Search found 58 matches

by Vinita Saxena 2I
Sat Mar 14, 2020 9:02 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Mnemonic for Oxidation and Reduction
Replies: 7
Views: 131

Re: Mnemonic for Oxidation and Reduction

I line up the consonants and the vowels: Reduced + Cathode, Oxidized + Anion
by Vinita Saxena 2I
Sat Mar 14, 2020 9:00 pm
Forum: Calculating Work of Expansion
Topic: Mnemonic for State Functions
Replies: 3
Views: 79

Re: Mnemonic for State Functions

PDTVHUGS:
If you're feeling under Pressure or Depressed, all you want to do is watch TV and get HUGS. Good luck!
by Vinita Saxena 2I
Fri Mar 13, 2020 5:44 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 11
Views: 143

Re: Final

It'll be up Sunday at the same final time, 11:30.
by Vinita Saxena 2I
Thu Mar 12, 2020 12:18 pm
Forum: General Rate Laws
Topic: Factors Affecting k
Replies: 16
Views: 156

Re: Factors Affecting k

Yes, it can change if the temperature changes, that is the only way it can change
by Vinita Saxena 2I
Tue Mar 10, 2020 7:51 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure Rule
Replies: 4
Views: 79

Re: Pressure Rule

Only count the moles of gas, those are the ones most affected by a change in pressure
by Vinita Saxena 2I
Tue Mar 10, 2020 6:43 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: delta g
Replies: 6
Views: 45

Re: delta g

It depends on what information you're given!
by Vinita Saxena 2I
Tue Mar 10, 2020 6:42 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Ka Kb
Replies: 11
Views: 142

Re: Ka Kb

Use Ka or Kb when using ICE tables
by Vinita Saxena 2I
Tue Mar 10, 2020 6:41 pm
Forum: Administrative Questions and Class Announcements
Topic: Situation for Lecture, Discussion, and Final
Replies: 3
Views: 129

Re: Situation for Lecture, Discussion, and Final

We just have to wait for emails from Lavelle and TAs telling us what they're planning.
by Vinita Saxena 2I
Tue Mar 10, 2020 6:35 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: catalysts in balanced equations
Replies: 6
Views: 51

Re: catalysts in balanced equations

That's right, catalysts are present at the start and end of the reaction.
by Vinita Saxena 2I
Sun Mar 08, 2020 5:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Review Sessions
Replies: 6
Views: 68

Re: Final Review Sessions

All of the review sessions are now posted on the website!
by Vinita Saxena 2I
Sun Mar 08, 2020 3:06 pm
Forum: Balancing Redox Reactions
Topic: Cathode and Anode
Replies: 16
Views: 362

Re: Cathode and Anode

Electrons travel from cathode to anode, so cathode>anode means work is done.
by Vinita Saxena 2I
Sun Mar 08, 2020 3:02 pm
Forum: Balancing Redox Reactions
Topic: Half rxns
Replies: 27
Views: 403

Re: Half rxns

Adding electrons is the very last step, once you add the H+ for acidic or OH-/H2O for basic you add electrons to balance out charge. When adding the half reactions together make sure to multiply the reactions if needed so the electrons are equal.
by Vinita Saxena 2I
Sun Mar 08, 2020 2:59 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

It works the same! You can add carbon (gr) instead of platinum.
by Vinita Saxena 2I
Sun Mar 01, 2020 10:25 pm
Forum: Balancing Redox Reactions
Topic: Reducing Agent
Replies: 5
Views: 61

Re: Reducing Agent

That's right
by Vinita Saxena 2I
Sun Mar 01, 2020 10:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 6
Views: 43

Re: Cell Diagrams

Put the solids on the outsides, but other than that there is no convention for the order when there is a comma
by Vinita Saxena 2I
Thu Feb 27, 2020 11:52 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Which half reaction is cathode or anode?
Replies: 6
Views: 367

Re: Which half reaction is cathode or anode?

Typically the anode is on the left and the cathode is on the right. The anode is the oxidized side and the cathode is the reduced side.
by Vinita Saxena 2I
Thu Feb 27, 2020 11:51 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: log and ln in Nernst
Replies: 8
Views: 76

Re: log and ln in Nernst

It doesn't matter, but usually biologists use the log version of the equation
by Vinita Saxena 2I
Sun Feb 23, 2020 8:45 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Difference
Replies: 5
Views: 53

Re: Difference

Here you can pretty much measure delta G instead of using delta H, delta S, etc to calculate it.
by Vinita Saxena 2I
Sun Feb 23, 2020 8:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Going from pKa to pH
Replies: 10
Views: 167

Re: Going from pKa to pH

Use pKa to get the concentration of H3O+ (using an ice table) and then use the concentration of H3O+ to get the pH
by Vinita Saxena 2I
Sun Feb 23, 2020 8:32 pm
Forum: Balancing Redox Reactions
Topic: Determining direction of flow
Replies: 15
Views: 175

Re: Determining direction of flow

Convention is to write anion (oxidation) on the left and cation (reduction) on the right. Therefore left to right means anion to cation.
by Vinita Saxena 2I
Sun Feb 23, 2020 8:27 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: max potential
Replies: 4
Views: 41

Re: max potential

The cell potential is different at each time after you flip the switch because the battery is slowly dying/reaching equilibrium. Because of this, it is not at max potential anymore. Max potential is right before you flip the switch because the battery is building up, and then once you flip the switc...
by Vinita Saxena 2I
Sun Feb 23, 2020 8:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram
Replies: 4
Views: 25

Re: Cell Diagram

They show how the two beakers are connected (through a salt bridge and with a conductor) and where they are separate. It's a tool to help you visualize what's going on.
by Vinita Saxena 2I
Sun Feb 23, 2020 8:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 15
Views: 211

Re: Test 2

Since it's only 50 minutes long and worth 50 points, it will be similar to Test 1 but since we have more topics for Test 2 it will most likely be harder
by Vinita Saxena 2I
Sun Feb 23, 2020 8:01 pm
Forum: Balancing Redox Reactions
Topic: Steps
Replies: 7
Views: 86

Re: Steps

The big thing is the number of electrons on each side have to be the same, so multiply each half reaction by a number to get the same total electrons on each side. Other than that it's pretty much the same!
by Vinita Saxena 2I
Sun Feb 16, 2020 5:57 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: 3/2R & 5/2R
Replies: 9
Views: 185

Re: 3/2R & 5/2R

when using the specific heat capacity of a gas, they'll specify if it's under constant pressure or constant volume. That'll tell you which to use.
by Vinita Saxena 2I
Sun Feb 16, 2020 5:55 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: spontaneity
Replies: 34
Views: 633

Re: spontaneity

Gibbs free energy is usually a delta, so final minus initial. When delta G is negative the products have less gibbs free energy, making the reation spontaneous
by Vinita Saxena 2I
Sun Feb 16, 2020 5:52 pm
Forum: Calculating Work of Expansion
Topic: Reversible vs Irreversible
Replies: 13
Views: 242

Re: Reversible vs Irreversible

Irreversible is when the system changes all at once and reversible is when the system changes a tiny bit at a time so the surroundings and the system are always equal to each other at every partial change.
by Vinita Saxena 2I
Sun Feb 16, 2020 5:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Video Outlines
Replies: 3
Views: 130

Re: Video Outlines

No video outlines, the only ones he has are chemical equilibrium.
by Vinita Saxena 2I
Sun Feb 16, 2020 5:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure and Moles
Replies: 7
Views: 82

Re: Pressure and Moles

Just count the coefficients since the subscripts are part of the molecule, not separate molecules.
by Vinita Saxena 2I
Sun Feb 16, 2020 5:45 pm
Forum: Administrative Questions and Class Announcements
Topic: when are your #of posts on CC collected each week?
Replies: 4
Views: 116

Re: when are your #of posts on CC collected each week?

Sunday at 11:59pm and Lavelle has a system that counts it up at the end of the quarter I believe
by Vinita Saxena 2I
Sun Feb 16, 2020 5:43 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equilibrium
Replies: 15
Views: 137

Re: Equilibrium

When delta G is 0 there is no preference to products or reactants, so it is at equilibrium.
by Vinita Saxena 2I
Sun Feb 09, 2020 12:42 am
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: Entropy vs. moles
Replies: 3
Views: 36

Re: Entropy vs. moles

Yes, because there are more possible states and arrangements of the 5 moles of H2O compared to 2 moles H2O.
by Vinita Saxena 2I
Sun Feb 09, 2020 12:39 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Constant pressure
Replies: 19
Views: 190

Re: Constant pressure

In a vacuum there is no external pressure, so there is nothing to push back against, meaning w=0
by Vinita Saxena 2I
Sun Feb 09, 2020 12:36 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Lecture example
Replies: 2
Views: 27

Re: Lecture example

In this case, specific heat capacity uses grams, but if he had used the molar heat capacity then he would have needed to convert to moles using the concentrations.
by Vinita Saxena 2I
Sun Feb 09, 2020 12:34 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Topics on the Midterm
Replies: 22
Views: 232

Re: Topics on the Midterm

Micah3J wrote:Does anyone have a list of the formulas we should be familiar with for this midterm?

The formula sheet is the same one we got for Test 1
by Vinita Saxena 2I
Sun Feb 09, 2020 12:32 am
Forum: Administrative Questions and Class Announcements
Topic: Grading
Replies: 7
Views: 90

Re: Grading

You need at least 250 points to pass the class and Lavelle curves the final grade distributions after the final has been graded
by Vinita Saxena 2I
Sat Feb 08, 2020 5:32 pm
Forum: General Science Questions
Topic: Midterm
Replies: 17
Views: 362

Re: Midterm

the pizza rolls worksheet has the same concepts and questions that will be on the midterm but it is not formatted the same way as the midterm.
by Vinita Saxena 2I
Sun Feb 02, 2020 1:43 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Definition of First Law
Replies: 9
Views: 75

Re: Definition of First Law

Heat energy, like all energy, can't be created or destroyed, also known as conservation of matter.
by Vinita Saxena 2I
Sun Feb 02, 2020 1:41 pm
Forum: Phase Changes & Related Calculations
Topic: Multiple Phase Changes
Replies: 4
Views: 45

Re: Multiple Phase Changes

If we need to know this you'll be given the graph, just use the graph to figure out the different cutoffs to calculate the reaction changes.
by Vinita Saxena 2I
Sun Feb 02, 2020 1:38 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Constant pressure
Replies: 19
Views: 190

Re: Constant pressure

Yes, constant external pressure
by Vinita Saxena 2I
Sun Feb 02, 2020 1:37 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed system
Replies: 5
Views: 82

Re: Closed system

The volume of a closed system can change if there is a piston, especially when gases are involved.
by Vinita Saxena 2I
Sun Feb 02, 2020 1:30 pm
Forum: Calculating Work of Expansion
Topic: Equation
Replies: 4
Views: 40

Re: Equation

Since Lavelle put it in his math help, I believe we will need to use it if needed.
by Vinita Saxena 2I
Sun Jan 26, 2020 6:40 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs Water
Replies: 4
Views: 33

Re: Steam vs Water

Adding on, steam can be any temperature above 100, while water can be 100 degrees max. So when steam hits your skin it condenses from a higher temperature, releasing a lot of heat in the phase change, which causes severe burns.
by Vinita Saxena 2I
Sun Jan 26, 2020 6:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard enthalpy of element in most stable form
Replies: 5
Views: 52

Re: Standard enthalpy of element in most stable form

They are zero because the most stable form is the form they are found, which means it takes energy to change its form. This gives a baseline to start with, like how Lavelle gave the example of sea level being 0 for airplanes.
by Vinita Saxena 2I
Sun Jan 26, 2020 6:32 pm
Forum: Phase Changes & Related Calculations
Topic: Physical or Phase Changes
Replies: 7
Views: 62

Re: Physical or Phase Changes

There is no formula, so they will give us the values
by Vinita Saxena 2I
Sun Jan 26, 2020 6:31 pm
Forum: Phase Changes & Related Calculations
Topic: Steam Burns
Replies: 9
Views: 114

Re: Steam Burns

When steam touches your skin it has to change state, so it releases a lot of energy into your skin. Water is already a liquid so there is no phase change, which means less heat is released
by Vinita Saxena 2I
Sun Jan 26, 2020 6:27 pm
Forum: Ideal Gases
Topic: PV=NRT
Replies: 7
Views: 80

Re: PV=NRT

You don't need to know that
by Vinita Saxena 2I
Mon Jan 20, 2020 4:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Converting K to Kc
Replies: 4
Views: 69

Re: Converting K to Kc

K is Kc if you are using concentrations, but you can convert Kc to Kp using PV=nRT since n/V is concentration(molarity).
by Vinita Saxena 2I
Mon Jan 20, 2020 4:15 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure changes
Replies: 5
Views: 32

Re: Pressure changes

There will be no change in equilibrium, even if there is a change in pressure.
by Vinita Saxena 2I
Thu Jan 16, 2020 1:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and liquids
Replies: 3
Views: 20

Re: Solids and liquids

Solids don't react in solution and liquids don't dissociate enough to change the reaction, so they don't count in the k equations
by Vinita Saxena 2I
Thu Jan 16, 2020 1:33 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas and Le Chatliers
Replies: 7
Views: 72

Re: Inert Gas and Le Chatliers

An inert gas doesn't react with the reactants so it does not change the concentration or the reaction in any way since it also does not change the volume.
by Vinita Saxena 2I
Thu Jan 16, 2020 1:31 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas
Replies: 5
Views: 55

Re: Inert Gas

Yes, the only inert gases are noble gases
by Vinita Saxena 2I
Sun Jan 12, 2020 2:20 pm
Forum: Administrative Questions and Class Announcements
Topic: General HW question
Replies: 9
Views: 92

Re: General HW question

It is mostly graded on completeness, check with your TA for how they specifically grade it.
by Vinita Saxena 2I
Sun Jan 12, 2020 2:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Increased Pressure by Inert Gas
Replies: 2
Views: 21

Re: Increased Pressure by Inert Gas

By adding an inert gas you aren't changing the concentration of the reactants or products, they are the same amount in the same volume, so since the concentration is the same there is no reaction.
by Vinita Saxena 2I
Sun Jan 12, 2020 2:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc vs Kp
Replies: 10
Views: 72

Re: Kc vs Kp

The values will not be the same but they will be equal to the same thing after some converting.
by Vinita Saxena 2I
Thu Jan 09, 2020 11:45 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K values
Replies: 4
Views: 51

Re: K values

If it is greater than 10^-3 but less than 1 it slightly favors the reactants, but not strongly.
by Vinita Saxena 2I
Thu Jan 09, 2020 11:40 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Re: Q and Ke: Small K value and Large K value
Replies: 7
Views: 59

Re: Q and Ke: Small K value and Large K value

Q changes based on where the reaction is, whereas K does not change except when temperature changes.

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