## Search found 35 matches

Wed Jun 13, 2018 11:48 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Drawing orbitals [ENDORSED]
Replies: 1
Views: 213

### Drawing orbitals[ENDORSED]

Does anyone know if we are expected to know how to draw d orbitals? I know we learned how to do s and p really well but I am unsure about d.
Thanks.
Sat Jun 09, 2018 11:21 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 12.49
Replies: 3
Views: 271

### 12.49

Does anyone know if for questions like 12.49 on the final,
12.49 Which is the stronger base, the hypobromite ion, BrO , or morphine, C17H19O3N? Justify your answer
will we be given the pKb values?
Thanks.
Sat Jun 09, 2018 11:05 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 12.19
Replies: 1
Views: 227

### 12.19

Hello, I am struggling to understand question 12.19 from the textbook, The concentration of HCl in hydrochloric acid is reduced to 12% of its initial value by dilution. What is the difference in the pH values of the two solutions? The answer says that pH will increase by 0.92 but how do we calculate...
Fri Jun 08, 2018 6:08 pm
Forum: Identifying Acidic & Basic Salts
Topic: Final
Replies: 3
Views: 369

### Final

Does anyone know if we have to know the enthalpy changes for the breakdown formulas of acids (H-A) like written in section 12.9 on page 481? Thanks.
Sun Jun 03, 2018 3:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook 4.21 part d
Replies: 3
Views: 202

### Textbook 4.21 part d

Hello, during discussion section my TA told us that we do not need to know specific angles for things besides the 6 basic structures if they were all bonded electron pairs. However, the answer to this problem in the solutions manual is 107 ^{\circ} for the N2H4 molecule. Do we have to be able to wri...
Sat Jun 02, 2018 9:41 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Final
Replies: 5
Views: 267

### Final

The lecture outline for coordination compounds listed these as the assignments, but does anyone know which ones we do not have to do as we skipped over the naming part of the chapter? Thanks.
Read: Ch 17.5, 17.6, Box 17.1, Toolbox 17.1, Table 17.4
Do Problems: 29, 31, 33, 35, 37
Sat Jun 02, 2018 9:00 pm
Forum: Hybridization
Topic: Hybridization Notation
Replies: 3
Views: 175

### Hybridization Notation

On page 124, the textbook lists the notation of the hybridization of an ethane molecule as $\sigma$
(C2sp3,C2sp3). Is this the notation we need to use every time we are asked to write out the hybridization of a molecule?
Thanks.
Sat Jun 02, 2018 8:48 pm
Forum: Hybridization
Topic: Electron Promotion
Replies: 1
Views: 160

### Electron Promotion

Can someone please explain the concept of electron promotion in the hybridization of orbitals? I am confused about what the purpose of it is.
Thanks.
Sat Jun 02, 2018 8:43 pm
Forum: Hybridization
Topic: Hybrid Orbitals
Replies: 3
Views: 257

### Hybrid Orbitals

Can someone please explain what the following means in the textbook? It is on page 123 for reference.
h1 s + px + py + pz
h2 s - px - py + pz
h3 s - px + py - pz
h4 s + px - py - pz
Tue May 22, 2018 11:15 am
Forum: Lewis Structures
Topic: Spacing in Structure for Molecules with an Expanded Octet
Replies: 1
Views: 139

### Re: Spacing in Structure for Molecules with an Expanded Octet

I don't think this matters for test 3, but when we get more into the different structures, there are rules for this kind of thing, based on which repulsion is greatest.
Tue May 22, 2018 11:12 am
Forum: Lewis Structures
Replies: 3
Views: 225

Hello,
I am kind of confused about how to determine on which molecule the radical should go. Does it go on the central atom, or on one of the bonding atoms? Is there a specific rule for this? Thanks.
Tue May 22, 2018 11:10 am
Forum: Lewis Structures
Topic: Test 3 [ENDORSED]
Replies: 4
Views: 484

### Test 3[ENDORSED]

Hi, just making sure, I know it says that the test in chapter 3, but on the Chemical Bonds sheet there is also material from chapter 6. Chapter 6 is not on the exam, correct?
Thu May 17, 2018 3:31 pm
Forum: Resonance Structures
Topic: 3.59 part c resonance structure? [ENDORSED]
Replies: 3
Views: 259

### Re: 3.59 part c resonance structure?[ENDORSED]

When a question asks to draw out the lewis structure of a molecule that has resonance, do we need to draw all the different resonance structures for it, or just one? Thanks.
Thu May 17, 2018 3:30 pm
Forum: Lewis Structures
Topic: Naming compounds
Replies: 3
Views: 244

### Naming compounds

Do we need to know how to name compounds and understand the structure of compounds based on their names for test 3 for drawing Lewis structures? Thanks.
Thu May 17, 2018 3:28 pm
Forum: Lewis Structures
Topic: Dots vs lines to represent electrons
Replies: 8
Views: 470

### Dots vs lines to represent electrons

Hello,
Can we use lines to represent two electrons when drawing lewis structures? Not just for bonds but also for lone pairs on atoms. We did not discuss this in lecture but in discussion this was brought up as an option. Thanks.
Tue May 08, 2018 9:30 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Module Questions 21 and 22
Replies: 1
Views: 316

### Module Questions 21 and 22

Please help. I keep doing these two questions from the modules and I get the same wrong answer every time. For 21 I get C and for 22 I get D but those are incorrect. Does anyone know how to solve these? Thanks. 21. The electron is not confined to the nucleus and we now know that the size of an atom ...
Tue May 08, 2018 1:50 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Paramagnetic vs Diamagnetic
Replies: 2
Views: 229

### Paramagnetic vs Diamagnetic

What is the difference between Paramagnetic vs Diamagnetic? Thanks
Tue May 08, 2018 12:12 pm
Forum: Quantum Numbers and The H-Atom
Topic: Question 5 Worksheet 4
Replies: 1
Views: 206

### Question 5 Worksheet 4

This is the question, but I do not understand why the answer is 32. If it is quantum number 4, shouldn't that mean, 4s^2, 4p^6, and 4d^10 and so that would be 18 and then two electrons can fit in each one with opposite spins, so it would be 36? Can someone please clarify? Thanks. 5. What is the maxi...
Tue May 08, 2018 9:09 am
Forum: Quantum Numbers and The H-Atom
Topic: Quantum Mechanics Worksheet #9 [ENDORSED]
Replies: 4
Views: 534

### Re: Quantum Mechanics Worksheet #9[ENDORSED]

Hi, was just wondering where you got this worksheet from?
Thanks
Sun May 06, 2018 12:17 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm Topics [ENDORSED]
Replies: 33
Views: 2680

### Re: Midterm Topics[ENDORSED]

Taizha 1C wrote:Does anyone know if we need to know aufbau, hund, and pauli principles?

Yes, we need to know these.
Fri May 04, 2018 5:25 pm
Forum: Properties of Light
Topic: Frequency and Wavelength
Replies: 3
Views: 270

### Re: Frequency and Wavelength

Frequency and wavelength are inversely proportional. This can be seen in the equation of c=\lambda \nu If you rearrange this so that lambda and nu are on opposites sides of the equation, \nu = (c/\lambda) then you see that as lambda increases, nu decreases and so they are inversely proportio...
Fri May 04, 2018 5:20 pm
Forum: *Particle in a Box
Topic: Midterm [ENDORSED]
Replies: 1
Views: 482

### Midterm[ENDORSED]

Do we need to know anything about particle in a box for the midterm? Thanks.
Tue May 01, 2018 5:50 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm Topics [ENDORSED]
Replies: 33
Views: 2680

### Re: Midterm Topics[ENDORSED]

Just making sure, on the document sent to us by email and posted here, it says Chemistry 14A-1 11am class. Is this for our class or a different one?
Thanks
Mon Apr 23, 2018 4:37 pm
Forum: Photoelectric Effect
Topic: Module Questions 33 and 34 [ENDORSED]
Replies: 3
Views: 2020

### Module Questions 33 and 34[ENDORSED]

Hello, I managed to figure out 33 was 7.22x10-19J, but I do not understand how to then use this to solve 34. Can someone please help me? Thanks. 33. Molybdenum metal must absorb radiation with a minimum frequency of 1.09 x 1015 s-1 before it can emit an electron from its surface. Answer the followin...
Mon Apr 23, 2018 4:32 pm
Forum: Photoelectric Effect
Topic: Module Question 31 and 32
Replies: 1
Views: 142

### Module Question 31 and 32

Hello, I am trying to answer question 32, and I get that question 31's answer is 550.7nm, but I don't understand how to now solve 32. Could someone please help me? Thanks. 31. This and the following question relates to the same metal used in a series of photoelectric experiments. A. If 3.607 x 10-19...
Mon Apr 23, 2018 4:30 pm
Forum: Photoelectric Effect
Topic: Module Question 29
Replies: 5
Views: 190

### Module Question 29

Hello, could someone please help me answer this question? Thanks Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. B. How much energy is required to remove an electron from one sodium atom? A. 2.501 x 10-22...
Sat Apr 21, 2018 6:36 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1J=1kg.m^2.s^-2
Replies: 3
Views: 140

### 1J=1kg.m^2.s^-2

Hi,
I am trying to understand how 1J=1kg.m^2.s^-2. How are these units equal to each other? Does anyone know the proof?
Thanks.
Sat Apr 21, 2018 6:32 pm
Forum: Properties of Electrons
Topic: 1.57 [ENDORSED]
Replies: 2
Views: 195

### Re: 1.57[ENDORSED]

It's not one of the problems required for test 2 so I would not be worried about it for now.
OR
Tue Apr 17, 2018 4:54 pm
Forum: DeBroglie Equation
Topic: Second test questions [ENDORSED]
Replies: 3
Views: 342

### Second test questions[ENDORSED]

Hello, I was just wondering since test 2 is until 1.5 and not 1.6, which questions does that equate to from the ones assigned? If these are the assignments, Read: Ch 1 Do Problems: 3, 5, 7, 9, 11, 13, 15, 21, 23, 25, 27, 33, 37, 39, 41, 43, 55, 57, 59, 65, 67, 69, To which question is applicable for...
Fri Apr 13, 2018 3:44 pm
Forum: Properties of Light
Topic: Value of Speed of Light** (Shoutout to Dr. Lavelle for calling me out in lecture today) [ENDORSED]
Replies: 4
Views: 287

### Re: Value of Speed of Light** (Shoutout to Dr. Lavelle for calling me out in lecture today)[ENDORSED]

Ya, the value used in the solution manual was 2.998*10^8, but in class we were using the rounded 3.00*10^8.
Fri Apr 13, 2018 3:35 pm
Forum: SI Units, Unit Conversions
Topic: Do we have to convert final answer to make it simpler? [ENDORSED]
Replies: 4
Views: 291

### Do we have to convert final answer to make it simpler?[ENDORSED]

Hello,
I was just wondering if during tests we are going to have to convert to the lowest possible SI unit that our final answer is given in. For example if we get that the wavelength is 551*10^-9 m, do we have to convert it to 551 nm or can we just leave it in the original form in meters? Thanks.
Fri Apr 13, 2018 3:29 pm
Forum: Properties of Light
Topic: Value of speed of light [ENDORSED]
Replies: 4
Views: 272

### Value of speed of light[ENDORSED]

Hello
I was trying to answer question 1.7 and when I looked in the solution manual I saw that it put the speed of light constant to be 2.998*10^8, however in class we were using the rounded 3.00*10^8 so I was wondering which one we should use in calculations? Thanks.
Sun Apr 08, 2018 12:09 pm
Forum: Empirical & Molecular Formulas
Topic: Finding the molecular formula [ENDORSED]
Replies: 5
Views: 326

### Re: Finding the molecular formula[ENDORSED]

An example of this is if you have an empirical formula CH2O. The molar mass for this would be 12.011+(1.008*2)+15.99=30.017 gmol-1. If it told you that the molar mass of the molecule you are trying to find, in this case Glucose is 180.102 gmol-1, than you would divide 180.102 gmol-1 by 30.017, and y...
Sun Apr 08, 2018 10:57 am
Forum: Significant Figures
Topic: Amount of significant figures in calculations.
Replies: 2
Views: 147

### Amount of significant figures in calculations.

Are we supposed to round calculations that aren't the final answers? How many significant figures am I supposed to use throughout the question and then how many do I need to use to calculate the final answer? Thanks.
Thu Apr 05, 2018 2:52 pm
Forum: Significant Figures
Topic: Questions F11
Replies: 4
Views: 300

### Questions F11

In question F11 in part c it asks to determine the mass percentage composition: 12.2% N, 5.26% H, 26.9% P, and 55.6% O. When I solved for the moles of O I got 55.6g/16.00gmol=3.48 mol because the number with the least significant figures is 3, but the solutions manual says 3.475 mol. Is this an erro...