Jasmine 2C wrote:KeyaV1C wrote:I don’t think it is. I saw the Thursday one floating around here but not the Tuesday one. Did you have any specific questions on the Tuesday test?
I wanted to know the answer for Question 4
Search found 103 matches
- Sat Mar 14, 2020 7:09 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Tuesday Test 2 Answer Key
- Replies: 4
- Views: 111
Re: Tuesday Test 2 Answer Key
- Sat Mar 14, 2020 2:08 pm
- Forum: Administrative Questions and Class Announcements
- Topic: W20, Week 10 Discussion 2F, 2I, 2L
- Replies: 10
- Views: 3665
Re: W20, Week 10 Discussion 2F, 2I, 2L
I had a question about the answer to question 3 part a. Wouldn't the order of rxn with respect to HgCl2 and C204 ^2- be 1 and 1 because when the concentrations double, the rates also double? Thanks! I had the same question but I think the rate with respect to C2O4 is second order and with respect t...
- Sat Mar 14, 2020 12:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Tuesday Test 2 Answer Key
- Replies: 4
- Views: 111
Re: Tuesday Test 2 Answer Key
I don’t think it is. I saw the Thursday one floating around here but not the Tuesday one. Did you have any specific questions on the Tuesday test?
- Fri Mar 13, 2020 1:17 pm
- Forum: Zero Order Reactions
- Topic: Calculus
- Replies: 10
- Views: 188
Re: Calculus
All the equations on the sheet are given to us. Plus the exam is open book so I don’t think you need to know any calc for the final
- Fri Mar 13, 2020 1:06 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Kinetics vs thermodynamics
- Replies: 3
- Views: 111
Re: Kinetics vs thermodynamics
Kinetics describes the pathway of reactions, with an emphasis on the activation energy that signifies the energy difference between the free energy of reactants and the transition state. Kinetic analysis is about the speed or rate of reaction, using experimental techniques to observe reactant &...
- Fri Mar 13, 2020 12:55 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam vs Boiling water
- Replies: 2
- Views: 144
Re: Steam vs Boiling water
When water goes from gas to liquid it is undergoing a phase change and therefore requires a lot more energy than just a temperature change. When steam hits your skin, energy will be released as it undergoes a phase change. This energy release causes a much worse burn than if the same amount of boili...
- Tue Mar 10, 2020 8:15 pm
- Forum: Student Social/Study Group
- Topic: Final Exam
- Replies: 22
- Views: 688
Re: Final Exam
Clara Cho 2K wrote:Do you think we will still meet for discussion?
I don’t think so
- Wed Mar 04, 2020 5:28 pm
- Forum: Balancing Redox Reactions
- Topic: inferring half rxns from equation
- Replies: 4
- Views: 127
Re: inferring half rxns from equation
EMurphy_2L wrote:oh also when can you just neglect elements? like 6L.9) KMnO4 and FeCl are involved in the reaction but just MnO4 and Fe are written in the redox reaction and cell diagram????
I’m not too sure but I think you can ignore elements when their oxidation states don’t change during the reaction
- Wed Mar 04, 2020 5:27 pm
- Forum: Balancing Redox Reactions
- Topic: inferring half rxns from equation
- Replies: 4
- Views: 127
Re: inferring half rxns from equation
For part c you have to split up the half reactions in order to calculate the overall standard cell potential
[Cl2 + 2e --> 2Cl-] + [2H+ --> H2 + 2e] = Cl2 + 2H —> 2 HCl
For part d you have to reverse the sign on the cell potential in order to get the correct reaction
[Cl2 + 2e --> 2Cl-] + [2H+ --> H2 + 2e] = Cl2 + 2H —> 2 HCl
For part d you have to reverse the sign on the cell potential in order to get the correct reaction
- Wed Mar 04, 2020 5:22 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Variables
- Replies: 3
- Views: 63
Re: Variables
R -> gas constant = 8.314 J/(mol*K)
T -> temperature in kelvin
F -> faradays constant = 96,485 C/mol
n -> number of electrons transferred
T -> temperature in kelvin
F -> faradays constant = 96,485 C/mol
n -> number of electrons transferred
- Wed Mar 04, 2020 5:18 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration Cell
- Replies: 7
- Views: 127
Re: Concentration Cell
A concentration cell is a cell that is has two half-cells with the same electrodes, but with different concentrations. The voltage difference is created by electron transfer from the cell with the lower concentration to the cell with the higher concentration. An example for this could be a cell wher...
- Wed Mar 04, 2020 5:14 pm
- Forum: Balancing Redox Reactions
- Topic: hydrogen
- Replies: 3
- Views: 68
Re: hydrogen
Ghadir Seder 1G wrote:so something is neither oxidized or reduced when its in the same oxidation state in both the reactants and products?
Yeah if the oxidation states are the same, the element is neither reduced nor oxidized
- Wed Mar 04, 2020 5:12 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: 6N 17: Cell doing work
- Replies: 3
- Views: 85
Re: 6N 17: Cell doing work
Yeah generally a negative delta G -> spontaneous reaction therefore the cell does work
- Wed Mar 04, 2020 5:11 pm
- Forum: General Science Questions
- Topic: Test 2 Grades [ENDORSED]
- Replies: 23
- Views: 692
Re: Test 2 Grades [ENDORSED]
I think we’ll get our tests back during discussion
- Sun Mar 01, 2020 2:15 pm
- Forum: General Rate Laws
- Topic: units
- Replies: 9
- Views: 116
Re: units
I think it’s M/s - mols*L^-1*s^-1
- Sun Mar 01, 2020 2:13 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cells
- Replies: 6
- Views: 94
Re: Galvanic Cells
The cell potential of a galvanic cell is always positive
- Sun Mar 01, 2020 2:11 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: how can you tell
- Replies: 11
- Views: 241
Re: how can you tell
In general, short reaction times favor kinetic control while longer reaction times favor thermodynamic control
- Wed Feb 26, 2020 1:15 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Strength of a reducing agent
- Replies: 3
- Views: 78
Re: Strength of a reducing agent
Metals with small ionization energies and low electro-negativities tend to be good reducing agents
- Wed Feb 26, 2020 1:09 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Which one is Product? Cathode or Anode?
- Replies: 5
- Views: 96
Re: Which one is Product? Cathode or Anode?
The product is always in the cathode end
- Sun Feb 23, 2020 4:53 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: chemistry community posts
- Replies: 12
- Views: 157
Re: chemistry community posts
I think the posts get checked every Sunday
- Tue Feb 18, 2020 7:13 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: reaction at equilibrium
- Replies: 6
- Views: 122
Re: reaction at equilibrium
Since Gibbs free energy is a measure of energy available to do work, when the reaction is at equilibrium, no more work is being done and therefore delta G is 0.
- Tue Feb 18, 2020 7:08 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing half reactions
- Replies: 11
- Views: 148
Re: Balancing half reactions
I’m not too sure if I understand your question, but when you’re balancing redox reactions when you’re given individual reactions, you need to make sure the electrons cancel out.
- Tue Feb 18, 2020 7:03 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Answer is different for 5G.15
- Replies: 5
- Views: 97
Re: Answer is different for 5G.15
I got -27 kJ/mol as my answer.
- Tue Feb 18, 2020 7:01 pm
- Forum: Van't Hoff Equation
- Topic: 5.55
- Replies: 2
- Views: 39
Re: 5.55
All elements in their standard states will have 0 as their standard Gibbs free energy of formation.
- Mon Feb 17, 2020 10:02 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 5G.17
- Replies: 2
- Views: 79
Re: 5G.17
This is what the graph in the solution section of the book looks like
- Sun Feb 16, 2020 12:43 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Van't Hoff Equation
- Replies: 2
- Views: 43
Re: Van't Hoff Equation
I don’t think so
- Sat Feb 15, 2020 1:18 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: How do you know if something is a salt solution?
- Replies: 6
- Views: 175
Re: How do you know if something is a salt solution?
This is a useful link: https://courses.lumenlearning.com/cheminter/chapter/calculating-ph-of-salt-solutions/ When you are given a problem with a salt in water, the salt dissociates. Ex. NaF + H20 -> Na+ + HF + OH - Since the Na+ is a stable ion and doesn't contribute to the pH, you can set up an ice...
- Sat Feb 15, 2020 1:14 pm
- Forum: Van't Hoff Equation
- Topic: Equation
- Replies: 5
- Views: 85
Re: Equation
This equation allows you to tell whether a reaction is spontaneous or not deepening on given entropy and enthalpy values. You can also calculate temperatures for which the reaction is spontaneous.
- Sat Feb 08, 2020 2:16 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Nonlinear vs linear molecules
- Replies: 4
- Views: 61
Re: Nonlinear vs linear molecules
Nonlinear molecules have 3 rotational degrees from the 3 axes of rotation. Since there is symmetry about only one axis, linear molecules have 2 rotational degrees. The degrees of freedom contribute to the heat capacity.
- Sat Feb 08, 2020 2:05 pm
- Forum: Phase Changes & Related Calculations
- Topic: Friday Thermochem/dynamics Lecture
- Replies: 2
- Views: 68
Re: Friday Thermochem/dynamics Lecture
I just emailed them to you!
- Sat Feb 08, 2020 2:01 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Microstates
- Replies: 6
- Views: 71
Re: Microstates
Increasing the number of molecules in a system can increase the number of microstates, since there are more possible arrangements of the molecules. Increasing the volume can also increase the number of positions where each molecule can be, which would increase the number of microstates. I don’t thin...
- Tue Feb 04, 2020 12:45 pm
- Forum: Calculating Work of Expansion
- Topic: Identifying constant pressure in a question
- Replies: 3
- Views: 100
Re: Identifying constant pressure in a question
Non-expansion work is one way of knowing that the pressure is constant
- Mon Feb 03, 2020 8:25 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated systems
- Replies: 4
- Views: 83
Re: Isolated systems
In a closed system, the matter within the system is constant, however, energy can be transferred from the system to its surroundings and vice versa. In an isolated system, neither matter nor energy can be transferred between the system and its surroundings.
- Thu Jan 30, 2020 5:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Test 1 Problem 1
- Replies: 1
- Views: 47
Re: Test 1 Problem 1
You have to set up an ICE table with the concentrations given to you
- Wed Jan 29, 2020 5:33 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 4 Homework
- Replies: 3
- Views: 60
Re: Week 4 Homework
I don’t think so. I would just do some of the intro thermochemistry problems to be on the safe side.
- Wed Jan 29, 2020 2:46 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Work
- Replies: 2
- Views: 37
Re: Work
Irreversible expansion occurs against a constant external pressure so the equation is just w= - P* Δ V. Reversible expansion has a pressure that keeps changing so then the equation is w= -nRT ln(V2/V1)
- Wed Jan 29, 2020 2:40 pm
- Forum: Calculating Work of Expansion
- Topic: expansion vs nonexpansion
- Replies: 5
- Views: 57
Re: expansion vs nonexpansion
Expansion work is pressure-volume work whereas non-expansion work is anything else such as electrical, frictional, etc. For example, biological instances of non-expansion work include muscle contraction and nerve impulses.
- Tue Jan 28, 2020 3:06 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta H and Delta U Relation
- Replies: 2
- Views: 40
Re: Delta H and Delta U Relation
I think Delta H = Delta U when there is no work being done, implying that the volume is constant.
- Thu Jan 23, 2020 4:06 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam vs liquid
- Replies: 7
- Views: 90
Re: Steam vs liquid
When water goes from gas to liquid it undergoes a phase change which requires a lot more energy than just a temperature change. When steam hits your skin, a lot of energy will be released as it condenses. This energy causes a much worse burn than if the same amount of boiling water were to hit your ...
- Thu Jan 23, 2020 3:58 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Shifting Forward or Reverse
- Replies: 7
- Views: 47
Re: Shifting Forward or Reverse
When the reactant is removed, the equilibrium shifts to make more reactant in order to make up for the loss.
- Wed Jan 22, 2020 2:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Percentage Ionization
- Replies: 2
- Views: 35
Re: Percentage Ionization
[Concentration of deprotonated species] / [Initial concentration of original species] * 100%
- Wed Jan 22, 2020 1:32 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Initial concentrations are the same at equilibrium?
- Replies: 3
- Views: 38
Re: Initial concentrations are the same at equilibrium?
When K is really small, the value of x tends to be really small as well, barely changing the concentration of the reactants.
- Wed Jan 22, 2020 12:28 pm
- Forum: Phase Changes & Related Calculations
- Topic: Exo/endo definition
- Replies: 3
- Views: 44
Re: Exo/endo definition
Endothermic and exothermic refer to transfer of heat (q) or changes in enthalpy ΔRH. The classifications endergonic and exergonic refer to changes in free energy.
- Wed Jan 15, 2020 1:23 pm
- Forum: Ideal Gases
- Topic: mole fraction
- Replies: 4
- Views: 46
Re: mole fraction
yeah it is
- Wed Jan 15, 2020 1:10 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle
- Replies: 6
- Views: 50
Re: Le Chatelier's Principle
Yes it does. Increasing the pressure of a reaction by decreasing volume favors the side of the reaction with less mols of gas. If you increase pressure by adding an inert gas, it doesn’t change the concentration of reactants or products.
- Wed Jan 15, 2020 1:05 pm
- Forum: Phase Changes & Related Calculations
- Topic: Autoprotolysis
- Replies: 15
- Views: 186
Re: Autoprotolysis
In autoprotolysis a proton is transferred between two identical molecules, one of which releases a proton which is accepted by the other molecule. Ex. H20 + H20 -> h30+ + OH-
- Wed Jan 15, 2020 1:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: increasing yield
- Replies: 2
- Views: 24
Re: increasing yield
you would increase the yield by removing products from the reaction
- Wed Jan 15, 2020 12:31 pm
- Forum: Ideal Gases
- Topic: bars vs atm
- Replies: 8
- Views: 82
Re: bars vs atm
1 bar is 0.986923 atm. The unit you use depends on the R value you use so that the units cancel out
- Sun Jan 12, 2020 10:51 am
- Forum: Ideal Gases
- Topic: aqueous elements in eq calculation
- Replies: 8
- Views: 76
Re: aqueous elements in eq calculation
We don't include solids and liquids in equilibrium constants because they don't affect the reaction reaching equilibrium. Equilibrium constants depend on the pressure of gases and concentrations of aqueous solutions in the reaction.
- Sun Jan 12, 2020 10:49 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: meaning of equilibrium [ENDORSED]
- Replies: 3
- Views: 67
Re: meaning of equilibrium [ENDORSED]
Chemical equilibrium is the state in which the forward reaction rate and the reverse reaction rate are equal. At equilibrium, the concentrations of the reactants and the products do not change. This implies that the concentrations of products and reactants don’t have to be equal at equilibrium.
- Sun Jan 12, 2020 10:47 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: when to use Kc vs Kp
- Replies: 11
- Views: 96
Re: when to use Kc vs Kp
The sure brackets around the compound just indicate that you’re writing the concentration of the compound => [] = concentration. You use p to calculate kp only when the compounds in the reaction are gases.
- Sat Jan 11, 2020 3:04 pm
- Forum: Ideal Gases
- Topic: K vs Q [ENDORSED]
- Replies: 7
- Views: 156
Re: K vs Q [ENDORSED]
The primary difference between K and Q is that K describes a reaction at equilibrium, whereas Q describes a reaction that is not at equilibrium.
- Thu Jan 09, 2020 5:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K values and stability of product
- Replies: 2
- Views: 23
Re: K values and stability of product
If the K value is 1 then the concentrations of products and reactants in the rxn are equal. If the K value is larger than 10^3 then the equilibrium sits at the right and the reaction favors the products more.
- Fri Dec 06, 2019 2:16 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: homework 6C. 21b
- Replies: 2
- Views: 163
Re: homework 6C. 21b
The CH3 group has electron donating properties, making it less electron withdrawing than the H attached to the carboxyl group in formic acid. That’s why formic acid is slightly stronger than CH3COOH
- Fri Dec 06, 2019 2:11 pm
- Forum: Lewis Acids & Bases
- Topic: Identifying Acids and Bases
- Replies: 3
- Views: 79
Re: Identifying Acids and Bases
They should yield the same answer.
- Fri Dec 06, 2019 2:06 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: speed of light
- Replies: 2
- Views: 127
Re: speed of light
Since no particles can travel faster than the speed of light, it makes no sense that a particle with mass (ie. electron) would be able to travel faster than the speed of light.
- Fri Dec 06, 2019 2:04 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: midterm #6A
- Replies: 1
- Views: 121
Re: midterm #6A
The solutions are posted on the website:https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/Midterm_ans.pdf "The electron configuration of Mg is 1s2 2s2 2p6 3s2. Mg2+ 1s2 2s2 2p6 Highest energy level is 2p for all five electrons. Principle quantum number, n = 2 (also called shell)...
- Fri Dec 06, 2019 2:02 pm
- Forum: *Titrations & Titration Calculations
- Topic: Titration
- Replies: 1
- Views: 123
Re: Titration
Just that it is a method where a solution of known concentration is used to determine the concentration of an unknown solution.
- Thu Dec 05, 2019 7:20 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Emission Spectrum of Hydrogen
- Replies: 1
- Views: 137
Re: Emission Spectrum of Hydrogen
Absorption is usually negative and emission is positive
- Thu Dec 05, 2019 7:17 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Sulfato
- Replies: 1
- Views: 39
Re: Sulfato
Sulfato is usually monodentate, but there are less common examples when it can be bidentate
- Wed Dec 04, 2019 10:34 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Isomers on the final
- Replies: 1
- Views: 30
Re: Isomers on the final
I’m pretty sure all we need to know about isomers is that the double bonds on the molecule prevent the isomers from rotating between cis and trans geometry and that they are held in place because the pi bond prevents rotation.
- Wed Dec 04, 2019 10:06 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 6C 21 part b
- Replies: 2
- Views: 44
Re: 6C 21 part b
If the conjugate base is more stable, the compound it corresponds to is more acidic. If you look at the conjugate bases for formic acid and acetic acid, both conjugate bases are stabilized by resonance, and electronegativity. The main difference is that there's a CH3 group instead of an H adjacent t...
- Wed Dec 04, 2019 9:48 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Oxoacids
- Replies: 2
- Views: 44
Re: Oxoacids
An oxoacid is a compound whose molecule contains at least one hydroxy group bonded to an atom that is doubly bonded to at least one oxygen atom. Ex. Carboxylic acids, sulfuric acid, nitric acid, and phosphoric acid.
- Wed Dec 04, 2019 9:23 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: nomenclature in J.7
- Replies: 1
- Views: 49
Re: nomenclature in J.7
That sounds about right. I’m pretty sure the only naming we need to know is for coordination compounds
- Wed Dec 04, 2019 9:18 am
- Forum: Coordinate Covalent Bonds
- Topic: When do we use the prefixes bis, tris, tetrakis, etc?
- Replies: 4
- Views: 192
Re: When do we use the prefixes bis, tris, tetrakis, etc?
When a ligand has a prefix (di-, tri-, tetra-) you need to use bis- and tris. Ex. [Pt(H2NCH2CH2NH2)2Cl2]Cl2 -> dichlorobis(ethylenediamine)platinum(IV) chloride
- Wed Dec 04, 2019 9:08 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pK
- Replies: 2
- Views: 44
Re: pK
pK is just the negative log of a constant. pKa is the negative log of the acid dissociation constant/ Ka value. pKb is the negative log of the base dissociation constant/ Kb value.
- Tue Dec 03, 2019 9:10 am
- Forum: Hybridization
- Topic: Energy levels in naming hybridizations
- Replies: 2
- Views: 53
Re: Energy levels in naming hybridizations
I think it’s okay to leave out the 2 because in all the homework problems, the solutions were always written without the energy level
- Tue Dec 03, 2019 9:07 am
- Forum: Student Social/Study Group
- Topic: Grades
- Replies: 14
- Views: 485
Re: Grades
On the syllabus he said "This class does not use a curve," so I don’t think he'll adjust the grades.
- Sat Nov 30, 2019 5:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Acids and Bases
- Replies: 1
- Views: 65
Re: Acids and Bases
I think that’s for 14B. For A we don’t really have to do much with Acids and Bases other than calculate pH or identify compounds as acidic and basic
- Sat Nov 30, 2019 5:49 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: salt and water formation
- Replies: 5
- Views: 63
Re: salt and water formation
When an acid and a base react, the compound formed by the cation of the base and the anion of the acid is a salt
- Tue Nov 26, 2019 5:08 pm
- Forum: Lewis Acids & Bases
- Topic: Identifying Lewis Acids and Bases
- Replies: 3
- Views: 44
Re: Identifying Lewis Acids and Bases
Generally, metal oxides are basic and non-metallic oxides form acids. You can characterize whether compounds are acidic or basic by looking at the location of the atoms on the periodic table.
- Tue Nov 26, 2019 5:04 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric
- Replies: 8
- Views: 137
Re: Amphoteric
You can tell by the location of the atoms on the periodic table. Be, Al, Ga, Sn, Pb, and Sb form amphoteric compounds. Anything to the left of them on the period table forms bases, and anything to the right forms acids.
- Tue Nov 26, 2019 5:02 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis Acid Lone Pairs
- Replies: 2
- Views: 29
Re: Lewis Acid Lone Pairs
If it helps you can also think of it in terms of protons or hydrogen atoms. For example if you have HCl in gas phase, it is a relatively stable molecule, but if you look at HCl in its aqueous phase, it loses the H atom and forms a Cl- ion. HCl (aq) + H2O(liquid) -> Cl-(aq) + H3O+(aq). HCl is an acid...
- Sat Nov 23, 2019 10:46 am
- Forum: Lewis Acids & Bases
- Topic: bronsted and lewis acids
- Replies: 2
- Views: 41
Re: bronsted and lewis acids
Yes Bronstead and Lewis definitions are just different definitions for the same thing. If a molecule loses a proton (generally H atom) it gains a lone pair.
- Sat Nov 23, 2019 10:43 am
- Forum: Administrative Questions and Class Announcements
- Topic: finals
- Replies: 5
- Views: 89
Re: finals
I think the topics will probably be evenly distributed
- Sat Nov 23, 2019 10:42 am
- Forum: Lewis Acids & Bases
- Topic: carboxyl group COOH
- Replies: 3
- Views: 60
Re: carboxyl group COOH
The carboxyl group is a weak organic acid therefore making the compound acidic
- Thu Nov 21, 2019 4:27 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: bond angles
- Replies: 3
- Views: 54
Re: bond angles
I don’t think we have to memorize the exact number. Saying >109.5 on the exam should be fine.
- Thu Nov 21, 2019 4:22 pm
- Forum: Dipole Moments
- Topic: Lewis Structure and Polarity
- Replies: 3
- Views: 92
Re: Lewis Structure and Polarity
I attached the Lewis structure below. The dipole moments don’t cancel therefore it’s a polar molecule.
- Sat Nov 16, 2019 3:25 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: ion-ion
- Replies: 1
- Views: 43
Re: ion-ion
NaCl could be one example — the + charged sodium cation is attracted to the - charged chloride anion.
- Sat Nov 16, 2019 3:23 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Equatorial/Axial Lone Pairs
- Replies: 3
- Views: 35
Re: Equatorial/Axial Lone Pairs
They prefer the equatorial position
- Sat Nov 16, 2019 3:18 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: Dipole-dipole interactions
- Replies: 2
- Views: 46
Re: Dipole-dipole interactions
If you look at the structures of the molecules you can see that CH4 and CCl4 don’t have dipole moments. So the molecules for which the interactions would be important are b, c, and d.
- Sat Nov 16, 2019 3:15 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: biological examples?
- Replies: 3
- Views: 49
Re: biological examples?
Water and DNA base pairing are common examples of hydrogen bonds.
- Sat Nov 16, 2019 3:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Determining VSEPR Model
- Replies: 3
- Views: 88
Re: Determining VSEPR Model
I don’t think it should matter since it’s the atom positions that are used to determine the name of the VSEPR shape.
- Wed Nov 06, 2019 11:56 am
- Forum: Administrative Questions and Class Announcements
- Topic: Equation Sheet
- Replies: 2
- Views: 54
Re: Equation Sheet
On the 14A website there is an equation sheet posted. I’m pretty sure we will be getting the equations from that sheet.
- Wed Nov 06, 2019 11:52 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: 1A.15
- Replies: 1
- Views: 66
Re: 1A.15
Here’s how I did it:
- Tue Nov 05, 2019 2:08 pm
- Forum: Ionic & Covalent Bonds
- Topic: molecular polarity
- Replies: 3
- Views: 73
Re: molecular polarity
It is more polar because there is a greater difference in electronegativity between the C-O bond than the B-O bond.
- Tue Nov 05, 2019 2:05 pm
- Forum: Octet Exceptions
- Topic: Homework Problem 2.C.3
- Replies: 2
- Views: 65
Re: Homework Problem 2.C.3
I didn’t draw out all the resonance structures, but you would just change the location of the double bonds in order to draw all of them out.
- Tue Nov 05, 2019 1:59 pm
- Forum: Lewis Structures
- Topic: 2B.1 c
- Replies: 2
- Views: 59
Re: 2B.1 c
Nitrogen has a lower ionization energy than oxygen because of the way the shells are filled. It is one of the two exceptions to the ionization energy trend.
- Sun Nov 03, 2019 2:22 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: dino nugget midterm review 10d
- Replies: 4
- Views: 77
Re: dino nugget midterm review 10d
Because of the way the shells in N and O are filled, O has a lower ionization energy than nitrogen. This happens because it’s more preferable to have a half filled shell in O than only 2 e- in N. I’m pretty sure they said that B and O are the only two exceptions to the trend.
- Sun Nov 03, 2019 1:46 pm
- Forum: Ionic & Covalent Bonds
- Topic: coulomb potential energy and Madelung constant, as well as lattice energy
- Replies: 4
- Views: 92
Re: coulomb potential energy and Madelung constant, as well as lattice energy
I don’t think we went over these concepts in class
- Sun Nov 03, 2019 1:36 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: Interionic and Intermolecular forces
- Replies: 2
- Views: 114
Re: Interionic and Intermolecular forces
I don’t think we need to know the details for how they are related, but usually the forces between molecules determine the physical properties of liquids and solids. In solids the intermolecular force is high, in liquids it is medium, and in gasses it is low.
- Sun Nov 03, 2019 1:30 pm
- Forum: Electronegativity
- Topic: Ionic or covalent?
- Replies: 17
- Views: 284
Re: Ionic or covalent?
If a compound is made from a metal and a non-metal, its bonding will usually be ionic and if it’s made from two non-metals, its bonding should be covalent
- Sun Nov 03, 2019 1:27 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 1D.23
- Replies: 1
- Views: 51
Re: 1D.23
A) N=3, L=1 corresponds with 3p => 3 orbitals
B) corresponds with 5d, ml= -1 => 1 orbital (even though d has 5 orbitals only one of them has ml=-1)
C) 2p, ml=0 => 1 orbital
D) n=2 (is the actual question in the book) => s or p => 1+3 = 4 orbitals
Hope that helps!
B) corresponds with 5d, ml= -1 => 1 orbital (even though d has 5 orbitals only one of them has ml=-1)
C) 2p, ml=0 => 1 orbital
D) n=2 (is the actual question in the book) => s or p => 1+3 = 4 orbitals
Hope that helps!
- Sat Oct 19, 2019 9:23 am
- Forum: *Shrodinger Equation
- Topic: Schrodinger for exam
- Replies: 20
- Views: 448
Re: Schrodinger for exam
I don’t think we need to know it in too much detail. I’m pretty sure we only need to know it in the context of the quantum numbers that correspond to a solution for a wave function.
- Sat Oct 19, 2019 9:19 am
- Forum: *Shrodinger Equation
- Topic: Concepts of Schrodinger equation
- Replies: 3
- Views: 72
Re: Concepts of Schrodinger equation
Here’s what I have in my notes: Schrodinger's wave function equation -> Uses a wave function to describe position of e- in an atom -> Ψ: height of wave at position (x, y, z) -> Ψ^2: represents probability of finding an e- / electron density distribution H(Hamiltonian)Ψ = E(energy)Ψ ↳ operate a chang...
- Sat Oct 19, 2019 9:09 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra Post Module Assessment
- Replies: 1
- Views: 50
Re: Atomic Spectra Post Module Assessment
1m = 1,650,763.73 wavelengths of radiation.
1 wavelength: 1m/1,650,763.73 = 6.06*10^-7 = 605 nm
1 wavelength: 1m/1,650,763.73 = 6.06*10^-7 = 605 nm
- Sat Oct 19, 2019 9:06 am
- Forum: DeBroglie Equation
- Topic: Wave Properties of Electrons Module q. 14
- Replies: 4
- Views: 63
Re: Wave Properties of Electrons Module q. 14
When two troughs interact/ two crests interact, it leads to a larger total amplitude, implying constructive interference. It’s destructive when the crest of one wave interacts with the trough of another.
- Sat Oct 19, 2019 9:03 am
- Forum: DeBroglie Equation
- Topic: Deriving the DeBrogile Equation
- Replies: 8
- Views: 113
Re: Deriving the DeBrogile Equation
It’s probably a good idea to remember how to derive it especially since it’s a pretty short derivation. λ=h/p and p=mv so λ=h/mv
- Sun Oct 06, 2019 12:40 am
- Forum: General Science Questions
- Topic: HW# H.7
- Replies: 1
- Views: 92
Re: HW# H.7
I’m pretty sure in class Dr. Lavelle said that we do not need to memorize nomenclature for now. I would suggest looking up the names of the chemicals in order to find out their molecular formula, and then try balancing the equations from there.
- Sun Oct 06, 2019 12:37 am
- Forum: Significant Figures
- Topic: Rules for Significant Figures
- Replies: 4
- Views: 113
Re: Rules for Significant Figures
On the Chem 14A class website there’s a link that has everything in detail you need to know about sig figs:
https://lavelle.chem.ucla.edu/wp-conten ... OUT_SF.pdf
https://lavelle.chem.ucla.edu/wp-conten ... OUT_SF.pdf