Search found 49 matches

by Annika Zhang 1F
Sat Dec 07, 2019 7:24 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH and hydronium and hydroxide ion concentrations
Replies: 2
Views: 60

Re: pH and hydronium and hydroxide ion concentrations

more hydroxide ions means a more basic solution while more hydronium ions produce a more acidic solution
by Annika Zhang 1F
Sat Dec 07, 2019 7:22 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: acid & bases to memorize
Replies: 3
Views: 95

Re: acid & bases to memorize

I would just memorize the strong acids or bases
by Annika Zhang 1F
Sat Dec 07, 2019 7:22 pm
Forum: Biological Examples
Topic: Hydrogen Bonding sites
Replies: 8
Views: 117

Re: Hydrogen Bonding sites

as long as one molecule has O,N,or F it is a potential bonding site as long as there is a Hydrogen on the other molecule
by Annika Zhang 1F
Sat Dec 07, 2019 7:19 pm
Forum: Conjugate Acids & Bases
Topic: cations
Replies: 2
Views: 102

Re: cations

are you referring to conjugate acids and bases?
by Annika Zhang 1F
Sat Dec 07, 2019 7:18 pm
Forum: Conjugate Acids & Bases
Topic: Reaction arrows
Replies: 3
Views: 113

Re: Reaction arrows

Annika Zhang 1F wrote:reverse arrow are only denoted if the reaction doesn't dissociate completely


edit: if the acid doesn't dissociate completely. this is used primarily for weak acids and bases
by Annika Zhang 1F
Sat Dec 07, 2019 7:17 pm
Forum: Conjugate Acids & Bases
Topic: Reaction arrows
Replies: 3
Views: 113

Re: Reaction arrows

reverse arrow are only denoted if the reaction doesn't dissociate completely
by Annika Zhang 1F
Sat Dec 07, 2019 7:16 pm
Forum: Student Social/Study Group
Topic: Grades
Replies: 14
Views: 435

Re: Grades

test grades are not adjusted but I heard final grades might be
by Annika Zhang 1F
Sat Dec 07, 2019 7:15 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: KA
Replies: 3
Views: 76

Re: KA

multiply concentrations of products and divide it by the concentrations of multipled reactants reactants; don't include concentrations of liquids
by Annika Zhang 1F
Sat Dec 07, 2019 7:12 pm
Forum: Naming
Topic: Ligands
Replies: 6
Views: 110

Re: Ligands

You would do well to memorize the table. If you forget you can try drawing the Lewis structure to figure it out, but this is difficult for more complicated ligands https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/NamingCoordinationCompounds.pdf is this the table you are referring t...
by Annika Zhang 1F
Sat Dec 07, 2019 7:11 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: hydrogen bonding
Replies: 3
Views: 117

Re: hydrogen bonding

hydrogen can occur is there is a H in one molecule and there is any one of O,N,F in the other
by Annika Zhang 1F
Sat Dec 07, 2019 7:10 pm
Forum: Naming
Topic: Wrong order
Replies: 4
Views: 76

Re: Wrong order

ligands should be denoted in alphabetical order not including prefixes
by Annika Zhang 1F
Sat Dec 07, 2019 7:09 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Stoichiometric Point
Replies: 2
Views: 122

Re: Stoichiometric Point

the equivalence point is the point at which chemically equivalent quantities of reactants have been mixed however this could mean equal quantities of a strong acid and weak base it d9esnt indicate what reactants are being used
by Annika Zhang 1F
Sat Dec 07, 2019 7:07 pm
Forum: Sigma & Pi Bonds
Topic: pi bonds
Replies: 8
Views: 205

Re: pi bonds

905174774 wrote:FOr pi bonds, a triple bond is considered one sigma bond and two pi bonds right?


yes, after the initial sigma bond acting as a single bond, each additional bond is a pi bond
by Annika Zhang 1F
Sat Dec 07, 2019 7:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Final exam
Replies: 17
Views: 310

Re: Final exam

ShastaB4C wrote:Does anyone know approximately how many questions the final exam will be?


It should be 1.5 times the lengthof the midterm
by Annika Zhang 1F
Sat Dec 07, 2019 7:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Final exam
Replies: 17
Views: 310

Re: Final exam

Madeline Phan 4H wrote:How much of the acid-base section is going to be on the final? I'm not sure what to focus on.

the number of questions depends on the amount of time we spent on the topic
by Annika Zhang 1F
Sat Dec 07, 2019 7:04 pm
Forum: Administrative Questions and Class Announcements
Topic: Final exam
Replies: 17
Views: 310

Re: Final exam

the final does not cover the pre midterm content as thoroughly, while it still includes those topic, it mostly focuses on post midterm content
by Annika Zhang 1F
Sat Dec 07, 2019 7:02 pm
Forum: Naming
Topic: cisplatin
Replies: 4
Views: 63

Re: cisplatin

cisplatin is a non targeting chemotherapy drug that prevents cell growth. memorize the shape; it could be on the final
by Annika Zhang 1F
Sat Dec 07, 2019 7:00 pm
Forum: Polyprotic Acids & Bases
Topic: Ions
Replies: 3
Views: 109

Re: Ions

Lyndon said memorized the ligand sheet on lavelles website
by Annika Zhang 1F
Sat Dec 07, 2019 6:59 pm
Forum: Sigma & Pi Bonds
Topic: Sigma Vs Pi
Replies: 12
Views: 244

Re: Sigma Vs Pi

sigma bond are when given a lewis structure are noted by single bonds while each additional bond is a double bond
by Annika Zhang 1F
Sat Dec 07, 2019 6:58 pm
Forum: Lewis Acids & Bases
Topic: reactions
Replies: 2
Views: 42

Re: reactions

acid and base reactions are frequently strong or weak acids/bases reacted with an aqueous solution
by Annika Zhang 1F
Sat Dec 07, 2019 6:57 pm
Forum: Trends in The Periodic Table
Topic: Electronegativity
Replies: 11
Views: 224

Re: Electronegativity

electronegativity increases up and to the right of the period stable. this would be useful in determining things like bond strengths
by Annika Zhang 1F
Sat Dec 07, 2019 6:54 pm
Forum: Lewis Acids & Bases
Topic: bases
Replies: 5
Views: 194

Re: bases

when given the equation, strong bases completely ionize so they only have a single sided arrow while weak bases have double sided arrows
by Annika Zhang 1F
Sat Dec 07, 2019 6:53 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: when to use what equation
Replies: 5
Views: 64

Re: when to use what equation

to find pH you generally use -log[H+] when given H+ concentration or 14-(-log[OH-]) the given the concentration of OH-.
by Annika Zhang 1F
Sat Dec 07, 2019 6:51 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radii
Replies: 11
Views: 294

Re: Atomic Radii

atomic radii is especially useful for determining strength of bonds, bond length, and periodic trends like electronegativity.
by Annika Zhang 1F
Sat Dec 07, 2019 6:49 pm
Forum: SI Units, Unit Conversions
Topic: midterm/final
Replies: 18
Views: 642

Re: midterm/final

actually based on the types of questions given out during review it could be heavily calculation based but still have many conceptual questions
by Annika Zhang 1F
Sat Dec 07, 2019 6:48 pm
Forum: SI Units, Unit Conversions
Topic: midterm/final
Replies: 18
Views: 642

Re: midterm/final

more calculation based
by Annika Zhang 1F
Sat Dec 07, 2019 6:46 pm
Forum: Properties of Light
Topic: relationship between frequency and intensity?
Replies: 3
Views: 140

Re: relationship between frequency and intensity?

Frequency is related to photon's energy and intensity is related to number of photons emitted in radiation
by Annika Zhang 1F
Sat Dec 07, 2019 6:43 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Weak Acids
Replies: 4
Views: 59

Re: Weak Acids

if given the equation for the acid, it should have a double sided arrow to separate products and reactants
by Annika Zhang 1F
Sat Dec 07, 2019 6:40 pm
Forum: Hybridization
Topic: hybridization of lone pairs
Replies: 1
Views: 99

Re: hybridization of lone pairs

lone pairs are in their own hybrid orbital so they count as one electron group towards hybridization
by Annika Zhang 1F
Sat Dec 07, 2019 6:35 pm
Forum: Conjugate Acids & Bases
Topic: chemical equations of acids and bases
Replies: 2
Views: 103

Re: chemical equations of acids and bases

a double sided arrow indicates a weaker acid or basethat doesn't dissociate completely. the single sided arrow represents the dissociation of a strong acid or base that dissociates completely.
by Annika Zhang 1F
Sat Dec 07, 2019 6:31 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH sig figs
Replies: 11
Views: 155

Re: pH sig figs

most of the time sig figs for pH only go to one decimal place after the whole number
by Annika Zhang 1F
Sat Dec 07, 2019 6:30 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: negative pH
Replies: 4
Views: 83

Re: negative pH

a negative pH represents a solution where the molarity of hydrogen ions is more than 1
by Annika Zhang 1F
Sat Dec 07, 2019 6:26 pm
Forum: Sigma & Pi Bonds
Topic: Sigma Bonds
Replies: 2
Views: 111

Re: Sigma Bonds

pi bonds are weaker because sigma bonds have a larger orbital overlap but combined with a sigma bond, it creates a stronger bond
by Annika Zhang 1F
Sat Dec 07, 2019 6:22 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ka for strong/weak acids
Replies: 2
Views: 52

Re: Ka for strong/weak acids

ka is used for weak acids!
by Annika Zhang 1F
Sat Dec 07, 2019 6:20 pm
Forum: Naming
Topic: Naming coordination compounds
Replies: 2
Views: 42

Re: Naming coordination compounds

Lyndon said to memorize it all
by Annika Zhang 1F
Tue Nov 05, 2019 10:18 pm
Forum: Bond Lengths & Energies
Topic: Midterm
Replies: 8
Views: 139

Re: Midterm

8 free response but there will be multiple parts to each question
by Annika Zhang 1F
Sun Oct 13, 2019 11:34 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Test 1 Grading
Replies: 12
Views: 457

Re: Test 1 Grading

Im not completely sure how the test is graded but I assumed that because it was free response, partial credit would be issued. Thus, it would be similar to how the AP exam is usually graded where is the concept, or the work was done in the right direction, it would get a certain number of points.
by Annika Zhang 1F
Sun Oct 13, 2019 11:26 pm
Forum: Empirical & Molecular Formulas
Topic: empirical = molecular?
Replies: 15
Views: 565

Re: empirical = molecular?

after finding the empirical formula, you divide the mass of the molecular formula by that of the empirical formula. Should the value derived from the equation be the value of 1, that means that the empirical formula is equal to that of the molecular formula
by Annika Zhang 1F
Sun Oct 13, 2019 11:24 pm
Forum: Properties of Light
Topic: What is Threshold Energy?
Replies: 9
Views: 127

Re: What is Threshold Energy?

Threshold energy is the lowest possible amount of kinetic energy needed to collied and eject electrons.
by Annika Zhang 1F
Sun Oct 13, 2019 11:12 pm
Forum: Empirical & Molecular Formulas
Topic: Converting from grams to percentage
Replies: 11
Views: 307

Re: Converting from grams to percentage

when finding the empirical formulas, percentages are usually given for each element's make up in the compound. Thus, when we are given only the percentage without a specific mass of the sample, we assume that there is a 100g sample. This allows you to covert percentage directly to it's same numerica...
by Annika Zhang 1F
Sun Oct 13, 2019 11:07 pm
Forum: General Science Questions
Topic: Powerpoint Slides
Replies: 4
Views: 96

Re: Powerpoint Slides

Dr.Lavelle unfortunately doesn't post ppt slides on his website. I do believe, however, that each lecture has been bruincasted but I'm not entirely sure. If you need help on specific topics, I would refer to the modules on Dr. Lavelle's website or to attend TA or UA office hours.
by Annika Zhang 1F
Sun Oct 13, 2019 11:00 pm
Forum: SI Units, Unit Conversions
Topic: Angstrom
Replies: 16
Views: 468

Re: Angstrom

An angstrom is 10^-10, an incredibly small unit of measurement. Thus, the angstrom is most commonly used to measure wavelength or minuscule distances. If you look towards the bottom of the provided formula sheet, you'll see the conversion units from one angstrom to however many meters.
by Annika Zhang 1F
Thu Oct 03, 2019 11:57 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity Equation
Replies: 2
Views: 63

Re: Molarity Equation

in terms of molarity, the equation is mols of solute/ volume of the solution. the solute IS in mols, however, the solution is in liters rather than mols. Thus, the equation does not cancel out mols. <mols solute/liters of solution>
by Annika Zhang 1F
Thu Oct 03, 2019 11:54 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Determining Molar Mass
Replies: 19
Views: 198

Re: Determining Molar Mass

when determining molar mass and using it to derive another unit, I personally don't round the molar mass unless it has 2 decimal points with 9's (2.99 up to 3) this way, the answer I get in the end is most accurate and allows me to round up to the correct number of sig figs and a more accurate value
by Annika Zhang 1F
Thu Oct 03, 2019 11:50 pm
Forum: SI Units, Unit Conversions
Topic: scientific notation
Replies: 7
Views: 81

Re: scientific notation

the amount of sig figs you need to round to typically determine when you use scientific notation.

Ex: if I need 12345 with 2 sig figs, it would be 1.2x10^4
by Annika Zhang 1F
Thu Oct 03, 2019 11:47 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Avogadro's Number?
Replies: 16
Views: 371

Re: Avogadro's Number?

Avogadros number is a constant, 6.022 x 10^23. It describes the number of atoms, molecules, or "things" in a mole. Typically you use this constant when the question asks you to find the number of molecules OR atoms in a mol. Take the number of mols derived from the problem and use dimensio...
by Annika Zhang 1F
Thu Oct 03, 2019 11:44 pm
Forum: Significant Figures
Topic: How would sig figs be used in a problem?
Replies: 7
Views: 71

Re: How would sig figs be used in a problem?

sig figs would play a role primarily in the beginning and in the end solution of a problem. Professor Lavelle wasn't too clear on if they would affect the validity of your final answer but to be safe, I would take the numeric values given at the beginning of the problem and check for their sig figs,...
by Annika Zhang 1F
Thu Oct 03, 2019 11:40 pm
Forum: SI Units, Unit Conversions
Topic: Can someone explain why we use kg for mass as the base unit?
Replies: 9
Views: 591

Re: Can someone explain why we use kg for mass as the base unit?

I myself don't completely understand the answer to this question as well but I believe the kilogram was made to be the base unit for mass because initially, the kilogram was developed by the French government but after the revolution, the standing Republican government decided to adopt the metric sy...

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