Search found 93 matches

by Mina Tadros 3L
Sun Feb 28, 2021 11:14 pm
Forum: Ideal Gases
Topic: K and Q
Replies: 16
Views: 426

Re: K and Q

Q is the reaction quotient, which is the ratio of products to reactants that are not at equilibrium. In contrast, K is the equilibrium constant, which is also the ratio of products to reactants, but they have already reached equilibrium.
by Mina Tadros 3L
Sun Feb 28, 2021 11:11 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: n in ∆G = -nFE
Replies: 52
Views: 124

Re: n in ∆G = -nFE

n is the number of moles of electrons that are being transferred after balancing the redox reaction.
by Mina Tadros 3L
Sun Feb 28, 2021 11:08 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Molar Entropy
Replies: 10
Views: 22

Re: Molar Entropy

The higher the atomic number, the greater the number of microstates, which increases the disorder.
by Mina Tadros 3L
Sun Feb 28, 2021 11:06 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: work
Replies: 19
Views: 38

Re: work

When work is done on the system, the work is positive, but when the system does work, the work is negative.
by Mina Tadros 3L
Sun Feb 28, 2021 11:03 pm
Forum: *Electrophiles
Topic: Anode vs Cathode
Replies: 12
Views: 22

Re: Anode vs Cathode

The anode is where oxidation occurs (releasing electrons), whereas the cathode is where reduction occurs (the gaining of electrons). I don't really know of a mnemonic that could help you easily differentiate between the two.
by Mina Tadros 3L
Sun Feb 21, 2021 8:07 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Q and K
Replies: 35
Views: 78

Re: Q and K

If Q>K, then there are more products present than is needed for equilibrium; thus, the reaction will proceed to the reactants until equilibrium is established. If Q<K, then there are more reactants present than is needed for equilibrium to be established; thus, the reaction will proceed towards the ...
by Mina Tadros 3L
Sun Feb 21, 2021 8:02 pm
Forum: Balancing Redox Reactions
Topic: cool acronym
Replies: 25
Views: 99

Re: cool acronym

I also learned this acronym in AP chem, haha! It honestly is very helpful.
by Mina Tadros 3L
Sun Feb 21, 2021 7:53 pm
Forum: Student Social/Study Group
Topic: Post Midterm 2 De-stressing
Replies: 92
Views: 258

Re: Post Midterm 2 De-stressing

To be honest, I usually just take a nap after a stressful midterm/week. It helps me recharge and be prepared for the next week.
by Mina Tadros 3L
Sun Feb 21, 2021 7:52 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Hfus
Replies: 9
Views: 22

Re: Hfus

You would use delta H fusion when you are dealing with a phase change from a solid to a liquid.
by Mina Tadros 3L
Sun Feb 21, 2021 7:50 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Which R Values to use
Replies: 21
Views: 50

Re: Which R Values to use

When you are dealing with the ideal gas law, PV=nRT, you would use 0.08206 since its units are (atm)(L)/(mol)(K). This matches every aspect of the ideal gas law. However, it depends on the units you are given. For instance, one of the R values is 8.314 J/(K)(mol). This is typically used when you are...
by Mina Tadros 3L
Sun Feb 14, 2021 9:54 pm
Forum: Calculating Work of Expansion
Topic: U, q, w
Replies: 11
Views: 53

Re: U, q, w

Delta U = q + w, delta U being the change in internal energy, q being the heat added or released from the system, and w is the work the system does. When q = 0, then you are dealing with an isothermal system, meaning delta U = 0 and therefore, q = -w. When the system does not work due to constant vo...
by Mina Tadros 3L
Sun Feb 14, 2021 9:42 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Adding Equations
Replies: 16
Views: 42

Re: Adding Equations

Whenever you are dealing with state properties such as enthalpy and entropy, you can add every process and calculation conducted. This is because it does not matter what path the system undertook. All we care about is the final and initial states.
by Mina Tadros 3L
Sun Feb 14, 2021 9:40 pm
Forum: Administrative Questions and Class Announcements
Topic: cc update
Replies: 23
Views: 128

Re: cc update

Dr. Lavelle usually updates them after every midterm, so the chem community posts will most likely be updated soon since our 2nd midterm is coming up.
by Mina Tadros 3L
Sun Feb 14, 2021 9:38 pm
Forum: Calculating Work of Expansion
Topic: negative vs positive work
Replies: 21
Views: 62

Re: negative vs positive work

When the system is compressed, work is positive, but when the system expands, work is negative since it is doing work by pushing against external pressure.
by Mina Tadros 3L
Sun Feb 14, 2021 9:33 pm
Forum: Student Social/Study Group
Topic: Fav Shows of the Moment
Replies: 104
Views: 252

Re: Fav Shows of the Moment

Attack on Titan and Jujutsu Kaisen! Highly recommend both!
by Mina Tadros 3L
Sun Feb 07, 2021 3:39 pm
Forum: Phase Changes & Related Calculations
Topic: H and q
Replies: 47
Views: 183

Re: H and q

Heat, which is not a state function, is denoted by q, while enthalpy, which is a change in heat at constant pressure, is a state function, and thus, it is denoted by delta H.
by Mina Tadros 3L
Sun Feb 07, 2021 3:36 pm
Forum: Phase Changes & Related Calculations
Topic: Endothermic v. Exothermic
Replies: 106
Views: 331

Re: Endothermic v. Exothermic

Exothermic reactions are a release in heat and, thus, they have a negative value associated with them. An absorption in energy/heat is an endothermic process, and, therefore, it will always be positive.
by Mina Tadros 3L
Sun Feb 07, 2021 3:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem Community Grade Error
Replies: 15
Views: 102

Re: Chem Community Grade Error

Dr. Lavelle included this week in the grading, but don’t worry, once you complete your posts for this week, it will automatically update. As long as you have 50 posts by the end of the quarter, you’ll be fine.
by Mina Tadros 3L
Sun Feb 07, 2021 3:26 pm
Forum: Phase Changes & Related Calculations
Topic: Vapor vs gas
Replies: 96
Views: 258

Re: Vapor vs gas

Vapor and gas are the same thing.
by Mina Tadros 3L
Sun Feb 07, 2021 3:26 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Can heat capacities be negative?
Replies: 52
Views: 161

Re: Can heat capacities be negative?

Heat capacity cannot be negative because it is the amount of energy required to raise a substance's temperature by 1 degree Celsius.
by Mina Tadros 3L
Sun Jan 31, 2021 11:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Taking the Anti-Log
Replies: 36
Views: 120

Re: Taking the Anti-Log

To go from pKa or pKb to Ka or Kb, you would do 10^-(pKa or pKb).
by Mina Tadros 3L
Sun Jan 31, 2021 11:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water as a Reactant
Replies: 9
Views: 36

Re: Water as a Reactant

Just like everyone has been saying, you would assume it is a liquid unless stated otherwise. Also, since liquid water is in large excess in a reaction, it is disregarded from the equilibrium constant.
by Mina Tadros 3L
Sun Jan 31, 2021 11:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKa and conjugate base
Replies: 4
Views: 21

Re: pKa and conjugate base

The larger the pKa, the weaker the acid and the weaker the acid, the stronger is its conjugate base.
by Mina Tadros 3L
Sun Jan 31, 2021 11:11 pm
Forum: Ideal Gases
Topic: Exo vs Endothermic
Replies: 30
Views: 114

Re: Exo vs Endothermic

Endothermic is when heat is absorbed, so there is sufficient energy to break the bonds within a molecule. Exothermic, on the other hand, is when energy is released, which typically occurs when bonds are being formed. You would know it is exothermic for this reaction because it appears to be a combus...
by Mina Tadros 3L
Sun Jan 31, 2021 11:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: is HClO3 weak or strong? [ENDORSED]
Replies: 49
Views: 258

Re: is HClO3 weak or strong? [ENDORSED]

HClO3 is a strong acid.
by Mina Tadros 3L
Sun Jan 24, 2021 9:35 pm
Forum: Ideal Gases
Topic: Bars to atm [ENDORSED]
Replies: 41
Views: 244

Re: Bars to atm [ENDORSED]

Dr. Lavelle said that we should assume 1 bar=1 atm since they are relatively close in amount to be considered equivalent in our calculations.
by Mina Tadros 3L
Sun Jan 24, 2021 9:33 pm
Forum: Student Social/Study Group
Topic: Study Strategies
Replies: 31
Views: 61

Re: Study Strategies

Do as many practice problems as you can, read the textbook, review your notes, and attend review sessions. Hope this helps :)
by Mina Tadros 3L
Sun Jan 24, 2021 9:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to use ICE box
Replies: 23
Views: 116

Re: When to use ICE box

You would use the ICE box when you are given an initial concentration of a weak acid or base, and you are trying to calculate the equilibrium concentration of both the products and the reactants.
by Mina Tadros 3L
Sun Jan 24, 2021 9:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #2 Week 2
Replies: 5
Views: 22

Re: Sapling #2 Week 2

You have to check if and see if it truly is negligible or not. The way you do that is by calculating the percentage protanated or deprotonated. If the percentage is less than 5%, it is fine to disregard the x in the denominator in your calculation. However, if it is greater than 5%, you will have to...
by Mina Tadros 3L
Sun Jan 24, 2021 9:23 pm
Forum: Phase Changes & Related Calculations
Topic: Steam
Replies: 32
Views: 140

Re: Steam

Steam burns at 100 degrees Celcius are more severe than water burns at 100 degrees Celcius because you have to consider the amount of energy required for the phase change. Thus, when steam begins to condense when it touches a colder surface, you have to add the energy released from the phase change ...
by Mina Tadros 3L
Sun Jan 17, 2021 11:11 pm
Forum: Phase Changes & Related Calculations
Topic: Determining Stronger Acids
Replies: 18
Views: 57

Re: Determining Stronger Acids

The smaller the pKa, the stronger the acid. Also, the greater the Ka, the stronger the acid.
by Mina Tadros 3L
Sun Jan 17, 2021 11:09 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 46
Views: 205

Re: Q and K

Q is the reaction quotient, which is essentially the ratio of products to reactants of a reaction that is not at equilibrium. K, on the other hand, is the equilibrium constant, which is the ratio of products to reactants at equilibrium. You can relate Q to K to find out which direction the reaction ...
by Mina Tadros 3L
Sun Jan 17, 2021 11:06 pm
Forum: Student Social/Study Group
Topic: Chemistry Community Posts
Replies: 22
Views: 68

Re: Chemistry Community Posts

You have to complete 5 posts every week for a total of 50 posts by the end of the quarter.
by Mina Tadros 3L
Sun Jan 17, 2021 11:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units to know
Replies: 11
Views: 40

Re: Units to know

You should also know atmospheres and torr (1 atm=760 torr) when dealing with partial pressures.
by Mina Tadros 3L
Sun Jan 17, 2021 11:02 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Ka vs. Kb
Replies: 30
Views: 129

Re: Ka vs. Kb

Ka is the acidity constant, whereas Kb is the basicity constant. They are both solved in the same way: [P]/[R]. You would use them whenever a question asks for you to solve for the equilibrium constant or you are trying to calculate the equilibrium concentration of a reactant or product that is pres...
by Mina Tadros 3L
Sun Jan 17, 2021 10:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: C in ICE Box
Replies: 19
Views: 86

Re: C in ICE Box

Whatever is reacting to form something else will be the negative one. That is because as the reaction proceeds, the reactant's concentration will begin to decrease while the product(s) it is forming will be increasing. That is why it would be positive for products, and for reactants, it would be neg...
by Mina Tadros 3L
Sun Jan 10, 2021 11:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: change in K
Replies: 22
Views: 106

Re: change in K

Temperature is the only factor that affects K. For instance, if you are dealing with an endothermic reaction, and you increase the temperature, the system will try to offset this increase in temperature by shifting towards the products. This will cause the product's concentration to increase and, th...
by Mina Tadros 3L
Sun Jan 10, 2021 11:01 pm
Forum: Ideal Gases
Topic: T variable in pv=nrt [ENDORSED]
Replies: 38
Views: 326

Re: T variable in pv=nrt [ENDORSED]

When dealing with the ideal gas law, you must always use kelvin for temperature.
by Mina Tadros 3L
Sun Jan 10, 2021 10:56 pm
Forum: Ideal Gases
Topic: Kc vs Kp
Replies: 109
Views: 1004

Re: Kc vs Kp

When you are given the concentration of the reactants and products, you use Kc. However, if you are given the partial pressures of the reactants and products, you would use Kp.
by Mina Tadros 3L
Sun Jan 10, 2021 10:51 pm
Forum: Ideal Gases
Topic: Non-Ideal gases?
Replies: 26
Views: 154

Re: Non-Ideal gases?

Pretty sure we will be only dealing with ideal gasses in this course.
by Mina Tadros 3L
Sun Jan 10, 2021 10:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs. Q
Replies: 53
Views: 218

Re: K vs. Q

Correct. Whenever you take the ratio of the concentration (or partial pressure) of products over reactants when it is not at equilibrium, you are solving for Q, the reaction quotient. If the reaction is at equilibrium, then the ratio of products to reactants is the equilibrium constant, K.
by Mina Tadros 3L
Sun Jan 10, 2021 10:46 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O
Replies: 44
Views: 332

Re: H2O

You only include H2O in the equilibrium constant if it is a gas. If it is a solid or a liquid, you do not include it.
by Mina Tadros 3L
Thu Dec 17, 2020 3:13 am
Forum: General Science Questions
Topic: 14B enrollment
Replies: 9
Views: 128

Re: 14B enrollment

Yes. Dr. Lavelle has designed this course to flow smoothly, with every new topic covered being built upon the previous topics discussed. Since we ended with an introduction to acids and bases in Chem 14A, I believe we will begin with a more detailed explanation of acids and bases in Chem 14B.
by Mina Tadros 3L
Thu Dec 17, 2020 3:07 am
Forum: *Titrations & Titration Calculations
Topic: Polyprotic Acids and Bases
Replies: 3
Views: 72

Re: Polyprotic Acids and Bases

Polyprotic acids are acids that are able to be deprotonated more than once. For instance, H2SO4: 1) H2SO4 + H2O ----> HSO4^- + H+ 2) HSO4^- + H20 ----> SO4^2- + H+.
by Mina Tadros 3L
Thu Dec 17, 2020 3:01 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook problem 9C.9
Replies: 4
Views: 32

Re: Textbook problem 9C.9

Coordination numbers are the number of ligands that are attached to the central metal cation. These are only for the ligands within the coordination sphere. Since [NiCl4] has 4 ligands attached to the central metal cation, then it has a coordination number of 4. [Ag(NH3)2] has two, thus, it has a co...
by Mina Tadros 3L
Thu Dec 17, 2020 2:57 am
Forum: Lewis Acids & Bases
Topic: Lewis vs Bronsted
Replies: 20
Views: 114

Re: Lewis vs Bronsted

Lewis acids and bases deal with electrons, whereas Bronsted acids and bases deal with protons. A Lewis acid is any atom that can accept a pair of electrons from a lewis base, forming a coordinate covalent bond. A Bronsted acid is a compound that is able to release a proton (H+). A Bronsted base is a...
by Mina Tadros 3L
Thu Dec 17, 2020 2:54 am
Forum: General Science Questions
Topic: Passing Grade
Replies: 34
Views: 288

Re: Passing Grade

50% of all the points you can earn (250/500) would give you a C-, which is considered a passing grade.
by Mina Tadros 3L
Sun Dec 06, 2020 10:53 pm
Forum: Bronsted Acids & Bases
Topic: Strong & Weak Acid
Replies: 6
Views: 45

Re: Strong & Weak Acid

The longer the bond, the stronger the acid. This is because longer bonds are weaker in strength, and thus, are easier to deprotonate.
by Mina Tadros 3L
Sun Dec 06, 2020 10:43 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Ligands
Replies: 9
Views: 124

Re: Ligands

The number of ligands is the number of lewis bases (electron-pair donors) attached to the central metal cation. This would also be the coordination number for the coordination compound.
by Mina Tadros 3L
Sun Dec 06, 2020 10:39 pm
Forum: Significant Figures
Topic: When should I start looking at sig figs?
Replies: 31
Views: 256

Re: When should I start looking at sig figs?

I always do all the calculations first, and then I look for sig figs at the very end. This allows my answer to be as accurate as possible, with very minimal to no rounding error.
by Mina Tadros 3L
Sun Dec 06, 2020 10:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 7
Views: 40

Re: Polarity

Yes, if the molecule has polar bonds, but the dipole moments cancel, it would be a nonpolar molecule.
by Mina Tadros 3L
Sun Dec 06, 2020 10:32 pm
Forum: Student Social/Study Group
Topic: How are you?
Replies: 117
Views: 885

Re: How are you?

Stressed. Studying for finals and finishing up remaining assignments has been exhausting. I cannot wait for break.
by Mina Tadros 3L
Sun Nov 29, 2020 11:39 pm
Forum: Significant Figures
Topic: 40. versus 40
Replies: 23
Views: 192

Re: 40. versus 40

Correct.
by Mina Tadros 3L
Sun Nov 29, 2020 11:36 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Polarity
Replies: 14
Views: 89

Re: Polarity

Lone pairs do not automatically make a molecule polar. Only if the lone pairs are located in one particular section of the molecule (thus, they're not canceling each other) will the molecule be polar.
by Mina Tadros 3L
Sun Nov 29, 2020 11:32 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 11
Views: 89

Re: Resonance

Certain resonance structures have a more stable formal charge since they are closer to 0. Structures with the least amount of formal charge tend to be the most stable, and thus, they are the resonance structures that contribute the most to the molecular structure.
by Mina Tadros 3L
Sun Nov 29, 2020 11:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar v nonpolar molecules
Replies: 30
Views: 181

Re: polar v nonpolar molecules

Polar molecules are molecules that have dipoles that do not cancel. Nonpolar molecules have dipoles that do cancel. Also, if there are differences in electronegativity because the atoms bound to the central atom are not uniform, then it will be a polar molecule.
by Mina Tadros 3L
Sun Nov 29, 2020 11:11 pm
Forum: Hybridization
Topic: Lecture #23
Replies: 13
Views: 125

Re: Lecture #23

Yes, since it is a resonance structure, they are delocalized.
by Mina Tadros 3L
Sun Nov 29, 2020 11:09 pm
Forum: Student Social/Study Group
Topic: Tips for Staying Focused
Replies: 52
Views: 605

Re: Tips for Staying Focused

I usually make a plan for the day that I follow. For example, I have to study for chem from time X to time Y, and only after I completed this schedule, will I take a break. I also like to put my phone away, so I don't get distracted if I get a call or a text.
by Mina Tadros 3L
Sun Nov 22, 2020 5:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 21
Views: 128

Re: Bond Angles

Bond angles are not calculated. They are experimentally determined.
by Mina Tadros 3L
Sun Nov 22, 2020 5:31 pm
Forum: Bond Lengths & Energies
Topic: electron repulsion
Replies: 15
Views: 153

Re: electron repulsion

Repulsion occurs between lone pairs and bonding pairs. However, the strength of the repulsions are different: lone pair-lone pair repulsion > lone pair-bonding pair repulsions > bonding pair-bonding pair repulsions.
by Mina Tadros 3L
Sun Nov 22, 2020 5:28 pm
Forum: Coordinate Covalent Bonds
Topic: Hydrogen bonds
Replies: 19
Views: 175

Re: Hydrogen bonds

Carbon and Hydrogen have similar electronegativities, and thus, have a small electronegativity difference. However, since Fluorine, Oxygen, and NItrogen are more electronegative than Carbon, there is a greater electronegativity difference. This is why hydrogen bonds are only present in bonds with Ni...
by Mina Tadros 3L
Sun Nov 22, 2020 5:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Thanksgiving
Replies: 26
Views: 208

Re: Thanksgiving

I believe we may still have lectures on our break. We had one during Veterans day, so I don't see why this would be any different.
by Mina Tadros 3L
Sun Nov 22, 2020 5:18 pm
Forum: Student Social/Study Group
Topic: Big Sad: Midterm 2
Replies: 86
Views: 954

Re: Big Sad: Midterm 2

Don't stress about it too much. There is still a lot of time left for you to make up for any bad score. Keep your head up. You got this!
by Mina Tadros 3L
Sun Nov 15, 2020 8:10 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures on Midterm
Replies: 31
Views: 164

Re: Drawing Lewis Structures on Midterm

When drawing Lewis Structures, you should always draw the most stable and plausible structure, which would be the one with the least amount of formal charge.
by Mina Tadros 3L
Sun Nov 15, 2020 8:08 pm
Forum: Ionic & Covalent Bonds
Topic: D orbitals
Replies: 3
Views: 31

Re: D orbitals

Since it is an exception, Ag has an electron configuration of [Kr]4d^10 5s^1 (it is more stable to have all the d orbitals paired than having 4 paired orbitals and 1 unpaired orbital). Thus. for Ag^+1, the electron configuration would be [Kr]4d^10 since we are removing an electron from the valence s...
by Mina Tadros 3L
Sun Nov 15, 2020 7:46 pm
Forum: General Science Questions
Topic: Midterm #2
Replies: 11
Views: 84

Re: Midterm #2

We will be tested on the material we did not cover in outline 2 and all of the material in outline 3.
by Mina Tadros 3L
Sun Nov 15, 2020 7:40 pm
Forum: Lewis Structures
Topic: Confusions with Expanded Octets in Period 3
Replies: 2
Views: 40

Re: Confusions with Expanded Octets in Period 3

Elements in the 3p block can have expanded octets because in the n=3 shell, there are s,p, and d orbitals present (n=3 l=2). The presence of empty d-orbitals allows for expanded octets since they can hold additional electrons.
by Mina Tadros 3L
Sun Nov 15, 2020 7:35 pm
Forum: Resonance Structures
Topic: Formal Charge
Replies: 11
Views: 104

Re: Formal Charge

The most stable structure would be the one with the atoms having a formal charge closest to 0. Also, you should always make sure that the most electronegative atom holds the negative formal charge since it is the most capable of holding the electrons. If the most electronegative atom has a + formal ...
by Mina Tadros 3L
Tue Nov 10, 2020 3:44 am
Forum: Lewis Structures
Topic: Central Atom
Replies: 20
Views: 95

Re: Central Atom

The least electronegative atom will go in the center.
by Mina Tadros 3L
Sun Nov 08, 2020 10:14 pm
Forum: Student Social/Study Group
Topic: Chemistry Among Us
Replies: 43
Views: 508

Re: Chemistry Among Us

I am not trying to die, so I would help shut off the reactor.
by Mina Tadros 3L
Sun Nov 08, 2020 10:11 pm
Forum: Electronegativity
Topic: Noble Gases
Replies: 40
Views: 2185

Re: Noble Gases

No, they are omitted. This is due to noble gases having a full octet. A full octet means that the element or compound is not reactive. If these full octet elements were to add an electron, it would require energy and, thus, the electron affinity for it would be negative.
by Mina Tadros 3L
Sun Nov 08, 2020 10:06 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Effective Nuclear Charge
Replies: 2
Views: 17

Re: Effective Nuclear Charge

As you move across the periodic table, you are increasing in the number of protons in the nucleus. This increase in the number of protons causes the effective nuclear charge to increase since the more protons there are, the greater the pull on the electrons.
by Mina Tadros 3L
Sun Nov 08, 2020 9:59 pm
Forum: Student Social/Study Group
Topic: Mid-quarter Check in
Replies: 67
Views: 296

Re: Mid-quarter Check in

I'm doing alright. A little stressed here and there, and I barely have any time to relax :(. But overall, I am still hanging in there...at least for now.
by Mina Tadros 3L
Sun Nov 01, 2020 8:18 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical formula question
Replies: 7
Views: 50

Re: Empirical formula question

When calculating empirical formulas, you will have to have them as whole numbers. Thus, when calculating empirical formulas, you would have to multiply every single element in a way that gets rid of any fraction.
by Mina Tadros 3L
Sun Nov 01, 2020 8:14 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electronic Configurations
Replies: 8
Views: 46

Re: Writing Electronic Configurations

It depends on what the question is asking. If the question asks for the long hand electron configuration, you will write every aspect of that element's electron configuration. If it asks for the shorthand, you will write the noble gas that is right above the element you are writing the electron conf...
by Mina Tadros 3L
Sun Nov 01, 2020 8:10 pm
Forum: Photoelectric Effect
Topic: Participation points
Replies: 16
Views: 177

Re: Participation points

I believe the TAs check the date and time you make a post. Therefore, to receive all 5 points for a week, you would have to make sure you make 5 posts before midnight every Sunday.
by Mina Tadros 3L
Sun Nov 01, 2020 8:08 pm
Forum: DeBroglie Equation
Topic: Avogadro's Number
Replies: 21
Views: 160

Re: Avogadro's Number

Avogadro's number is 6.022 x 10^23, and you would use it when looking for formula units, atoms, photons, and any particle (just not moles or grams).
by Mina Tadros 3L
Sun Nov 01, 2020 8:02 pm
Forum: Properties of Light
Topic: Is c always the speed of light?
Replies: 88
Views: 509

Re: Is c always the speed of light?

Yes, c will always be the speed of light. It is constant, after all. The reason why it is a constant is due to the inverse relationship between wavelength and frequency. Whenever you double wavelength, you are halving the frequency, and when you multiply these two values together, you will always ob...
by Mina Tadros 3L
Sun Oct 25, 2020 5:59 pm
Forum: Student Social/Study Group
Topic: Midterm Prep
Replies: 15
Views: 102

Re: Midterm Prep

I'm not sure about the number of problems in the midterm, but I know how to prep. The best way to prep would be to read from the textbook and do as many practice problems as possible. This will allow you to apply your knowledge and gain practice on how to tackle particular problems. I hope this help...
by Mina Tadros 3L
Sun Oct 25, 2020 5:55 pm
Forum: Properties of Light
Topic: Balmer or Lyman Series
Replies: 9
Views: 50

Re: Balmer or Lyman Series

If you are given a wavelength that is less than 400nm, then you would use the Lyman series (n=1) because the Lyman series absorbs or emits energy in the UV region. However, if you are dealing with the visible region, you would use the Balmer series (n=2).
by Mina Tadros 3L
Sun Oct 25, 2020 5:53 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron Density Distribution
Replies: 8
Views: 82

Re: Electron Density Distribution

The electron density distribution is the arrangement of electrons within an orbital. It is essentially the probability of finding an electron at a particular position in the (wave function)^2. If you are at a peak or a trough, you will have a high probability of finding an electron. However, if you ...
by Mina Tadros 3L
Sun Oct 25, 2020 5:47 pm
Forum: Empirical & Molecular Formulas
Topic: Dealing with Diatomic Elements
Replies: 11
Views: 118

Re: Dealing with Diatomic Elements

Since it gives you nitrogen by itself, it would be N2, but you would have to convert moles of N2 to N when dealing with empirical formulas.
by Mina Tadros 3L
Sun Oct 25, 2020 5:43 pm
Forum: Quantum Numbers and The H-Atom
Topic: Emitting a Photon
Replies: 9
Views: 55

Re: Emitting a Photon

Whenever an excited electron falls back down to its ground state, it will emit photons that release energy. This electron can continuously release photons at every energy level until it has reached its ground state, where the electron becomes relaxed.
by Mina Tadros 3L
Sun Oct 18, 2020 8:33 pm
Forum: SI Units, Unit Conversions
Topic: unit conversions
Replies: 24
Views: 280

Re: unit conversions

When doing conversions, I usually use 10^x (x being all real numbers). This simplifies my conversions since I do not have to waste my time writing out the full value.
by Mina Tadros 3L
Sun Oct 18, 2020 8:29 pm
Forum: Significant Figures
Topic: sig fig
Replies: 20
Views: 188

Re: sig fig

I usually change my sig figs at the very end to ensure that my calculations are as close to the real value as possible. If you keep rounding midway, your answer begins to deviate from the final actual value.
by Mina Tadros 3L
Sun Oct 18, 2020 8:25 pm
Forum: SI Units, Unit Conversions
Topic: studying tactics
Replies: 8
Views: 35

Re: studying tactics

1)Attend as many sessions as possible. This will allow you to get extra practice problems, not in the textbook nor the Chem 14A website. Also, they go over how to do them, so if you are ever stuck, they explain the problems step-by-step. 2) Do as many practice problems as you can. It is common that ...
by Mina Tadros 3L
Tue Oct 13, 2020 8:15 pm
Forum: SI Units, Unit Conversions
Topic: How to Show Your Work
Replies: 16
Views: 152

Re: How to Show Your Work

I would highly recommend showing your work. It makes everything easier. By showing my work, I can understand where to start and where to manipulate the equation to get the variable I am looking for. Also, it helps with keeping track of my units. As I stated earlier, I highly recommend you show your ...
by Mina Tadros 3L
Tue Oct 13, 2020 7:47 pm
Forum: Balancing Chemical Reactions
Topic: Mixed Numbers
Replies: 7
Views: 91

Re: Mixed Numbers

If you get a fraction for one of the stoichiometric coefficients when you are trying to balance, you would have to multiply every stoichiometric coefficient in the chemical equation in a way that gets rid of the fraction. For instance, in the chemical equation C6H14 + O2 ------> CO2 + H2O, you would...
by Mina Tadros 3L
Sun Oct 11, 2020 5:00 pm
Forum: SI Units, Unit Conversions
Topic: Unit Conversion Tips
Replies: 5
Views: 41

Re: Unit Conversion Tips

The best tip I can give you is to set them up as a fraction. That way, you will see which units cancel each other out and which units remain. This will allow you to visualize what the final units will be in your answer. I hope this helped!
by Mina Tadros 3L
Wed Oct 07, 2020 11:40 am
Forum: Balancing Chemical Reactions
Topic: Fractions
Replies: 26
Views: 169

Re: Fractions

For balancing, the stoichiometric coefficients should always be whole numbers. For instance, if one of your stoichiometric coefficients were 5/2, you would multiply every stoichiometric coefficient with 2 in order to maintain the same ratio. This is because you can't have a fraction of an atom.
by Mina Tadros 3L
Wed Oct 07, 2020 11:34 am
Forum: Significant Figures
Topic: How man Sig Figs to use in the Textbook Problems
Replies: 7
Views: 80

Re: How man Sig Figs to use in the Textbook Problems

The number of sig figs used changes depending on the problem you are doing. For multiplying or dividing, the number of sig figs used in your final answer should be based on the lowest amount of sig figs used in your calculations. For adding and subtracting, however, the sig figs depend on the least ...
by Mina Tadros 3L
Mon Oct 05, 2020 11:58 am
Forum: Molarity, Solutions, Dilutions
Topic: Units for Dilution Equation [ENDORSED]
Replies: 23
Views: 216

Re: Units for Dilution Equation [ENDORSED]

For volume, as long as the units remain constant in the initial and final, you can use either mL or L. It does not matter as long as the question does not specify. However, if you are looking for molarity, you will have to convert to L since M = mol/liter.
by Mina Tadros 3L
Mon Oct 05, 2020 11:46 am
Forum: Limiting Reactant Calculations
Topic: Textbook problem M5?
Replies: 7
Views: 101

Re: Textbook problem M5?

After figuring out the limiting reactant (ClO2) and identifying the excess reactant (BrF3), you can use the stoichiometric coefficients given in the chemical equation to find how many moles of BrF3 is produced with 12 moles of ClO2. Since we are given 12 moles of ClO2, we can use the mol/mol ratio t...

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