Search found 62 matches

Sat Mar 16, 2019 10:23 pm
Forum: First Order Reactions
Topic: Rate Law
Replies: 2
Views: 256

Re: Rate Law

My TA said deriving the rate law was on one of the previous finals so you should know how to do it to be safe
Sat Mar 16, 2019 9:15 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre-equilibrium approach q
Replies: 3
Views: 348

Re: Pre-equilibrium approach q

Why is the k1 multiplied by 2?
Fri Mar 15, 2019 10:40 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Deriving
Replies: 3
Views: 119

Re: Deriving

It will be easier to figure out the derivation if you know the final equation for each order rate law
Fri Mar 15, 2019 10:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 14
Views: 325

Re: Anode and Cathode

Another way to distinguish cathode and anode is to make sure the Ecell comes out to a positive number when you subtract them
Fri Mar 15, 2019 10:34 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: When to use Nernst
Replies: 3
Views: 146

Re: When to use Nernst

The Nernst equation is used when galvanic cell concentrations are not in standard conditions, meaning they are not 1 M. The concentrations are used in the Q value of the equation.
Fri Mar 15, 2019 10:32 pm
Forum: General Rate Laws
Topic: Rate constants
Replies: 1
Views: 50

Re: Rate constants

the rate is equal to k[A]^x, it changes according to initial concentration, the rate constant is the k value which doesn't change for the given reaction
Fri Mar 15, 2019 10:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Concentration Cells
Replies: 1
Views: 74

Re: Concentration Cells

Questions involving concentration cells will most likely involve the Nernst equation since there are differing concentrations.
Thu Mar 14, 2019 11:05 am
Forum: General Rate Laws
Topic: reaction rate(s)?
Replies: 4
Views: 334

Re: reaction rate(s)?

When does the reaction rate also depend on the concentration of the products?
Mon Mar 11, 2019 11:50 pm
Forum: Phase Changes & Related Calculations
Topic: Isothermal
Replies: 9
Views: 483

Re: Isothermal

The problem will most likely tell you if the system is isothermal, or constant temperature. This is also usually indicated by reversible expansion
Mon Mar 11, 2019 11:49 pm
Forum: Ideal Gases
Topic: ICE
Replies: 8
Views: 207

Re: ICE

x would be negligible because it is so small and has little effect on the concentration
Mon Mar 11, 2019 11:48 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Study Advice
Replies: 73
Views: 3786

Re: Study Advice

Does anyone have notes from Lyndon's review session today that they are willing to share?
Sun Feb 24, 2019 11:57 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Spontaneous?
Replies: 13
Views: 392

Re: Spontaneous?

if delta G is negative, the reaction is spontaneous, if delta G is positive it is nonspontaneous
Sun Feb 24, 2019 11:56 pm
Forum: Balancing Redox Reactions
Topic: Mnemonic for Redox
Replies: 5
Views: 248

Re: Mnemonic for Redox

oil rig, oxidation is loss, reduction is gain
Sun Feb 24, 2019 11:55 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 3
Replies: 14
Views: 445

Re: Test 3

yeah i think so
Tue Feb 12, 2019 8:53 pm
Forum: Calculating Work of Expansion
Topic: 0 work vs no work
Replies: 4
Views: 184

Re: 0 work vs no work

i believe they are the same thing
Tue Feb 12, 2019 8:48 pm
Forum: Phase Changes & Related Calculations
Topic: Slope of heating curve
Replies: 8
Views: 528

Re: Slope of heating curve

Higher heat capacity means a less steep slope because it requires more energy (along x-axis) to raise the temperature (along y-axis) of the substance. In terms of the heating curve graph: when looking at y/x, the larger x is, or the energy, the smaller the slope-> less steep.
Tue Feb 12, 2019 8:41 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: extensive & intensive properties and heat capacities
Replies: 1
Views: 88

Re: extensive & intensive properties and heat capacities

Heat capacity is an intensive property because it is not dependent on the amount of substance, you can tell by the units of heat capacity Joules/degree celsius, molar and specific heat capacity DO depend on the amount of substance making them extensive properties, their units are Joules/degree celsi...
Thu Feb 07, 2019 2:13 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding Inert Gas
Replies: 10
Views: 802

Re: Adding Inert Gas

Adding an inert gas doesn't affect the reaction equilibrium because the gas addition doesnt alter the volume, volume is the factor that has an effect on pressure and if volume is unaffected the pressure is unaffected as well.
Thu Feb 07, 2019 2:09 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy units
Replies: 3
Views: 98

Re: Entropy units

Entropy unit is J/K
Thu Feb 07, 2019 2:07 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work
Replies: 4
Views: 143

Re: Work

When work is positive, the surroundings are doing work on the system, ex: compression of piston, when work is negative, the system is doing work on the surroundings, ex: expansion of piston.
Thu Jan 31, 2019 2:20 pm
Forum: Ideal Gases
Topic: atm vs. bar?
Replies: 23
Views: 750

Re: atm vs. bar?

bar is slightly more accurate than atm, by one percent
Thu Jan 31, 2019 2:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bomb Calorimeter
Replies: 2
Views: 113

Re: Bomb Calorimeter

A bomb calorimeter has constant volume
Sun Jan 27, 2019 5:57 pm
Forum: Ideal Gases
Topic: Approximations for ICE
Replies: 20
Views: 520

Re: Approximations for ICE

When k is less than 10^-3
Sun Jan 27, 2019 5:56 pm
Forum: Phase Changes & Related Calculations
Topic: Steam
Replies: 7
Views: 213

Re: Steam

When steam touches your skin it releases around eight times as much kJ of energy than if boiling water were to touch your skin based on waters phase change graph.
Sun Jan 27, 2019 5:55 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas
Replies: 6
Views: 240

Re: Inert Gas

An inert gas does not affect the equilibrium because the volume is not changing, therefore the concentrations are not changing.
Sun Jan 27, 2019 5:54 pm
Forum: Phase Changes & Related Calculations
Topic: Delta H
Replies: 11
Views: 700

Re: Delta H

positive delta H is endothermic and negative delta H is exothermic
Sun Jan 27, 2019 5:54 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Properties
Replies: 3
Views: 116

Re: State Properties

Yes heat (enthalpy) is a state property.
Sun Jan 27, 2019 5:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5%
Replies: 10
Views: 349

Re: 5%

If the x value is less than 5% of the initial concentration, then the approximation (of removing the -x from the equation) is valid.
Mon Jan 14, 2019 7:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K changing with temperature [ENDORSED]
Replies: 3
Views: 127

Re: K changing with temperature[ENDORSED]

K is unaffected by pressure but affected by temperature.
Mon Jan 14, 2019 7:16 pm
Forum: Ideal Gases
Topic: When is pv=nrt used? [ENDORSED]
Replies: 5
Views: 219

Re: When is pv=nrt used?[ENDORSED]

You can use this equation to find an unknown (pressure, volume, molarity or temp)
Mon Jan 14, 2019 7:15 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: "Shifting"
Replies: 15
Views: 1041

Re: "Shifting"

Shifting refers to the direction in which a the reaction favors, more of the product or reactant.
Sat Dec 08, 2018 12:56 am
Forum: Naming
Topic: churro 31
Replies: 4
Views: 228

Re: churro 31

405169322 wrote:What is the chemical formula for Pentaamminenitritonickel(III)?

[Ni(NH3)5(NO2)]2+
Sat Dec 08, 2018 12:53 am
Forum: Naming
Topic: churro 32
Replies: 1
Views: 94

Re: churro 32

405169322 wrote:What is the chemical formula for Bisethylenediaminediiodomanganese (IV) ion?

[Mn(en)2(I)2]2+
Sat Dec 08, 2018 12:35 am
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11168

Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

CaminaB_1D wrote:can someone explain 23 and why porphyrin ligand is tetradentrate

Porphyrin is tetradentate because there are four binding sites of the ligand (the four N's in the diagram) to the Fe. The prefix to the dentate has to do with how many binding sites there are for a single ligand.
Tue Dec 04, 2018 12:27 pm
Forum: Naming
Topic: "(en)" and "(edta)"?
Replies: 3
Views: 128

Re: "(en)" and "(edta)"?

EDTA is a significant ligand molecule
Tue Dec 04, 2018 12:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs angular?
Replies: 15
Views: 409

Re: Bent vs angular?

Bent and angular are the same.
Tue Dec 04, 2018 12:24 pm
Forum: Naming
Topic: H20 as ligand
Replies: 2
Views: 84

Re: H20 as ligand

It's written based on the molecules location in relation to the central atom to clarify that the O provides the electrons bonded to the central atom.
Mon Nov 26, 2018 1:07 pm
Forum: Dipole Moments
Topic: dipole
Replies: 6
Views: 259

Re: dipole

Dipoles occur due to partial charges on atoms in molecules
Mon Nov 26, 2018 1:04 pm
Forum: Hybridization
Topic: Bonds
Replies: 5
Views: 170

Re: Bonds

Also, a single bond is sigma bond, a double is sigma bond plus one pi bond, and triple is sigma bond plus two pi bonds
Mon Nov 26, 2018 1:01 pm
Forum: Hybridization
Topic: When to hybridized?
Replies: 6
Views: 173

Re: When to hybridized?

How do you determine hybridized orbital orientation?
Sun Nov 18, 2018 9:00 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Intermolecular Forces
Replies: 7
Views: 556

Re: Intermolecular Forces

London dispersion forces are always present between molecules, for polar and non-polar, however they are the only intermolecular forces present for non-polar.
Sun Nov 18, 2018 8:56 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bond Definition
Replies: 14
Views: 1018

Re: Coordinate Covalent Bond Definition

Coordinate covalent bond is one in which both the electrons on the bond come from the same atom
Sun Nov 18, 2018 8:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipoles
Replies: 5
Views: 220

Re: Dipoles

Dipoles are a result of a partial positive and negative charge on atoms in molecules. You can determine this by figuring out if the molecule is polar or non-polar. Polar signifies that the molecules will experience the dipole-dipole interaction.
Mon Nov 12, 2018 2:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipoles
Replies: 5
Views: 220

Re: Dipoles

Dipoles are a result of partial charges of atoms (or areas) in molecules, this can be determined by looking at the electronegativities of the elements involved, more electronegative elements pull electrons in closer creating a partial negative charge in the molecule
Fri Nov 09, 2018 4:58 pm
Forum: Octet Exceptions
Topic: EXPANDED OCTET
Replies: 5
Views: 238

Re: EXPANDED OCTET

Group 13 elements can have expanded octets because they have access to their 3-d orbital since its not filled
Fri Nov 09, 2018 4:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Tetrahedral Shape Question
Replies: 3
Views: 151

Re: Tetrahedral Shape Question

Yes, because molecules exist on a 3 dimensional axis, they use space in directions X, Y, and Z. This is the reason why the angles are 109.5 degrees instead of 90 because they have room to evenly distribute into the Z plane as well creating a larger angle.
Wed Oct 31, 2018 11:56 am
Forum: Electronegativity
Topic: Periodic Trends [ENDORSED]
Replies: 3
Views: 187

Re: Periodic Trends[ENDORSED]

ionization energy increases as you move towards the right side of the periodic table because the number of electrons in the valence shell of the atom increase, therefore, it takes more energy to remove the atom's valence electrons since the valence shell is almost or completely filled
Wed Oct 31, 2018 11:49 am
Forum: Lewis Structures
Topic: Valence Electrons
Replies: 7
Views: 210

Re: Valence Electrons

Phosphorus, Sulfur and Chlorine can accommodate more than 8 valence electrons.
Wed Oct 31, 2018 11:48 am
Forum: Lewis Structures
Topic: Central Atom
Replies: 13
Views: 331

Re: Central Atom

The central atom is the element with the lowest ionization energy.
Wed Oct 24, 2018 12:21 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 6
Views: 248

Re: Nodal Planes

How do you determine how many subshells there are from an n value, for example if n = 3, how can you determine subshells from this?
Wed Oct 24, 2018 11:44 am
Forum: DeBroglie Equation
Topic: De Broglie wavelengths
Replies: 3
Views: 172

Re: De Broglie wavelengths

Is de Broglie more commonly used for small or large particles? Does size matter?
Wed Oct 24, 2018 11:43 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Wave functions
Replies: 4
Views: 201

Re: Wave functions

Im confused, is a wave function defined by its quantum numbers? If not, what is the relation between wave functions and quantum numbers?
Wed Oct 24, 2018 11:40 am
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 5
Views: 283

Re: Magnetic Quantum Number

Can someone give me the the most simple definition of a wavefunction?
Wed Oct 17, 2018 12:27 pm
Forum: Administrative Questions and Class Announcements
Topic: How to find my posts
Replies: 57
Views: 48523

Re: How to find my posts

How can I create a new topic? The only way CC allows me to post is if I am replying in an existing thread, but I have some questions where I would want to create a new topic.
Wed Oct 17, 2018 12:22 pm
Forum: *Shrodinger Equation
Topic: Shrodinger Equation Meaning
Replies: 3
Views: 171

Re: Shrodinger Equation Meaning

What is a wave function, do they have specific values, and can someone explain conceptually too?
Wed Oct 17, 2018 11:24 am
Forum: Properties of Light
Topic: Chapter 1 Homework Question [ENDORSED]
Replies: 7
Views: 2715

Re: Chapter 1 Homework Question[ENDORSED]

For question 15 in chapter 1B, how does the textbook get part b, I understand why the equation is used (E=h/v) however I don't know how they got 2.5x10^16 for the v used.
Mon Oct 15, 2018 11:48 am
Forum: Properties of Light
Topic: Speed of Light
Replies: 41
Views: 1406

Re: Speed of Light

The speed of light is constant and will not change, there may be a more specific value, however, it is most commonly known as 3x10^8 m/s
Mon Oct 15, 2018 11:47 am
Forum: DeBroglie Equation
Topic: Rest Mass?
Replies: 4
Views: 199

Re: Rest Mass?

Rest mass is when an "object" is not in motion, has mass. Therefore, electrons, protons, etc. have rest mass because they still have measurable mass when they are not moving (as if you were holding one). Photons do not have rest mass because they primarily exist in motion.
Mon Oct 15, 2018 11:42 am
Forum: Molarity, Solutions, Dilutions
Topic: Units?
Replies: 8
Views: 474

Re: Units?

The ending value of volume should be in Liters because Molarity is calculated in moles per liter
Sun Oct 07, 2018 12:28 pm
Forum: SI Units, Unit Conversions
Topic: Modules?
Replies: 8
Views: 342

Re: Modules?

I did the first four modules and the videos that accompany them are the exact same lectures Lavelle did during week 1, they are helpful to go back and rewatch to get a better grasp on the topic. Also, I don't think they are graded at all.
Sun Oct 07, 2018 12:24 pm
Forum: Balancing Chemical Reactions
Topic: Balancing reactions tips
Replies: 29
Views: 1177

Re: Balancing reactions tips

Keep track of each element by creating a small tea chart on the side! You can keep updating the chart when coefficients become higher values
Sun Oct 07, 2018 11:36 am
Forum: Molarity, Solutions, Dilutions
Topic: Dilutions Problems
Replies: 3
Views: 134

Re: Dilutions Problems

In question G5, once you are solving for the volume needed to obtain 2.15 mmil of Na+ why do you need to divide by 2 mol of Na+?

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