Search found 40 matches

Mon Dec 02, 2019 8:36 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH calcuations
Replies: 8
Views: 93

Re: pH calcuations

It may also be helpful to remember that pH + pOH = 14.
Mon Dec 02, 2019 8:35 am
Forum: Calculating the pH of Salt Solutions
Topic: pH formula?
Replies: 21
Views: 733

Re: pH formula?

The formula for pH is -log[H+] and pOH is -log[OH-]. I don't think we need to know the derivation, but it is helpful to know that pH + pOH = 14
Mon Dec 02, 2019 8:31 am
Forum: Calculating the pH of Salt Solutions
Topic: pH of acids
Replies: 13
Views: 612

Re: pH of acids

The lower the pH is, the more H+ ions it has, making it more acidic. Higher pHs have a lower H+ concentration and are weaker acids.
Mon Dec 02, 2019 8:29 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH scale
Replies: 12
Views: 111

Re: pH scale

Most solutions fall between 0 and 14, there are very few acids that would be negative and very few bases that would fall above 14.
Mon Dec 02, 2019 8:28 am
Forum: Identifying Acidic & Basic Salts
Topic: Final: Strong/ Weak Acids/Bases
Replies: 11
Views: 913

Re: Final: Strong/ Weak Acids/Bases

I believe it would be best to memorize the strong acids and strong bases for the final.
Sat Nov 23, 2019 6:10 pm
Forum: Naming
Topic: Naming Order
Replies: 6
Views: 78

Re: Naming Order

I believe you would list the ligands in alphabetical order.
Sat Nov 23, 2019 6:09 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: [Fe(CN)6]4-
Replies: 5
Views: 66

Re: [Fe(CN)6]4-

Since CN has a -1 charge, the -4 overall charge is given to calculate the charge of iron (Fe), which is +2.
Sat Nov 23, 2019 6:07 pm
Forum: Naming
Topic: Cation/Anion
Replies: 7
Views: 344

Re: Cation/Anion

In the chemical formula, the cation will be listed first followed by the anion.
Sat Nov 23, 2019 6:06 pm
Forum: Naming
Topic: Chloro vs Chlorito
Replies: 10
Views: 545

Re: Chloro vs Chlorito

I think that both suffixes are acceptable, but the -o form would probably be best to use since that is what we are taught in lectures.
Sat Nov 23, 2019 6:03 pm
Forum: Naming
Topic: Naming Compounds (general question)
Replies: 5
Views: 102

Re: Naming Compounds (general question)

I think we would only have to know the general rules for naming coordination complexes.
Sun Nov 17, 2019 12:39 am
Forum: Determining Molecular Shape (VSEPR)
Topic: axial vs equitorial
Replies: 3
Views: 54

Re: axial vs equitorial

Axial bonds are parallel to the axis of the ring while equatorial bonds are perpendicular to the axis (at the equator).
Sun Nov 17, 2019 12:38 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 4
Views: 57

Re: Bond Angles

I believe you only need to be able to state that the bond angle is less than the expected angle. I don't think you need to give a more exact approximation.
Sun Nov 17, 2019 12:36 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 4
Views: 63

Re: Bond Angles

The electronegativity of the atoms can slightly change the bond angles even if two molecules have the same shape.
Sun Nov 17, 2019 12:32 am
Forum: Determining Molecular Shape (VSEPR)
Topic: What is VSPER
Replies: 14
Views: 353

Re: What is VSPER

The VSEPR model stands for the Valence-Shell Electron-Pair Repulsion model. You do not need to have the acronym memorized. However, it may help with your understanding of the concepts of the model.
Sun Nov 17, 2019 12:31 am
Forum: Determining Molecular Shape (VSEPR)
Topic: polar or non polar?
Replies: 7
Views: 169

Re: polar or non polar?

In order to determine if the molecule is polar or non-polar, you would use the electronegativity of the atoms as well as the Lewis structure. The electronegativity would show you the charges of the bonds and the Lewis structure would show you if the dipoles cancel.
Sat Nov 09, 2019 5:29 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 18
Views: 185

Re: Drawing Lewis Structures

You should draw the Lewis structure so that the sum of the formal charges is the charge of the overall molecule, which may not necessarily be zero.
Sat Nov 09, 2019 5:28 pm
Forum: Lewis Structures
Topic: When to draw Resonance Structures
Replies: 14
Views: 173

Re: When to draw Resonance Structures

If the question specifically says to asks to draw resonance structures than you should do so. Otherwise, just draw the most stable Lewis Structure.
Sat Nov 09, 2019 5:25 pm
Forum: Lewis Structures
Topic: Formal Charges
Replies: 15
Views: 237

Re: Formal Charges

Since the central atom is usually the least electronegative, the surrounding atoms would have the charge.
Sat Nov 09, 2019 5:23 pm
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 4
Views: 72

Re: Lewis Structures

Electrons are shifted toward the more electronegative atom, so the more electronegative atom is the one with the negative charge.
Sat Nov 09, 2019 5:21 pm
Forum: Lewis Structures
Replies: 26
Views: 461

Dr. Lavelle announced that the midterms would be handed back during lecture on Wednesday (11/13).
Sun Oct 27, 2019 10:12 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Bonds
Replies: 11
Views: 143

Re: Covalent Bonds

Correct, covalent bonds occur between two non-metals. This differs from the metal-nonmetal ionic bonds.
Sun Oct 27, 2019 10:10 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic VS. Covalent Bond
Replies: 8
Views: 120

Re: Ionic VS. Covalent Bond

Ionic bonds occur between a metal and a non-metal. Covalent bonds result from the bonding of two non-metals.
Sun Oct 27, 2019 10:09 pm
Forum: Ionic & Covalent Bonds
Topic: Homework
Replies: 13
Views: 203

Re: Homework

I believe you can do problems from either section. However, it might be beneficial to focus this week's homework on chemical bonds since it is a new topic.
Sun Oct 27, 2019 10:06 pm
Forum: DeBroglie Equation
Topic: Protons and Electrons
Replies: 4
Views: 74

Re: Protons and Electrons

Since protons and neutrons have the same mass, if they had the same velocity they would also have the same wavelength.
Sun Oct 27, 2019 10:04 pm
Forum: Ionic & Covalent Bonds
Topic: periodic table
Replies: 10
Views: 123

Re: periodic table

Electronegativity increases from left to right of the periodic table and decreases as you move down a group.
Sat Oct 19, 2019 9:00 pm
Forum: Properties of Light
Topic: Midterm Exam
Replies: 21
Views: 260

Re: Midterm Exam

The midterm should cover weeks 1-5, so fundamentals, quantum world, and chemical bonding.
Sat Oct 19, 2019 8:59 pm
Forum: Properties of Light
Topic: Equations and Constants
Replies: 6
Views: 100

Re: Equations and Constants

My TA said all of the equations and constants will be provided on exams (same formula sheet as Test 1).
Sat Oct 19, 2019 8:58 pm
Forum: Properties of Light
Topic: What are the units of hertz
Replies: 41
Views: 462

Re: What are the units of hertz

Hertz is a unit of frequency measured as cycles per second.
Sat Oct 19, 2019 8:56 pm
Forum: Properties of Light
Topic: Next test
Replies: 23
Views: 388

Re: Next test

Since the equation sheet given to us on the first test had many formulas and constants that we didn't need for Test 1, I'm assuming the same sheet will be used for the entire quarter for every exam.
Sat Oct 19, 2019 8:54 pm
Forum: Properties of Light
Topic: Unit for Wavelength
Replies: 34
Views: 370

Re: Unit for Wavelength

The standard unit for wavelength is meters (m). However it is often shown in problems as picometers (pm), nanometers (nm), or even Angstroms (A).
Sun Oct 13, 2019 4:25 pm
Forum: General Science Questions
Topic: Rusty on High School Chem [ENDORSED]
Replies: 197
Views: 138986

Re: Rusty on High School Chem[ENDORSED]

There are so many resources provided on the class website to help brush up on high school chemistry. Especially the video modules and lectures. Reviewing topics from the textbook will also help knock the rust off.
Sun Oct 13, 2019 4:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 175
Views: 13423

Re: Advice from a Medical Student - Part II[ENDORSED]

Sun Oct 13, 2019 4:20 pm
Forum: Limiting Reactant Calculations
Topic: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
Replies: 68
Views: 3858

Re: Showing Work for Limiting Reactant Calculations on Tests[ENDORSED]

You don’t have to show as much work. However, it may help so if you make a calculating mistake, graders can see each step and you can get partial credit for completing the steps correctly even with a calculating error.
Sun Oct 13, 2019 4:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 2 Homework Problems [ENDORSED]
Replies: 67
Views: 3450

Re: Week 2 Homework Problems[ENDORSED]

Week 2 homework can be on the fundamentals or quantum world since lectures are on QW but the test during W2 is on the fundamentals. The Week 3 homework must be on the QW though.
Sun Oct 13, 2019 4:15 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Test 1 [ENDORSED]
Replies: 107
Views: 5080

Re: Test 1[ENDORSED]

All of the materials for the Tests (1 & 2) and Exams (Midterm & Final) are provided. There is also a conversions/formula sheet on the first page. Also remember to have a scientific calculator instead of a graphing since graphing calculators are not allowed.
Fri Oct 04, 2019 5:14 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Theoretical vs. Actual Yield
Replies: 38
Views: 3383

Re: Theoretical vs. Actual Yield

Theoretical yield will never be higher than actual yield. Theoretical yield is the result if the reaction is 100% efficient and there are no impurities or errors during the experiment. Theoretical yield represents the maximum yield.
Fri Oct 04, 2019 5:12 pm
Forum: Student Social/Study Group
Topic: Final Jitters
Replies: 127
Views: 33509

Re: Final Jitters

I recommend not studying right before the test starts because it will make you more nervous and also psych you out on the material. I always tell myself that I’ve studied the material well and it helps me feel prepared.
Fri Oct 04, 2019 5:04 pm
Forum: Empirical & Molecular Formulas
Topic: When should one start rounding in a problem?
Replies: 11
Views: 221

Re: When should one start rounding in a problem?

It’s best to round at the very end of the problem once you have an answer so that you are more precise. Rounding during steps in the problem can result in errors.
Fri Oct 04, 2019 4:59 pm
Forum: SI Units, Unit Conversions
Replies: 22
Views: 386