Search found 64 matches

by Sarah Zhao 4C
Sun Mar 17, 2019 1:28 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 825842

Re: Post All Chemistry Jokes Here

Julia Cheng 4C wrote:What’s the funniest chemistry joke?

My final grade - don’t you C?


It just wasn't meant to B.
by Sarah Zhao 4C
Sat Mar 16, 2019 11:21 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature and Le Chatlier's Principle
Replies: 6
Views: 40

Re: Temperature and Le Chatlier's Principle

In raising the temperature, the reaction will tend to form the side that has more energy. In endothermic reactions, that will be the products and in exothermic reactions, the reactants. In lowering the temperature, the reaction will tend to form the side that has less energy. In endothermic reaction...
by Sarah Zhao 4C
Sat Mar 16, 2019 11:19 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Changing E˚ values
Replies: 2
Views: 28

Re: Changing E˚ values

NO! E knot values can only change when you inverse the reaction. If you have to multiple to get the electrons to cancel out, the E knot values remain the same.
by Sarah Zhao 4C
Sat Mar 16, 2019 11:16 am
Forum: Student Social/Study Group
Topic: Lyndon's Review Sess
Replies: 6
Views: 116

Re: Lyndon's Review Sess

The post is titled LYNDON'S PORK RAMEN REVIEW. It was the very last result for me.
by Sarah Zhao 4C
Sun Mar 10, 2019 11:24 pm
Forum: Second Order Reactions
Topic: Derivation of the integrated rate law
Replies: 2
Views: 24

Re: Derivation of the integrated rate law

a = 100% or 1
by Sarah Zhao 4C
Sun Mar 10, 2019 11:23 pm
Forum: Second Order Reactions
Topic: half-life
Replies: 4
Views: 69

Re: half-life

You can't multiply it by four but you can square it by four!
Break down the math:
1/2 x 4 = 2
vs
(1/2)^4 = 1/16
by Sarah Zhao 4C
Thu Mar 07, 2019 1:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2 Problem 6 b&c
Replies: 1
Views: 71

Test 2 Problem 6 b&c

Can someone explain the problems and provide the answer?
by Sarah Zhao 4C
Sun Mar 03, 2019 4:27 pm
Forum: Zero Order Reactions
Topic: Units of k in Zero Order Reactions
Replies: 4
Views: 42

Re: Units of k in Zero Order Reactions

M/s and mol/(L*s) are the same and used interchangeably so either one will be fine
by Sarah Zhao 4C
Sun Mar 03, 2019 4:25 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Non-Spontaneous
Replies: 3
Views: 36

Re: Non-Spontaneous

Electrolytic cells just mean that electrolysis is occurring in that cell. The cell overall is a non-spontaneous reaction being driven to perform via an outside voltage.
If anything, I would say that galvanic cells can power electrolytic cells, thus helping to drive a non-spontaneous reaction
by Sarah Zhao 4C
Mon Feb 25, 2019 10:47 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: constant N
Replies: 2
Views: 39

Re: constant N

nevermind, it's moles of electrons transferred in the reaction
by Sarah Zhao 4C
Mon Feb 25, 2019 10:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: constant N
Replies: 2
Views: 39

constant N

For the equation DELTA G = -N F E, how do you know what number to use for n? I know its moles but moles of what?!
by Sarah Zhao 4C
Sun Feb 24, 2019 3:23 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrodes
Replies: 2
Views: 43

Electrodes

In a Cu/Zn galvanic cell, why can we use Cu as an electrode but must use Pt as the other?
by Sarah Zhao 4C
Sun Feb 24, 2019 3:18 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Not at Equilibrium
Replies: 3
Views: 42

Re: Not at Equilibrium

You use delta G = standard delta G + RTlnQ
by Sarah Zhao 4C
Sun Feb 17, 2019 4:49 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibb's Free energy
Replies: 4
Views: 58

Re: Gibb's Free energy

Use the Gibb's Free Energy equation to determine spontaneity. While is is usually true that delta G follows the sign for delta H, please do not use this as a rule of thumb.
by Sarah Zhao 4C
Sun Feb 17, 2019 4:46 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Positive Gibbs Free Energy
Replies: 3
Views: 46

Re: Positive Gibbs Free Energy

Non-spontaneous does not mean that it cannot happen. It rather means that it requires an input of energy to happen.
by Sarah Zhao 4C
Sun Feb 17, 2019 4:45 pm
Forum: Van't Hoff Equation
Topic: Different Constants of Eqn
Replies: 2
Views: 58

Re: Different Constants of Eqn

Yep yep
by Sarah Zhao 4C
Mon Feb 11, 2019 3:32 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Using R
Replies: 10
Views: 135

Re: Using R

We know which R to use based off what pressure unit is being used in the problem
by Sarah Zhao 4C
Mon Feb 11, 2019 3:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond enthalpies
Replies: 3
Views: 39

Re: bond enthalpies

all compounds will have bond enthalpies. the only ones that won't are elements!
by Sarah Zhao 4C
Mon Feb 11, 2019 3:26 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 3/2R and 5/2R
Replies: 2
Views: 38

Re: 3/2R and 5/2R

3/2R is for Cv and 5/2R is for Cp. It's on the constants sheet
by Sarah Zhao 4C
Sun Feb 03, 2019 11:59 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Closed System with a Piston
Replies: 2
Views: 36

Re: Closed System with a Piston

Pistons moving affects the volume and thus the pressure of the system. If PV=nRT, then yes, very much affected
by Sarah Zhao 4C
Sun Feb 03, 2019 11:57 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Cup of Tea
Replies: 17
Views: 219

Re: Cup of Tea

It's open because you can change the amount of tea. If you are able to pour more tea into it, it's because it is open!
by Sarah Zhao 4C
Sat Jan 26, 2019 4:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 5
Views: 57

Re: Hess's Law

Yep, and you can multiple the reaction coefficients and reverse the reaction so they cancel out. Just make sure you do the same to the enthalpy, respectively, multiple them or change the sign.
by Sarah Zhao 4C
Sat Jan 26, 2019 4:32 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: states of reactants and products
Replies: 3
Views: 47

Re: states of reactants and products

Nope! Just make sure that if you are canceling things out, that they are the same state.
by Sarah Zhao 4C
Sat Jan 26, 2019 4:32 pm
Forum: Phase Changes & Related Calculations
Topic: work and heat
Replies: 2
Views: 41

Re: work and heat

I know for work that the positive and negative just mean that work is done on or done by the system. Meaning that the total amount of work is the absolute value of work done on and work done by added up.
by Sarah Zhao 4C
Tue Jan 15, 2019 3:10 pm
Forum: General Science Questions
Topic: Strong and Weak Acids and Bases
Replies: 2
Views: 98

Re: Strong and Weak Acids and Bases

Strong acids you will just need to memorize. Strong bases on the other hand is metal hydroxide where the metal is from the alkaline metals (Group 1) or alkaline earth metals (Group 2)
by Sarah Zhao 4C
Tue Jan 15, 2019 3:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ionization Constant
Replies: 2
Views: 36

Re: Ionization Constant

In terms of water, the ionization constant is the same as the equilibrium constant. In the breaking down of water, it creates ions H+ and OH-. So we are able to interchangeable use the words ionization constant.
by Sarah Zhao 4C
Tue Jan 15, 2019 3:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework error?
Replies: 2
Views: 90

Re: Homework error?

I would use whichever one gets you to the answer in the solution manual. You made need to do the problem with both concentrations to determine if it was a typo or if they used the 10^-3 number throughout the whole problem.
by Sarah Zhao 4C
Sun Dec 09, 2018 10:49 pm
Forum: Naming
Topic: Ates, Ides, Etc.
Replies: 1
Views: 55

Re: Ates, Ides, Etc.

-ate if for when the entire coordination compound has a negative charge aka when there are metals present before the coordination compound. -ide is for when the compound charge is positive or net neutral
by Sarah Zhao 4C
Sun Dec 09, 2018 10:48 pm
Forum: Bond Lengths & Energies
Topic: Intermolecular forces
Replies: 1
Views: 129

Re: Intermolecular forces

No, bond length is within the molecule while an intermolecular force is between the molecules
by Sarah Zhao 4C
Sun Dec 09, 2018 10:47 pm
Forum: Amphoteric Compounds
Topic: Amphiprotic vs Amphoteric
Replies: 2
Views: 64

Re: Amphiprotic vs Amphoteric

These words are actually interchangable!
by Sarah Zhao 4C
Sun Dec 09, 2018 10:46 pm
Forum: General Science Questions
Topic: Final Grades
Replies: 2
Views: 155

Re: Final Grades

I have never seen my grades online before we've gotten them back so I'm assuming that it is second week of winter quarter.
by Sarah Zhao 4C
Sun Dec 09, 2018 10:45 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: tetrahedral or square planar?
Replies: 5
Views: 180

Re: tetrahedral or square planar?

Sometimes it can be either one and you may not know if the central atom is a transition metal with no roman numeral
by Sarah Zhao 4C
Sun Dec 02, 2018 8:58 pm
Forum: Naming
Topic: Naming Question
Replies: 5
Views: 80

Re: Naming Question

OH2 has a charge of 0. Its water: H20 or OH2. So having 5 of them would still make the charge 0. Cl has a charge of -1. It is a halogen, so it will always have a charge of -1 The total charge of the coordinate compound is +1. So to get the compound from the -1 provided by the Cl to the +1 of the com...
by Sarah Zhao 4C
Sun Dec 02, 2018 8:54 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted Base
Replies: 2
Views: 36

Re: Bronsted Base

They go by different definitions but they identify the same molecules as bases
tldr; they are the same
by Sarah Zhao 4C
Sun Dec 02, 2018 8:52 pm
Forum: Amphoteric Compounds
Topic: Amphoteric compounds besides water
Replies: 6
Views: 86

Re: Amphoteric compounds besides water

So besides water, they get kind of weird.
Hydrogen carbonate, bisulfate, amino acids, BUT MOST IMPORTANTLY (and probably the only one you will need to know) WATER
by Sarah Zhao 4C
Sun Dec 02, 2018 8:51 pm
Forum: Naming
Topic: Knowing oxidation states
Replies: 11
Views: 111

Re: Knowing oxidation states

Yes you will
But pretty much everything except for transition metals will be the charge of the neutral atom.
by Sarah Zhao 4C
Sun Dec 02, 2018 5:39 pm
Forum: Amphoteric Compounds
Topic: Naming conjugated compounds
Replies: 1
Views: 28

Re: Naming conjugated compounds

greek-prefix ligand name (for all ligands, IN ALPHABETICALLY ORDER) and then the metal name (roman number)
by Sarah Zhao 4C
Sun Nov 25, 2018 2:31 am
Forum: Properties of Electrons
Topic: Determining the Probability of Finding an Electron in an Orbital: Test 2
Replies: 2
Views: 86

Re: Determining the Probability of Finding an Electron in an Orbital: Test 2

If I'm understanding your question correctly, there is zero possibility to find an electron in the center because the p orbital takes a infinity sign shape and in the middle, there is a nodal plane where no electron can exist.
by Sarah Zhao 4C
Sun Nov 25, 2018 2:30 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Atomic Placement of CH2F2
Replies: 1
Views: 21

Re: Atomic Placement of CH2F2

So carbon will be the central atom because it is the least electronegative.
And it will be have 4 elements around it. It does not matter where it goes. But CH2F2 is a non-polar molecule so by putting the H opposite each other and the F opposite each other, it gaurentees that.
by Sarah Zhao 4C
Sun Nov 25, 2018 2:28 am
Forum: Hybridization
Topic: Test 3
Replies: 13
Views: 153

Re: Test 3

Yes, Test 3 includes bonding trends, shapes, molecular shape, polarity, and hybridization.
by Sarah Zhao 4C
Sun Nov 25, 2018 2:25 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear structure with lone pairs
Replies: 6
Views: 111

Re: Linear structure with lone pairs

Replying assuming that you mean AX2E3: AX2 is also linear
by Sarah Zhao 4C
Sun Nov 25, 2018 2:21 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing VSEPR
Replies: 2
Views: 42

Re: Drawing VSEPR

Does not matter. All ends up being the same VSEPR structure.

It just might be easier to identify if you do it horizontally.
by Sarah Zhao 4C
Fri Nov 16, 2018 4:55 pm
Forum: Student Social/Study Group
Topic: last problem on midterm
Replies: 4
Views: 225

Re: last problem on midterm

Nitrogen can only have a maximum of 8 electrons; its in period 2. If you give it two double bonds, it will have 10!
by Sarah Zhao 4C
Fri Nov 16, 2018 4:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Planar vs Pyramidal
Replies: 5
Views: 90

Re: Planar vs Pyramidal

Or in a simpler manner of explaining, trigonal planar has 3 bonding regions while trigonal pyramidal has 4! The only difference is the lone pair of electrons on trigonal pyramidal, which forces the bonds to be repelled.
by Sarah Zhao 4C
Fri Nov 16, 2018 4:49 pm
Forum: Hybridization
Topic: Sigma and Pi
Replies: 5
Views: 69

Re: Sigma and Pi

First bond will always be sigma because they need to have a sigma bond in order for the electrons to be oriented in a way to form a pi bond.

Yes there can be more than 3 bonds but that gets complicated and I'm assuming we don't need to know it for this chapter.
by Sarah Zhao 4C
Thu Nov 08, 2018 11:08 pm
Forum: Bond Lengths & Energies
Topic: Bond Energy
Replies: 2
Views: 55

Re: Bond Energy

I don't think we need to know how to calculate it for this class.

At most, just know the relationship.
It has an inverse relationship with bond length (the longer the bond, the easier to break) and thus is directly related to atomic radius (the greater the atomic radius, the longer the bond)
by Sarah Zhao 4C
Thu Nov 08, 2018 11:02 pm
Forum: Electronegativity
Topic: Electronegativity and Polarizability
Replies: 4
Views: 121

Re: Electronegativity and Polarizability

Polarizability is the ease to release an electron. A higher electronegativity means that electrons are more tightly held together. So polarizability and electronegativity are inversely related.
by Sarah Zhao 4C
Thu Nov 08, 2018 10:57 pm
Forum: Dipole Moments
Topic: Dipole - Dipole vs. Hydrogen Bonding
Replies: 4
Views: 72

Re: Dipole - Dipole vs. Hydrogen Bonding

So yes, H-bonds are the weakest types of bonds. Key word here being BONDS. So it's being compared to stronger covalent bonds and even stronger ionic bonds.

Dipole-dipole is an inter molecular force!
by Sarah Zhao 4C
Sat Nov 03, 2018 10:11 pm
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 4715

Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]

Thank you Lyndon for pushing through today's review session. Feel better and good luck on your own midterms :)
by Sarah Zhao 4C
Sat Nov 03, 2018 9:58 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: H-Atom Calculation
Replies: 2
Views: 84

Re: H-Atom Calculation

Yes, it's the same thing!
by Sarah Zhao 4C
Sat Nov 03, 2018 9:57 pm
Forum: Trends in The Periodic Table
Topic: Cation and Anion Ionic Radius
Replies: 3
Views: 30

Re: Cation and Anion Ionic Radius

Anions are larger than their parent ion because there is one more electron with the same nuclear charge.
Cation are smaller than their parent ion because there is less electrons with the same nuclear charge.
by Sarah Zhao 4C
Sat Nov 03, 2018 9:55 pm
Forum: Lewis Structures
Topic: lewis acid/base
Replies: 3
Views: 31

Re: lewis acid/base

So we know that a Lewis base is an electron donor and a Lewis acid is a lone pair acceptor. So in most cases, you can just look at it this way:

The cation will be the Lewis acid. The anion will be the Lewis base.
Ex. OH- + H+ -> H20

OH- is the Lewis base
H+ is the Lewis acid
by Sarah Zhao 4C
Sun Oct 28, 2018 6:12 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: What are degenerate orbitals?
Replies: 2
Views: 77

Re: What are degenerate orbitals?

Degenerate orbitals are orbitals of the same energy level

Any s-orbital would have 1 degenerate orbital
Any p-orbital would have 3 degenerate orbitals
Any d-orbital would have 5 degenerate orbitals
Any f-orbital would have 7 degenerate orbitals
by Sarah Zhao 4C
Sun Oct 28, 2018 6:08 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 5
Views: 146

Re: Magnetic Quantum Number

It's the function used to calculate the energy of an electron
by Sarah Zhao 4C
Tue Oct 23, 2018 4:51 pm
Forum: Quantum Numbers and The H-Atom
Topic: Principle Quantum #
Replies: 5
Views: 143

Re: Principle Quantum #

In the simplest form, principle quantum number (n) = the shell
by Sarah Zhao 4C
Tue Oct 23, 2018 4:29 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 5
Views: 146

Magnetic Quantum Number

I understand that for the p orbital, you can determine based off the magnetic quantum number if it is Px, Py, or Pz. But for the s, d, or f orbitals, are we supposed to be able to recognize which value of m lines up with which axis pairs?

I'm sorry if that wording made no sense.
by Sarah Zhao 4C
Mon Oct 15, 2018 3:15 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Negative sign in front of Bohr Frequency Condition
Replies: 4
Views: 61

Re: Negative sign in front of Bohr Frequency Condition

Negative because the energy of the electron is decreasing but the energy is positive because it is being released as a photon
by Sarah Zhao 4C
Mon Oct 15, 2018 3:08 pm
Forum: Properties of Electrons
Topic: 7th edition 1A.11
Replies: 3
Views: 60

Re: 7th edition 1A.11

Just memorize it for the sake of doing so
by Sarah Zhao 4C
Mon Oct 15, 2018 3:04 pm
Forum: Properties of Light
Topic: Momentum of Photon
Replies: 4
Views: 83

Re: Momentum of Photon

Mass of a photon is on the constants/equations sheet!
by Sarah Zhao 4C
Wed Oct 03, 2018 10:18 pm
Forum: Empirical & Molecular Formulas
Topic: Multiplying to get an integer in the empirical formula
Replies: 4
Views: 116

Re: Multiplying to get an integer in the empirical formula

Multiply anything that isn't less than .2 away from a whole number
by Sarah Zhao 4C
Wed Oct 03, 2018 10:18 pm
Forum: Empirical & Molecular Formulas
Topic: Multiplying to get an integer in the empirical formula
Replies: 4
Views: 116

Re: Multiplying to get an integer in the empirical formula

Multiply anything that isn't less than .2 away from a whole number
by Sarah Zhao 4C
Wed Oct 03, 2018 9:55 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 825842

Re: Post All Chemistry Jokes Here

What do you get when you put Avogadro's number in the blender?

GuacaMOLE
by Sarah Zhao 4C
Wed Oct 03, 2018 9:48 pm
Forum: SI Units, Unit Conversions
Topic: formula units [ENDORSED]
Replies: 68
Views: 21407

Re: formula units [ENDORSED]

Formula units is the equivalent of molecules for different compounds.

Molecules are for molecular compounds. Formula units are for atomic compounds.

Go to advanced search