topic: Is either Method better?
Replies: 4
Views: 205

Is either Method better?

So when finding which reactant is limiting, the text suggest there are two ways to go about it: to use the stoichiometric ratio to find which is in excess, or to calculate how many moles of product each reactant can form. Do both of these methods apply for every problem, or will there ever be a time...
by lizzygaines1D
Fri Oct 06, 2017 3:21 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical equations too slow... any advice? [ENDORSED]
Replies: 18
Views: 1369

Re: Balancing Chemical equations too slow... any advice? [ENDORSED]

yes to agree with my classmates, keeping a little value list is super helpful. I just list all the elements underneath the arrow and keep a small tally, crossing them out and updating them as I balance.

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