Search found 109 matches

by 205154661_Dis2J
Sat Mar 14, 2020 4:24 pm
Forum: Balancing Redox Reactions
Topic: Oxidation/Reduction
Replies: 17
Views: 219

Re: Oxidation/Reduction

In Test 2, we were asked what species was being oxidized/reduced and for those, we looked at the molecule being reduced or oxidized.
by 205154661_Dis2J
Sat Mar 14, 2020 4:18 pm
Forum: Balancing Redox Reactions
Topic: Half rxns
Replies: 27
Views: 405

Re: Half rxns

There are two really helpful resources on Lavelle's website where it tells you what to do for acidic and basic solutions. From that, you can see what differs basic rxns from acidic rxns.
by 205154661_Dis2J
Sat Mar 14, 2020 4:17 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: n in NFE
Replies: 19
Views: 199

Re: n in NFE

N stands for the number of electrons transferred. So you would have to separate your redox rxns into the reduction and oxidation rxn in order to see how many electrons are being transferred after you balanced both reactions.
by 205154661_Dis2J
Sat Mar 14, 2020 4:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2 on Standard Cell Potential
Replies: 6
Views: 42

Re: Test 2 on Standard Cell Potential

To determine which rxn is your anode or cathode, remember that your highest Ecell would be your cathode and your lowest one would be your anode. Then when determining Gibbs free energy, you would use -nFE in order to figure it out.
by 205154661_Dis2J
Sat Mar 14, 2020 4:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: inert gases
Replies: 6
Views: 87

Re: inert gases

what of the elements such as platinum that seem to be attached to a cell diagram? Pt(s) is used as a conductor when there is no conductive solid participating in the redox reaction. It is added to the cell diagram but does not participate. Platinum is just used as a conductor when there is no condu...
by 205154661_Dis2J
Sat Mar 14, 2020 4:07 pm
Forum: Balancing Redox Reactions
Topic: Determing balanced rxns for a basic solution
Replies: 5
Views: 105

Re: Determing balanced rxns for a basic solution

There is a step-by-step PDF on Lavelle's website that is super clear and concise when balancing rxns for basic solutions. I have attached it below:

https://lavelle.chem.ucla.edu/wp-conten ... itions.pdf
by 205154661_Dis2J
Sat Mar 14, 2020 4:05 pm
Forum: Balancing Redox Reactions
Topic: Acid or base?
Replies: 5
Views: 146

Re: Acid or base?

We should be given the information in the question whether it is basic or acidic, whether it is explicitly stated or they give us the pH.
by 205154661_Dis2J
Sat Mar 14, 2020 4:04 pm
Forum: Balancing Redox Reactions
Topic: Test 2 Return
Replies: 20
Views: 335

Re: Test 2 Return

My TA said we would be able to pick it up from the graduate mailbox in Young Hall.
by 205154661_Dis2J
Sat Mar 14, 2020 4:03 pm
Forum: Balancing Redox Reactions
Topic: QD3 Midterm
Replies: 5
Views: 119

Re: QD3 Midterm

You are assuming that acetic acid dissolved into CHCH3COO- and H+ due to the pH of 6.
by 205154661_Dis2J
Sat Mar 14, 2020 3:59 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E potential
Replies: 8
Views: 73

Re: E potential

Yes, the cathode is always (I think) the highest Epotential and the lowest one is the anode.
by 205154661_Dis2J
Sat Mar 14, 2020 3:57 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Lyndon Review: 1D
Replies: 5
Views: 112

Re: Lyndon Review: 1D

If you are referring to the mass of the anode being increased, then the Ecell would not be affected. The mass does not affect the Ecell. As stated before, I believe this was a question on Test 2.
by 205154661_Dis2J
Sun Mar 01, 2020 11:26 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Determining n
Replies: 5
Views: 85

Determining n

How do you determine n? I find it pretty confusing at times.
by 205154661_Dis2J
Sun Mar 01, 2020 11:24 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8023
Views: 1404263

Re: Post All Chemistry Jokes Here

Q: What kind of dogs do chemists have?

A: Laboratory Retrievers.
by 205154661_Dis2J
Sun Mar 01, 2020 11:22 pm
Forum: General Rate Laws
Topic: Order
Replies: 5
Views: 74

Re: Order

You can look at the graphs provided or you can look at the units used in a specific problem if they do not specifically tell you which order it is. That is why it is important to know and memorize the units for the orders!
by 205154661_Dis2J
Sun Mar 01, 2020 11:20 pm
Forum: General Rate Laws
Topic: Integrated Rate Law
Replies: 5
Views: 62

Re: Integrated Rate Law

The differential rate law is rxn rate as a function of reactant concentration. The integrated rate law tells us how much reactant concentration changes over time, so we add the variable time to it.
by 205154661_Dis2J
Sun Mar 01, 2020 11:18 pm
Forum: General Rate Laws
Topic: tangent lines
Replies: 5
Views: 88

Re: tangent lines

You can just take the derivative to make it easier.
by 205154661_Dis2J
Sun Feb 23, 2020 11:34 pm
Forum: Balancing Redox Reactions
Topic: Test 2 Topics
Replies: 7
Views: 67

Re: Test 2 Topics

Test 2 includes the last page on Thermodynamics and what we have learned so far in Electrochemistry!
by 205154661_Dis2J
Sun Feb 23, 2020 11:33 pm
Forum: Balancing Redox Reactions
Topic: Test 2
Replies: 9
Views: 89

Re: Test 2

The test will be during Week 9 whenever you have your discussion!
by 205154661_Dis2J
Sun Feb 23, 2020 11:32 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: State
Replies: 5
Views: 39

Re: State

It should be given right next to the molecule, based on the context of the problem.
by 205154661_Dis2J
Sun Feb 23, 2020 11:30 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Difference in phases
Replies: 5
Views: 57

Re: Difference in phases

The single line represents molecules in different phases, whereas a comma separates the molecules but represents the same phase.
by 205154661_Dis2J
Sun Feb 23, 2020 11:29 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Positive or Negative Sign
Replies: 4
Views: 57

Re: Positive or Negative Sign

As stated above, you would change the sign to positive or negative depending on the direction of the reaction from the standard reduction potential. That is why it is also very important to know whether a half reaction is an oxidation or reduction.
by 205154661_Dis2J
Sun Feb 23, 2020 11:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 5
Views: 62

Re: salt bridge

A salt bridge maintains electrical neutrality within the internal circuit, which prevents the cell from rapidly running its reaction to equilibrium. When there is no net change anymore, the cell can no longer do work.
by 205154661_Dis2J
Sun Feb 23, 2020 11:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Platinum
Replies: 2
Views: 44

Platinum

Why did we use platinum on Friday in Lavelle's lecture? In what cases would we use it?
by 205154661_Dis2J
Sun Feb 16, 2020 11:07 pm
Forum: Balancing Redox Reactions
Topic: How do you combine half reactions together?
Replies: 2
Views: 19

How do you combine half reactions together?

How do you combine half reactions together?
by 205154661_Dis2J
Sun Feb 16, 2020 11:05 pm
Forum: Balancing Redox Reactions
Topic: Reduction vs. oxidation
Replies: 29
Views: 262

Re: Reduction vs. oxidation

As mentioned before, oxidation is losing electrons while reduction is gaining electrons. You can either memorize "the LEO goes GER" or OIL RIG.
by 205154661_Dis2J
Sun Feb 16, 2020 11:04 pm
Forum: Balancing Redox Reactions
Topic: Electrochemisty
Replies: 10
Views: 106

Re: Electrochemisty

The answer to this might be obvious but how does this connect to batteries? At a basic level, batteries are storage places for chemical reactions to occur. These chemical reactions can be used to generate electrical energy for our usage. In addition, Professor Lavelle mentioned on Friday that when ...
by 205154661_Dis2J
Sun Feb 16, 2020 11:02 pm
Forum: Balancing Redox Reactions
Topic: Memorizing charges
Replies: 11
Views: 100

Re: Memorizing charges

I believe we are expected to memorize the most common ones and it also good practice!
by 205154661_Dis2J
Sun Feb 16, 2020 11:01 pm
Forum: Balancing Redox Reactions
Topic: Why do we split equations?
Replies: 12
Views: 113

Why do we split equations?

I understand that splitting equations means separating the reduction equation from the oxidation equation but what is the purpose?
by 205154661_Dis2J
Sun Feb 16, 2020 10:58 pm
Forum: Balancing Redox Reactions
Topic: redox reaction
Replies: 10
Views: 85

Re: redox reaction

An acronym that I find very useful is as mentioned above, OIL RIG. Oxidation is losing electrons, reduction is gaining electrons.
by 205154661_Dis2J
Mon Feb 10, 2020 12:05 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: HW 4D7
Replies: 4
Views: 43

Re: HW 4D7

For gases, the change in enthalpy is defined by that equation. This is because when gas is produced work is done to clear the other gases so the enthalpy is lower than the internal energy. This is explained in detail on pg 274 in the textbook (4D.2) Thank you so much for explaining! Do you know why...
by 205154661_Dis2J
Sun Feb 09, 2020 11:58 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: when to change sign of enthalpies
Replies: 7
Views: 81

Re: when to change sign of enthalpies

If you mean 4A, we change the sign of enthalpies when we reverse the equation. For example, we reversed equation 2 because we wanted Vodka on the product side since we have it on the product side in the overall recipe. We then multiplied it by two since we want 2 Vodka on the product side to match t...
by 205154661_Dis2J
Sun Feb 09, 2020 11:53 pm
Forum: Phase Changes & Related Calculations
Topic: Homework Problem 4C.13
Replies: 3
Views: 43

Re: Homework Problem 4C.13

It is very helpful to draw the graph. We see that in order to melt ice, we need to go through the plateau on the heating curve that turns a solid into liquid. So we have to include that in our calculations .
by 205154661_Dis2J
Sun Feb 09, 2020 11:49 pm
Forum: Phase Changes & Related Calculations
Topic: 4B.5
Replies: 7
Views: 108

Re: 4B.5

We know that internal energy is q+w. We know from the question that q is 5.50kJ. Now we need to figure out the work done. Thus, we would be using the equation w = -PΔV to figure that out. Then when work is calculated, we add 5.50kJ + work done and that will be the change in internal energy.
by 205154661_Dis2J
Sun Feb 09, 2020 11:45 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: HW 4D7
Replies: 4
Views: 43

HW 4D7

For 4D7, why are we using the equation DeltaH= DeltaU + DeltaNRT? I do not quite understand why we are including DeltaNRT.
by 205154661_Dis2J
Sun Feb 09, 2020 11:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4C7
Replies: 1
Views: 30

4C7

For 4C7, I know we calculated the enthalpy of vaporization for part b by turning 22.45g of ethanol into moles (which gives you 0.48), and then dividing 21.2kJ of energy by 0.48. This, in turn gives you 44.16 for the enthalpy of vaporization but I do not understand the question conceptually. Why are ...
by 205154661_Dis2J
Sun Feb 09, 2020 11:32 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4D3
Replies: 1
Views: 40

4D3

For Part B on 4D3, I was a little confused on why we would use 1.40g of carbon monoxide to calculate the internal energy (converting that into moles) instead of 1.00 mol CO(g) which was what was given on part b. I might be totally reading the question wrong, but can someone explain it?
by 205154661_Dis2J
Mon Jan 27, 2020 12:11 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Reversible Reactions
Replies: 3
Views: 44

Re: Reversible Reactions

A chemical rxn is reversible when it can convert back to the reactants. For example, combustion is irreversible since its entirety was "consumed." For reversible rxns, the reactants are never fully consumed or dissociated/ionized.
by 205154661_Dis2J
Mon Jan 27, 2020 12:06 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Water Phase Change
Replies: 6
Views: 58

Re: Water Phase Change

As mentioned above, the molecules of water are held together by hydrogen bonding; breaking those bonds require a great amount of energy.
by 205154661_Dis2J
Mon Jan 27, 2020 12:04 am
Forum: Phase Changes & Related Calculations
Topic: Chem 14A Final Pickup
Replies: 8
Views: 82

Re: Chem 14A Final Pickup

You will still be able to pick up your Final this week!
by 205154661_Dis2J
Mon Jan 27, 2020 12:03 am
Forum: Phase Changes & Related Calculations
Topic: 3 Methods
Replies: 4
Views: 46

Re: 3 Methods

We will most likely be using all three; it definitely depends on what the question is asking. However, keep in mind that Method 2 is the least accurate as mentioned in lecture.
by 205154661_Dis2J
Mon Jan 27, 2020 12:02 am
Forum: Phase Changes & Related Calculations
Topic: Enthalpy
Replies: 5
Views: 63

Re: Enthalpy

Enthalpy is a state function because it only depends on initial and final values in the rxn; thus, the path doesn't matter.
by 205154661_Dis2J
Mon Jan 27, 2020 12:00 am
Forum: Phase Changes & Related Calculations
Topic: Hess's Law
Replies: 5
Views: 50

Re: Hess's Law

Similarly to the former statement, Hess' law allows us to combine equations to generate new rxns whose enthalpy change can be calculated, since it is a state function.
by 205154661_Dis2J
Sun Jan 19, 2020 11:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Q
Replies: 14
Views: 84

Re: K vs Q

K is a constant used when the rxn is at equilibrium. Q can be used at any time in the rxn to determine the shift of a rxn, either left or right.
by 205154661_Dis2J
Sun Jan 19, 2020 11:30 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Relationship between pressure and volume
Replies: 10
Views: 86

Re: Relationship between pressure and volume

As formerly mentioned, pressure and volume are inversely proportional. When volume decreases, pressure increases. When volume increases, pressure decreases.
by 205154661_Dis2J
Sun Jan 19, 2020 11:27 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Effect of increasing pressure on reactions
Replies: 6
Views: 83

Re: Effect of increasing pressure on reactions

The reaction would shift towards the side with fewer moles!
by 205154661_Dis2J
Sun Jan 19, 2020 11:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5% rule
Replies: 8
Views: 70

Re: 5% rule

We test it out by dividing equilibrium concentration/initial concentration x 100. if the value is less than 5%, the approximation is valid.
by 205154661_Dis2J
Sun Jan 19, 2020 11:18 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Shifts Left or Right
Replies: 15
Views: 170

Re: Reaction Shifts Left or Right

The reaction will shift to the left because the reverse reaction is endothermic. Increasing heat/temperature will cause the rxn to favor the reactants.
by 205154661_Dis2J
Sun Jan 12, 2020 5:54 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: appliction of principle
Replies: 5
Views: 52

Re: appliction of principle

Le Chatelier's Principle applies to changes in temperature, volume or concentration.
by 205154661_Dis2J
Sun Jan 12, 2020 5:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for K
Replies: 21
Views: 206

Re: Units for K

Equilibrium constants have no units; this is because it is a ratio of similar quantities.
by 205154661_Dis2J
Sun Jan 12, 2020 5:32 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction shifts right or left?
Replies: 14
Views: 211

Re: Reaction shifts right or left?

If the rxn shifts left, that means that a forward reaction is favored, thus producing more reactants. If the rxn shifts right, that means that a reverse reaction is favored, thus producing more products.
by 205154661_Dis2J
Sun Jan 12, 2020 5:28 pm
Forum: Ideal Gases
Topic: Bars vs atmospheres
Replies: 13
Views: 88

Re: Bars vs atmospheres

They are both units of pressure; I think it depends on the question and what units that specific question wants you to use.
by 205154661_Dis2J
Sun Jan 12, 2020 5:15 pm
Forum: Ideal Gases
Topic: Units of Pressure
Replies: 8
Views: 73

Re: Units of Pressure

I do not think we will be expected to memorize them as it will most likely be provided in a formula sheet but it is good to understand them!
by 205154661_Dis2J
Sun Jan 12, 2020 5:12 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: changing conditions
Replies: 6
Views: 59

Re: changing conditions

As explained by Dr. Lavelle, a reaction tends to favor the side that has less substance to reach equilibrium. If we take away product, the reaction will favor the products in order to balance the products and reactants or reach equilibrium.
by 205154661_Dis2J
Sun Jan 12, 2020 5:07 pm
Forum: Ideal Gases
Topic: PV = nRT
Replies: 16
Views: 160

Re: PV = nRT

The P stands for pressure
V is volume
n is the number of moles
R is the ideal gas constant
and T is temperature.
by 205154661_Dis2J
Sun Jan 12, 2020 5:03 pm
Forum: Ideal Gases
Topic: Topics on Test 1
Replies: 37
Views: 417

Re: Topics on Test 1

Test 1 will probably consist of Outline 1 and Outline 2!
by 205154661_Dis2J
Sun Dec 08, 2019 3:38 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8023
Views: 1404263

Re: Post All Chemistry Jokes Here

I am definitely "(dien)" after that chemistry final!!!!
by 205154661_Dis2J
Sun Dec 08, 2019 3:31 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bond
Replies: 8
Views: 194

Re: Coordinate Covalent Bond

In a regular covalent bond, the atoms involved in the bonding share a pair of electrons. However, in a coordinate covalent bond, two electrons are contributed by a single atom.
by 205154661_Dis2J
Sun Dec 08, 2019 3:27 pm
Forum: Sigma & Pi Bonds
Topic: Sigma Vs Pi
Replies: 10
Views: 217

Re: Sigma Vs Pi

Sigma bonds are stronger than pi bonds because sigma bonds head-on overlap while pi bonds overlap side by side. When there is one bond, that forms a sigma bond. When there are two bonds, there is one sigma bond and pi bond. When there are three bonds, there are 2pi bonds and one sigma bond.
by 205154661_Dis2J
Sun Dec 08, 2019 3:20 pm
Forum: Properties of Light
Topic: Speed of Light
Replies: 7
Views: 236

Re: Speed of Light

The standard unit for speed of light is m / s. The units are also given in the constants sheet provided to us during finals/midterms.
by 205154661_Dis2J
Sun Dec 08, 2019 3:17 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8023
Views: 1404263

Re: Post All Chemistry Jokes Here

When you tell a chemistry joke and there are no reactions :(
by 205154661_Dis2J
Fri Dec 06, 2019 12:16 pm
Forum: Electronegativity
Topic: Periodic Table Trend
Replies: 5
Views: 151

Periodic Table Trend

What is the trend for electronegativity and ionization energy?
by 205154661_Dis2J
Fri Dec 06, 2019 11:41 am
Forum: Coordinate Covalent Bonds
Topic: Coordinate covalent bonds
Replies: 7
Views: 209

Re: Coordinate covalent bonds

I understand the coordinate covalent bonds are covalent bonds in which both electrons come from the same atom, but what does the necessarily mean? I do not quite understand what it is stating.
by 205154661_Dis2J
Fri Dec 06, 2019 11:30 am
Forum: Coordinate Covalent Bonds
Topic: Hemoglobin and Myoglobin
Replies: 1
Views: 132

Hemoglobin and Myoglobin

What about hemoglobin and myoglobin do we need to know for the final?
by 205154661_Dis2J
Fri Dec 06, 2019 11:28 am
Forum: Dipole Moments
Topic: Melting and Boiling Points
Replies: 9
Views: 242

Melting and Boiling Points

Can we assume that melting and boiling points will always be higher for hydrogen bonds than any other intermolecular force?
by 205154661_Dis2J
Fri Dec 06, 2019 11:02 am
Forum: Resonance Structures
Topic: Resonance
Replies: 3
Views: 118

Resonance

Can resonance structures determine the strength of an acid? Or is there no correlation between both?
by 205154661_Dis2J
Fri Dec 06, 2019 10:14 am
Forum: Trends in The Periodic Table
Topic: Atomic Radius vs Ionic Radius
Replies: 3
Views: 138

Atomic Radius vs Ionic Radius

I know atomic radius and ionic radius both follow the same periodic trend but what is the difference between them?
by 205154661_Dis2J
Wed Dec 04, 2019 8:36 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordinate Compounds
Replies: 3
Views: 44

Coordinate Compounds

What are some key concepts to know about coordinate compounds for the final?
by 205154661_Dis2J
Mon Dec 02, 2019 5:48 pm
Forum: Lewis Acids & Bases
Topic: Definition
Replies: 7
Views: 111

Re: Definition

A Lewis acid is an electron-pair acceptor while a Lewis base is an electron-pair donor.
by 205154661_Dis2J
Mon Dec 02, 2019 5:18 pm
Forum: Conjugate Acids & Bases
Topic: Water as an Acid/Base
Replies: 20
Views: 631

Re: Water as an Acid/Base

Yes H2O is an amphoteric compound so it depends fully on what it is reacting with.
by 205154661_Dis2J
Mon Dec 02, 2019 5:13 pm
Forum: Biological Examples
Topic: Chemotherapy
Replies: 6
Views: 105

Re: Chemotherapy

I think for class, we need to know mainly about Cisplatin, which binds to DNA to kill cancer cells.
by 205154661_Dis2J
Mon Dec 02, 2019 4:26 pm
Forum: Lewis Acids & Bases
Topic: Long bonds vs Short bonds?
Replies: 9
Views: 151

Re: Long bonds vs Short bonds?

Since long bonds are farther away from the nuclei, it is easier to remove H+ so thus long bonds are strong acids. Conversely, short bonds are harder to break so they are weak acids.
by 205154661_Dis2J
Mon Dec 02, 2019 4:19 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Class wed 11/27
Replies: 7
Views: 85

Re: Class wed 11/27

Lavelle went over neutralization and relative acidity. He also stated that an acidic solution's H3O+ is greater than OH- and the opposite occurs for basic solutions.
by 205154661_Dis2J
Mon Dec 02, 2019 4:07 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Ionization in Water
Replies: 8
Views: 601

Re: Ionization in Water

Strong bases are completely ionized in water while weak bases are partially/incompletely ionized in water.
by 205154661_Dis2J
Mon Dec 02, 2019 3:59 pm
Forum: Lewis Acids & Bases
Topic: Lewis acid & Bronstead Acid
Replies: 3
Views: 55

Re: Lewis acid & Bronstead Acid

A Lewis acid is an electron acceptor while a Bronsted acid is a proton donor.
by 205154661_Dis2J
Mon Dec 02, 2019 3:56 pm
Forum: Lewis Acids & Bases
Topic: Weak vs. Strong
Replies: 8
Views: 252

Re: Weak vs. Strong

Strong acids are completely ionized in water or solution while strong bases are completely ionized in solution. Weak acids and bases are partially dissociated in water/solution.
by 205154661_Dis2J
Mon Dec 02, 2019 3:53 pm
Forum: Amphoteric Compounds
Topic: Identifying Amphoteric Compounds
Replies: 5
Views: 61

Re: Identifying Amphoteric Compounds

The one amphoteric compound we have gone over in lecture is H2O since it can act as a base and acid. I think it is sufficient enough to know that H2O is the main amphoteric compound.
by 205154661_Dis2J
Sun Nov 24, 2019 8:25 pm
Forum: Hybridization
Topic: Hybrid orbitals
Replies: 5
Views: 55

Re: Hybrid orbitals

You always draw the Lewis structure first to determine the hybrid orbitals.
by 205154661_Dis2J
Sun Nov 24, 2019 8:18 pm
Forum: Dipole Moments
Topic: Polar or nonpolar
Replies: 8
Views: 134

Re: Polar or nonpolar

O2 would be considered nonpolar since the bonds are evenly distributed and cancel out, thus there is no net dipole. We can also say that because they have the same electronegativity, there is never an electronegativity difference between them, therefore it is nonpolar.
by 205154661_Dis2J
Sun Nov 24, 2019 8:14 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 15
Views: 310

Re: Electronegativity

The higher the electronegativity, the stronger the bond is and the shorter the bond length is. Since the electronegativity is higher, then the closer a bond becomes to being ionic rather than covalent.
by 205154661_Dis2J
Sun Nov 24, 2019 8:10 pm
Forum: Sigma & Pi Bonds
Topic: Sigma and Pi Bonds
Replies: 7
Views: 98

Re: Sigma and Pi Bonds

A single bond is a sigma bond, while a pi bond occurs with double and triple bonds. For double bonds, there is one pi bond and sigma bond. For a triple bond, there is two sigma bonds and one pi bond.
by 205154661_Dis2J
Sun Nov 24, 2019 8:08 pm
Forum: Ionic & Covalent Bonds
Topic: Hydrogen Bond Sites
Replies: 5
Views: 188

Re: Hydrogen Bond Sites

If an H bonds with a Fluorine, Nitrogen, or Oxygen, it is considered a hydrogen bond.
by 205154661_Dis2J
Sun Nov 24, 2019 8:07 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordinate covalent bonds
Replies: 5
Views: 68

Re: Coordinate covalent bonds

A coordinate covalent bond is when one atom donates both electrons in a covalent bond.
by 205154661_Dis2J
Sun Nov 24, 2019 8:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Shape
Replies: 29
Views: 731

Re: Bent Shape

A bent shape can have up to one or two lone pairs around the central atom.
by 205154661_Dis2J
Sun Nov 17, 2019 8:26 pm
Forum: Bond Lengths & Energies
Topic: Electron Density
Replies: 10
Views: 198

Re: Electron Density

Yes, lone pairs are considered regions of electron density because they alter the molecular structure significantly. For example, a lone pair on a central atom can turn a trigonal planar into a trigonal pyramidal.
by 205154661_Dis2J
Sun Nov 17, 2019 8:23 pm
Forum: Bond Lengths & Energies
Topic: Shorter bond lengths
Replies: 12
Views: 116

Re: Shorter bond lengths

The bond length between atoms with two or more bonds are shorter than those with single bonds. The more electrons, the stronger the pull is and the shorter the bond length is.
by 205154661_Dis2J
Sun Nov 17, 2019 8:16 pm
Forum: Bond Lengths & Energies
Topic: Angle Distortion
Replies: 4
Views: 63

Re: Angle Distortion

We can tell when a VSEPR model has distortion because usually the central atom will have a lone pair or more. When the central atom has a lone pair, it pushes the bond electrons closer to one another, thereby making the bond angle smaller.
by 205154661_Dis2J
Sun Nov 17, 2019 8:12 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 7
Views: 95

Re: Polarity

For a molecule to be polar, it must possess a non-zero value of dipole moment. In the molecule CCl4, the bond polarity is canceled by the symmetric tetrahedral shape causing the dipole moment to be zero.
by 205154661_Dis2J
Sun Nov 17, 2019 8:05 pm
Forum: Bond Lengths & Energies
Topic: Bond Length
Replies: 15
Views: 259

Re: Bond Length

The bond length is determined experimentally, so we do not determine the bond lengths ourselves.
by 205154661_Dis2J
Sun Nov 03, 2019 10:29 pm
Forum: Bond Lengths & Energies
Topic: Why Are Double Bonds Shorter
Replies: 16
Views: 511

Re: Why Are Double Bonds Shorter

Double bonds are shorter because the pull/attraction to the nucleus is greater than single bonds.
by 205154661_Dis2J
Sun Nov 03, 2019 10:24 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Distorted Electrons
Replies: 4
Views: 106

Re: Distorted Electrons

What exactly are the characteristics of distorted electrons?
by 205154661_Dis2J
Sun Nov 03, 2019 10:22 pm
Forum: Electronegativity
Topic: electronegativity trend
Replies: 9
Views: 91

Re: electronegativity trend

Electronegativity goes down the periodic table because as the electrons are farther away from the nucleus, there is decreased attraction thereby lessening the pull.
by 205154661_Dis2J
Sun Nov 03, 2019 10:19 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bonds
Replies: 5
Views: 223

Coordinate Covalent Bonds

What is exactly the significance of coordinate covalent bonds and how does it help us understand bond structure in general?
by 205154661_Dis2J
Sun Nov 03, 2019 10:17 pm
Forum: Octet Exceptions
Topic: Expanded Valence Shells
Replies: 6
Views: 61

Re: Expanded Valence Shells

Elements past the third period can have expanded valence shells due to the presence of a d-orbital.
by 205154661_Dis2J
Sun Oct 27, 2019 2:32 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent bonds
Replies: 5
Views: 81

Re: Covalent bonds

Usually, covalent bonds are between two nonmetals and involves the sharing of electron pairs between atoms. There might be some exceptions to it, as the individual above stated but mainly, covalent bonds are between two nonmetals.
by 205154661_Dis2J
Sun Oct 27, 2019 2:25 pm
Forum: Lewis Structures
Topic: Anion/Cations
Replies: 2
Views: 46

Anion/Cations

How exactly would I represent anions and cations in Lewis structures? Would these be implied by removing an electron from the Lewis structure if it is cation and adding an electron if it is an anion?
by 205154661_Dis2J
Sun Oct 27, 2019 2:20 pm
Forum: Lewis Structures
Topic: Expanded Octet
Replies: 6
Views: 64

Re: Expanded Octet

It is stated that d-orbitals can carry more than 8e-. The examples that Dr. Lavelle gave in lecture were the elements, Chlorine, Phosphorus and Sulfur.
by 205154661_Dis2J
Sun Oct 27, 2019 2:11 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 8
Views: 71

Resonance

Is the purpose of resonance structures to help us draw the best/most accurate Lewis Structure? I am still slightly confused on resonance and what the purpose of it is.
by 205154661_Dis2J
Sun Oct 27, 2019 1:29 pm
Forum: Lewis Structures
Topic: Clarification
Replies: 6
Views: 81

Clarification

Can someone explain whether the octet rule is more important than obtaining a 0 formal charge or vice versa?

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