Search found 62 matches
- Sat Mar 16, 2019 10:23 pm
- Forum: First Order Reactions
- Topic: Rate Law
- Replies: 2
- Views: 484
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: 618
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: 413
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: 933
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: 370
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: 166
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: 235
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: 686
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: 1074
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: 635
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: 6746
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: 1517
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: 970
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: 2273
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: 475
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: 3255
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: 225
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: 4484
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: 299
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: 484
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: 25
- Views: 2820
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: 285
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: 1529
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: 637
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: 561
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: 1932
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: 324
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: 743
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: 287
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: 526
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: 1699
Re: "Shifting"
Shifting refers to the direction in which a the reaction favors, more of the product or reactant.
Re: churro 31
405169322 wrote:What is the chemical formula for Pentaamminenitritonickel(III)?
[Ni(NH3)5(NO2)]2+
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: 20769
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: 354
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: 1126
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: 163
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: 533
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: 430
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: 465
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: 1357
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: 1796
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: 439
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: 439
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: 550
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: 356
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: 443
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: 602
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: 850
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: 541
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: 276
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: 417
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: 520
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: 163
- Views: 160995
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: 267
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: 4743
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: 2698
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: 381
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: 773
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: 668
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: 2039
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: 225
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+?