Search found 60 matches
- Sun Dec 08, 2019 7:36 pm
- Forum: Bronsted Acids & Bases
- Topic: Hydrogen Bonding
- Replies: 16
- Views: 1170
Re: Hydrogen Bonding
No, hydrogen bonding is a type of intermolecular force not a type of acid base reaction.
- Sun Dec 08, 2019 7:35 pm
- Forum: Sigma & Pi Bonds
- Topic: How to Find Sigma Bonds and Pi Bonds
- Replies: 15
- Views: 1249
Re: How to Find Sigma Bonds and Pi Bonds
Using the Lewis Structure then you can determine which is the central atom (or the one being asked for in the question) and look at the number bonds. The first bond will always be a sigma bond, a double bond has a sigma and pi, and a triple bond will be one sigma and two pi.
Re: -ate
Nothing for positive only if the ion is an anion (negatively charged).
- Sun Dec 08, 2019 10:31 am
- Forum: Lewis Acids & Bases
- Topic: all acids and bases
- Replies: 4
- Views: 401
Re: all acids and bases
Yes, lewis acid accepts protons and lewis base is the one that gives. A Bronstead acid donates a H+ while a base will a accept the H+.
- Sun Dec 08, 2019 10:26 am
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Ka only in weak acids and bases?
- Replies: 2
- Views: 294
Re: Ka only in weak acids and bases?
Ka is only given for weak acids because they don’t dissociate completely so just assume complete dissociation for strong acids.
- Sun Dec 01, 2019 10:41 pm
- Forum: General Science Questions
- Topic: Bruincasts
- Replies: 9
- Views: 791
Re: Bruincasts
Lectures are not bruincasted and slides are also not uploaded, but if you want to review past topics Dr. Lavelle does have the Audio-Visual Focus-Topics on the class website.
- Sun Dec 01, 2019 10:33 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Studying for final exam
- Replies: 8
- Views: 664
Re: Studying for final exam
Study your lecture notes since in past finals an example from lecture was asked about. I would also recommend going to review sessions whenever you can since there is a lot of material that we must review.
Re: Chelating
Liliana Aguas 3G wrote:What day of lecture notes was this topic mostly covered?
I believe November 20.
- Sun Dec 01, 2019 10:18 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Textbook
- Replies: 5
- Views: 2143
Re: Textbook
Acids and bases are covered in Fundamentals J and Chapter 6.
Re: 9C.1 B
You find the chrage of cobalt by first calculating what the total charge of the hexaammine is (0 since NH3 is neutral) and then the total charge of the complex ion (3+) in this problem that would mean that the charge of cobalt is 3+ hence the answer being hexaammine cobalt(III).
- Sun Dec 01, 2019 10:09 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acids Vs. Bases
- Replies: 11
- Views: 891
Re: Acids Vs. Bases
(Bronstead) acids are proton donors while (brontead) bases are proton acceptors.
- Sun Dec 01, 2019 10:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma Bond
- Replies: 10
- Views: 623
Re: Sigma Bond
Yes the first bind is always a sigma bind while all other bonds formed will be pi bonds.
- Sun Dec 01, 2019 9:59 pm
- Forum: Lewis Acids & Bases
- Topic: Strong versus weak
- Replies: 5
- Views: 392
Re: Strong versus weak
A strong acid completely ionizes in a solution, producing more protons in the solution.
- Sun Nov 24, 2019 9:06 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligand
- Replies: 10
- Views: 549
Re: Ligand
A ligand is a molecule which is attached to a central metal. Ligands make up the coordination sphere.
- Sun Nov 24, 2019 9:05 pm
- Forum: Sigma & Pi Bonds
- Topic: sigma and pi bonds
- Replies: 27
- Views: 1736
Re: sigma and pi bonds
The first bond made is always a sigma bond while any other bonds made will be pi. (A double bond consists of one sigma and one pi bond. A triple bond consists of one sigma and two pi bonds)
- Sun Nov 24, 2019 8:56 pm
- Forum: Naming
- Topic: Week 9 and Week 10 HW?
- Replies: 21
- Views: 1073
Re: Week 9 and Week 10 HW?
Does anyone know if the HW for both weeks is due on week 10 for all discussions or only those after Wednesday?
- Sun Nov 24, 2019 8:54 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T-Shape
- Replies: 5
- Views: 443
Re: T-Shape
The electron pairs are in the "trigonal planar" part of the molecule because that forms the shape with the least amount of repulsion.
- Sun Nov 24, 2019 8:49 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Intermolecular forces
- Replies: 5
- Views: 374
Re: Intermolecular forces
You can identify the type of intermolecular forces by looking at the dipole moments of the molecules.
- Sun Nov 24, 2019 8:33 pm
- Forum: Lewis Structures
- Topic: Bent or Angular?
- Replies: 18
- Views: 1216
Re: Bent or Angular?
The terms are interchangeable since they mean the same thing, just know what they are and you should be fine.
- Thu Nov 21, 2019 12:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs linear
- Replies: 56
- Views: 4422
Re: Bent vs linear
A bent molecule will have a lone pair, or two in the case of AX2E2, on the central atom as opposed to a linear which has no lone pairs around the central atom.
- Tue Nov 19, 2019 2:17 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: h bonding and dipole dipole
- Replies: 4
- Views: 293
Re: h bonding and dipole dipole
Yes, hydrogen bonding a type of dipole-dipole interaction.
- Sun Nov 17, 2019 10:02 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: vsepr angles
- Replies: 10
- Views: 503
Re: vsepr angles
Yes, so that, if asked, you can make comparisons between the angles of different shapes.
- Sun Nov 17, 2019 10:00 pm
- Forum: Hybridization
- Topic: Test 2
- Replies: 11
- Views: 617
Re: Test 2
I don't think so, the only topics Dr. Lavelle said would be on the test from Monday's lecture are sigma and pi bonds.
- Sun Nov 17, 2019 9:51 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: london forces
- Replies: 5
- Views: 247
Re: london forces
Since electron's are constantly moving, there is potential for a temporary dipole to be present (the electrons would happen to be more towards one side).
- Sun Nov 17, 2019 9:48 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: This Week Test
- Replies: 12
- Views: 779
Re: This Week Test
Have we gone over sigma and pi bonds yet? Do we have any more information about what exact material will be tested? Lavelle said he would discuss sigma and pi bonds on Monday. ... so are sigma and pi bonds going to be on the test? I think the TAs said they were trying to have the tests done by Sund...
- Sun Nov 17, 2019 9:42 pm
- Forum: Lewis Structures
- Topic: Balanced Lewis Structures
- Replies: 6
- Views: 461
Re: Balanced Lewis Structures
When drawing Lewis structure you should focus on the formal charges that make the molecule the most stable. Since Lewis structures are two-dimensional models the placement of atoms around the central atom isn't the most important aspect when drawing them.
- Sun Nov 17, 2019 9:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Geometry versus shape
- Replies: 3
- Views: 236
Re: Geometry versus shape
The geometry of a molecule only looks at the number of electron dense areas. However, when looking at the shape you take into account how the lone pairs around the central atom will affect the overall three-dimensional shape because they cause elctron repulsion.
- Sun Nov 17, 2019 9:30 pm
- Forum: Resonance Structures
- Topic: Formal Charge Question
- Replies: 16
- Views: 946
Re: Formal Charge Question
They have to sum up to the overall formal charge. Each atom's formal charge may vary but they all have to add up to the same overall charge.
- Sun Nov 17, 2019 9:28 pm
- Forum: Student Social/Study Group
- Topic: Final Exam
- Replies: 10
- Views: 691
Re: Final Exam
Yes, the exam will cover the material of all the quarter.
- Sun Nov 17, 2019 9:23 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: Stronger molecular force?
- Replies: 2
- Views: 225
Stronger molecular force?
Between ion-dipole and h-bonding which is the stronger molecular force? I thought it was ion-dipole because there is a full formal charge however I am not sure if this reasoning is correct.
- Sun Nov 17, 2019 9:12 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: induced dipole
- Replies: 4
- Views: 256
Re: induced dipole
An induced-dipole occurs when a temporary dipole occurs causing/inducing a dipole in a nonpolar molecule. On the other hand, a permanent dipole occurs when a polar molecule is always more elctronegative than the other molecule.
- Sun Nov 17, 2019 9:05 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 10
- Views: 570
Re: Lone Pairs
Lone pairs still affect molecular geometery because they still cause repulsion amongst electrons of other atoms.
- Mon Nov 11, 2019 9:25 pm
- Forum: Einstein Equation
- Topic: E=hv [ENDORSED]
- Replies: 52
- Views: 18592
Re: E=hv [ENDORSED]
E is the energy of the photon and the work function is the threshold energy, the energy needed to remove an electron.
- Mon Nov 11, 2019 9:19 pm
- Forum: Einstein Equation
- Topic: E=hv vs E=pc?
- Replies: 8
- Views: 1777
Re: E=hv vs E=pc?
E=hv would be used if the frequency is given or you can find it by manipulating c=(lambda)v, E=pc would be used when the momentum cana be found such as when the velocity or momentum is given.
- Mon Nov 11, 2019 9:16 pm
- Forum: Resonance Structures
- Topic: What is a Resonance "Structure"
- Replies: 12
- Views: 1066
Re: What is a Resonance "Structure"
A resonance structure would be possible ways to draw the Lewis structure of a molecule which has resonance, multiple bonds can be drawn in different locations, the actual structure would be a blend of all the different structures.
- Sun Nov 03, 2019 8:03 pm
- Forum: Electronegativity
- Topic: size
- Replies: 8
- Views: 522
Re: size
Atomic radius increases down a group and decreases across a period(from left to right). Electronegativity decreases down a group and increases across a period (left to right).
- Sun Nov 03, 2019 7:58 pm
- Forum: Resonance Structures
- Topic: All Molecules?
- Replies: 4
- Views: 265
Re: All Molecules?
No, resonance structures only occur when bonds can be moved to multiple locations.
- Sun Nov 03, 2019 7:51 pm
- Forum: Bond Lengths & Energies
- Topic: Strength of Bonds
- Replies: 16
- Views: 715
Re: Strength of Bonds
Shorter bonds are stronger than longer bonds since short bonds involve more elctrons, this which causes the nuclei to be more attracted. Conversely, longer bonds don't make nuclei as strongly attracted and therefore result in them being easily broken.
- Sun Nov 03, 2019 7:43 pm
- Forum: Resonance Structures
- Topic: Resonance structures
- Replies: 15
- Views: 861
Re: Resonance structures
Resonance structures are possible ways that the Lewis structure can be drawn (when there are multiple way to arrange electrons but the arrangement of the atoms doesn't change). A better representation of the structure would be a resonance hybrid/ an average of all the possible structures.
- Sun Nov 03, 2019 7:38 pm
- Forum: Lewis Structures
- Topic: Drawing Lewis Structures
- Replies: 5
- Views: 244
Re: Drawing Lewis Structures
When you draw a lewis structure you have to pay special attention to the valence electrons in each atom; they help determine if there are single/double/triple bonds. There is normally a center atom, and that is normally the atom that has the lowest ionization energy. For bonds (when the molecule is...
- Sun Nov 03, 2019 6:53 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: The equation
- Replies: 3
- Views: 269
Re: The equation
A lone pair would be the dots that aren't bonded but are still surrounding the element (those which don't have a line connecting to another element). The L in the formal charge equation would be the number of lone electrons for the element you are calculating it for.
- Sun Nov 03, 2019 6:44 pm
- Forum: Trends in The Periodic Table
- Topic: Drawing Structures
- Replies: 3
- Views: 188
Re: Drawing Structures
You know you can draw a chemical structure in several ways you can see multiple bonds in different locations, this is known as resonance. Resonance structures are indicator for more stable structures.
- Sun Nov 03, 2019 6:38 pm
- Forum: Lewis Structures
- Topic: Single bond
- Replies: 2
- Views: 165
Re: Single bond
A bond represents that two electrons are being shared by the elements. Two bonds would mean that there are four electrons shared by the elements.
- Sun Nov 03, 2019 6:37 pm
- Forum: Bond Lengths & Energies
- Topic: Midterm Question
- Replies: 5
- Views: 373
Re: Midterm Question
In the syllabus it lists that the topics in the Chemical Bonds unit are: (ionic and covalent bonds; Lewis structures of inorganic, organic, and biological compounds; resonance structures; formal charge; Lewis acids and bases; coordinate covalent bonds; octet rule exceptions; ionic versus covalent b...
- Sun Oct 27, 2019 8:23 pm
- Forum: Ionic & Covalent Bonds
- Topic: HW 2A.21d
- Replies: 5
- Views: 229
Re: HW 2A.21d
I believe Lavelle mentioned this odd configuration along with one other one that I am forgetting right now. He said that these two configurations are anomalies that we just have to memorize without much further explanation. Some areas of chemistry (and science in general) are proven experimentally ...
- Sun Oct 27, 2019 8:18 pm
- Forum: Ionic & Covalent Bonds
- Topic: Homework
- Replies: 13
- Views: 689
Re: Homework
Can we do problems from both sections or must they be exclusively from one?
- Sun Oct 27, 2019 8:10 pm
- Forum: Resonance Structures
- Topic: Octet
- Replies: 13
- Views: 869
Re: Octet
An octet would be an atom that has 8 valence electrons, noble gases all have octets. The octet rule refers to elements wanting to bond in order to reach eight valence elctrons and stability, the exceptions are H, He, Li, and Be.
- Sun Oct 27, 2019 7:58 pm
- Forum: Lewis Structures
- Topic: Choosing the central atom
- Replies: 16
- Views: 805
Re: Choosing the central atom
The central atom is the one with the lowest ionization energy(decrese down a group and increase across a period).
- Sun Oct 27, 2019 7:55 pm
- Forum: Ionic & Covalent Bonds
- Topic: Resonance
- Replies: 10
- Views: 432
Re: Resonance
Resonance doesn't mean that the molecule has different structures, rather that the Lewis structure for it can be arranged in various ways (not just three).
- Sun Oct 27, 2019 7:44 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: p-orbitals
- Replies: 11
- Views: 495
Re: p-orbitals
Unless otherwise specified by the question, you can just write 1s^2 2s^2 2p^3.
- Sun Oct 20, 2019 10:01 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Magnetic Quantum Number
- Replies: 5
- Views: 254
Re: Magnetic Quantum Number
The thrid quantum number tells us the specific orbital in a subshell, such as whether the electron can be foud in px py or pz.
- Sun Oct 20, 2019 9:18 pm
- Forum: Properties of Light
- Topic: Equations and Constants
- Replies: 6
- Views: 279
Re: Equations and Constants
All equations and constants are given in the equation sheet, however derivations of equations are not given so its safer (and better) to know what each variable corresponds to in case a question on the exam requires it and to gain a better understanding of the concepts.
- Sun Oct 20, 2019 9:14 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Neon- electron configuration
- Replies: 3
- Views: 293
Re: Neon- electron configuration
Elements like neon meet the octet rule meaning they have eight electron in its valence shell. The octet rule states that all elements want to have eight electrons in their valence shell, so neon and other elements like it aren't as likely to bond with other elements.
- Sun Oct 20, 2019 9:06 pm
- Forum: Properties of Light
- Topic: Next test
- Replies: 23
- Views: 1117
Re: Next test
Yes, according to my TA we will get the equation sheet from the first test for every test.
- Sun Oct 20, 2019 8:59 pm
- Forum: Photoelectric Effect
- Topic: Speed of Light
- Replies: 29
- Views: 1655
Re: Speed of Light
The speed of light is a constant (2.998 x 10^8) as others have mentioned 3.0 x 10^8 is sometimes used, however it would be better if you used 2.998 x 10^8 so that your sig figs at the end are correct.
- Sat Oct 05, 2019 7:08 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Solution problem
- Replies: 3
- Views: 165
Re: Solution problem
The molarity is given by amount of solute molecules (moles) divided by the volume of the solution (liters), the molar amount of solute would therefore be the numerator.
- Sat Oct 05, 2019 7:03 pm
- Forum: Limiting Reactant Calculations
- Topic: Amount of Limiting Reactants
- Replies: 2
- Views: 219
Re: Amount of Limiting Reactants
By definition a limiting reactant is the reactant that will be completely consumed. There will be more of one than the other causing the reaction to stop there. Whatever is left of the reactants would be labeled as excess reactants. If the reactants are equal then they will not limit each other, rat...
- Sat Oct 05, 2019 6:55 pm
- Forum: SI Units, Unit Conversions
- Topic: Unit Conversion
- Replies: 5
- Views: 189
Re: Unit Conversion
You can multiply the number of kilograms by 1000 grams since that is the conversion number not in scientific notation (1kg=1000g).
- Sat Oct 05, 2019 6:44 pm
- Forum: Empirical & Molecular Formulas
- Topic: Ratios of Empirical Formulas
- Replies: 3
- Views: 240
Re: Ratios of Empirical Formulas
Just try to estimate what would number multiplied by .16 is close to 1. To my understanding, you simply have to be really close to a whole number. In this example, 2.16 * 6 = 12.96 which is close to 13. However, if the factor you use gives you (in the example lets say 3) a result (6.48) that is not ...
- Sat Oct 05, 2019 6:32 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Atoms, Molecules, and Formula Units
- Replies: 4
- Views: 337
Re: Atoms, Molecules, and Formula Units
You can find atoms, molecules, and formula units using Avogadro’s constant because scientists have determined 6.022x10^23 of atoms/particles/ molecules is equal to 1 mol. You can use the substance’s molar mass to calculate what is being asked for. For example if you were given to find the mass of an...