Search found 77 matches

by 205405339
Wed Mar 11, 2020 9:54 am
Forum: Administrative Questions and Class Announcements
Topic: take home FINAL DEADLINE
Replies: 15
Views: 232

take home FINAL DEADLINE

I was wondering by what time and day do we need to submit our take-home final by?
by 205405339
Tue Mar 10, 2020 5:30 pm
Forum: Balancing Redox Reactions
Topic: Half Reactions
Replies: 15
Views: 68

Re: Half Reactions

in acidic solutions, you balance oxygen by adding H2O to the side lacking oxygen and you balance H by adding H+ to the side needing hydrogen. in basic solutions, you add H2O to the side lacking oxygen to balance oxygen. Then to balance hydrogen, add H2O to the side needing hydrogen and add OH- to th...
by 205405339
Tue Mar 10, 2020 5:27 pm
Forum: Zero Order Reactions
Topic: 0 order
Replies: 8
Views: 55

Re: 0 order

zero order means concentration of reactants has no effect on rate so if trial 1 had the same concentration of reactant a but had twice the concentration of reactant b compared to trial 2, trial 1 will still have the same rate as trial 2. essentially rate is unaffected by the change in reactant conce...
by 205405339
Tue Mar 10, 2020 5:24 pm
Forum: Second Order Reactions
Topic: determining order
Replies: 9
Views: 31

Re: determining order

When given experimental data, input the given values into time vs ln[a] (first order), time vs 1/[a] (second order), and time vs [a] (zero order) and look for the graph with the linear graph. this determines the order of that particular reactant.
by 205405339
Tue Mar 10, 2020 5:19 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts and Rate Law
Replies: 4
Views: 25

Re: Catalysts and Rate Law

From what I remember from Lavelle's lecture, catalysts are purely mechanisms that lower activation energy and are not included in the equation, therefore, they will not be in the rate law
by 205405339
Tue Mar 10, 2020 5:14 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Problem 6N.1 part b
Replies: 4
Views: 48

Re: Problem 6N.1 part b

yes, if both half reactions only show 1 mole of electrons being transferred then n=1 thus the solution manual is wrong
by 205405339
Tue Mar 10, 2020 5:11 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow step
Replies: 7
Views: 38

Re: Slow step

It will be given which step is the slow step as we can not determine which is the slow step purely based off the equations
by 205405339
Tue Mar 10, 2020 5:02 pm
Forum: Administrative Questions and Class Announcements
Topic: Discussion Sections
Replies: 4
Views: 45

Re: Discussion Sections

yea I'm curious about this too cuz i didn't turn in week 10 homework yet
by 205405339
Mon Mar 09, 2020 3:47 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Slow Step
Replies: 4
Views: 19

Re: Slow Step

the question will usually indicate which step is the fast step and which is the slow step as we have not learned a process for determining slow steps yet
by 205405339
Sat Mar 07, 2020 7:53 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: finding n in G=-nFE
Replies: 15
Views: 157

Re: finding n in G=-nFE

use the highest number of moles of electrons transferred according to the half reactions
by 205405339
Sat Mar 07, 2020 6:39 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: the intermediate in a reaction
Replies: 10
Views: 107

Re: the intermediate in a reaction

the intermediate is a species produced in one step then consumed in the next step so the intermediate species will not appear in the overall reaction equation as it is depleted by the end of the next step.
by 205405339
Sat Mar 07, 2020 6:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: galvanic cells
Replies: 8
Views: 79

Re: galvanic cells

the half reaction with the more negative reduction potential will be the anode
by 205405339
Sat Mar 07, 2020 6:09 pm
Forum: General Science Questions
Topic: Test 2 Grades [ENDORSED]
Replies: 23
Views: 285

Re: Test 2 Grades [ENDORSED]

tests are handed back during discussion
by 205405339
Fri Mar 06, 2020 11:48 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Figuring out n
Replies: 15
Views: 83

Re: Figuring out n

n is the moles of electrons transferred so use the number of electrons found in the half reaction with the most electrons
by 205405339
Fri Mar 06, 2020 11:45 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst
Replies: 10
Views: 108

Re: Nernst

lnQ can always be converted to logQ thru the equation: lnQ=2.303logQ
by 205405339
Fri Mar 06, 2020 11:41 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: units of k
Replies: 9
Views: 66

Re: units of k

units of k can be determined by (M/s) / (M^n) where n is the total reaction order
by 205405339
Fri Mar 06, 2020 11:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Determining the cathode/anode
Replies: 9
Views: 79

Re: Determining the cathode/anode

the anode is the one with the most negative potential
by 205405339
Fri Mar 06, 2020 11:27 pm
Forum: First Order Reactions
Topic: rate constants
Replies: 19
Views: 122

Re: rate constants

rate constants are always positive and don't have units
by 205405339
Fri Mar 06, 2020 11:25 pm
Forum: First Order Reactions
Topic: Time Conversions
Replies: 9
Views: 396

Re: Time Conversions

both should have the same units. it does not really matter what unit it is as long as units match
by 205405339
Tue Mar 03, 2020 9:41 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6N.7.b & n in nernst equation
Replies: 1
Views: 16

6N.7.b & n in nernst equation

so i thought n was the moles of electrons transferred but thats not the case for 6N.7.b. can someone explain
by 205405339
Tue Mar 03, 2020 6:12 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6N.1.b
Replies: 1
Views: 21

6N.1.b

for b, the solution says In+3 needs 2 electrons to become In +2 and this sets n=2 for the Nernst equation but this number of moles of electrons is clearly wrong
by 205405339
Tue Mar 03, 2020 1:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.1
Replies: 1
Views: 27

6M.1

why do we assume Cu+2/Cu is the anode?
by 205405339
Sat Feb 29, 2020 2:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode vs Cathode
Replies: 15
Views: 60

Re: Anode vs Cathode

usually anode will be to the left and the cathode will be to the right. Also oxidation occurs at the anode and reduction happens at the cathode
by 205405339
Sat Feb 29, 2020 2:13 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox Reactions
Replies: 3
Views: 27

Re: Balancing Redox Reactions

you balance reactions in acidic solutions by adding H2O to balance the oxygen and adding H+ to balance hydrogen. In basic solutions, you add H2O to balance the oxygens then to balance the hydrogen, you add H2O to the side needing the hydrogen then add OH- to the other side
by 205405339
Sat Feb 29, 2020 2:10 pm
Forum: Balancing Redox Reactions
Topic: Test 2
Replies: 19
Views: 150

Re: Test 2

I think Lavelle said test 2 is the 2nd half of outline 4 and all of outline 5 (electrochemistry)
by 205405339
Sat Feb 29, 2020 2:07 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic vs Voltaic Cells
Replies: 4
Views: 30

Re: Galvanic vs Voltaic Cells

from what i remember, galvanic and voltaic cells are the exact same thing
by 205405339
Sat Feb 29, 2020 2:03 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: E potentials
Replies: 5
Views: 28

Re: E potentials

it will always be given as reduction as it allows for easy comparison to determine what will be oxidized and what will be reduced based the voltage value for the reduction reaction
by 205405339
Sat Feb 29, 2020 1:54 pm
Forum: Balancing Redox Reactions
Topic: Reducing/Oxidizing Agents
Replies: 13
Views: 57

Re: Reducing/Oxidizing Agents

the molecule that contains the element being oxidized is the reducing agent and the molecule that contains the element being reduced is the oxidizing agent
by 205405339
Tue Feb 25, 2020 9:52 pm
Forum: Balancing Redox Reactions
Topic: adding e-
Replies: 7
Views: 44

Re: adding e-

you add electrons to the side with the more positive charge to balance the charge on both sides of the equation
by 205405339
Tue Feb 25, 2020 9:50 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 4
Views: 30

Re: Anode and Cathode

anode is being oxidized so its losing electrons whereas cathode is being reduced so its gaining electrons
by 205405339
Tue Feb 25, 2020 9:48 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: G(not) and G
Replies: 15
Views: 109

Re: G(not) and G

G9not) is under standard conditions whereas G is not and G(n0t) will contribute to the value of G
by 205405339
Mon Feb 24, 2020 3:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 9
Views: 47

Re: Cell Diagrams

a single bar is a porous disk and a double bar is a salt bridge
by 205405339
Mon Feb 24, 2020 3:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic/Voltaic Cells
Replies: 4
Views: 38

Re: Galvanic/Voltaic Cells

galvanic cells from what i understand are basically like batteries that produce a voltage difference and consist of a cation and anion that produces a transfer of electrons across the cell. the potential of this cell is greatest when little to no current is going thru
by 205405339
Sat Feb 22, 2020 11:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: single line in cell diagram
Replies: 3
Views: 19

Re: single line in cell diagram

porous disk is repped by a single line and double line is salt bridge
by 205405339
Sat Feb 22, 2020 6:37 pm
Forum: Balancing Redox Reactions
Topic: Charge of oxygen
Replies: 15
Views: 98

Re: Charge of oxygen

at least from previous classes I took, it is usually safe to assume that O2 will have a -2 charge
by 205405339
Sat Feb 22, 2020 6:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: max potential in Galvanic Cell
Replies: 4
Views: 21

Re: max potential in Galvanic Cell

I think when current flows, the voltage decreases as electrons flow thus why max potential is when the switch is open
by 205405339
Sat Feb 22, 2020 2:03 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: E cell
Replies: 6
Views: 55

Re: E cell

usually, a table with the standards will be given to us
by 205405339
Thu Feb 20, 2020 9:51 pm
Forum: Balancing Redox Reactions
Topic: oxidation numbers
Replies: 4
Views: 26

Re: oxidation numbers

if oxidation number decreases, it means it was reduced by gaining electrons
by 205405339
Wed Feb 19, 2020 2:03 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: G vs G knot
Replies: 15
Views: 91

Re: G vs G knot

G knot is under standard conditions. G is the total so it will include G knot
by 205405339
Wed Feb 19, 2020 2:02 pm
Forum: Balancing Redox Reactions
Topic: Test 2 [ENDORSED]
Replies: 12
Views: 110

Re: Test 2 [ENDORSED]

test 2 is the week after next week
by 205405339
Tue Feb 18, 2020 9:36 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Kelvin or Celsius?
Replies: 47
Views: 500

Re: Kelvin or Celsius?

temperature is always kelvin
by 205405339
Tue Feb 18, 2020 9:40 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: ∆G = ∆Gº + RT lnQ
Replies: 12
Views: 100

Re: ∆G = ∆Gº + RT lnQ

∆Gº is basically just ∆G but under standard conditions
by 205405339
Tue Feb 18, 2020 9:37 am
Forum: Van't Hoff Equation
Topic: K rather than Kc
Replies: 10
Views: 73

Re: K rather than Kc

K=(RT)^(change in n) x Kc
by 205405339
Fri Feb 14, 2020 4:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K
Replies: 12
Views: 86

Re: K

when calculating K look for (aq) or (g) and exclude (s) or (l)
by 205405339
Sat Feb 08, 2020 4:31 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeters
Replies: 17
Views: 97

Re: Calorimeters

calorimeters maintain the same volume so constant volume
by 205405339
Sat Feb 08, 2020 4:30 pm
Forum: Phase Changes & Related Calculations
Topic: Steam burns more than water
Replies: 5
Views: 62

Re: Steam burns more than water

the energy from steam is higher than the energy for water
by 205405339
Fri Feb 07, 2020 8:34 pm
Forum: Phase Changes & Related Calculations
Topic: Negative Work
Replies: 18
Views: 141

Re: Negative Work

just remember a system doing work isn't gaining work therefore its doing negative work
by 205405339
Fri Feb 07, 2020 8:33 pm
Forum: Calculating Work of Expansion
Topic: Units for Work
Replies: 5
Views: 29

Re: Units for Work

From what i remember, most professors usually provide conversions on the test in the form of a formula chart or at least include a needed conversion in the question
by 205405339
Fri Feb 07, 2020 8:31 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Equations
Replies: 3
Views: 29

Re: Equations

i usually write all the formulas on one piece of paper to remember all the relevant equations for the topic at hand
by 205405339
Thu Feb 06, 2020 7:01 pm
Forum: Calculating Work of Expansion
Topic: Kelvin vs Celsius
Replies: 5
Views: 30

Re: Kelvin vs Celsius

You always use Kelvin no matter what equation it is so if you are given celsius convert to kelvin
by 205405339
Mon Feb 03, 2020 9:15 pm
Forum: Phase Changes & Related Calculations
Topic: -w vs w
Replies: 15
Views: 93

Re: -w vs w

POV is from the system so if the system is doing work, its positive and if its having work done on it its negative
by 205405339
Mon Feb 03, 2020 9:13 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Molar Heat Capacity
Replies: 4
Views: 33

Re: Molar Heat Capacity

its usually (n)(Cp or Cv)(delta T)
by 205405339
Sun Feb 02, 2020 5:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Positive or negative work?
Replies: 8
Views: 43

Re: Positive or negative work?

Work is seen from the system's POV so if a piston is pushing down on a system, the system is the one receiving the work therefore the system isn't the one doing the work hence work by the system will be negative
by 205405339
Sun Feb 02, 2020 1:21 pm
Forum: Calculating Work of Expansion
Topic: Gas constant
Replies: 5
Views: 37

Re: Gas constant

use the gas constant that matches the units given in the question
by 205405339
Thu Jan 30, 2020 1:35 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Qv vs Qp
Replies: 7
Views: 38

Re: Qv vs Qp

q at constant volume and q at constant pressure
by 205405339
Tue Jan 28, 2020 7:12 pm
Forum: Ideal Gases
Topic: Kc vs Kp
Replies: 43
Views: 307

Re: Kc vs Kp

You use Kp because K=kp for all cases. Kc=K when certain conditions are met
by 205405339
Tue Jan 28, 2020 7:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reaction enthalpy
Replies: 14
Views: 73

Re: reaction enthalpy

To break bonds, energy has to be brought in aka endothermic reaction and to form bonds, energy must leave the system aka exothermic
by 205405339
Mon Jan 27, 2020 10:46 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework sections
Replies: 7
Views: 64

Re: Homework sections

i would assume we are starting at 4A rn
by 205405339
Sun Jan 26, 2020 2:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Temperature (K)
Replies: 4
Views: 24

Re: Temperature (K)

temperature can affect the rate of the reaction leading to different equilibrium concentrations
by 205405339
Sun Jan 26, 2020 2:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Polyprotic Acids
Replies: 2
Views: 14

Re: Polyprotic Acids

yes it was included in the outline questions
by 205405339
Sat Jan 25, 2020 8:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka of strong acid
Replies: 3
Views: 26

Re: Ka of strong acid

Im guessing its more than one since Ka will usually be [conjeguate base][H30+]/[Strong acid] and [H30+]=[strong acid]
by 205405339
Thu Jan 23, 2020 8:59 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: removing H2 from N2 + 3H2 -> 2NH3
Replies: 7
Views: 52

Re: removing H2 from N2 + 3H2 -> 2NH3

removing H2 causes an absence of H2 thus causing the reaction to form more H2 since there is an absence of it
by 205405339
Thu Jan 23, 2020 8:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling Learning 14B
Replies: 3
Views: 61

Re: Sapling Learning 14B

you can still access the textbook thru the 14a course
by 205405339
Wed Jan 22, 2020 8:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Percent Ionization
Replies: 4
Views: 26

Re: Percent Ionization

its [A-]/[HA] but if [H30+]=[A-] then [H30+]/[HA] will yield the same % value
by 205405339
Tue Jan 21, 2020 10:11 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: exothermic reactions
Replies: 19
Views: 113

Re: exothermic reactions

reverse reaction is endothermic thus forming reactants when heat is added
by 205405339
Mon Jan 20, 2020 3:33 pm
Forum: Ideal Gases
Topic: R constant for PV=nRT
Replies: 7
Views: 46

Re: R constant for PV=nRT

R can have different values depending on what units are needed for the equation
by 205405339
Sun Jan 19, 2020 11:21 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: reaction quotient
Replies: 4
Views: 30

Re: reaction quotient

usually if we're asked to calculate Q then a K value should be provided to help us determine if it has reached equilibrium
by 205405339
Sat Jan 18, 2020 9:48 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Kb vs Ka
Replies: 5
Views: 23

Re: Kb vs Ka

Kb is for weak base reactions and Ka is for weak acid reactions
by 205405339
Sat Jan 18, 2020 10:24 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between K and Q?
Replies: 11
Views: 56

Re: Difference between K and Q?

K represents the concentrations at equilibrium whereas Q represents concentrations not at equilibrium
by 205405339
Thu Jan 16, 2020 1:34 pm
Forum: Ideal Gases
Topic: ICE tables
Replies: 9
Views: 80

Re: ICE tables

usually questions will include words like "moles" which is used for concentrations. if it doesnt have "moles" i would guess pressures is the way to go
by 205405339
Thu Jan 16, 2020 1:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K units
Replies: 10
Views: 65

Re: K units

K is just a number that is used to show the ratio of products to reactants. I dont think K is ever used in equations so it doesnt need units anyways
by 205405339
Fri Jan 10, 2020 4:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Exercise 5G.1
Replies: 4
Views: 37

Re: Exercise 5G.1

according to one of the TA's, a Higher pressure of the reactant just implies that more reactant was added and the presence of reactants/products does not affect the equilibrium constant. Also, for d, a higher amount of reactants will yield a higher amount of products thus initial concentrations will...
by 205405339
Thu Jan 09, 2020 10:17 pm
Forum: Ideal Gases
Topic: eq constant
Replies: 4
Views: 31

Re: eq constant

Essentially solids and liquids are in such great excess and it is impossible to come up with a value for their concentration hence why they are omitted
by 205405339
Thu Jan 09, 2020 10:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: liquids and aqueous solutions
Replies: 4
Views: 22

Re: liquids and aqueous solutions

Aqueous solutions can have their concentrations measured and these concentrations are what allow us to calculate K. However, solids and liquids are in such great excess in solutions where it is too hard to calculate their concentrations hence why they are omitted from the equilibrium constant
by 205405339
Thu Jan 09, 2020 10:11 pm
Forum: Ideal Gases
Topic: 5G1 true/false
Replies: 8
Views: 69

Re: 5G1 true/false

Instead of looking at K as Kc look at it as Kp. Kp= (partial pressure of products) / (partial pressure of reactants) according to this equation, an increase in the partial pressure of reactants would lead to a decrease in the equilibrium constant instead of an increase in the equilibrium constant, w...
by 205405339
Thu Jan 09, 2020 10:07 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Temperatures and Equilibrium
Replies: 4
Views: 33

Re: Temperatures and Equilibrium

all reactions will eventually reach a point where molar concentrations will become constant so in other words all reactions attain equilibrium after a certain period of time. Temperature, however, will affect the forward and reverse reaction rates thus affecting the equilibrium constant.
by 205405339
Thu Jan 09, 2020 10:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G.1.C explanation (SSM)
Replies: 2
Views: 25

5G.1.C explanation (SSM)

in the student solutions manual, it says that question C is false because the amount of reactants/products doesn't affect the equilibrium constant if the temperature is constant but the question is asking if the equilibrium constant will increase if the reactant starts at a higher pressure so should...

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