Search found 39 matches

by NatalieSDis1A
Sun Jun 10, 2018 1:01 am
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids/Bases
Replies: 8
Views: 400

Re: Conjugate Acids/Bases

A conjugate base is the leftover after an acid donates a proton. A conjugate acid is what is formed when a base accepts a proton. For example the conjugate base of HCO 3 - is CO 3 - because the acid HCO 3 - lost a proton. So that's how I point them out. I believe you are correct about the water part...
by NatalieSDis1A
Sat Jun 09, 2018 12:13 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 12.19
Replies: 1
Views: 174

Re: 12.19

Hello, we are trying to find the difference so we should subtract pH final - pH initial.
initial pH = -log (HCl)
final pH = -log(.12HCl)
final - initial = -log(.12HCl) - -log(HCl)
-(log(.12HCl)- log(HCl))
** log law: logA - logB = log (A/B)
-log (.12HCL/HCl)
-log(.12) = .92
by NatalieSDis1A
Wed Jun 06, 2018 7:56 am
Forum: Hybridization
Topic: Hybridization
Replies: 3
Views: 120

Re: Hybridization

The sum of the subscripts should equal the total number of regions of electron density.
by NatalieSDis1A
Wed Jun 06, 2018 12:26 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Wording of Questions Regarding Molecular Shape
Replies: 2
Views: 115

Re: Wording of Questions Regarding Molecular Shape

You are correct in saying that an atom with two bonds and one lone pair would be called angular. No matter the wording of the question, we would never call a molecule with 2 bonds and one lone pair trigonal planar. Trigonal planar has 3 bonds while angular has 2 bonds and one lone pair. However, one...
by NatalieSDis1A
Mon Jun 04, 2018 10:13 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 4 ligands shape?
Replies: 6
Views: 187

Re: 4 ligands shape?

I read in the book that square planar is usually formed when the central metal atom has d8 electron configuration. So that's why Pt2+ and Au3+ have the square planar complex.
by NatalieSDis1A
Tue May 29, 2018 8:51 pm
Forum: Resonance Structures
Topic: How to determine resonance
Replies: 2
Views: 166

Re: How to determine resonance

Molecules have resonance when the atoms stay in the same location but the locations of the lone pairs and the bonding pairs can be changed.
by NatalieSDis1A
Tue May 29, 2018 8:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Form vs. Shape
Replies: 2
Views: 71

Re: Form vs. Shape

I am not familiar with the post you are referring to but I am not sure if there is a formal distinction between form and shape. The person above me is perhaps correct in pointing out that water's bent shape is derived from a tetrahedral shape, but I am not aware of referring to the shape a lone pair...
by NatalieSDis1A
Tue May 29, 2018 8:28 pm
Forum: Bond Lengths & Energies
Topic: HW problem 6.99
Replies: 1
Views: 157

Re: HW problem 6.99

Hello I looked at this problem using Vsepr models. If we look at F - H ~ F (~ represents hydrogen bond) there are no lone pairs on H so we have AX2 and it is therefore linear and the bond angle is 180 degrees. Now looking at H - F ~ H we would have lone pairs. F already has 3 sets of lone pairs but ...
by NatalieSDis1A
Sun May 27, 2018 9:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Difference in angles
Replies: 3
Views: 102

Re: Difference in angles

I think you might have been confused because with certain Vsepr structures, such as trigonal bipyramidal, we can know the bond angles. However, when a lone pare is introduced it can effect the bond angles. For instance if a bond in a trigonal bipyramidal structure were replaced with a lone pair the ...
by NatalieSDis1A
Sun May 27, 2018 9:20 pm
Forum: Ionic & Covalent Bonds
Topic: Partial charge or full charge
Replies: 4
Views: 586

Re: Partial charge or full charge

I believe fully positive or negative atoms occur in ionic bonds while partially positive or negative atoms occur in covalent bonds.
by NatalieSDis1A
Sun May 27, 2018 9:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs on non-central atoms
Replies: 4
Views: 114

Re: Lone pairs on non-central atoms

They affect the bond angle because they take up more space and generate stronger repulsion than a regular bond.
by NatalieSDis1A
Sun May 20, 2018 2:23 pm
Forum: Lewis Structures
Topic: 3.41 c [ENDORSED]
Replies: 4
Views: 167

Re: 3.41 c [ENDORSED]

My question for this problem is more related to how to choose which atom is the central atom. At first, I made my structure with NH2 as the center atom, with CH2 and COOH on either side. However, the answer in the textbook has CH2 as the center atom. Why is this? Does it have to do with the formal ...
by NatalieSDis1A
Thu May 17, 2018 9:03 pm
Forum: Lewis Structures
Topic: Radicals
Replies: 2
Views: 105

Re: Radicals

I think radicals only becomes non-radical when it reacts with an antioxidant. However, I believe an antioxidant would neutralize the unpaired electron and it wouldn't be a radical anymore. So I agree with the person above.
by NatalieSDis1A
Thu May 17, 2018 8:38 pm
Forum: Lewis Structures
Topic: 3.41 c [ENDORSED]
Replies: 4
Views: 167

3.41 c [ENDORSED]

IMG_4883.JPG


Hello, I am confused about the placement of the right most oxygen and hydrogen. Why does the book come to the conclusion it does? (The question is to complete the lewis structure for H2C(NH2)COOH)

Thanks!
by NatalieSDis1A
Wed May 16, 2018 9:04 am
Forum: Ionic & Covalent Bonds
Topic: Electron affinity [ENDORSED]
Replies: 6
Views: 209

Re: Electron affinity [ENDORSED]

Electron affinity is how likely an element is to gain an electron while electron ionization is the energy required to lose an electron. If we look at Fluorine we can see why these two concepts have the same trend. Fluorine has a high electron affinity because it wants to gain an electron to have an ...
by NatalieSDis1A
Thu May 10, 2018 10:23 pm
Forum: Resonance Structures
Topic: Help on 2.51
Replies: 3
Views: 157

Re: Help on 2.51

a. The electron configuration for Bi is [Xe] 4f^14 5d^10 6s^2 6p^3. All of the shell are full except for the p block so we want to look at that. I think it's helpful to draw out the orbitals for this. if you look at the 6p orbital ___ ___ ___ we would draw three parallel arrows (according to Hund's ...
by NatalieSDis1A
Thu May 10, 2018 10:15 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: H-Atom
Replies: 3
Views: 210

Re: H-Atom

The Rydberg constant was experimentally determined for Hydrogen only.
by NatalieSDis1A
Thu May 10, 2018 10:10 pm
Forum: Ionic & Covalent Bonds
Topic: Help on 2.45
Replies: 2
Views: 92

Re: Help on 2.45

c. Start on you periodic table at helium. Then move to the next row to Lithium to enter the 2s orbital. The 2 p block starts at Boron and the second element in the p block is carbon. The answer is carbon.

d. We were not assigned this part.
by NatalieSDis1A
Sun May 06, 2018 9:02 pm
Forum: Trends in The Periodic Table
Topic: 2.67
Replies: 3
Views: 90

Re: 2.67

Adding onto the previous post, ionization energies increase across a period AND decreases down a group. Ionization energy is the energy require to remove an electron while electron affinity is the energy that is released when an electron is added. More informally, electron affinity was explained to ...
by NatalieSDis1A
Thu May 03, 2018 3:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: f orbital
Replies: 1
Views: 53

Re: f orbital

Lanthanum is part of the d block. The electron configuration would [Xe} 5d^1 6s^2. The electron configuration for Lutetium is [Xe] 4f^14 5d^1 6s^2. I believe the f block has a its own set of exceptions but we do not have to know them. We are only being tested on the first row of the d block.
by NatalieSDis1A
Wed May 02, 2018 11:00 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Post Module Question #8/9 [ENDORSED]
Replies: 3
Views: 521

Re: Post Module Question #8/9 [ENDORSED]

I think the key here is realizing that Hydrogen has 1 electron so if you have a certain amount of electrons you have that amount of hydrogen atoms. I believe thats the why the hydrogen add on is in parentheses, signifying that the answer is the same for j/mol of electron and j/ mol of hydrogen atom....
by NatalieSDis1A
Tue May 01, 2018 9:22 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 2.55 part c
Replies: 3
Views: 123

Re: Homework 2.55 part c

Gianna Graziano 1A wrote:Hi Natalie,
2.55(c) actually has a typo, as stated in Dr. Lavelle's correction to the textbook problems the correct answer is actually (n-1) d^3 ns^2. You were right!


Thank you! I didn’t know such a thing existed
by NatalieSDis1A
Mon Apr 30, 2018 3:49 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 2.55 part c
Replies: 3
Views: 123

Homework 2.55 part c

2.55 Give the notation for the valence-shell configuration (including the outermost d electrons) of (a) the alkali metals; (b) Group 15 elements; (c) Group 5 transition metals; (d) "coinage" metals (Cu, Ag, Au). Hello, I got parts a,b, and d of this problem correct. However the answer to p...
by NatalieSDis1A
Wed Apr 25, 2018 10:18 pm
Forum: Quantum Numbers and The H-Atom
Topic: Homework problem 2.1 (d) [ENDORSED]
Replies: 2
Views: 100

Re: Homework problem 2.1 (d) [ENDORSED]

I answered that the radius increases because when we move from 1s to 2p we are increasing the size of the probability function. The books says this "the average distance of an electron from the nucleus when it occupies any of the orbitals in the shell with n = 2 is greater than when n = 1, and ...
by NatalieSDis1A
Wed Apr 25, 2018 12:47 pm
Forum: Properties of Light
Topic: Homework Problem(s) [ENDORSED]
Replies: 6
Views: 214

Re: Homework Problem(s) [ENDORSED]

I was needing help on question 1.13 part B in which it asks "What is the name given to the spectroscopic series to which this transition belongs?" The answer being 2.8x10^-7 m or 2.8x10^9 nm. Can someone answer me to what series it is and why? For 1.13 part A I got 486 nm. For part B, a w...
by NatalieSDis1A
Mon Apr 23, 2018 12:21 pm
Forum: Properties of Light
Topic: Homework Problem(s) [ENDORSED]
Replies: 6
Views: 214

Re: Homework Problem(s) [ENDORSED]

Those masses would be given to us on a test.
by NatalieSDis1A
Mon Apr 16, 2018 10:15 pm
Forum: Properties of Light
Topic: HW 1.15
Replies: 4
Views: 175

Re: HW 1.15

The book does say that the Lyman series is defined by n1 = 1but why is that? Couldn't we still be in the Lyman series and start at, for instance, n =2 and go to n = 3?
by NatalieSDis1A
Mon Apr 16, 2018 9:53 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: #42 In Post-Module Assessment [ENDORSED]
Replies: 5
Views: 174

Re: #42 In Post-Module Assessment [ENDORSED]

You're right it should be E4 - Ex. Since, I used a positive energy I was able to switch them. Really, the 7.55 X 10^-20 should be negative since we are losing energy. If you don't switch them is look like this: -7.55 X 10^-20 = E4 - Ex We also can calculate that E4 = (-hr/16) = -1.36 X 10^-19 Using ...
by NatalieSDis1A
Mon Apr 16, 2018 8:21 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: #42 In Post-Module Assessment [ENDORSED]
Replies: 5
Views: 174

Re: #42 In Post-Module Assessment [ENDORSED]

Update: I figure it out!

I made the mistakes of not converting the frequency to energy and subtracting in the wrong order.

E = hv

E = h (1.14 X 10^14) = 7.55 X 10^-20

7.55 X 10^-20 = Ex - E4

Ex = (-hr)/x^2 = -6.06 X 10^-20

x^2 = 35.9

x = n = 6
by NatalieSDis1A
Mon Apr 16, 2018 8:04 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: #42 In Post-Module Assessment [ENDORSED]
Replies: 5
Views: 174

Re: #42 In Post-Module Assessment [ENDORSED]

I am also stuck on this one but I do not think you plug in every quantum level. I began by using the formula E n = (-hR/n 2 ). If we consider 1.14 X 10 14 to be the delta E, I think the formula delta E = e final - E initial should work. My progress so far looks like this: 1.14 X 10 14 = E 4 - E x 1....
by NatalieSDis1A
Sat Apr 14, 2018 3:38 pm
Forum: Photoelectric Effect
Topic: Photons in a light source [ENDORSED]
Replies: 4
Views: 86

Re: Photons in a light source [ENDORSED]

I reviewed my notes and cannot find where that was said. are you sure it said photons? you could be mistaking that for electrons. if so no electrons are ejected if the energy of the photon is not greater than or equal to the work function aka the energy needed to eject an electron. so back to the s...
by NatalieSDis1A
Sat Apr 14, 2018 3:25 pm
Forum: Photoelectric Effect
Topic: E(Photon) greater than/equal to (Energy Remove e-) [ENDORSED]
Replies: 2
Views: 87

Re: E(Photon) greater than/equal to (Energy Remove e-) [ENDORSED]

The statement from the book is correct. I think you may have accidentally wrote it down backwards.
If E(photon) < threshold energy then the electron will not eject.
If E(photon) > threshold energy then the electron will eject.
by NatalieSDis1A
Sat Apr 14, 2018 11:23 am
Forum: Photoelectric Effect
Topic: Released electrons [ENDORSED]
Replies: 1
Views: 77

Released electrons [ENDORSED]

What happens after an electron is released from a metal in the photoelectric experiment. Does it eventually return to the cation? In the case of the threshold energy equaling the energy of the photon, does the electron release and immediately rejoin the cation? I'm trying to picture the experiment i...
by NatalieSDis1A
Sat Apr 14, 2018 11:03 am
Forum: Photoelectric Effect
Topic: Photons in a light source [ENDORSED]
Replies: 4
Views: 86

Photons in a light source [ENDORSED]

Assuming you had some light source, are all of the photons in that light source of the same energy level? The formula E = hv makes me think the answer would be yes but in lecture, one of the slides said "low frequency light has no photons with efficient energy" which makes me think some li...
by NatalieSDis1A
Thu Apr 12, 2018 8:57 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamental practice problem L.7 part b
Replies: 2
Views: 200

Re: Fundamental practice problem L.7 part b

I did it like this:

454 g fat (1mol fat/ 891.48 g fat) = .509 mol fat

.509 mol fat (163 mol O2/ 2 mol fat) = 41.507 mol O2

41.507 mol O2 (32 g O2/ 1 mol O2) = 1328.16g O2 = 1.33 x 103 g O2
by NatalieSDis1A
Wed Apr 11, 2018 12:22 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Parent acids
Replies: 1
Views: 173

Parent acids

I have not taken chemistry in 3.5 years so I am trying to figure out the correct naming of cations and anions. In section F.D.2 the book has a chart of common anions and their parent acids but doesn't say anything about the parent acids. It appears that the parent acids just have an H added to the a...
by NatalieSDis1A
Sun Apr 08, 2018 1:21 pm
Forum: Limiting Reactant Calculations
Topic: M.15
Replies: 5
Views: 2806

Re: M.15

How do you come up with the equation Al + Cl2 --> AlCl3. I get that Cl is a diatomic molecule so it makes sense that we should use Cl2 but how do we know to put Cl3 in the product?
by NatalieSDis1A
Sun Apr 08, 2018 11:00 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E.15 [ENDORSED]
Replies: 10
Views: 693

Re: E.15 [ENDORSED]

This may be a bit obvious but I did not realize that M is not an element. It just stands for metal. I was confused about why people were saying to treat it as a variable but it is literally nothing more than a variable. And a sulfide is a compound with sulfur so it makes sense to combine the molar m...
by NatalieSDis1A
Sun Apr 08, 2018 10:52 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Knowing molecular formulas
Replies: 1
Views: 82

Knowing molecular formulas

For question E.9 in the homework it asks for the formula of magnesium sulfate heptahydrate. However, the question does not provide information (such as number of moles of each element used or percent composition) to find the molecular formula. Should I know from the chemical name what the molecular ...

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