Search found 65 matches

by Mingzi Yang 1E
Sun Jan 24, 2021 6:12 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature
Replies: 45
Views: 123

Re: Temperature

If a reaction is endothermic, then it will favor product formation because more reactant is added. If a reaction is exothermic, then it will favor reactant formation because more product is added.
by Mingzi Yang 1E
Sun Jan 24, 2021 6:03 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 11
Views: 35

Le Chatelier's Principle

How much do we need to know about Le Chatelier's Principle for the upcoming midterm?
by Mingzi Yang 1E
Sun Jan 24, 2021 6:02 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Increase in Pressure
Replies: 30
Views: 74

Re: Increase in Pressure

Changes in pressure affect reactions with gases.
by Mingzi Yang 1E
Sun Jan 24, 2021 5:55 pm
Forum: Phase Changes & Related Calculations
Topic: H and q
Replies: 25
Views: 69

Re: H and q

Heat is denoted with q. H / delta H is for enthalpy.
by Mingzi Yang 1E
Sun Jan 24, 2021 5:52 pm
Forum: Phase Changes & Related Calculations
Topic: Endothermic v. Exothermic
Replies: 61
Views: 159

Re: Endothermic v. Exothermic

Endothermic reactions have a positive delta H and exothermic reactions have a negative delta H.
by Mingzi Yang 1E
Sat Jan 16, 2021 11:32 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Confusion with terms
Replies: 9
Views: 86

Re: Confusion with terms

Yes, they mean the same thing. The term "shifting" always confuses me too.
by Mingzi Yang 1E
Sat Jan 16, 2021 11:31 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Memorizing relationship of Q and K
Replies: 9
Views: 41

Re: Memorizing relationship of Q and K

I remember in a workshop with Michael, he mentioned that there is a trick: if K>Q, the reaction proceeds right, since the arrow is pointing to the right, and if K<Q, the reaction proceeds left, since the arrow is pointing to the left. This trick only works if K is written before the Q. Thank you fo...
by Mingzi Yang 1E
Sat Jan 16, 2021 11:29 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ka vs kb
Replies: 20
Views: 60

Re: ka vs kb

K in general is the equilibrium constant. The subscript a (Ka) is for acids and b (Kb) is for bases.
by Mingzi Yang 1E
Sat Jan 16, 2021 11:22 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: q vs k
Replies: 62
Views: 163

Re: q vs k

If Q equals K, the reaction is at equilibrium. Q is calculated the same way as K when the reaction is not at equilibrium.
by Mingzi Yang 1E
Sat Jan 16, 2021 11:20 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O as a Gas
Replies: 69
Views: 406

Re: H2O as a Gas

If H2O is a gas, it should be included in the ICE table. If it is a liquid, we don't include it.
by Mingzi Yang 1E
Sun Jan 10, 2021 5:52 pm
Forum: Ideal Gases
Topic: Difference between real and ideal gas
Replies: 10
Views: 76

Re: Difference between real and ideal gas

Grace_Remphrey_2J wrote:Here's a table I find super helpful when looking at the difference between real and ideal gas. Hope this helps!
Screen Shot 2021-01-10 at 3.26.10 PM.png

This table is helpful! Thank you!
by Mingzi Yang 1E
Sun Jan 10, 2021 5:50 pm
Forum: Ideal Gases
Topic: PV=nRT
Replies: 74
Views: 451

Re: PV=nRT

P=pressure (in atm)
V=volume of gas (in L)
n= number of moles
R= gas constant
T= temperature (in Kelvin)

n/V = concentration
by Mingzi Yang 1E
Sun Jan 10, 2021 5:45 pm
Forum: Ideal Gases
Topic: Bars to atm [ENDORSED]
Replies: 35
Views: 173

Re: Bars to atm [ENDORSED]

There is a very small difference between the two values, so we would approximate 1 bar = 1 atm as the unit of pressure.
by Mingzi Yang 1E
Sun Jan 10, 2021 5:35 pm
Forum: Ideal Gases
Topic: Units of Temperature
Replies: 82
Views: 288

Re: Units of Temperature

Kelvin should be used as the unit of temperature in this case.
by Mingzi Yang 1E
Sun Jan 10, 2021 5:34 pm
Forum: Ideal Gases
Topic: Kc vs Kp
Replies: 109
Views: 936

Re: Kc vs Kp

You use Kp when all the reactants and products are gases. If the reactants and products are given in molar concentration, then you should use Kc.
by Mingzi Yang 1E
Fri Dec 11, 2020 11:13 pm
Forum: Naming
Topic: Naming quizlet
Replies: 41
Views: 269

Re: Naming quizlet

Thank you for sharing this quizlet!
by Mingzi Yang 1E
Fri Dec 11, 2020 11:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 337
Views: 139665

Re: Saying Thank You to Dr. Lavelle

Thank you Dr. Lavelle for this great quarter despite that it is online. Everything is helpful and super organized!
by Mingzi Yang 1E
Fri Dec 11, 2020 11:08 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH formula?
Replies: 46
Views: 934

Re: pH formula?

Ariel Guan 1G wrote:pH = -log[H+]
[H+] = 10^(-pH)
pOH = -log[OH-]
[OH-] = 10^(-pOH)
14 = pH + pOH

This is helpful! Thank you.
by Mingzi Yang 1E
Fri Dec 11, 2020 11:06 pm
Forum: Bronsted Acids & Bases
Topic: Strong acids
Replies: 7
Views: 69

Re: Strong acids

Thank you for all your responses. They are helpful for me to distinguish some strong acids.
by Mingzi Yang 1E
Fri Dec 11, 2020 11:04 pm
Forum: Administrative Questions and Class Announcements
Topic: Are all questions on the final multiple choices?
Replies: 29
Views: 145

Re: Are all questions on the final multiple choices?

All questions are multiple choices, similar to the format of the two midterms.
by Mingzi Yang 1E
Sat Dec 05, 2020 9:51 pm
Forum: Lewis Acids & Bases
Topic: Water
Replies: 62
Views: 492

Re: Water

To provide a more technical and detailed answer: Water (H2O) is able to release a proton (H+) to form hydroxide ions. Water can also accept a proton to form hydronium (H3O+). Thus, water can act as both a Bronsted acid and a Bronsted base, making it amphoteric/amphiprotic. I found a diagram which a...
by Mingzi Yang 1E
Sat Dec 05, 2020 9:51 pm
Forum: Lewis Acids & Bases
Topic: Water
Replies: 62
Views: 492

Re: Water

Water is amphoteric, which can act as either acid or base depending on the reaction.
by Mingzi Yang 1E
Sat Dec 05, 2020 9:45 pm
Forum: Bronsted Acids & Bases
Topic: Strong acids
Replies: 7
Views: 69

Strong acids

What are some common strong acids that I should memorize???
by Mingzi Yang 1E
Sat Dec 05, 2020 9:39 pm
Forum: Naming
Topic: what does (en) mean?
Replies: 23
Views: 169

Re: what does (en) mean?

In one of the sapling homework problems (question 5 for me), the feedback includes a table (chempendix) of ligands. You can check it out to see some common ligand names and their denticity.
by Mingzi Yang 1E
Sat Dec 05, 2020 8:52 pm
Forum: Naming
Topic: Order of Ligands/naming
Replies: 28
Views: 141

Re: Order of Ligands/naming

If there are multiple ligands, name them based on their alphabetical order.
by Mingzi Yang 1E
Tue Nov 24, 2020 10:37 pm
Forum: Hybridization
Topic: Sp3d or dsp3
Replies: 22
Views: 868

Re: Sp3d or dsp3

I think either way is fine although Prof. Lavelle used dsp^3 in his lecture.
by Mingzi Yang 1E
Tue Nov 24, 2020 10:33 pm
Forum: Hybridization
Topic: hybridization of phosphorus (Sapling Q.11)
Replies: 21
Views: 96

Re: hybridization of phosphorus (Sapling Q.11)

Hi! This is another part of Sapling Q.11. I understood how your answers applied to the other diagram, but this diagram threw me for a loop. If any of you have advice on how to better understand and complete these questions it would be much appreciated! Thank you! P have three bonding pairs and one ...
by Mingzi Yang 1E
Tue Nov 24, 2020 10:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape Names
Replies: 50
Views: 299

Re: Shape Names

The shape of H2O is bent.
by Mingzi Yang 1E
Tue Nov 24, 2020 10:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Problem of viewing the lecture
Replies: 9
Views: 63

Re: Problem of viewing the lecture

Thank you for all responses. It was the problem of the browser that I was using. It got it work using firefox.
by Mingzi Yang 1E
Sun Nov 22, 2020 3:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Problem of viewing the lecture
Replies: 9
Views: 63

Problem of viewing the lecture

When I tried to watch the lecture videos, it shows a green screen instead of the actual video itself (the audio works normally). Is it because of my laptop or does anymore have the same problem accessing the lectures? I had no trouble accessing the videos before.
by Mingzi Yang 1E
Sun Nov 22, 2020 3:10 pm
Forum: Electronegativity
Topic: Periodic trend
Replies: 17
Views: 150

Re: Periodic trend

All three have the same trend on the periodic table, which they increase across a period and decreases down a group.
by Mingzi Yang 1E
Sun Nov 22, 2020 3:02 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability of anions
Replies: 6
Views: 62

Re: Polarizability of anions

Anions that are bigger and less electronegative are more polarizable. So nitrogen with a 3- charge is more polarized than oxygen with a 2- charge.
by Mingzi Yang 1E
Sun Nov 22, 2020 2:49 pm
Forum: Sigma & Pi Bonds
Topic: Triple bond?
Replies: 21
Views: 165

Re: Triple bond?

Stephen Min 2K wrote:
isha dis1k wrote:So just to clarify, as the bond numbers increase (etc. single to triple), the number of sigma bonds stay the same and pi and delta increase?


Yes, sigma bonds stay the same while pi bonds would increase, as bond order increases.

That makes sense. Thank you for clarifying.
by Mingzi Yang 1E
Sun Nov 22, 2020 2:47 pm
Forum: Sigma & Pi Bonds
Topic: Sigma and Pi Bond Lecture
Replies: 7
Views: 35

Re: Sigma and Pi Bond Lecture

Sigma and Pi bonds are discussed in lecture 22.
by Mingzi Yang 1E
Sun Nov 22, 2020 2:45 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 33
Views: 216

Re: Covalent Character

An ionic molecule displays the most covalent character when the two atoms have the least electronegativity difference when compared to the other ionic molecules.
by Mingzi Yang 1E
Sun Nov 15, 2020 8:31 pm
Forum: Dipole Moments
Topic: Dipole moment
Replies: 2
Views: 16

Dipole moment

What exactly is the dipole moment? What are some examples that can help me understand the concept of dipole moment? I have a hard time understanding what it is.
by Mingzi Yang 1E
Sun Nov 15, 2020 8:24 pm
Forum: Trends in The Periodic Table
Topic: Effective nuclear charge of an element
Replies: 3
Views: 16

Re: Effective nuclear charge of an element

Thank you for all the explanations. They really clarify and help me understand this concept!
by Mingzi Yang 1E
Sun Nov 15, 2020 8:19 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Does polarizability increase left to right?
Replies: 4
Views: 32

Re: Does polarizability increase left to right?

Generally, polarizability increases as the volume occupied by electrons increases. On rows of the periodic table, polarizability decreases from left to right (larger molecules are more polarizable than smaller ones). Polarizability increases down on columns of the periodic table. I hope this helps!...
by Mingzi Yang 1E
Sun Nov 15, 2020 8:14 pm
Forum: Electronegativity
Topic: Sapling Question 13
Replies: 7
Views: 35

Re: Sapling Question 13

The maximum number of water molecules should be 8 because the two oxygen and nitrogen atoms of the urea molecule can form hydrogen bonds with the hydrogen atoms of the water molecule. The four slightly positive hydrogen atoms of the urea molecule can each form a hydrogen bond with the slightly negat...
by Mingzi Yang 1E
Sun Nov 15, 2020 8:07 pm
Forum: Octet Exceptions
Topic: Radicals
Replies: 6
Views: 56

Radicals

Since radicals are one of the exceptions to the octet rule, how much should we know about radicals in this context and for the midterm?
by Mingzi Yang 1E
Sun Nov 08, 2020 8:29 pm
Forum: Electronegativity
Topic: Atom size
Replies: 22
Views: 819

Re: Atom size

I don't think the atomic size of an element is directly affected by its electronegativity. In terms of their trends in the periodic table, they have opposite trends.
by Mingzi Yang 1E
Sun Nov 08, 2020 8:24 pm
Forum: Ionic & Covalent Bonds
Topic: Electron Affinity vs. Electronegativity
Replies: 12
Views: 66

Re: Electron Affinity vs. Electronegativity

They are not the same. Electron affinity is the energy released when electrons are added to the atom and electronegativity is the electron pulling power of an atom.
by Mingzi Yang 1E
Sun Nov 08, 2020 8:17 pm
Forum: Trends in The Periodic Table
Topic: Effective nuclear charge of an element
Replies: 3
Views: 16

Effective nuclear charge of an element

How much do we need to know about the effective nuclear charge of an element? What does "shielding electrons" refer to in this context?
by Mingzi Yang 1E
Sun Nov 08, 2020 8:13 pm
Forum: Trends in The Periodic Table
Topic: # of electrons
Replies: 23
Views: 118

Re: # of electrons

The number of electrons of an element is the same as the atomic number. If it asks for the valence electron, then the column number of where the element is in, is the number of the valence electron.
by Mingzi Yang 1E
Sun Nov 08, 2020 8:10 pm
Forum: Trends in The Periodic Table
Topic: Size & Expected Knowledge
Replies: 5
Views: 69

Re: Size & Expected Knowledge

I think memorizing the trend (increases down a group and decreases across a period) is beneficial, especially when the test may ask for this type of question.
by Mingzi Yang 1E
Sat Oct 31, 2020 10:21 pm
Forum: Trends in The Periodic Table
Topic: Trends
Replies: 14
Views: 88

Re: Trends

Generally, the radius size increases down a group and decreases across a period. Besides all the concepts mentioned above that can help in memorizing the trends, I also like to memorize F as the element that has the "smallest" radius size and it helps me visualize the trends.
by Mingzi Yang 1E
Sat Oct 31, 2020 10:14 pm
Forum: Trends in The Periodic Table
Topic: Periodic Table & Electron Affinity
Replies: 11
Views: 86

Re: Periodic Table & Electron Affinity

Generally elements with high electron affinity are in top right of periodic table (group 17). Electron affinity increases across a period and decreases down a group.
by Mingzi Yang 1E
Sat Oct 31, 2020 10:10 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Sapling weeks 2-4 #16
Replies: 4
Views: 67

Re: Sapling weeks 2-4 #16

The excited-electron in the 3s orbital will return to the 2p orbital when it is in its ground state. So the ground state is 1s2 2s2 2p5 and the element is fluorine (F).
by Mingzi Yang 1E
Sat Oct 31, 2020 10:05 pm
Forum: Quantum Numbers and The H-Atom
Topic: when n=5 and l=4
Replies: 16
Views: 156

Re: when n=5 and l=4

Although n=5 and the general rule is l=n-1, I don't think l automatically equals to 4. l can equal to 1,2,3 or 4 depending on the situation.
by Mingzi Yang 1E
Sat Oct 31, 2020 3:57 pm
Forum: Ionic & Covalent Bonds
Topic: lone pairs
Replies: 5
Views: 55

Re: lone pairs

Yes. atoms with lone pairs are usually reactive because they would want to become more stable by forming bonds and fulfilling the octet.
by Mingzi Yang 1E
Sun Oct 25, 2020 4:13 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Clarification on the "uncertainty" part of this equation
Replies: 7
Views: 111

Clarification on the "uncertainty" part of this equation

What is the main takeaway from the Heisenberg Indeterminacy Equation?? I am still a little confused about this equation after listening to the lecture. Like what is this "uncertainty" that this equation is trying to find?
by Mingzi Yang 1E
Sun Oct 25, 2020 4:06 pm
Forum: Photoelectric Effect
Topic: Calculations
Replies: 18
Views: 97

Re: Calculations

I think it will be better to keep all decimal places and try not to round it until the end so the final answer can be more accurate. I usually round it only if this number contains too many decimal places that I can't keep track of.
by Mingzi Yang 1E
Sun Oct 25, 2020 3:57 pm
Forum: Photoelectric Effect
Topic: unit conversion hw Q 1.3
Replies: 7
Views: 238

Re: unit conversion hw Q 1.3

You should convert the wavelength to meters so units can be cancelled out in future calculations for that problem. It will be convenient if you convert all units into SI base units before starting your calculations.
by Mingzi Yang 1E
Sun Oct 25, 2020 3:48 pm
Forum: Photoelectric Effect
Topic: Conceptual understanding of the photoelectric experiment
Replies: 5
Views: 57

Conceptual understanding of the photoelectric experiment

What concepts should we understand from the photoelectric experiment ?? (if we get a conceptual question about it on the midterm)
by Mingzi Yang 1E
Sun Oct 25, 2020 3:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm calculator policy
Replies: 10
Views: 83

Re: Midterm calculator policy

I thought we have to have a scientific calculator??? So we don't have a restriction on the type of calculator we use??
by Mingzi Yang 1E
Fri Oct 16, 2020 10:37 pm
Forum: Properties of Light
Topic: Question regarding webcam
Replies: 8
Views: 95

Re: Question regarding webcam

According to the email Professor Lavelle sent, we can use another device such as an ipad to show our workplace on zoom if we don't have a webcam. In this case, we will need two devices, one for doing the exam and one for showing our workplace.
by Mingzi Yang 1E
Fri Oct 16, 2020 10:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 106
Views: 7184

Re: Accessing the E-textbook [ENDORSED]

alebenavides wrote:Does anyone know when we get our access code? I bought the book a few days ago but haven't received it so I had to get the free 10 day trial.


When I ordered mines, it took about 6 days for the code to get delivered. I hope you will get your access code soon.
by Mingzi Yang 1E
Fri Oct 16, 2020 10:11 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units
Replies: 9
Views: 107

Re: Formula Units

Is this question asking us to calculate the number of moles of the compound then?? No, the question is asking how many many molecules of the compound are present in 5.15 g of the compound. In order to find that number, you do need to find the number of moles of the compound by using its molecular w...
by Mingzi Yang 1E
Fri Oct 16, 2020 10:04 pm
Forum: DeBroglie Equation
Topic: What causes a diffraction pattern?
Replies: 9
Views: 111

Re: What causes a diffraction pattern?

According to the lecture today, a diffraction pattern results from both constructive and destructive interference.
by Mingzi Yang 1E
Fri Oct 16, 2020 10:00 pm
Forum: Einstein Equation
Topic: Equation Sheet
Replies: 15
Views: 132

Re: Equation Sheet

I think constants and other necessary information will be given for the exams.
by Mingzi Yang 1E
Wed Oct 07, 2020 10:15 pm
Forum: SI Units, Unit Conversions
Topic: Rounding in Between Steps [ENDORSED]
Replies: 22
Views: 204

Re: Rounding in Between Steps [ENDORSED]

I think if the number has many decimals, it will be better not to round it and use the exact number. But for example, if the decimal has four or five places and you want to follow the sig fig rule and round it to two places, it will be fine to do so according to my experience.
by Mingzi Yang 1E
Wed Oct 07, 2020 10:10 pm
Forum: Balancing Chemical Reactions
Topic: Fractions
Replies: 34
Views: 566

Re: Fractions

I think it is fine to have a fraction as the coefficient. But it will be more convenient if the fractions are converted into whole numbers, especially when you need to do further calculations such as finding the molecular formula etc.
by Mingzi Yang 1E
Wed Oct 07, 2020 10:02 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: precision for molar masses
Replies: 14
Views: 112

Re: precision for molar masses

If the molar mass is given in the question, the way I usually would do is not to round it. If the molar mass is not given, then I would write what the molar mass from the periodic table accordingly. But I notice that some molar masses vary (by one decimal, for example) depending on which periodic ta...
by Mingzi Yang 1E
Wed Oct 07, 2020 9:50 pm
Forum: Significant Figures
Topic: How many significant figures are in 7.00 x 10^2?
Replies: 25
Views: 614

Re: How many significant figures are in 7.00 x 10^2?

7.00 x 10^2 has three significant figures. The way I understand it is that we mainly focus on the number "7.00". Since 7.00 has a decimal in between 7 and the two zeros, the two zeros after the decimal will also be considered to be significant figures.
by Mingzi Yang 1E
Wed Oct 07, 2020 9:45 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units
Replies: 9
Views: 107

Re: Formula Units

Is this question asking us to calculate the number of moles of the compound then??

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