## Search found 24 matches

Wed Dec 06, 2017 3:57 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength of an Acid
Replies: 5
Views: 605

### Re: Strength of an Acid

I just know that HI is the strongest acid out of the four because it releases the most hydrogen ions into the solution. The pH is determined by [H+], and stronger acids have a lower pH. That means that stronger acids will release more hydrogens than weaker acids, and HI will release more hydrogens t...
Wed Dec 06, 2017 3:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How to assume X is too small
Replies: 3
Views: 429

### Re: How to assume X is too small

I think Dr. Lavelle mentioned that if K is less than 10^-4, then it can generally be assumed that X will be small enough to ignore, but we should definitely still check to make sure at the end.
Mon Nov 27, 2017 11:58 pm
Forum: Naming
Topic: Question 17.31c and d
Replies: 1
Views: 196

### Question 17.31c and d

Why is water is written as H2O in part c but OH2 in part d?
Mon Nov 27, 2017 3:12 pm
Forum: Ideal Gases
Topic: Problem 11.37 [ENDORSED]
Replies: 3
Views: 399

### Re: Problem 11.37[ENDORSED]

I thought the constant always stayed the same unless you reversed the reaction or changed the temperature?
Wed Nov 22, 2017 1:50 pm
Forum: Naming
Topic: Question 17.29a
Replies: 3
Views: 247

### Question 17.29a

Why is [Fe(CN)6]4- the hexacyanidoferrate(II) ion? Where does the ferrate come from? In what situations does the name of the transition metal change?
Wed Nov 22, 2017 1:43 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determine the Charge on Ligands
Replies: 4
Views: 3618

### Re: Determine the Charge on Ligands

I was under the impression that a single ligand always has the same charge. For example, the CN anion has a -1 charge. The charge on the transition metals can vary based on the overall charge of the coordination complex and the lewis structure.
Wed Nov 15, 2017 11:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR and Electrons
Replies: 3
Views: 318

### VSEPR and Electrons

When drawing the VSEPR models, should we still include the lone pairs?
Wed Nov 15, 2017 11:28 pm
Forum: Dipole Moments
Topic: Polar and non-polar molecules
Replies: 2
Views: 236

### Re: Polar and non-polar molecules

A quick way for me to determine whether a molecule is polar or not is to see whether it is symmetrical. Polar molecules are typically non-symmetrical, meaning that the electrons will be unbalanced and a dipole will form.
Wed Nov 15, 2017 11:24 pm
Forum: Electronegativity
Topic: Isoelectronic [ENDORSED]
Replies: 11
Views: 936

### Re: Isoelectronic[ENDORSED]

Isoelectronic ions have the same number of electrons, even though they have different numbers of protons.
Wed Nov 08, 2017 9:59 pm
Forum: Dipole Moments
Topic: Direction of the Dipole moment arrow [ENDORSED]
Replies: 3
Views: 433

### Re: Direction of the Dipole moment arrow[ENDORSED]

Dr. Lavelle has been drawing the arrow pointing to the negative end, so I'm following his conventions :)
Wed Nov 08, 2017 9:58 pm
Forum: Electronegativity
Topic: Electronegativity and Bond Strength
Replies: 4
Views: 808

### Re: Electronegativity and Bond Strength

I think bond strength has more to do with bond length than electronegativity. Shorter bonds are stronger. For example, fluorine-carbon bonds are stronger than chlorine-carbon bonds because the fluorine atom is smaller than the chlorine atom, so there is a stronger interaction with fluorine and carbon.
Thu Nov 02, 2017 12:31 am
Forum: Trends in The Periodic Table
Topic: Problem 2.61 Part C
Replies: 2
Views: 284

### Problem 2.61 Part C

Problem 2.61 asks which member of each pair has the smaller first ionization energy, Al or Na. Why does Na have a smaller first ionization energy than Al ? I thought that Al would have the smaller first ionization energy because it has one more orbital than Na that is farther from the nucleus. Is it...
Wed Nov 01, 2017 10:33 pm
Forum: Trends in The Periodic Table
Topic: Trends in the periodic table
Replies: 3
Views: 362

### Re: Trends in the periodic table

Electron affinity is the ability of an atom to pull electrons toward itself. Fluorine and the rest of the elements in the group have a high electron affinity, meaning that they have a strong tendency to pull electrons toward themselves because they are only one electron away from filling up their oc...
Wed Nov 01, 2017 10:20 pm
Forum: Bond Lengths & Energies
Topic: Bond Length
Replies: 5
Views: 437

### Re: Bond Length

I agree. Dr. Lavelle mentions pretty frequently in class that he looks up the values.
Sat Oct 28, 2017 12:25 am
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 4
Views: 852

### Re: Magnetic Quantum Number

I think that Dr. Lavelle mentioned that the values of ml don't correspond with any specific orientation because it's arbitrary which number to assign to which orbital. The values of ml are especially complicated with the five d orbitals.
Wed Oct 25, 2017 11:55 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 4
Views: 852

### Re: Magnetic Quantum Number

The magnetic quantum number refers to the different orbitals of a sub-shell (for example, the p x , p y , and p z orbitals). It is different from the angular momentum quantum number (l) that only describes whether it's s, p, d, or f. ml can take on the positive and negative values of l. For example,...
Wed Oct 18, 2017 11:19 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post Module #42
Replies: 3
Views: 331

### Re: Atomic Spectra Post Module #42

The equation for the change in energy is -hR/n^2 final minus -hR/n^2 initial.
You know the value of h, R, and n final (which is 4), and you can solve for the energy of the photon with the equation E=hv since you are given the frequency. Then there will only be one variable to solve for, n initial.
Wed Oct 18, 2017 11:05 pm
Forum: Photoelectric Effect
Topic: Rydberg
Replies: 11
Views: 1102

### Re: Rydberg

When you use the Rydberg formula, always do n final minus n initial . Dr. Lavelle used the example during class of temperature, where you use the final temperature minus the initial temperature to measure the change. The same can be said of money. If you start with 5 dollars and end up with 3 dollar...
Fri Oct 13, 2017 3:47 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module Question 18 [ENDORSED]
Replies: 3
Views: 417

### Re: Photoelectric Effect Module Question 18[ENDORSED]

Thank you!
Wed Oct 11, 2017 11:08 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module Question 18 [ENDORSED]
Replies: 3
Views: 417

### Photoelectric Effect Module Question 18[ENDORSED]

Question 18 reads: In the photoelectric effect what condition must occur for an electron to be emitted from a metal surface? The answer is both C and D: C. E (photon) = E (remove e-) D. E (photon) > E (remove e-) Why is the answer not just C? At the bare minimum, doesn't the energy of the photon hav...
Wed Oct 11, 2017 10:56 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8894
Views: 1531585

### Re: Post All Chemistry Jokes Here

Who's a really salty rapper?
NaCl-more
Thu Oct 05, 2017 4:04 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8894
Views: 1531585

### Re: Post All Chemistry Jokes Here

Why was the basic girl so salty? Because someone dumped acid on her!
Wed Oct 04, 2017 12:37 pm
Forum: SI Units, Unit Conversions
Topic: Homework Assignments
Replies: 2
Views: 355

### Re: Homework Assignments

Thank you so much!
Tue Oct 03, 2017 11:34 pm
Forum: SI Units, Unit Conversions
Topic: Homework Assignments
Replies: 2
Views: 355

### Homework Assignments

When turning in homework to the TA, are we required to complete four questions per section (four for E, four for F, etc.) or four total?