Search found 34 matches

by alexagreco1A
Mon Jun 11, 2018 9:50 pm
Forum: Lewis Structures
Topic: Radicals
Replies: 1
Views: 164

Radicals

How can we determine where the radical belongs in a Lewis Structure? For example, with ClO, the formal charges for each atom would be 0 if the radical were on the oxygen, but the correct structure has the radical on the chlorine. Why is this the case?
by alexagreco1A
Mon Jun 11, 2018 3:47 pm
Forum: Administrative Questions and Class Announcements
Topic: Grading question
Replies: 11
Views: 683

Re: Grading question

I think that it means 250 will be a C-, and then it is scaled up from there so if you have 350 it would be higher than that. I am not sure exactly how the curve works but that is my guess.
by alexagreco1A
Mon Jun 11, 2018 3:43 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Lone Pairs Affecting Bond Angles/Shape?
Replies: 4
Views: 275

Re: Lone Pairs Affecting Bond Angles/Shape?

Lone pairs affect bond angles by decreasing them due to increase repulsion. Because of this, any molecule with lone pairs will have bond angles that are slightly less than predicted.
by alexagreco1A
Mon Jun 11, 2018 3:01 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: weak acids
Replies: 4
Views: 265

Re: weak acids

I think in addition to knowing its properties, we generally need to know the weak acids that were discussed and how they behave.
by alexagreco1A
Sun Jun 03, 2018 5:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 4.19
Replies: 3
Views: 241

HW 4.19

Predict the shapes and estimate the bond angles of (b) (CH3)2Be

Why is the shape tetrahedral if there are no lone pairs and only two bonds on the central atom?
by alexagreco1A
Sun Jun 03, 2018 4:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Naming Structures
Replies: 8
Views: 255

Re: Naming Structures

Did you mean with the VSEPR model? If so, I do not think there is a trick but many are self-explanatory just by looking at the shape and the amount of bonds/lone pairs. (i.e. angular is similar to linear but slightly bent, T-shaped looks like a "T")
by alexagreco1A
Sun Jun 03, 2018 4:27 pm
Forum: Dipole Moments
Topic: Different types of dipole moments?
Replies: 3
Views: 189

Re: Different types of dipole moments?

I also am a bit confused as to which we need to know. There were many different types introduced in one lecture, but which ones should we know, and to what extent?
by alexagreco1A
Sun Jun 03, 2018 4:23 pm
Forum: Octet Exceptions
Topic: expanded octet
Replies: 12
Views: 554

Re: expanded octet

We know that only the elements that are in Group 3 or below can form an expanded octet, as they have unfilled d-orbitals, which Groups 1 and 2 do not have.
by alexagreco1A
Mon May 28, 2018 11:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle
Replies: 9
Views: 244

Re: Bond angle

Do we find the lowest energy Lewis Structure to determine the bond angle?
by alexagreco1A
Mon May 28, 2018 6:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 4.9
Replies: 10
Views: 547

HW 4.9

What is the shape of an ICl3 molecule (iodine is the central atom)?

I thought that this molecule would have a trigonal planar arrangement, as it is AX3, but the answer key says that it is t-shaped. How could this be?
by alexagreco1A
Mon May 28, 2018 5:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles and lone pairs
Replies: 4
Views: 194

Bond angles and lone pairs

How can we determine whether or not there must be lone pairs from the bond angle?
by alexagreco1A
Sun May 20, 2018 6:07 pm
Forum: Resonance Structures
Topic: Radicals
Replies: 13
Views: 636

Re: Radicals

I understand the concept of a radical, but when drawing Lewis structures, how do we decide which element has the unpaired electron?
by alexagreco1A
Sun May 20, 2018 5:13 pm
Forum: Lewis Structures
Topic: Where to put double bonds? [ENDORSED]
Replies: 3
Views: 146

Where to put double bonds? [ENDORSED]

In a problem like 3.41 (c): Write the Lewis structure for H2C(NH2)COOH, how do we know where to put the double bond?
by alexagreco1A
Sun May 20, 2018 5:00 pm
Forum: Lewis Structures
Topic: Friday's Lecture [ENDORSED]
Replies: 4
Views: 183

Re: Friday's Lecture [ENDORSED]

Will this material be on the exam this week, or is it only the material from Chapter 3?
by alexagreco1A
Fri May 18, 2018 11:58 am
Forum: Ionic & Covalent Bonds
Topic: 3.25
Replies: 2
Views: 110

3.25

On the basis of expected charges on the monatomic ions, give the chemical formula of each of the following compounds;
I am a bit confused about the elements in group 13 when it comes to determining their charges. Is there a pattern or a rule to follow here?
by alexagreco1A
Sun May 13, 2018 8:16 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Equation
Replies: 3
Views: 151

Re: Equation

It seems like the one you learned in high school may be a simplified version. Although it gives you the right answer, I feel like you should use the one that was given to us in class in terms of which will be more reliable.
by alexagreco1A
Sun May 13, 2018 7:12 pm
Forum: Resonance Structures
Topic: Bonds or Lone Pairs more important?
Replies: 7
Views: 443

Re: Bonds or Lone Pairs more important?

I do not believe that there is a rule as to which comes first, but I would think that a double bond would come before an expanded octet.
by alexagreco1A
Sun May 06, 2018 7:47 pm
Forum: Properties of Light
Topic: Homework 1.15
Replies: 2
Views: 222

Homework 1.15

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. I understand in this problem that hydrogen gives us n=1, but to find the other energy levels in the solution it converts the wavelength i...
by alexagreco1A
Sat May 05, 2018 5:12 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 2.55
Replies: 2
Views: 106

Homework 2.55

Give the notation for the valence-shell configuration (including the outermost d-electrons) of (b) Group 15 elements.

Why does the notation, ns^1np^3, not include d if some of the group 15 elements have d in their electron configuration?
by alexagreco1A
Sat May 05, 2018 4:53 pm
Forum: Ionic & Covalent Bonds
Topic: Help on 2.43
Replies: 3
Views: 132

Re: Help on 2.43

Part e for 2.43 asks the electron configuration for Tungsten. How do we do the electron configuration for the f subshell, or do we not need to know this for the midterm?
by alexagreco1A
Sat May 05, 2018 4:51 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm Topics [ENDORSED]
Replies: 33
Views: 1913

Re: Midterm Topics [ENDORSED]

Chapter 2 includes Zeff which we never went over in class, but is on the Chapter 2 homework. Will this topic be covered on the midterm?
by alexagreco1A
Sun Apr 29, 2018 9:24 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: The concept of Orbitals
Replies: 12
Views: 306

Re: The concept of Orbitals

I agree with the above explanations, but I wanted to add that they show the electron density, which allows us to determine the probability of the electron being in a certain place.
by alexagreco1A
Sun Apr 29, 2018 9:10 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.37
Replies: 2
Views: 115

2.37

Which of the following are true for many-electron atoms? If false, explain why.
c) Electrons having l=2 are better at shielding than electrons having l=1.

Why exactly is this false and how does the value of Zeff work?
by alexagreco1A
Sun Apr 29, 2018 8:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.27 [ENDORSED]
Replies: 4
Views: 189

2.27 [ENDORSED]

Write the subshell notation and the number of orbitals having the following quantum numbers:

When it asks for the number of orbitals, is that the same as asking for the number of subshells? If not, how do you solve for this?
by alexagreco1A
Sun Apr 22, 2018 8:41 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 3
Views: 177

Test 2

For the upcoming test, which equations will we be required to use? Which equations will be provided, and which should we memorize?
by alexagreco1A
Sun Apr 22, 2018 7:57 pm
Forum: Properties of Light
Topic: Homework 1.5
Replies: 6
Views: 208

Homework 1.5

Arrange the following types of photons of electromagnetic radiation in order of increasing energy: gamma rays, x-rays, visible light, ultraviolet radiation, microwaves. Why do gamma rays have the most amount of energy? If energy is proportional to frequency then how does the wavelength tell us about...
by alexagreco1A
Sun Apr 22, 2018 7:42 pm
Forum: Properties of Light
Topic: Question 1.3 [ENDORSED]
Replies: 6
Views: 208

Re: Question 1.3 [ENDORSED]

I have this question as well. The question asks: Which of the following happens when the frequency of electromagnetic radiation decreases? Explain your reasoning. Part c says: The extent of the change in the electrical field at a given point decreases.
by alexagreco1A
Sun Apr 15, 2018 9:04 pm
Forum: Properties of Light
Topic: Homework question 1.65
Replies: 2
Views: 134

Homework question 1.65

The energy required to break a C-C bond in a molecule is 348 kJ/mol. Will visible light be able to break this bond? If yes, what is the color of that light? If not, what type of electromagnetic radiation will be suitable? How would I go about solving this after converting this into Joules? How do I ...
by alexagreco1A
Sun Apr 15, 2018 8:57 pm
Forum: Administrative Questions and Class Announcements
Topic: Memorizing equations [ENDORSED]
Replies: 5
Views: 259

Memorizing equations [ENDORSED]

To what extent do we need to have all of the different equations memorized? What will be provided to us on the exams?
by alexagreco1A
Sun Apr 15, 2018 8:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Solving 1.11 [ENDORSED]
Replies: 3
Views: 142

Re: Solving 1.11 [ENDORSED]

I agree with these responses, but another way to put it is that the principal quantum number is the same for each of these lines, so Lyman- n=1, Balmer- n=2, etc.
by alexagreco1A
Sun Apr 15, 2018 8:36 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Confusion about Atomic Spectroscopy [ENDORSED]
Replies: 3
Views: 173

Re: Confusion about Atomic Spectroscopy [ENDORSED]

From what I gathered, atomic spectroscopy is the idea that we can determine elemental compositions by looking at the electromagnetic radiation absorbed or emitted by certain atoms
by alexagreco1A
Mon Apr 09, 2018 11:56 am
Forum: Molarity, Solutions, Dilutions
Topic: G.5 Part A) Molarity [ENDORSED]
Replies: 9
Views: 360

Re: G.5 Part A) Molarity [ENDORSED]

I am still confused about how to do part A, as the solution in the book uses 1 mol Na2CO2 instead of Na2CO3. Where does this come from?
by alexagreco1A
Sun Apr 08, 2018 6:56 pm
Forum: Balancing Chemical Reactions
Topic: Memorizing the charges of ions
Replies: 3
Views: 167

Memorizing the charges of ions

Do we need to memorize the charge of each ion, or will this be provided?
by alexagreco1A
Sun Apr 08, 2018 6:01 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E.15 [ENDORSED]
Replies: 10
Views: 694

Re: E.15 [ENDORSED]

I had this question as well. I understand the explanation that 'M' is the variable, but would we have to know how to go about determining the sulfides for the test this week?

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