Search found 30 matches

Fri Jul 28, 2017 5:55 pm
Forum: Conjugate Acids & Bases
Topic: HW: 12.17
Replies: 4
Views: 558

HW: 12.17

State whether the following oxides are acidic, basic, or amphoteric:
a) BaO
b) SO3
c) As2O3
d) Bi2O3

Can someone walk me through this problem?
I know that amphoteric means it can act as both acid / base, but I'm confused on how to solve this question
Thank you!
Fri Jul 28, 2017 5:53 pm
Forum: Conjugate Acids & Bases
Topic: HW: 12.13
Replies: 1
Views: 232

HW: 12.13

Draw the Lewis structure for each of the following species and identify each as a Lewis acid or Lewis base:
a) NH3
b) BF3
c) Ag+
d) F-
e) H-

How do we determine whether it's acid / base, based on Lewis structure?
Fri Jul 28, 2017 5:52 pm
Forum: Conjugate Acids & Bases
Topic: HW: 12.9
Replies: 2
Views: 451

HW: 12.9

In 12.9: Which of the following reactions can be classified as reactions between Brosted acids and bases? For those that can be so classified, identify the acid and the base. a) NH4I(aq) + H2O(l) --> NH3(aq) + H3O(aq) + I-(aq) b) NH3I(s) --> NH3(g) + HI(g) c) CH3COOH(aq) + NH3(aq) --> CH3CONH2(aq) +...
Mon Jul 24, 2017 8:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question 11.13
Replies: 3
Views: 356

Re: Question 11.13

Aqueous is included
Only solid + liquid NOT included
Sun Jul 23, 2017 6:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question 11.13
Replies: 3
Views: 356

Re: Question 11.13

The reason why the answer is 1/PBCl3^2 is because as stated in page 133 in the course reader, molar concentration of a pure substance (solid or liquid) does not change in a reaction This means that solid + liquid are not included in K expression As you can see in problem A, 2 BCl3(g) + 2 Hg (l) --> ...
Sun Jul 23, 2017 4:52 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Bonds (video)
Replies: 6
Views: 476

Re: Covalent Bonds (video)

Thank you so much this was so helpful and cute!
Sat Jul 22, 2017 7:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chapter 4 Hw , 4.15A
Replies: 2
Views: 268

Re: Chapter 4 Hw , 4.15A

Tetrahedral has a bond angle of 109.5
Sat Jul 22, 2017 7:43 pm
Forum: Hybridization
Topic: HW Problem 4.77
Replies: 3
Views: 356

Re: HW Problem 4.77

Ch 4 has a lot of molecular orbital theory problems, but Dr Lavelle said we won't go over them since there's not enough time!
Thu Jul 20, 2017 4:24 pm
Forum: Lewis Structures
Topic: More Lewis Structure Problems
Replies: 1
Views: 299

More Lewis Structure Problems

Here is a link that I found helpful when drawing lewis structures!
Hope it helps

Wed Jul 19, 2017 5:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Exercise 3.13
Replies: 2
Views: 414

Exercise 3.13

For each of the following ground-state atoms, predict the type of orbital (1s, 2p, 3d, 4f, etc.) from which an electron will need to be removed to form the +1 ions:
a) Zn
b) Cl
c) Al
d) Cu

Why is Zn and Cu in the 4s orbital?
Tue Jul 18, 2017 10:31 pm
Forum: Einstein Equation
Topic: Exam 1 - Q4A
Replies: 1
Views: 403

Exam 1 - Q4A

"In 1.0 s, a 60 W bulb emits 11 J of energy in the form of infrared radiation (heat) of wavelength 1850 nm. What is the energy per photon of light emitted? How many photons of infrared radiation does the lamp generate in 1.0 s?" Can someone walk me through this problem please? I think I go...
Sun Jul 16, 2017 3:32 pm
Forum: Quantum Numbers and The H-Atom
Topic: Writing e- configurations of atoms
Replies: 2
Views: 327

Writing e- configurations of atoms

In the course reader page 65, I'm still not 100% sure as to why e- configuration of chromium is, Cr: [Ar] 3d^5 4s^1 and copper is, Cu: [Ar] 3d^10 4s^1
Why is it not 3d^5 4s^2?
Also when writing e- configurations, what's the oder of orbitals? Is it f-orbital, d-orbital, p-orbital, and then s-orbital?
Sun Jul 16, 2017 3:27 pm
Forum: Ionic & Covalent Bonds
Topic: Polar vs. nonpolar
Replies: 2
Views: 251

Polar vs. nonpolar

How do we differentiate b/w polar and nonpolar bonds?
Also, do we look at the periodic table and go based off of that?
Tue Jul 11, 2017 11:41 pm
Forum: Quantum Numbers and The H-Atom
Topic: question on hw 2.29
Replies: 2
Views: 276

Re: question on hw 2.29

https://www.youtube.com/watch?v=wnLcJH-Heyo This is a short clip explaining quantum numbers, hope it helps!! a) 6 This is because when n=2, l=1 it's a p orbital and we know that p orbitals can hold 6 electrons b) 2 It's 2 electrons b/c the numbers are describing each orbitals and each orbitals can h...
Tue Jul 11, 2017 4:06 pm
Forum: Quantum Numbers and The H-Atom
Topic: Text Book Problem 2.29 (d)
Replies: 3
Views: 440

Re: Text Book Problem 2.29 (d)

It's 8 because n = 2 is s & p orbitals
s can hold 2 + p can hold 6 = 8
Tue Jul 11, 2017 4:03 pm
Forum: Properties of Light
Topic: Exercise 1.15 (Ch 1 : The Quantum World)
Replies: 4
Views: 401

Re: Exercise 1.15 (Ch 1 : The Quantum World)

When you do 1/0.112 it's 8.928571429 which is roughly about 9
Square root of that would be 3
Mon Jul 10, 2017 7:27 pm
Forum: Empirical & Molecular Formulas
Topic: Limiting Reactants?
Replies: 5
Views: 892

Re: Limiting Reactants?

When we are not given a molar mass, we can assume there are 100g of the sample. However, since the molar mass was given we can use that to find the actual amounts. Then how come for F.17 we don't need to do it that way? The question is: Osmium forms a molecular compound with mass percentage composi...
Mon Jul 10, 2017 7:01 pm
Forum: Empirical & Molecular Formulas
Topic: Limiting Reactants?
Replies: 5
Views: 892

Re: Limiting Reactants?

When we are not given a molar mass, we can assume there are 100g of the sample. However, since the molar mass was given we can use that to find the actual amounts. Then how come for F.17 we don't need to do it that way? The question is: Osmium forms a molecular compound with mass percentage composi...
Sun Jul 09, 2017 8:53 pm
Forum: Properties of Light
Topic: Electron Configuration
Replies: 4
Views: 321

Re: Electron Configuration

Dr. Lavelle said it's okay to write it as 1s^1 2s^2 2p^3!
Sun Jul 09, 2017 6:12 pm
Forum: Trends in The Periodic Table
Topic: Exercise 2.67
Replies: 4
Views: 435

Exercise 2.67

In 2.67: Which element of each of the following pairs has the higher electron affinity: a) oxygen or fluorine b) nitrogen or carbon c) chlorine or bromine d) lithium or sodium For b, why isn't nitrogen higher? Doesn't electron affinity increases upward for the groups and from left to right across pe...
Sun Jul 09, 2017 1:39 pm
Forum: Student Social/Study Group
Topic: Thoughts after Test 1?
Replies: 13
Views: 1130

Re: Thoughts after Test 1?

Yes this is what my TA said, "Although I strongly suggest students use pen, I do allow the use of pencil on tests within certain restrictions. Specifically if a test is is written in pencil then this removes the possibility of an exam regrade if a student feels that the test has been graded in ...
Sat Jul 08, 2017 10:11 pm
Forum: Student Social/Study Group
Topic: Thoughts after Test 1?
Replies: 13
Views: 1130

Re: Thoughts after Test 1?

I agree with Ben - you need to be able to pace yourself during the exam b/c 50 minutes feels really limiting (esp if there are a lot of parts to each questions) That's why when I study Dr. Lavelle's practice exams / do the work problems from the book, I set the timer to 45 minutes and pretend like I...
Sat Jul 08, 2017 5:50 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Ground state vs. excited state
Replies: 3
Views: 13396

Re: Ground state vs. excited state

Thank you guys :)
Sat Jul 08, 2017 4:34 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Ground state vs. excited state
Replies: 3
Views: 13396

Ground state vs. excited state

What does it mean for an electron configuration to represent a ground state or an excited state of an atom?
Is it talking about the opposite / same spin?

In 2.39: Determine whether each of the following electron configurations represents the ground state or an excited state of the atom given.
Wed Jul 05, 2017 4:32 pm
Forum: Limiting Reactant Calculations
Topic: Exercise M.21
Replies: 1
Views: 304

Exercise M.21

In M.21: A compound found in the nucleus of a human cell was found to be composed of carbon, hydrogen, oxygen, and nitrogen. A combustion analysis of 1.35g of the compound produced 2.20g of CO2 and 0.901g of H2O. When a separate 0.500-g sample of the compound was analyzed for nitrogen, 0.130g of N2 ...
Sun Jul 02, 2017 10:58 pm
Forum: DeBroglie Equation
Topic: Class Lecture Work Example Question [ENDORSED]
Replies: 2
Views: 374

Re: Class Lecture Work Example Question[ENDORSED]

During his office hour, Dr. Lavelle said mass of electron is always (9.10938 x 10^-31 kg) and this formula will be given in the tests On the first problem, we used 1.50 x 10^3 kg as our mass because it is given in the problem Lastly, we want SI units in m because SI unit for Joules is: kg * m^2 * s^...
Sun Jul 02, 2017 5:57 pm
Forum: Properties of Light
Topic: Protons & neutrons
Replies: 1
Views: 232

Protons & neutrons

In 1.37: Protons and neutrons have nearly the same mass. How different are their wavelengths? Calculate the wavelength of each particle when traveling at 2.75 x 10^5 ms^-1 in a particle accelerator and report the difference as a percentage of the wavelength of the neutron. In 1.41: What is the veloc...
Sun Jul 02, 2017 5:51 pm
Forum: Properties of Light
Topic: Exercise 1.15 (Ch 1 : The Quantum World)
Replies: 4
Views: 401

Re: Exercise 1.15 (Ch 1 : The Quantum World)

Thank you!!
Sat Jul 01, 2017 6:29 pm
Forum: Properties of Light
Topic: Exercise 1.15 (Ch 1 : The Quantum World)
Replies: 4
Views: 401

Exercise 1.15 (Ch 1 : The Quantum World)

In 1.15: In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6nm. 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. Question: after getting 0.112, how do we know that n2^2 = 9; n2 = 3?
Thu Jun 29, 2017 9:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Exercise 2.29
Replies: 10
Views: 1545

Exercise 2.29

For Exercise 2.29 (Chapter 2 The Quantum Mechanics in Action: Atoms)
How many electrons can have the following quantum numbers in an atom:
a) n = 2, l = 1
b) n = 4, l = 2, ml = -2
c) n = 2
d) n = 3, l = 2, ml = +1

Does anyone know how to solve this problem?