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: 1115
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: 716
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: 313
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: 686
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: 431
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: 7992
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: 529
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: 423
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: 1538
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: 866
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: 1908
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: 529
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: 626
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: 763
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: 1532
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: 1532
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: 557
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.
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: 1659
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: 666
- Wed Oct 11, 2017 11:08 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect Module Question 18 [ENDORSED]
- Replies: 3
- Views: 666
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: 9651
- Views: 3741213
Re: Post All Chemistry Jokes Here
Who's a really salty rapper?
NaCl-more
NaCl-more
- Thu Oct 05, 2017 4:04 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3741213
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: 490
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: 490
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?