Search found 98 matches

by Sidharth D 1E
Fri Mar 13, 2020 5:39 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation
Replies: 8
Views: 86

Re: Arrhenius Equation

To expand on that, reactions that give a straight line when lnkr is plotted against 1/T are said to show Arrhenius behavior
by Sidharth D 1E
Fri Mar 13, 2020 5:37 pm
Forum: Administrative Questions and Class Announcements
Topic: "Open Book" Final?
Replies: 30
Views: 762

Re: "Open Book" Final?

Sue Bin Park 2I wrote:do we know if the final is going to be timed? or will he post it and give us more than the 1.5 hours he said it would take?

I am pretty sure he mentioned allotting from 3-4 hours for the actual final exam, even though you should be able to finish it in half the time.
by Sidharth D 1E
Fri Mar 13, 2020 5:36 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 11
Views: 146

Re: Final

I'm pretty sure it will be posted on his class website, so thats where to look for it when Lavelle sends an email saying he posted it.
by Sidharth D 1E
Fri Mar 13, 2020 5:34 pm
Forum: Zero Order Reactions
Topic: Calculus
Replies: 10
Views: 108

Re: Calculus

I don't think there will by any derivations on the exam, so not much/basic calculus might be needed.
by Sidharth D 1E
Sun Mar 08, 2020 11:57 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Adding Pt(s) to a Cell Diagram
Replies: 14
Views: 140

Re: Adding Pt(s) to a Cell Diagram

For example when dealing with hydrogen gas in the galvanic cell, you would need to include Pt(s)
by Sidharth D 1E
Sun Mar 08, 2020 11:54 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration
Replies: 9
Views: 68

Re: Concentration

Are you referring to what to do given a concentration cell situation or in a galvanic cell?
by Sidharth D 1E
Sun Mar 08, 2020 11:53 pm
Forum: First Order Reactions
Topic: equation derivations
Replies: 5
Views: 36

Re: equation derivations

No, he mentioned at least on the midterm that there will not be any derivations so I think that same principle applies to the final.
by Sidharth D 1E
Sun Mar 08, 2020 11:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Formula Sheet
Replies: 7
Views: 76

Re: Formula Sheet

I believe you should be prepared to be given the one that is on Lavelle's website
by Sidharth D 1E
Sun Mar 08, 2020 11:50 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: n in NFE
Replies: 19
Views: 204

Re: n in NFE

N should be the number of electrons transferred in that scenario.
by Sidharth D 1E
Sun Mar 01, 2020 11:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 8
Views: 106

Re: Anode and Cathode

Also, traditionally in a galvanic cell diagram, the anode will be on the left side while the cathode will be on the right side.
by Sidharth D 1E
Sun Mar 01, 2020 11:07 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: cell diagrams
Replies: 8
Views: 81

Re: cell diagrams

My TA mentioned that Dr. Lavelle will most likely keep it simple with the anode on the left side and cathode on the right side.
by Sidharth D 1E
Sun Mar 01, 2020 11:03 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing cell diagrams
Replies: 7
Views: 70

Re: Writing cell diagrams

Yes, you separate sides of a reaction with a double line.
by Sidharth D 1E
Sun Mar 01, 2020 11:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 12
Views: 107

Re: Salt Bridge

No, there is no equation or formula we need to write down for the salt bridge. It's just important to draw it on the diagram.
by Sidharth D 1E
Sun Mar 01, 2020 11:00 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 9
Views: 82

Re: salt bridge

A salt bridge is meant to maintain charge as the electrons are transferred from the anode to cathode
by Sidharth D 1E
Sun Feb 23, 2020 5:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 9
Views: 84

Re: Salt Bridge

The purpose of a salt bridge is to maintain charge as the electrons are transferred from the anode to cathode
by Sidharth D 1E
Sun Feb 23, 2020 5:16 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 10
Views: 103

Re: salt bridge

A salt bridge is meant to maintain charge as the electrons are transferred from the anode to cathode
by Sidharth D 1E
Sun Feb 23, 2020 5:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: relevance of salt bridge
Replies: 9
Views: 57

Re: relevance of salt bridge

Salt bridges are meant to maintain charge as the electrons are transferred from the anode to cathode
by Sidharth D 1E
Sun Feb 23, 2020 5:10 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Electrode Potential
Replies: 4
Views: 52

Re: Electrode Potential

Normally the electrode potentials are given as standard reduction potentials.
by Sidharth D 1E
Sun Feb 23, 2020 5:07 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Identify the state
Replies: 3
Views: 31

Re: Identify the state

Most metals that are given in the question without a charge are in the solid state and those which have a charge normally are from a dissociated compound, so they will be aqueous.
by Sidharth D 1E
Sun Feb 16, 2020 7:23 pm
Forum: Balancing Redox Reactions
Topic: class example
Replies: 2
Views: 29

Re: class example

As a good rule of thumb, remember that oxygen in a compound other than O2 will have an oxidation number of -2 and hydrogen in a compound other than H2 will have an oxidation number of +1.
by Sidharth D 1E
Sun Feb 16, 2020 7:19 pm
Forum: Balancing Redox Reactions
Topic: Oxidation Reduction
Replies: 3
Views: 54

Re: Oxidation Reduction

Oxygen will have an oxidation number of -2, unless it is in O2, or other exceptions like hydrogen peroxide. I believe the same goes with hydrogen being +1.
by Sidharth D 1E
Sun Feb 16, 2020 7:15 pm
Forum: Balancing Redox Reactions
Topic: easier to split?
Replies: 6
Views: 63

Re: easier to split?

Lavelle suggested to split the redox reaction into two half reactions which separate the oxidation and the reduction reactions. You can use it to find out which elements are oxidized and reduced, and also balance redox reactions (since the number of electrons transferred should cancel out in the two...
by Sidharth D 1E
Sun Feb 16, 2020 7:11 pm
Forum: Balancing Redox Reactions
Topic: Seperating Redoz RXNS
Replies: 7
Views: 43

Re: Seperating Redoz RXNS

Half reactions separate the oxidation and the reduction reactions into two half reactions. You can use the individual two half reactions to find out which elements are oxidized and reduced, and also balance redox reactions (since the number of electrons transferred should end up cancelling out.
by Sidharth D 1E
Sun Feb 16, 2020 7:07 pm
Forum: Balancing Redox Reactions
Topic: redox reaction
Replies: 10
Views: 85

Re: redox reaction

Another acronym to remember it by is: OIL RIG = Oxidation is the Loss of electrons and Reduction is the Gains of electrons.
by Sidharth D 1E
Sun Feb 09, 2020 9:57 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: GFE and Hess's Law
Replies: 2
Views: 23

Re: GFE and Hess's Law

Yes, we can use Hess' law for Gibbs Free Energy because it's a state function.
by Sidharth D 1E
Sun Feb 09, 2020 9:54 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: spontaneity
Replies: 18
Views: 150

Re: spontaneity

Also, if a question mentions that a chemical reaction is favorable, it means that the reaction is spontaneous.
by Sidharth D 1E
Sun Feb 09, 2020 9:49 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: constant p
Replies: 4
Views: 43

Re: constant p

It means that a change in the enthalpy of a system is equal to the heat released or absorbed at constant pressure. Since the external pressure is equivalent to the pressure of the system:
deltaH = q - P(deltaV) + P(deltaV), so deltaH equals q.
by Sidharth D 1E
Sun Feb 09, 2020 9:43 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Difference between Cv and Cp?
Replies: 8
Views: 74

Re: Difference between Cv and Cp?

Also, for nonlinear molecules, Cv is 3R and Cp is 4R
by Sidharth D 1E
Fri Feb 07, 2020 6:10 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy
Replies: 2
Views: 26

Re: Entropy

The change in entropy of the universe is always positive because some form of energy is always released (whether that may be from the system or the surroundings), even if it's endothermic.
by Sidharth D 1E
Sun Feb 02, 2020 10:02 pm
Forum: Calculating Work of Expansion
Topic: Enthalpy
Replies: 5
Views: 29

Re: Enthalpy

A state function is something where the path doesn't matter, only the initial and final state. The reason why it's important is that since the path doesn't matter, you can subtract, add, multiply, and divid state functions (entropy in this case) as necessary.
by Sidharth D 1E
Sun Feb 02, 2020 10:00 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Steam burns
Replies: 8
Views: 71

Re: Steam burns

Steam has more energy than boiling water does (40.7 kJ vs 5 kJ). So when the steam hits your skin you are immediately feeling 40.5 KJ of heat rather than 5KJ. Steam also absorbs heat so it will also increase in temperature.
by Sidharth D 1E
Sun Feb 02, 2020 9:57 pm
Forum: Phase Changes & Related Calculations
Topic: Pressure in an Open Beaker
Replies: 10
Views: 84

Re: Pressure in an Open Beaker

Since the beaker is open and exposed to the atmosphere (which is very large in comparison to the beaker), the pressure is constant. The beaker can also equilibrate with the pressure of its surroundings.
by Sidharth D 1E
Sun Feb 02, 2020 9:53 pm
Forum: Calculating Work of Expansion
Topic: Constant Pressure
Replies: 3
Views: 35

Re: Constant Pressure

Also, constant pressure can be assumed if you are dealing with an open system.
by Sidharth D 1E
Sun Feb 02, 2020 9:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm dates
Replies: 11
Views: 107

Re: Midterm dates

Also, the review sessions that are listed on Dr. Lavelle's website match the topics that we will be tested on.
by Sidharth D 1E
Thu Jan 30, 2020 12:46 pm
Forum: Calculating Work of Expansion
Topic: Reversible processes and greatest work
Replies: 3
Views: 33

Re: Reversible processes and greatest work

When looking at the reversible, isothermal expansion of an ideal gas, if the external pressure of a system were to be increased even infinitesimally at any stage of the expansion, the piston would move in instead of out. Therefore, the work done during a reversible expansion of a gas is the maximum ...
by Sidharth D 1E
Thu Jan 30, 2020 12:37 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Qv vs Qp
Replies: 7
Views: 45

Re: Qv vs Qp

Both of these are used to find enthalpy/delta H but also find change in internal energy which is q + w. Therefore, q can either be qp or qv depending on the given conditions.
by Sidharth D 1E
Thu Jan 23, 2020 1:16 pm
Forum: Calculating the pH of Salt Solutions
Topic: Adding an Acid or Base in Water
Replies: 3
Views: 97

Re: Adding an Acid or Base in Water

Due to the autoprotolysis of water, there is already a concentration of 1 x 10-7 M of [H3O+], so that amount of HCl would not have any impact.
by Sidharth D 1E
Thu Jan 23, 2020 1:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G part c
Replies: 3
Views: 37

Re: 5G part c

Increasing the pressure of the reactant will not impact the equilibrium constant, it will only shift the equilibrium to the right.
by Sidharth D 1E
Thu Jan 23, 2020 12:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1 Material
Replies: 3
Views: 50

Re: Test 1 Material

Only the first two topics: Chemical Equilibrium, and Acid and Base Equilibria are on the exam, so anything we are learning about thermodynamics will be on the midterm.
by Sidharth D 1E
Thu Jan 23, 2020 12:50 pm
Forum: General Science Questions
Topic: Test 1: Sig Figs
Replies: 7
Views: 125

Re: Test 1: Sig Figs

I think that Sig Figs do count on the exam, and refer to this link on how to use them: https://lavelle.chem.ucla.edu/wp-conten ... OUT_SF.pdf
by Sidharth D 1E
Thu Jan 23, 2020 12:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1
Replies: 4
Views: 50

Re: Test 1

Focus on the lecture material and the homework problems given on the syllabus, because they are meant to mimic the questions on the test.
by Sidharth D 1E
Thu Jan 23, 2020 12:37 pm
Forum: Ideal Gases
Topic: ICE table approximation
Replies: 10
Views: 78

Re: ICE table approximation

You can approximate if the K value for the table is less than 10-3.
by Sidharth D 1E
Thu Jan 23, 2020 12:35 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5I 25
Replies: 2
Views: 40

Re: 5I 25

You should just only need to know how to plug values of a quadratic equation into the quadratic formula.
by Sidharth D 1E
Sun Jan 12, 2020 7:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Comparing K Values
Replies: 4
Views: 53

Re: Comparing K Values

When K is at or near 1, the energy of the reactants and the products are the same, which is extremely rare.
by Sidharth D 1E
Sun Jan 12, 2020 7:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp
Replies: 6
Views: 51

Re: Kp

Kp is meant to be used when dealing with the partial pressures of various gases, and Kc is meant to be used for concentrations.
by Sidharth D 1E
Sun Jan 12, 2020 7:39 pm
Forum: Ideal Gases
Topic: Kc vs Kp
Replies: 5
Views: 71

Re: Kc vs Kp

Yes, they are both calculated the same way, and the states of the reactants and products will identify whether to use Kc or Kp.
by Sidharth D 1E
Sun Jan 12, 2020 7:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Q
Replies: 10
Views: 70

Re: K and Q

If Q < K, at some time during the reaction, then the forward reaction is favored.
If Q > K, at some time during the reaction, then the reverse reaction is favored.
by Sidharth D 1E
Sun Jan 12, 2020 7:29 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pressure and volume
Replies: 4
Views: 36

Re: pressure and volume

The formula for Boyle's law is P1V1=P2V2, which illustrates the concept mentioned above.
by Sidharth D 1E
Sat Dec 07, 2019 9:47 pm
Forum: Lewis Structures
Topic: Expanded Octets
Replies: 2
Views: 120

Re: Expanded Octets

Cl should not be able to accommodate for more than an octet because the principle quantum number is 2, and there is no 2d orbital that exists.
by Sidharth D 1E
Sat Dec 07, 2019 9:45 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: resonance in relation to pH
Replies: 2
Views: 58

Re: resonance in relation to pH

Resonance allows for the delocalization of electrons, so that reduces the strength of the H-O bond, which allows the acid to be stronger.
by Sidharth D 1E
Sat Dec 07, 2019 9:44 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Heme complex and myoglobin/hemoglobin
Replies: 3
Views: 162

Re: Heme complex and myoglobin/hemoglobin

A heme complex attached to a protein is what makes up myoglobin (which can attach to a single O2 molecule. Four myoglobin together make up a single hemoglobin.
by Sidharth D 1E
Sat Dec 07, 2019 9:42 pm
Forum: Biological Examples
Topic: Coordination Compounds
Replies: 2
Views: 36

Re: Coordination Compounds

by Sidharth D 1E
Sat Dec 07, 2019 9:41 pm
Forum: Biological Examples
Topic: Transition Metal Cations
Replies: 1
Views: 35

Re: Transition Metal Cations

They help chemically by binding directly to the molecule and they structurally affect the active site of the molecule. It makes the bond weaker of the molecule that they are trying to change, thereby reducing the activation energy required for the reaction.
by Sidharth D 1E
Sat Dec 07, 2019 9:38 pm
Forum: Identifying Acidic & Basic Salts
Topic: 6C.17
Replies: 2
Views: 128

Re: 6C.17

The questions before that (6C.16) gives you more information regarding the the comparison, so I think that is what you use to help you figure out the question.
by Sidharth D 1E
Sat Dec 07, 2019 9:36 pm
Forum: Quantum Numbers and The H-Atom
Topic: Calculating quantum numbers
Replies: 4
Views: 167

Re: Calculating quantum numbers

Identifying the subshell in which the electron exists in will give you the first two quantum numbers, and the orbital will give ml and the spin of the electron will tell you if it is +1/2 or -1/2.
by Sidharth D 1E
Sat Dec 07, 2019 9:34 pm
Forum: Bronsted Acids & Bases
Topic: Strong Acids and Bases
Replies: 6
Views: 163

Re: Strong Acids and Bases

Also, anything that is a group 1 or 2 metal cation that is attached to an oxide (o2-) can also be a strong base. ex: CaO and Na2O
by Sidharth D 1E
Sat Dec 07, 2019 9:32 pm
Forum: Biological Examples
Topic: memorizing examples
Replies: 3
Views: 39

Re: memorizing examples

I think we could be tested for their functions, so just memorize them to be on the safer side.
by Sidharth D 1E
Sun Nov 24, 2019 10:33 pm
Forum: Hybridization
Topic: Why does hybridization occur
Replies: 3
Views: 37

Re: Why does hybridization occur

Atoms in a molecule hybridize because hybridized orbitals results in lower energy orbitals and they form a more stable compound.
by Sidharth D 1E
Sun Nov 24, 2019 10:30 pm
Forum: Hybridization
Topic: hybridization number
Replies: 5
Views: 47

Re: hybridization number

Remember that each lone pair is considered as a separate area of electron density and that multiple bonds between the same two atoms is considered as one area of electron density.
by Sidharth D 1E
Sun Nov 24, 2019 10:27 pm
Forum: Hybridization
Topic: Hybridization and Bond Length
Replies: 1
Views: 45

Re: Hybridization and Bond Length

An easy example to remember how bond length is affected by hybridization is this: the length of a sigma bond between a carbon atom and another atom is shorter for a carbon atom with a hybridization of sp2 than a carbon atom with a hybridization of sp3.
by Sidharth D 1E
Sun Nov 24, 2019 10:24 pm
Forum: Hybridization
Topic: Identifying hybridizations
Replies: 2
Views: 24

Re: Identifying hybridizations

I would say another way is to count how many regions of electron density there are that surround the atom (counting multiple bonds as one region of electron density and each lone pair as an area of electron density).
by Sidharth D 1E
Sun Nov 24, 2019 10:22 pm
Forum: Hybridization
Topic: Bond Strength
Replies: 2
Views: 43

Re: Bond Strength

Yes, for example the sigma bond length between a carbon atom and another atom is shorter for a carbon atom with a hybridization of sp2 than for a carbon atom with a hybridization of sp3.
by Sidharth D 1E
Sun Nov 17, 2019 9:25 pm
Forum: Dipole Moments
Topic: How to tell
Replies: 2
Views: 81

Re: How to tell

Induced dipole-induced dipole interactions occur between all molecules. Dipole-dipole interactions occur between any molecules that have polar bonds, meaning there is an unequal sharing of electrons within the atoms of a molecule.
by Sidharth D 1E
Sun Nov 17, 2019 9:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs. Nonpolar
Replies: 8
Views: 91

Re: Polar vs. Nonpolar

They mean that the dipole-dipole vectors from two opposite atoms when added together equal to zero. A nonpolar molecule has a net dipole movement of zero.
by Sidharth D 1E
Sun Nov 17, 2019 9:19 pm
Forum: Hybridization
Topic: Hybridization focus
Replies: 4
Views: 42

Re: Hybridization focus

The test will probably focus on elements up until the 3p block.
by Sidharth D 1E
Sun Nov 17, 2019 9:15 pm
Forum: Hybridization
Topic: d orbital
Replies: 3
Views: 41

Re: d orbital

In terms of hybridization, this allows an atom to have up to 5 or 6 areas of surrounding electron density (whether it may be lone pairs or bonds) and the hybridization for those central atoms would be sp3d and sp3d2 respectively.
by Sidharth D 1E
Sun Nov 17, 2019 9:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape and lone pairs
Replies: 2
Views: 32

Re: Molecular shape and lone pairs

For the example you gave AX2E3, the lone pairs would be occupying the three planar areas of electron density and the two bonding locations would be on opposite poles, and that means the angle between them would be 180 degrees and the molecule as a whole would be linear.
by Sidharth D 1E
Sun Nov 17, 2019 9:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: single vs. double/triple bonds
Replies: 4
Views: 50

Re: single vs. double/triple bonds

The two electron pairs that are in a double bond stay together and repel other bonds or lone pairs together as a unit. The same goes for triple bonds and that is why they are considered as a single region of electron density in VSEPR.
by Sidharth D 1E
Sun Nov 10, 2019 11:36 pm
Forum: Bond Lengths & Energies
Topic: Size
Replies: 9
Views: 105

Re: Size

The bigger the atoms are that are bonded together, the larger the bond length due to the electron-electron repulsions of the electron shells that distance the nucleus of an atom from the valence electrons that are involved in the bonding.
by Sidharth D 1E
Sun Nov 10, 2019 11:35 pm
Forum: Bond Lengths & Energies
Topic: Bond Lengths
Replies: 2
Views: 40

Re: Bond Lengths

The additional bonding between the two atoms pulls the nuclei of the two atoms closer to each other, and for that reason double bonds are shorter than single bonds.
by Sidharth D 1E
Sun Nov 10, 2019 11:34 pm
Forum: Dipole Moments
Topic: Intermolecular Forces
Replies: 2
Views: 20

Re: Intermolecular Forces

Van der Waals forces are the dipole-dipole interactions that exist between all molecules due to the natural movement of electrons within each molecule. They are relatively weak interactions, but are increase with a greater number of electrons interacting between the atoms of two separate molecules.
by Sidharth D 1E
Sun Nov 10, 2019 11:31 pm
Forum: Electronegativity
Topic: Formula for Difference
Replies: 7
Views: 189

Re: Formula for Difference

I dont think need to know anything other than trends for electronegativity
by Sidharth D 1E
Sun Nov 10, 2019 11:30 pm
Forum: Dipole Moments
Topic: Dipole Moment
Replies: 6
Views: 63

Re: Dipole Moment

All molecules have some sort of dipole-dipole interaction (which is the van der Waals' forces that we discussed in class)
by Sidharth D 1E
Sun Nov 03, 2019 11:37 pm
Forum: Octet Exceptions
Topic: Period 3
Replies: 2
Views: 56

Re: Period 3

Atoms in that period have empty 3d-orbitals to accommodate for the expanded octet.
by Sidharth D 1E
Sun Nov 03, 2019 11:34 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge
Replies: 16
Views: 211

Re: Formal charge

The next best option is to have the most elements with a formal charge of 0, with negative formal charges with the most electronegative elements of the molecule and positive formal charges with the most electropositive elements of the molecule.
by Sidharth D 1E
Sun Nov 03, 2019 11:32 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge when it's not labelled?
Replies: 2
Views: 54

Re: Formal Charge when it's not labelled?

Yes, we should still account for formal charge, because it allows for us to figure out the best structure that would work for that molecule.
by Sidharth D 1E
Sun Nov 03, 2019 11:32 pm
Forum: Lewis Structures
Topic: Expanded Octet
Replies: 4
Views: 82

Re: Expanded Octet

Yes, it is more stable, because the formal charges for the molecule for the expanded octet result in the more dominant resonance structure.
by Sidharth D 1E
Sun Nov 03, 2019 11:29 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 3
Views: 66

Re: Ionization Energy

Ionization energy is the energy needed to remove an electron from an atom and electron affinity is the energy released when an electron is added to a gas-phase atom. Ionization energy increases down a period because an atom that only needs to lose one electron to form an octet, would require less en...
by Sidharth D 1E
Sun Oct 27, 2019 10:15 pm
Forum: Ionic & Covalent Bonds
Topic: 2A. 1 Question
Replies: 2
Views: 35

Re: 2A. 1 Question

Are those valence electrons also used in bonding when we draw out lewis structures?
by Sidharth D 1E
Sun Oct 27, 2019 10:11 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Constant
Replies: 3
Views: 54

Re: Heisenberg Constant

in the book, they abbreviate their "h" as being h/2(pi) already.
by Sidharth D 1E
Sun Oct 27, 2019 10:09 pm
Forum: Ionic & Covalent Bonds
Topic: electron configuration
Replies: 5
Views: 83

Re: electron configuration

They are different because to achieve maximum stability, those atoms take an electron from the 4s subshell and place it in the 3d subshell, so that they can have a full 3d subshell and half full 4s subshell (3d10 and 4s1).
by Sidharth D 1E
Sun Oct 27, 2019 10:01 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Stability of D orbitals
Replies: 3
Views: 54

Re: Stability of D orbitals

An atom is most stable when its subshells have complete orbitals (in this case d10) or when they have half complete orbitals (in this case d5). This is due to the symmetric distribution of electrons contributing to the atoms' stability
by Sidharth D 1E
Sun Oct 27, 2019 9:57 pm
Forum: Ionic & Covalent Bonds
Topic: Bond lengths
Replies: 3
Views: 47

Re: Bond lengths

In class, he gave us those as the experimentally found values for the bond lengths, so those are the values for those bonds in specifically those molecules.
by Sidharth D 1E
Sun Oct 20, 2019 1:03 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital questions
Replies: 1
Views: 43

Re: Orbital questions

Yes, for the 3d orbitals: they are dxy, dyz, dzx, dx2-y2, and dz2 respectively
by Sidharth D 1E
Sun Oct 20, 2019 1:00 pm
Forum: Trends in The Periodic Table
Topic: Period 5 trend
Replies: 2
Views: 53

Re: Period 5 trend

Because the principle quantum number of the 4d subshell is less than the principle quantum number of the 5s subshell (4 < 5), the 4d state has lower energy.
by Sidharth D 1E
Sun Oct 20, 2019 12:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: writing electron configurations
Replies: 4
Views: 65

Re: writing electron configurations

So, what 1s 2 2s 2 2px 2py, means, is that carbon has 6 electrons, and it occupies these locations. First, there are 2 electrons located in the 1s orbital (which if you are following the periodic table follow the spots of Hydrogen and Helium). Next, there are another 2 electrons located in the 2s or...
by Sidharth D 1E
Sun Oct 20, 2019 12:48 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: quantum number n, l, m
Replies: 13
Views: 155

Re: quantum number n, l, m

how are orbitals, shells, and subshells related to one another? im not sure i understand Shells are composed of electrons that share the same principal quantum number (n), whereas subshells are composed of electrons that share the same angular momentum quantum number (l). Orbitals are composed of e...
by Sidharth D 1E
Sun Oct 20, 2019 12:45 pm
Forum: Quantum Numbers and The H-Atom
Topic: d orbitals
Replies: 4
Views: 86

Re: d orbitals

Furthermore, it is written in that way, because if that element would lose an electron, it would lose it from the 4s2 orbital, not the 3d orbital.
by Sidharth D 1E
Sun Oct 13, 2019 5:39 pm
Forum: Properties of Electrons
Topic: Lyman, Balmer and Paschen Series
Replies: 2
Views: 30

Re: Lyman, Balmer and Paschen Series

Specifically, the ultraviolet region corresponds with the Lyman series, the visible region with the Balmer series, and the infrared region with the Paschen series.
by Sidharth D 1E
Sun Oct 13, 2019 5:34 pm
Forum: Properties of Electrons
Topic: Equations for electrons
Replies: 4
Views: 29

Re: Equations for electrons

Make sure to watch his Audio-Visual Focus Topic on Wave Properties of Light: https://lavelle.chem.ucla.edu/wp-conten ... t.wmv.html
by Sidharth D 1E
Sun Oct 13, 2019 5:24 pm
Forum: DeBroglie Equation
Topic: De Broglie's Equation
Replies: 4
Views: 100

Re: De Broglie's Equation

For example, for the problem we did with the 0.1 kg baseball moving at 35 m/s, the resulting wavelength that this mass would emit is 1.9 x 10-34 m, which is a wavelength we cannot measure and, therefore, prove or disprove.
by Sidharth D 1E
Sun Oct 13, 2019 5:13 pm
Forum: General Science Questions
Topic: Audio-Visual focus topics
Replies: 4
Views: 43

Re: Audio-Visual focus topics

There is no exact time when you are supposed to do the Audio-Visual focus topics, as some people prefer to use them for revision on topics we learn in class, or to learn from them before class. Personally, I use them for revision.
by Sidharth D 1E
Sun Oct 13, 2019 5:07 pm
Forum: Properties of Light
Topic: Memorization of Electromagnetic Spectrum
Replies: 3
Views: 71

Re: Memorization of Electromagnetic Spectrum

In addition, it's probably noteworthy that visible light exists at around a wavelength of 500 nm and that the human eye detects EM radiation (visible light) within the 700 nm (red light) to 400 nm (violet light) region.
by Sidharth D 1E
Sun Oct 06, 2019 7:48 pm
Forum: Empirical & Molecular Formulas
Topic: E15 Homework Problem
Replies: 3
Views: 140

Re: E15 Homework Problem

1st, I think the question is asking for the sulfide of the metal, not chloride (you mixed up E15 with E16) Step 1: Calculate the molar mass of the known parts of that compound [ the (OH) 2 ] molar mass of (OH) 2 is 34.02 g/mol Step 2: Subtract that known molar mass from the total to get the molar ma...
by Sidharth D 1E
Sun Oct 06, 2019 7:41 pm
Forum: Balancing Chemical Reactions
Topic: Question H17
Replies: 1
Views: 43

Re: Question H17

Step 1: Writing the base equation: C 7 H 16 (g) + O 2 (g) --> CO 2 (g) + H 2 O(g) Step 2: Balance the number of Carbons and Hydrogens on both sides because there are only one compound on either side that includes carbon, and one compound on either side that includes hydrogen: C 7 H 16 (g) + O 2 (g) ...
by Sidharth D 1E
Sun Oct 06, 2019 7:34 pm
Forum: Significant Figures
Topic: Homework
Replies: 4
Views: 84

Re: Homework

He means that the homework (5 problems) that we submit in our discussion sections, should be related to content that we have recently covered within our lectures. For the first week, our homework was due on a lecture day, but the next set of 5 problems are due next discussion class.
by Sidharth D 1E
Sun Oct 06, 2019 7:31 pm
Forum: Significant Figures
Topic: Sig Fig
Replies: 1
Views: 46

Re: Sig Fig

Our answer needs to have the same number of significant figures as the lowest number of significant numbers of any of the given values. For example, if we are given a sodium carbonate solution of 2.111 g to a 250. mL flask, the two givens have 4 significant figures and 3 significant figures respecti...
by Sidharth D 1E
Sun Oct 06, 2019 7:23 pm
Forum: Balancing Chemical Reactions
Topic: What's the matter?
Replies: 2
Views: 55

Re: What's the matter?

As far as what we have been practicing in our discussion sections, we do not need to worry about the states of the molecules until the very last step when stating a chemical equation or a net ionic equation.

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