CHEMISTRY COMMUNITY

Caitlin_Murphy_3C

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.

Caitlin_Murphy_3C

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.

Caitlin_Murphy_3C

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!

Caitlin_Murphy_3C

I believe all bent molecules are polar due asymmetry caused by the lone pair(s) located on the central atom.

Caitlin_Murphy_3C

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?

Caitlin_Murphy_3C

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?

Caitlin_Murphy_3C

how do we know the charges of the ions within the compound? Is there a way to determine them?

Caitlin_Murphy_3C

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.

Caitlin_Murphy_3C

I understand the basic concept of finding the hybridization of an atom in a compound, but what exactly causes this hybridization to occur?

Caitlin_Murphy_3C

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...

Caitlin_Murphy_3C

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

Caitlin_Murphy_3C

My TA said however you want to format it is fine, as long as you have 14 problems total!

Caitlin_Murphy_3C

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?

Caitlin_Murphy_3C

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?

Caitlin_Murphy_3C

How can you predict whether a molecule is polar or nonpolar based on its lewis structure?

Caitlin_Murphy_3C

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!

Caitlin_Murphy_3C

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?

Caitlin_Murphy_3C

can a double bond and single bond for the same element be the same length?

Caitlin_Murphy_3C

what is the difference between a dipole and an induced dipole? How do their bond properties vary?

Caitlin_Murphy_3C

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).

Caitlin_Murphy_3C

can someone please explain to me the inert pair effect? (discussed in topic 1F)

Caitlin_Murphy_3C

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!

Caitlin_Murphy_3C

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...

Caitlin_Murphy_3C

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 ...

Caitlin_Murphy_3C

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...

Caitlin_Murphy_3C

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...

Caitlin_Murphy_3C

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...

Caitlin_Murphy_3C

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...

Caitlin_Murphy_3C

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.

Caitlin_Murphy_3C

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...

Caitlin_Murphy_3C

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...

Caitlin_Murphy_3C

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.

Caitlin_Murphy_3C

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.

Caitlin_Murphy_3C

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!

Caitlin_Murphy_3C

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?

Caitlin_Murphy_3C

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!

CHEMISTRY COMMUNITY

Search found 36 matches

Re: Lewis Acid

Re: exhibiting wave-like properties

oxidation number

Re: Bent Structures

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

Net Ionic Equations

Re: Naming/ oxidation numbers/ charges

Re: How to Write Second Pi Bond in Triple Bond

hybridization

Re: S-Character Bond Angle Trend

Re: Double Bonds

Re: Homework for week 9

stating the hybridization of an atom

Calculating Amount of Sigma/Pi Bonds

Polar vs Nonpolar molecules

Re: Drawing Molecules

difference in electronegativity

Re: Bond Length

Dipole vs Induced Dipole

Re: Bond Lengths

The Inert Pair Effect

Re: Excitation of an atom

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

electron configurations

Molecular Formula to Ionic Compounds

Heisenberg Indeterminacy Equation as an inequality

Re: Concentration

Re: 4th Quantum Number [ENDORSED]

Re: Is homework graded for correctness or completeness?

Investigating Atoms: Topic 1A Problem 1A.15

De Broglie Equation

Re: Test #2

Re: Rounding Using Significant Figures

Re: Steps to calculating Molecular Formulas

Nomenclature for Chem14A [ENDORSED]

Rounding Using Significant Figures