Search found 103 matches

by KeyaV1C
Sat Mar 14, 2020 7:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Tuesday Test 2 Answer Key
Replies: 4
Views: 50

Re: Tuesday Test 2 Answer Key

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
by KeyaV1C
Sat Mar 14, 2020 2:08 pm
Forum: Administrative Questions and Class Announcements
Topic: W20, Week 10 Discussion 2F, 2I, 2L
Replies: 10
Views: 418

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...
by KeyaV1C
Sat Mar 14, 2020 12:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Tuesday Test 2 Answer Key
Replies: 4
Views: 50

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?
by KeyaV1C
Fri Mar 13, 2020 1:17 pm
Forum: Zero Order Reactions
Topic: Calculus
Replies: 10
Views: 37

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
by KeyaV1C
Fri Mar 13, 2020 1:06 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics vs thermodynamics
Replies: 3
Views: 23

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 &...
by KeyaV1C
Fri Mar 13, 2020 12:55 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs Boiling water
Replies: 2
Views: 25

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...
by KeyaV1C
Tue Mar 10, 2020 8:15 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 22
Views: 257

Re: Final Exam

Clara Cho 2K wrote:Do you think we will still meet for discussion?

I don’t think so
by KeyaV1C
Wed Mar 04, 2020 5:28 pm
Forum: Balancing Redox Reactions
Topic: inferring half rxns from equation
Replies: 4
Views: 34

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
by KeyaV1C
Wed Mar 04, 2020 5:27 pm
Forum: Balancing Redox Reactions
Topic: inferring half rxns from equation
Replies: 4
Views: 34

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
by KeyaV1C
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: 22

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
by KeyaV1C
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: 45

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...
by KeyaV1C
Wed Mar 04, 2020 5:14 pm
Forum: Balancing Redox Reactions
Topic: hydrogen
Replies: 3
Views: 33

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
by KeyaV1C
Wed Mar 04, 2020 5:12 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 6N 17: Cell doing work
Replies: 3
Views: 36

Re: 6N 17: Cell doing work

Yeah generally a negative delta G -> spontaneous reaction therefore the cell does work
by KeyaV1C
Wed Mar 04, 2020 5:11 pm
Forum: General Science Questions
Topic: Test 2 Grades [ENDORSED]
Replies: 23
Views: 238

Re: Test 2 Grades [ENDORSED]

I think we’ll get our tests back during discussion
by KeyaV1C
Sun Mar 01, 2020 2:15 pm
Forum: General Rate Laws
Topic: units
Replies: 9
Views: 70

Re: units

I think it’s M/s - mols*L^-1*s^-1
by KeyaV1C
Sun Mar 01, 2020 2:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 6
Views: 24

Re: Galvanic Cells

The cell potential of a galvanic cell is always positive
by KeyaV1C
Sun Mar 01, 2020 2:11 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: how can you tell
Replies: 11
Views: 87

Re: how can you tell

In general, short reaction times favor kinetic control while longer reaction times favor thermodynamic control
by KeyaV1C
Wed Feb 26, 2020 1:15 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Strength of a reducing agent
Replies: 3
Views: 41

Re: Strength of a reducing agent

Metals with small ionization energies and low electro-negativities tend to be good reducing agents
by KeyaV1C
Sun Feb 23, 2020 4:53 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: chemistry community posts
Replies: 12
Views: 56

Re: chemistry community posts

I think the posts get checked every Sunday
by KeyaV1C
Tue Feb 18, 2020 7:13 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: reaction at equilibrium
Replies: 6
Views: 34

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.
by KeyaV1C
Tue Feb 18, 2020 7:08 pm
Forum: Balancing Redox Reactions
Topic: Balancing half reactions
Replies: 11
Views: 62

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.
by KeyaV1C
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: 45

Re: Answer is different for 5G.15

I got -27 kJ/mol as my answer.
by KeyaV1C
Tue Feb 18, 2020 7:01 pm
Forum: Van't Hoff Equation
Topic: 5.55
Replies: 2
Views: 20

Re: 5.55

All elements in their standard states will have 0 as their standard Gibbs free energy of formation.
by KeyaV1C
Mon Feb 17, 2020 10:02 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5G.17
Replies: 2
Views: 32

Re: 5G.17

This is what the graph in the solution section of the book looks like
by KeyaV1C
Sun Feb 16, 2020 12:43 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Van't Hoff Equation
Replies: 2
Views: 25

Re: Van't Hoff Equation

I don’t think so
by KeyaV1C
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: 5
Views: 55

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...
by KeyaV1C
Sat Feb 15, 2020 1:14 pm
Forum: Van't Hoff Equation
Topic: Equation
Replies: 5
Views: 29

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.
by KeyaV1C
Sat Feb 08, 2020 2:16 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Nonlinear vs linear molecules
Replies: 4
Views: 29

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.
by KeyaV1C
Sat Feb 08, 2020 2:05 pm
Forum: Phase Changes & Related Calculations
Topic: Friday Thermochem/dynamics Lecture
Replies: 2
Views: 45

Re: Friday Thermochem/dynamics Lecture

I just emailed them to you!
by KeyaV1C
Sat Feb 08, 2020 2:01 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Microstates
Replies: 6
Views: 39

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...
by KeyaV1C
Tue Feb 04, 2020 12:45 pm
Forum: Calculating Work of Expansion
Topic: Identifying constant pressure in a question
Replies: 3
Views: 18

Re: Identifying constant pressure in a question

Non-expansion work is one way of knowing that the pressure is constant
by KeyaV1C
Mon Feb 03, 2020 8:25 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated systems
Replies: 4
Views: 25

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.
by KeyaV1C
Thu Jan 30, 2020 5:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1 Problem 1
Replies: 1
Views: 33

Re: Test 1 Problem 1

You have to set up an ICE table with the concentrations given to you
by KeyaV1C
Wed Jan 29, 2020 5:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 4 Homework
Replies: 3
Views: 44

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.
by KeyaV1C
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: 31

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)
by KeyaV1C
Wed Jan 29, 2020 2:40 pm
Forum: Calculating Work of Expansion
Topic: expansion vs nonexpansion
Replies: 5
Views: 34

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.
by KeyaV1C
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: 17

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.
by KeyaV1C
Thu Jan 23, 2020 4:06 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs liquid
Replies: 7
Views: 36

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 ...
by KeyaV1C
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: 32

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.
by KeyaV1C
Wed Jan 22, 2020 2:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Percentage Ionization
Replies: 2
Views: 28

Re: Percentage Ionization

[Concentration of deprotonated species] / [Initial concentration of original species] * 100%
by KeyaV1C
Wed Jan 22, 2020 1:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Initial concentrations are the same at equilibrium?
Replies: 3
Views: 28

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.
by KeyaV1C
Wed Jan 22, 2020 12:28 pm
Forum: Phase Changes & Related Calculations
Topic: Exo/endo definition
Replies: 3
Views: 35

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.
by KeyaV1C
Wed Jan 15, 2020 1:23 pm
Forum: Ideal Gases
Topic: mole fraction
Replies: 4
Views: 30

Re: mole fraction

yeah it is
by KeyaV1C
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: 19

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.
by KeyaV1C
Wed Jan 15, 2020 1:05 pm
Forum: Phase Changes & Related Calculations
Topic: Autoprotolysis
Replies: 15
Views: 103

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-
by KeyaV1C
Wed Jan 15, 2020 1:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: increasing yield
Replies: 2
Views: 18

Re: increasing yield

you would increase the yield by removing products from the reaction
by KeyaV1C
Wed Jan 15, 2020 12:31 pm
Forum: Ideal Gases
Topic: bars vs atm
Replies: 8
Views: 48

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
by KeyaV1C
Sun Jan 12, 2020 10:51 am
Forum: Ideal Gases
Topic: aqueous elements in eq calculation
Replies: 8
Views: 48

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.
by KeyaV1C
Sun Jan 12, 2020 10:49 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: meaning of equilibrium [ENDORSED]
Replies: 3
Views: 25

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.
by KeyaV1C
Sun Jan 12, 2020 10:47 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: when to use Kc vs Kp
Replies: 11
Views: 52

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.
by KeyaV1C
Sat Jan 11, 2020 3:04 pm
Forum: Ideal Gases
Topic: K vs Q [ENDORSED]
Replies: 7
Views: 55

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.
by KeyaV1C
Thu Jan 09, 2020 5:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K values and stability of product
Replies: 2
Views: 17

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.
by KeyaV1C
Fri Dec 06, 2019 2:16 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: homework 6C. 21b
Replies: 2
Views: 57

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
by KeyaV1C
Fri Dec 06, 2019 2:11 pm
Forum: Lewis Acids & Bases
Topic: Identifying Acids and Bases
Replies: 3
Views: 36

Re: Identifying Acids and Bases

They should yield the same answer.
by KeyaV1C
Fri Dec 06, 2019 2:06 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: speed of light
Replies: 2
Views: 48

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.
by KeyaV1C
Fri Dec 06, 2019 2:04 pm
Forum: Quantum Numbers and The H-Atom
Topic: midterm #6A
Replies: 1
Views: 48

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)...
by KeyaV1C
Fri Dec 06, 2019 2:02 pm
Forum: *Titrations & Titration Calculations
Topic: Titration
Replies: 1
Views: 49

Re: Titration

Just that it is a method where a solution of known concentration is used to determine the concentration of an unknown solution.
by KeyaV1C
Thu Dec 05, 2019 7:20 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Emission Spectrum of Hydrogen
Replies: 1
Views: 48

Re: Emission Spectrum of Hydrogen

Absorption is usually negative and emission is positive
by KeyaV1C
Thu Dec 05, 2019 7:17 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Sulfato
Replies: 1
Views: 29

Re: Sulfato

Sulfato is usually monodentate, but there are less common examples when it can be bidentate
by KeyaV1C
Wed Dec 04, 2019 10:34 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Isomers on the final
Replies: 1
Views: 21

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.
by KeyaV1C
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: 32

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...
by KeyaV1C
Wed Dec 04, 2019 9:48 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Oxoacids
Replies: 2
Views: 33

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.
by KeyaV1C
Wed Dec 04, 2019 9:23 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: nomenclature in J.7
Replies: 1
Views: 41

Re: nomenclature in J.7

That sounds about right. I’m pretty sure the only naming we need to know is for coordination compounds
by KeyaV1C
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: 71

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
by KeyaV1C
Wed Dec 04, 2019 9:08 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pK
Replies: 2
Views: 31

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.
by KeyaV1C
Tue Dec 03, 2019 9:10 am
Forum: Hybridization
Topic: Energy levels in naming hybridizations
Replies: 2
Views: 34

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
by KeyaV1C
Tue Dec 03, 2019 9:07 am
Forum: Student Social/Study Group
Topic: Grades
Replies: 14
Views: 216

Re: Grades

On the syllabus he said "This class does not use a curve," so I don’t think he'll adjust the grades.
by KeyaV1C
Sat Nov 30, 2019 5:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Acids and Bases
Replies: 1
Views: 33

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
by KeyaV1C
Sat Nov 30, 2019 5:49 pm
Forum: Identifying Acidic & Basic Salts
Topic: salt and water formation
Replies: 5
Views: 33

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
by KeyaV1C
Tue Nov 26, 2019 5:08 pm
Forum: Lewis Acids & Bases
Topic: Identifying Lewis Acids and Bases
Replies: 3
Views: 23

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.
by KeyaV1C
Tue Nov 26, 2019 5:04 pm
Forum: Amphoteric Compounds
Topic: Amphoteric
Replies: 8
Views: 69

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.
by KeyaV1C
Tue Nov 26, 2019 5:02 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acid Lone Pairs
Replies: 2
Views: 19

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...
by KeyaV1C
Sat Nov 23, 2019 10:46 am
Forum: Lewis Acids & Bases
Topic: bronsted and lewis acids
Replies: 2
Views: 23

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.
by KeyaV1C
Sat Nov 23, 2019 10:43 am
Forum: Administrative Questions and Class Announcements
Topic: finals
Replies: 5
Views: 62

Re: finals

I think the topics will probably be evenly distributed
by KeyaV1C
Sat Nov 23, 2019 10:42 am
Forum: Lewis Acids & Bases
Topic: carboxyl group COOH
Replies: 3
Views: 30

Re: carboxyl group COOH

The carboxyl group is a weak organic acid therefore making the compound acidic
by KeyaV1C
Thu Nov 21, 2019 4:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 3
Views: 23

Re: bond angles

I don’t think we have to memorize the exact number. Saying >109.5 on the exam should be fine.
by KeyaV1C
Thu Nov 21, 2019 4:22 pm
Forum: Dipole Moments
Topic: Lewis Structure and Polarity
Replies: 3
Views: 53

Re: Lewis Structure and Polarity

I attached the Lewis structure below. The dipole moments don’t cancel therefore it’s a polar molecule.
by KeyaV1C
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: 16

Re: ion-ion

NaCl could be one example — the + charged sodium cation is attracted to the - charged chloride anion.
by KeyaV1C
Sat Nov 16, 2019 3:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Equatorial/Axial Lone Pairs
Replies: 3
Views: 27

Re: Equatorial/Axial Lone Pairs

They prefer the equatorial position
by KeyaV1C
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: 25

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.
by KeyaV1C
Sat Nov 16, 2019 3:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining VSEPR Model
Replies: 3
Views: 25

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.
by KeyaV1C
Wed Nov 06, 2019 11:56 am
Forum: Administrative Questions and Class Announcements
Topic: Equation Sheet
Replies: 2
Views: 34

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.
by KeyaV1C
Wed Nov 06, 2019 11:52 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1A.15
Replies: 1
Views: 51

Re: 1A.15

Here’s how I did it:
by KeyaV1C
Tue Nov 05, 2019 2:08 pm
Forum: Ionic & Covalent Bonds
Topic: molecular polarity
Replies: 3
Views: 48

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.
by KeyaV1C
Tue Nov 05, 2019 2:05 pm
Forum: Octet Exceptions
Topic: Homework Problem 2.C.3
Replies: 2
Views: 47

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.
by KeyaV1C
Tue Nov 05, 2019 1:59 pm
Forum: Lewis Structures
Topic: 2B.1 c
Replies: 2
Views: 38

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.
by KeyaV1C
Sun Nov 03, 2019 2:22 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: dino nugget midterm review 10d
Replies: 4
Views: 59

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.
by KeyaV1C
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: 41

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.
by KeyaV1C
Sun Nov 03, 2019 1:30 pm
Forum: Electronegativity
Topic: Ionic or covalent?
Replies: 17
Views: 140

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
by KeyaV1C
Sun Nov 03, 2019 1:27 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1D.23
Replies: 1
Views: 25

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!
by KeyaV1C
Sat Oct 19, 2019 9:23 am
Forum: *Shrodinger Equation
Topic: Schrodinger for exam
Replies: 9
Views: 160

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.
by KeyaV1C
Sat Oct 19, 2019 9:19 am
Forum: *Shrodinger Equation
Topic: Concepts of Schrodinger equation
Replies: 3
Views: 35

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...
by KeyaV1C
Sat Oct 19, 2019 9:09 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post Module Assessment
Replies: 1
Views: 31

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
by KeyaV1C
Sat Oct 19, 2019 9:06 am
Forum: DeBroglie Equation
Topic: Wave Properties of Electrons Module q. 14
Replies: 4
Views: 43

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.
by KeyaV1C
Sat Oct 19, 2019 9:03 am
Forum: DeBroglie Equation
Topic: Deriving the DeBrogile Equation
Replies: 8
Views: 85

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
by KeyaV1C
Sun Oct 06, 2019 12:40 am
Forum: General Science Questions
Topic: HW# H.7
Replies: 1
Views: 66

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.
by KeyaV1C
Sun Oct 06, 2019 12:37 am
Forum: Significant Figures
Topic: Rules for Significant Figures
Replies: 4
Views: 84

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

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