## Search found 36 matches

Sat Dec 08, 2018 10:09 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acid
Replies: 6
Views: 105

### Re: Lewis Acid

The strength of an acid depends on how easily the A-H bond can be broken. The stronger the acid, the weaker the bond. So, HBr is a stronger acid than HF because the atomic radius of Br is larger than the atomic radius of F, so the bond is longer (therefore weaker) and more easily broken.
Sat Dec 08, 2018 10:07 pm
Forum: DeBroglie Equation
Topic: exhibiting wave-like properties
Replies: 4
Views: 254

### Re: exhibiting wave-like properties

All particles are said to have wave-like properties. However, it is whether or not they are measurable that is the question. I believe it was said that wavelength is "measurable" when it anything larger than about 10^-14 m.
Thu Dec 06, 2018 7:00 pm
Forum: Naming
Topic: oxidation number
Replies: 4
Views: 107

### oxidation number

When finding the oxidation number of a transition metal in a coordination compound, the book says you need you subtract the charge of each ligand present from the overall charge. How do we know which ligands have what charge, or if they have a charge at all? Thanks!
Wed Dec 05, 2018 9:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Structures
Replies: 12
Views: 225

### Re: Bent Structures

I believe all bent molecules are polar due asymmetry caused by the lone pair(s) located on the central atom.
Wed Dec 05, 2018 9:04 pm
Forum: Conjugate Acids & Bases
Topic: Finding Conjugate Acid for Thymine (problem 6.21 7th editiion)
Replies: 1
Views: 52

### Finding Conjugate Acid for Thymine (problem 6.21 7th editiion)

Problem 6.21 asks us first to identify how many protons Thymine could potentially accept (2), then asks us where these protons would be located in the conjugate acids. Why is it that when forming a conjugate acid, the H attaches to the NH part of the molecule, instead of the O atoms?
Sun Dec 02, 2018 9:13 pm
Forum: Bronsted Acids & Bases
Topic: Net Ionic Equations
Replies: 2
Views: 97

### Net Ionic Equations

Will we need to know how to write net ionic equations for the final? How do you know the charge for each ion when finding the net ionic equation?
Sat Dec 01, 2018 5:34 pm
Forum: Naming
Topic: Naming/ oxidation numbers/ charges
Replies: 2
Views: 71

### Re: Naming/ oxidation numbers/ charges

how do we know the charges of the ions within the compound? Is there a way to determine them?
Tue Nov 27, 2018 11:14 am
Forum: Hybridization
Topic: How to Write Second Pi Bond in Triple Bond
Replies: 3
Views: 100

### Re: How to Write Second Pi Bond in Triple Bond

will we need to know how to name sigma and pi bonds for test 3? on the chapter outline it just says we need to know how to distinguish sigma and pi bonds by their shapes, properties, and component orbitals.
Mon Nov 26, 2018 8:02 pm
Forum: Hybridization
Topic: hybridization
Replies: 3
Views: 94

### hybridization

I understand the basic concept of finding the hybridization of an atom in a compound, but what exactly causes this hybridization to occur?
Fri Nov 23, 2018 2:19 pm
Forum: Hybridization
Topic: S-Character Bond Angle Trend
Replies: 3
Views: 60

### Re: S-Character Bond Angle Trend

as the s-character of a hybrid increases, the bond angle increases because there are fewer regions of electron density. for example, in an sp hybrid, there are only two regions of electron density, so these two regions are more spread out and therefore have a wider bond angle than say, an sp2 hybrid...
Fri Nov 23, 2018 2:04 pm
Forum: Sigma & Pi Bonds
Topic: Double Bonds
Replies: 9
Views: 433

### Re: Double Bonds

Yes, here is a rule of thumb:
a single bond has one sigma bond
a double bond has one sigma and one pi bond
a triple bond has one sigma and two pi bonds
Fri Nov 23, 2018 1:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework for week 9
Replies: 11
Views: 310

### Re: Homework for week 9

My TA said however you want to format it is fine, as long as you have 14 problems total!
Fri Nov 23, 2018 1:32 pm
Forum: Hybridization
Topic: stating the hybridization of an atom
Replies: 3
Views: 103

### stating the hybridization of an atom

Do we need to include the shell (n value) when stating the hybridization of an atom? For example, in homework problem 2F.5 part A (7th edition), the solutions manual says the answer as just "sp" instead of "2sp". On the test, will we need to include the 2?
Sun Nov 18, 2018 3:25 pm
Forum: Sigma & Pi Bonds
Topic: Calculating Amount of Sigma/Pi Bonds
Replies: 4
Views: 139

### Calculating Amount of Sigma/Pi Bonds

How do you calculate the amount of sigma and pi bonds in a molecule? Do you just use the Lewis Structure of the molecule and look at the types on bonds used in the most stable form?
Sun Nov 18, 2018 3:07 pm
Forum: Lewis Structures
Topic: Polar vs Nonpolar molecules
Replies: 7
Views: 228

### Polar vs Nonpolar molecules

How can you predict whether a molecule is polar or nonpolar based on its lewis structure?
Sun Nov 18, 2018 2:49 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing Molecules
Replies: 5
Views: 120

### Re: Drawing Molecules

I'm pretty sure for the test we will only be asked to draw the lewis structure of a molecule and then name the shape (and know the angles), not actually draw the three-dimensional shape!
Sun Nov 11, 2018 11:43 am
Forum: Electronegativity
Topic: difference in electronegativity
Replies: 5
Views: 158

### difference in electronegativity

can the difference in electronegativity of two atoms (forming a compound) be calculated? or is it just determined by looking at the periodic table and knowing the general trends of electronegativity?
Sun Nov 11, 2018 11:39 am
Forum: Bond Lengths & Energies
Topic: Bond Length
Replies: 9
Views: 308

### Re: Bond Length

can a double bond and single bond for the same element be the same length?
Sun Nov 11, 2018 11:35 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dipole vs Induced Dipole
Replies: 3
Views: 238

### Dipole vs Induced Dipole

what is the difference between a dipole and an induced dipole? How do their bond properties vary?
Sat Nov 03, 2018 4:14 pm
Forum: Bond Lengths & Energies
Topic: Bond Lengths
Replies: 3
Views: 113

### Re: Bond Lengths

That is a topic discussed in 1F, so I assume it will be on the midterm (Dr. Lavelle said everything on the syllabus through Topic 2C from the 7th edition is fair game).
Sat Nov 03, 2018 4:11 pm
Forum: Properties of Electrons
Topic: The Inert Pair Effect
Replies: 2
Views: 3806

### The Inert Pair Effect

can someone please explain to me the inert pair effect? (discussed in topic 1F)
Sat Nov 03, 2018 4:04 pm
Forum: Properties of Electrons
Topic: Excitation of an atom
Replies: 1
Views: 227

### Re: Excitation of an atom

When an atom becomes excited, an electron in that atom moves to an outer shell (a higher n value). The higher the n value, aka the further away it is from the nucleus, the more energy that electron (and atom) has. Hope this helps!
Sat Oct 27, 2018 11:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework problem 2A.23 (7th edition) [ENDORSED]
Replies: 1
Views: 78

### Homework problem 2A.23 (7th edition)[ENDORSED]

This problem states: On the basis of the expected charges on the monatomic ions, give the chemical formula of each of the following compounds: a) magnesium arsenide; b) Indium (III) sulfide; c) aluminum hydride; d0 hydrogen telluride; e) bismuth (III) fluoride. How would you go about solving this pr...
Sat Oct 27, 2018 10:57 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: electron configurations
Replies: 1
Views: 59

### electron configurations

when writing electron configurations, I get that you write out a noble gas core, then the valence electrons shown on the periodic table, (for example, the configuration for Fluorine is [He]2s^2,2p^2), but when it gets to the more complex elements like Bi and Pb, how do we know which orbitals needed ...
Sat Oct 27, 2018 10:20 pm
Forum: Ionic & Covalent Bonds
Topic: Molecular Formula to Ionic Compounds
Replies: 1
Views: 34

### Molecular Formula to Ionic Compounds

In Friday's lecture, when we did the example of how to draw the lewis structure of polyatomic species, Dr. Lavelle gave first the molecular formula of ammonium sulfate, then split this molecular formula into two ionic compounds ( (NH4)2SO4 -> NH4+ and SO42- ). In problems like this, do we need to kn...
Sat Oct 20, 2018 12:21 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Indeterminacy Equation as an inequality
Replies: 1
Views: 40

### Heisenberg Indeterminacy Equation as an inequality

Heisenberg Indeterminacy Equation shows that (deltaP)(deltaX) >/= (h/4pi) How does this inequality translate into an equation when completing practice problems using the Heisenberg Uncertainty Equation? Should our answer remain an inequality? In the in-class example the answer was a definitive numbe...
Sat Oct 20, 2018 12:02 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Concentration
Replies: 2
Views: 314

### Re: Concentration

To find the molar mass of Ca3(PO4)2, you need the molar mass of each element in the compound, which can be found on the periodic table. As for the subscript "2" outside of the parentheses (PO4), that needs to be distributed in. So, for the compound Ca3(PO4)2, you would have a total of: 3 C...
Fri Oct 19, 2018 11:53 pm
Forum: Quantum Numbers and The H-Atom
Topic: 4th Quantum Number [ENDORSED]
Replies: 1
Views: 65

### Re: 4th Quantum Number[ENDORSED]

in the Stern and Genach Experiment, a beam of silver atoms was passed through a magnetic field. The results showed that the beam interacted with the magnetic field, because it split into two beams after it passed through. This means that 1 unpaired electron can have two different "spin states&q...
Sun Oct 14, 2018 1:57 pm
Forum: Administrative Questions and Class Announcements
Topic: Is homework graded for correctness or completeness?
Replies: 5
Views: 234

### Re: Is homework graded for correctness or completeness?

Homework will always be graded for completeness! Your TA will essentially give you a check mark if you turn in work and an answer for 7 homework problems.
Sun Oct 14, 2018 1:55 pm
Forum: Properties of Light
Topic: Investigating Atoms: Topic 1A Problem 1A.15
Replies: 1
Views: 37

### Investigating Atoms: Topic 1A Problem 1A.15

Problem 1A.15 states: In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of "n" for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line. which equation would you use to go about...
Sun Oct 14, 2018 1:42 pm
Forum: Properties of Light
Topic: De Broglie Equation
Replies: 6
Views: 128

### De Broglie Equation

In class on Friday, Dr. Lavelle introduced the De Broglie Equation to show the relationship between wavelength of any moving object with its mass and velocity. When doing the class examples, I noticed the mass of objects were kept in kilograms. Do all masses need to be in kilograms when using the De...
Sun Oct 14, 2018 1:34 pm
Forum: Einstein Equation
Topic: Test #2
Replies: 4
Views: 142

### Re: Test #2

I'm pretty sure this week's discussion session will be completing practice problems and answering clarifying questions, similar to week one. The syllabus says the test will be next week during your discussion section.
Mon Oct 08, 2018 9:58 pm
Forum: Significant Figures
Topic: Rounding Using Significant Figures
Replies: 10
Views: 558

### Re: Rounding Using Significant Figures

Thank you so much! Yes, both those explanations helped a lot.
As for losing points on tests, I think we can receive partial credit if we round to the wrong decimal, but will get 1-2 points deducted if our answer does not have the correct number of sig figs.
Sun Oct 07, 2018 2:48 am
Forum: Empirical & Molecular Formulas
Topic: Steps to calculating Molecular Formulas
Replies: 3
Views: 147

### Re: Steps to calculating Molecular Formulas

When finding the empirical formula, after dividing each number by the smallest number of moles, how close do the new values need to be to a whole number to just round up/down? Vs multiplying each value by a certain integer to get it closer to a whole number?
Thanks!
Sun Oct 07, 2018 2:40 am
Forum: General Science Questions
Topic: Nomenclature for Chem14A [ENDORSED]
Replies: 1
Views: 128

### Nomenclature for Chem14A[ENDORSED]

I was noticing that in the fundamentals exercises, some problems simply gave you the name of a compound and not the chemical formula.
Will we need to know how to name chemical compounds/write the formula when given a name for the test?
Sun Oct 07, 2018 2:32 am
Forum: Significant Figures
Topic: Rounding Using Significant Figures
Replies: 10
Views: 558

### Rounding Using Significant Figures

Hi all! I'm a little confused on when to round using significant figures.
I am finding that rounding varies for each answer in the solutions manual for our textbook. Is there a way to know what to round to in an answer using sig figs?
Thank you!