## Search found 102 matches

Thu Feb 13, 2020 7:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Review session powerpoints
Replies: 4
Views: 38

### Re: Review session powerpoints

I know one of them was posted under this section.
Thu Feb 13, 2020 7:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Thermodynamic midterm review ppt 2/5 Chenxiang Wang
Replies: 4
Views: 147

### Re: Thermodynamic midterm review ppt 2/5 Chenxiang Wang

I'm not seeing this until now but it will be very helpful for the final!
Thu Feb 13, 2020 7:29 pm
Forum: Administrative Questions and Class Announcements
Replies: 8
Views: 65

It is uniform graders. Does anyone know if it'll take about a week like last time?
Thu Feb 13, 2020 7:28 pm
Forum: Administrative Questions and Class Announcements
Replies: 10
Views: 58

I think if he does it'll only be a few points.
Thu Feb 13, 2020 7:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 1
Views: 19

### Test 2

I know its early, but does anyone know what the second test will be on?
Sat Feb 08, 2020 2:11 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Molar Entropy
Replies: 3
Views: 16

### Molar Entropy

What takes precedence when comparing entropies between gases, the degeneracy or molecular weight?
Thu Feb 06, 2020 9:21 pm
Forum: Phase Changes & Related Calculations
Topic: Thermochemistry outline
Replies: 1
Views: 17

### Thermochemistry outline

Understand the environmental impact of burning fossil fuels, and the use of alternative
fuels as energy sources.

Does this relate to how fossil fuels release a lot of heat into the atmosphere?
Thu Feb 06, 2020 9:43 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: HW Question 4H.9
Replies: 1
Views: 11

### HW Question 4H.9

For HW 9.35, it says that Container A is filled with 1.0 mol of the atoms of an ideal monatomic gas. Container B has 1.0 mol of atoms bound together as diatomic molecules that are not vibrationally active. Container C has 1.0 mol of atoms bound together as diatomic molecules that are vibrationally a...
Tue Feb 04, 2020 11:20 am
Forum: Calculating Work of Expansion
Topic: Irreversible vs Reversible
Replies: 1
Views: 17

### Irreversible vs Reversible

With respect to external pressure, can anyone explain the difference between an irreversible and reversible expansion?
Tue Feb 04, 2020 10:37 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 4F.11
Replies: 1
Views: 37

### 4F.11

" During the test of an internal combustion engine, 3.00L of nitrogen gas at 18.5 degrees C was compressed suddenly (and irreversibly) to .500L by driving in a piston. In the process the temperature of the gas increased to 28.1 degrees C. Assume ideal behavior and 1.00 mole of nitrogen gas. Wha...
Sun Feb 02, 2020 2:31 pm
Forum: Calculating Work of Expansion
Topic: Homework Textbook
Replies: 1
Views: 10

### Homework Textbook

Hey, everyone! I don't have my textbook with me but wanted to do some homework, could anyone upload section 4F and 4 G homework sections, please!
Thu Jan 30, 2020 9:49 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Mondays Lecture Question
Replies: 3
Views: 16

### Re: Mondays Lecture Question

LNgo 1G wrote:Because the reaction in that example is between a string acid and a strong base, it is a neutralization acid and forms water. The density of pure water is about 1.0 g/mL.

Why are we using density?
Thu Jan 30, 2020 9:23 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Mondays Lecture Question
Replies: 3
Views: 16

### Mondays Lecture Question

On Monday, "in a constant P calorimeter at 25c. Mix 50.0ml each of 1.0M HCL and 1.0 M NaOH after mixing, T=31.9C. In his answer he assumed density of solution to be 1.0g/ml, why did he do this? Why didn't we just use how many moles we had for our equation? Also why did he multiply this number t...
Thu Jan 30, 2020 9:20 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Pressure
Replies: 7
Views: 23

### Constant Pressure

Can anyone please explain what it means to have constant pressure or constant volume?
Tue Jan 28, 2020 11:20 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Section
Replies: 2
Views: 22

### Re: Textbook Section

This is what I'm trying to figure out too. It seems we've covered 4E and parts of 4D and 4C but not 4A or 4B.
Tue Jan 28, 2020 11:18 am
Forum: Phase Changes & Related Calculations
Topic: Change in Temperature
Replies: 10
Views: 20

### Re: Change in Temperature

The equilibrium constant will only rise if your reaction is endothermic and you add heat. If you add heat and it's exothermic the equilibrium constant will decrease (this is because your reverse reaction is endothermic and so adding heat will cause a reaction to proceed in reverse direction.
Tue Jan 28, 2020 11:16 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4E.5
Replies: 2
Views: 20

### 4E.5

C for 4E.5 stated that there enthalpy is zero, but I dont understand how if new bonds are forming?
Tue Jan 28, 2020 10:11 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4A and B
Replies: 2
Views: 20

### Re: 4A and B

I would maybe wait till he covers it. I also noticed 4A and 4B had a lot of terms we havent covered.
Tue Jan 28, 2020 9:59 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4C.3
Replies: 3
Views: 59

### 4C.3

I am working on problem 4C.3, which asks to calculate the final temperature and the change in enthalpy when 765 J of energy is transferred as heat to 0.820 mol Kr (g) at 298 L and 1.00 atm. (at constant pressure and constant volume) When solving, they used 5/2 R to get the heat capacity, I'm wonderi...
Mon Jan 27, 2020 12:30 pm
Forum: Administrative Questions and Class Announcements
Topic: Fridays Lecture (week 3)
Replies: 1
Views: 62

### Fridays Lecture (week 3)

Hello everyone! I wasnt able to make it to Fridays lecture and was hoping someone could please share their notes. Thank you!!
Thu Jan 23, 2020 4:05 pm
Forum: Phase Changes & Related Calculations
Replies: 3
Views: 15

Dr. Lavelle said something about not going in the exact order of the book. Which sections of Focus 4 should we be reading first/doing the homework?
Thu Jan 23, 2020 4:01 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs liquid
Replies: 7
Views: 27

### Steam vs liquid

I got a little confused on Professors explanation of why steam causes a worse burn than boiling water, can anyone explain?
Mon Jan 20, 2020 7:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Module
Replies: 4
Views: 18

### Re: Module

okay! thanks i think i fixed it, can anyone confirm the answer is 2.10x10^-3
Mon Jan 20, 2020 6:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Module
Replies: 4
Views: 18

### Module

19. Calculate the reaction quotient, QC, from the following equilibrium data collected in a 3.00 L sealed reaction vessel for the reaction: AsH3 (g) ⇌ As (s) + H2 (g) AsH3 = 5.55 x 10-4 mol, As = 3.31 x 10-3 mol, H2 = 1.23 x 10-3 mol. I keep on getting 2.2 , can anyone tell me what I am doing wrong?...
Mon Jan 20, 2020 2:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kw temperature
Replies: 8
Views: 27

### Re: Kw temperature

Does anyone know how this number would change in response to temperature?
Mon Jan 20, 2020 2:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Percent ionization
Replies: 2
Views: 10

### Percent ionization

When we get a percentage of ionization, does that number represent how much we have left?
Mon Jan 20, 2020 1:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5 percent rule
Replies: 2
Views: 11

### 5 percent rule

Could anyone explain what the five percent rule is, please? Are you looking at x or your ionization percentage?
Mon Jan 20, 2020 1:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Workshop Monday
Replies: 2
Views: 53

### Workshop Monday

Hello everyone! Professor said that there would be a session today in covel, does anyone know if it will be Lyndon holding his regular session? I believe he said last week he wasn't holding it today so I was wondering if anyone knew.
Mon Jan 20, 2020 1:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Salt solutions
Replies: 1
Views: 21

### Salt solutions

Professor mentioned something about certain elements that don't affect ph and I was wondering if anyone could tell me what it was? I wasn't able to write it down.
Sun Jan 19, 2020 6:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Titration
Replies: 3
Views: 15

### Titration

Professor mentioned something about titration but that isn't on this test correct?
Sun Jan 19, 2020 6:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Buffer
Replies: 6
Views: 20

### Buffer

Can anyone explain what a buffer is please?
Thu Jan 16, 2020 10:36 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Questions 6C5,6c9
Replies: 1
Views: 21

### Questions 6C5,6c9

Could anyone post the table 6C.1 and 6C.2, I don't have my book with me but wanted to get some problems done. Thank you!
Tue Jan 14, 2020 10:08 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A.19
Replies: 6
Views: 46

### Re: 6A.19

I was looking at this too! Either they forgot to add mM to the problem or it is an error in the solutions manual. I got the answer to the ^-15.
Tue Jan 14, 2020 9:57 am
Forum: Resonance Structures
Topic: Resonance
Replies: 1
Views: 22

### Resonance

Hello, I was wondering why the N2H2 structure did not have resonance but the others did. Is there any rule for when something has resonance? Thank you.
Fri Jan 10, 2020 2:25 pm
Forum: Ideal Gases
Topic: ICE table
Replies: 7
Views: 296

### Re: ICE table

You set up your ice table to then be able to get your equilibrium constants. After that, you use the equation we have learned which is reactants/products.
Fri Jan 10, 2020 2:17 pm
Forum: Ideal Gases
Topic: Chatelier’s Principle
Replies: 8
Views: 41

### Re: Chatelier’s Principle

Do you happen to know on which page this falls on in the ideal gases section?
Fri Jan 10, 2020 2:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Graphing K and Q Values
Replies: 4
Views: 23

### Re: Graphing K and Q Values

I don't believe so, he has never mentioned this and I don't believe it's on the learning objectives on outline1.
Fri Jan 10, 2020 2:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp vs Kc
Replies: 6
Views: 21

### Re: Kp vs Kc

It becomes simpler when you see the phases that your reaction is in, which is usually given to you. For example, if it's in the gas phase you'd use partial pressures. Also if they are giving you units that relate to partial pressure then you'd use Kp.
Fri Jan 10, 2020 2:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pressure and Volume
Replies: 8
Views: 24

### Re: Pressure and Volume

It does not affect K. I believe it can affect the concentration of products and reactants but not the ratio between them.
Thu Jan 09, 2020 4:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework Question 5H.1
Replies: 2
Views: 17

### Homework Question 5H.1

I have attached the question below and the answer. However I was wondering if someone could go through how they came to find b and c. Why did they square root for b?
Thu Dec 05, 2019 7:15 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Sulfato
Replies: 1
Views: 17

### Sulfato

Is sulfato a chelating ligand? or is it monodentate?
Tue Dec 03, 2019 9:24 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Textbook question 6B.9
Replies: 2
Views: 45

### Re: Textbook question 6B.9

I saw this too, is there somewhere we can double check for the answers? Also, [OH]x[pOH]=10^-14. If you use the numbers in the answer key it doesnt work, but if you use the numbers we got, it does? So I'm thinking it probably was an error.
Tue Dec 03, 2019 6:38 pm
Forum: Calculating the pH of Salt Solutions
Topic: 6D.11 [ENDORSED]
Replies: 2
Views: 122

### 6D.11[ENDORSED]

The question states, Decide whether an aqueous solution of each of the following salts has a pH equal to or greater than, or less than 7. I was a little confused on how they got the reactions for AlCl3 and Cu(NO3)2.
I put the answer down below if that helps when trying to explain, thank you :)
Tue Dec 03, 2019 6:07 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.9
Replies: 5
Views: 37

### Re: 6B.9

Ryan Chang 3A wrote:You are using the correct formula to find the concentration of OH, which is [M]=10^-POH. Plugging in the numbers you get: 10^-14.176 = 6.668 x 10^-15 M, which is the correct answer.
The textbook says it would be 1.5x10^-14
Tue Dec 03, 2019 4:13 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.9 Row 2&1
Replies: 2
Views: 25

### Re: 6B.9 Row 2&1

Ah I see that makes sense!
Tue Dec 03, 2019 10:52 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.9 Row 2&1
Replies: 2
Views: 25

### 6B.9 Row 2&1

6B.9 asks you to find the missing values given only certain ones. On row 1 they give you a H30+ concentration of 1.5, you can find the ph to be .176. However, when I would try to get the [H30+] concentration through the pH to double check my answers I would not get 1.5 through the equation we're sup...
Tue Dec 03, 2019 10:34 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.9
Replies: 5
Views: 37

### 6B.9

The question asks to find the [OH], [Ph], and [OH] concentration with the given information that is 1.50M of [H30+]. You can get ph 0.176 and OH from that as 14.17. However, how would you get the OH concentration? I thought you would use the equation that is [M]= 10^-pOH. However, you get an incorre...
Mon Dec 02, 2019 8:52 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Finding concentration of H30+
Replies: 1
Views: 23

### Finding concentration of H30+

On homework question 6A.23, it says to calculate the initial molarity of Ba(OH)2 and the molarities of Ba2+, OH-, and H3O+. You can find the first two, which I got 0.05M for OH-. However I don't understand how'd you find the H3O+ concentration. Is there a certain formula you always use? The solution...
Tue Nov 26, 2019 9:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 1
Views: 28

### Test 2

Does anyone know if test scores appear as 0/50 while grades are being inputted?
Sun Nov 24, 2019 3:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Focus 9C.1 and 9C.2
Replies: 2
Views: 19

### Focus 9C.1 and 9C.2

Could anyone tell me the name of these topics?/ What is the section heading for these focuses. Thank you so much! :)
Wed Nov 20, 2019 1:40 pm
Forum: Lewis Structures
Topic: Strength of bonds
Replies: 3
Views: 49

### Strength of bonds

Which pair of atoms are most tightly bound, HO- or HS-, can anyone help me figuring out the answer?
Wed Nov 20, 2019 1:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 5
Views: 33

### Re: Polarity

Thank you Brittany!
Tue Nov 19, 2019 10:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 5
Views: 33

### Re: Polarity

Yes, but would the overall molecule be polar?
Tue Nov 19, 2019 10:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 5
Views: 33

### Polarity

Do double bonds ever play a role in polarity? For example, in GaF3, there is a double bond on one of the fluorines. Would this molecule be considered polar or nonpolar?
Tue Nov 19, 2019 9:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles
Replies: 3
Views: 34

### Bond angles

I had a question regarding CH2CHCN, what would be their bond angles? 120 would be present, would 180 be present as well between C-C-N?
Tue Nov 19, 2019 5:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma & Pi bonds
Replies: 5
Views: 42

### Sigma & Pi bonds

Sigma bonds can rotate while Pi bonds cant. What gives each this characteristic?
Tue Nov 19, 2019 3:16 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Types of forces
Replies: 4
Views: 30

### Re: Types of forces

Therefore, unless it says there are ions or other different molecules, we don't include those?
Tue Nov 19, 2019 1:02 pm
Forum: Lewis Structures
Topic: H2SeO4
Replies: 2
Views: 41

### Re: H2SeO4

Oh, I see! Thank you!
Tue Nov 19, 2019 12:56 pm
Forum: Lewis Structures
Topic: H2SeO4
Replies: 2
Views: 41

### H2SeO4

For H2SeO4, how would you know that the oxygen is bonded to hydrogen? Why would the hydrogen's not be bonded to Se?
Tue Nov 19, 2019 12:53 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Types of forces
Replies: 4
Views: 30

### Types of forces

For homework question, 3F.1, it says to name the types of forces that can occur for certain molecules. In the answer key, SO2, only has dipole-dipole and London forces. Why is dipole-induced dipole and ion-dipole not included in the list?
Tue Nov 19, 2019 9:48 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Square pyramidal
Replies: 3
Views: 23

### Re: Square pyramidal

Thank you!! It looks really helpful.
Mon Nov 18, 2019 8:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Square pyramidal
Replies: 3
Views: 23

### Square pyramidal

We never covered square pyramidal in lecture and I was wondering if anyone knew if we would be tested on this shape?
Mon Nov 18, 2019 6:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles
Replies: 2
Views: 20

### Bond angles

I was wondering what the bond angles would be for ICL2-, I know it's linear and would have a bond angle that's 180 but would there be any others? Thank you!
Sat Nov 16, 2019 2:04 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Strength of bonds
Replies: 3
Views: 13

### Re: Strength of bonds

I don't believe so, we just need to know the relative strength of each.
Sat Nov 16, 2019 1:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Acids and Bases
Replies: 4
Views: 26

### Re: Acids and Bases

I don't believe so, I believe acids and bases are covered in one of the last outlines of the quarter.
Sat Nov 16, 2019 11:50 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Induced dipole-induced dipole force [ENDORSED]
Replies: 1
Views: 28

### Re: Induced dipole-induced dipole force[ENDORSED]

An induced-dipole occurs when a dipole is created by the movement of electrons. As we know, electrons are always moving around. For a brief second, they'll be a partial negative/positive on an atom because of this random movement. This will occur in both molecules, leading to an attraction. It is ve...
Sat Nov 16, 2019 11:47 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs
Replies: 3
Views: 23

### Re: Lone pairs

Lone pairs occupy more space because lone pair can move more in a region than a bonding pair can. Electrons repel each other because of that negative-negative charge.
Sat Nov 16, 2019 11:45 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Test 2
Replies: 5
Views: 31

### Re: Test 2

Everything covered recently, and one slide from Monday's lecture. I believe it's going to be hybridization.
Sun Nov 10, 2019 6:24 pm
Forum: Student Social/Study Group
Replies: 8
Views: 77

It'll be after the lecture and not discussion. Most likely on Wednesday and TA's will be standing outside with the physical copies.
Sun Nov 10, 2019 6:16 pm
Forum: Bond Lengths & Energies
Topic: test 2
Replies: 16
Views: 91

### Re: test 2

Has he mentioned what parts of the outline it'll be?
Sun Nov 10, 2019 5:20 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen bonding
Replies: 7
Views: 20

### Re: Hydrogen bonding

They are another form of bonding that isn't covalent or ionic. It deals with partial negatives and positives.
Sun Nov 10, 2019 5:18 pm
Forum: Lewis Structures
Topic: Does the shape that I draw the Lewis structure matter?
Replies: 14
Views: 70

### Re: Does the shape that I draw the Lewis structure matter?

The simplest answer would be yes it matters. We'll be learning more about the correct way to draw them in the lectures.
Sun Nov 10, 2019 5:17 pm
Forum: Dipole Moments
Topic: What's a dipole
Replies: 4
Views: 17

### Re: What's a dipole

You know a dipole is occurring through periodic trends. For example, we know oxygen has a higher electronegativity than hydrogen so there will be a dipole moment between them.
Sun Nov 10, 2019 5:15 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 3
Views: 19

### Re: Covalent Character

This refers to when an ionic bond has some "covalent character." For example, between a small cation and large anion. The small cation is able to attract the electron in the anion through its polarizing power. The large anion isn't able to hold onto its electron so closely because it's far...
Sat Nov 02, 2019 10:36 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 28
Views: 184

### Re: Midterm

He said everything he covered up to now will be on the midterm, (Outline 3, D). The only thing we don't have to worry about is the very last slide he presented on Friday.
Sat Nov 02, 2019 7:52 pm
Forum: Ionic & Covalent Bonds
Topic: ionic bonds
Replies: 4
Views: 36

### ionic bonds

How does one determine when a bond is ionic and when it is covalent when only given the name? For example, how do we determine that sodium hypochlorite will be an ion?
Sat Nov 02, 2019 7:51 pm
Forum: Ionic & Covalent Bonds
Topic: Lewis Structure for Ionic Bonds
Replies: 4
Views: 36

### Lewis Structure for Ionic Bonds

Does anyone know when certain bonds would go inside the brackets or not? For example, ammonium chloride has the bonds between N and H4 inside brackets while Cl is outside with the negative charge. When would you know that you have to have certain ones separated by brackets while others are fine with...
Sat Nov 02, 2019 3:22 pm
Forum: Lewis Structures
Topic: Expanded Shells
Replies: 3
Views: 55

### Re: Expanded Shells

Got it! Thanks!
Sat Nov 02, 2019 3:19 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Calculator rounding
Replies: 3
Views: 41

### Re: Calculator rounding

Ti-30xs, it happened when I divided 1/ 1,650,763.73. It said it was 6.06x10-7, but it should be 6.058x10^-7.
Sat Nov 02, 2019 1:28 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Calculator rounding
Replies: 3
Views: 41

### Calculator rounding

Does anyone know how to prevent your calculator from rounding up? For example in the atomic spectra module, the answer should be 6.058x10^-7 but my calculator rounds up to 6.06x10^-7.
Fri Nov 01, 2019 9:22 pm
Forum: Lewis Structures
Topic: Expanded Shells
Replies: 3
Views: 55

### Expanded Shells

I understand the concept of why certain elements after period 3 can have expanded shells but what is the maximum number for these elements? And as a follow-up, how do you know it's that maximum number? Thank you!
Sun Oct 27, 2019 11:46 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: HW question 1B.25
Replies: 3
Views: 49

### HW question 1B.25

What is the minimum uncertainty in the speed of an electron confined to within a lead atom of diameter 350. pm? How would you model the atom as a one-dimensional box with a length equal to the diameter of the actual atom?

Thank you to anyone who can help with this question!
Sun Oct 27, 2019 11:40 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1B.15
Replies: 1
Views: 34

### 1B.15

This question was very detailed and I was hoping someone could break it down conceptually. Thank you! The velocity of an electron that is emitted from a metallic surface by a photon is 3.6x10^3 km/s. What is the wavelength of the radiation that caused photoejection of the electron?" (b) No elec...
Sun Oct 27, 2019 11:33 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Electromagnetic Spectrum
Replies: 3
Views: 35

### Electromagnetic Spectrum

Hi everyone! This question in the post-assessment for atomic spectra, it just made me wonder if we need to know what wavelengths correspond to which part of the electromagnetic spectrum. This is the question for reference. In the hydrogen atomic spectrum, what is the wavelength of light associated w...
Sun Oct 27, 2019 11:31 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectroscopy
Replies: 2
Views: 24

### Atomic Spectroscopy

This question is in the post-assessment and I had a little trouble with it. I'm assuming we have to combine equations but was just wondering which ones. Any conceptual tips would help too! In the hydrogen atomic spectrum, what is the wavelength of light associated with the n = 2 to n = 1 electron tr...
Sun Oct 27, 2019 11:30 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Post Assesment Question (Atomic Spectroscopy)
Replies: 1
Views: 25

### Post Assesment Question (Atomic Spectroscopy)

Hi everyone! So I know the equations we have to use for these types of equations but I'm lost on how we plug everything in and the steps needed to find the answer. Thank you! An excited hydrogen atom emits light with a frequency of 1.14 x 1014 Hz to reach the energy level n = 4. In what principle qu...
Tue Oct 15, 2019 4:40 pm
Forum: Properties of Light
Topic: HW Question 1A.15
Replies: 2
Views: 37

### HW Question 1A.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 during the emission of energy that leads to this spectral line. Can anyone help me understand the steps you need to do in order to get the...
Tue Oct 15, 2019 4:37 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals, 1D.11
Replies: 2
Views: 38

### Orbitals, 1D.11

Could anyone help me with the following question?

How many orbitals are in subshells with l equal to (0,2,1,3)
Tue Oct 15, 2019 3:30 pm
Forum: DeBroglie Equation
Topic: 1B.27
Replies: 1
Views: 39

### 1B.27

A bowling ball of mass 8.00 kg is rolled down a bowling alley lane at 5.00 ± 5.0 m/s. What is the minimum uncertainty in its position?

I was wondering why in the equation in the solutions manual they used Δv= 5 and not 10.
Tue Oct 15, 2019 3:22 pm
Forum: DeBroglie Equation
Topic: 1B.9 HW Question
Replies: 8
Views: 83

### 1B.9 HW Question

A lamp rated at 32W emits violet light of wavelength 420nm. How many photons of violet light can the lamp generate in 2 seconds? How many moles of photons are emitted in that time interval?
I'm wondering how to solve this problem/ how to convert photons to moles?
Tue Oct 15, 2019 3:16 pm
Forum: Balancing Chemical Reactions
Topic: HW Question L35
Replies: 2
Views: 47

### HW Question L35

I was looking back on a homework question and was wondering if anyone could offer advice on how to solve the following problem. Sodium bromide, NaBr, which is used to produce AgBr for use in photographic film, can itself be prepared as follows. FeBr+Br2 ---> FeBr2 FeBr2+Br2---> Fe3Br8 Fe3Br8+Na2CO3-...
Sun Oct 13, 2019 4:24 pm
Forum: Properties of Electrons
Topic: Assessing probablity of finding an electron given distance from nucleus
Replies: 2
Views: 23

### Assessing probablity of finding an electron given distance from nucleus

HW Question 1D.1

Which of the following increase when the electron in a hydrogen atom undergoes a transition from the 1s orbital to a 2p orbital? (a) The energy of the electron. (b) Value of n (c) Value of l. (d) Radium of the atom.

How would I answer each step?
Sun Oct 13, 2019 4:20 pm
Forum: Photoelectric Effect
Topic: Estimating the uncertainty in the location or speed of a particle
Replies: 1
Views: 24

### Estimating the uncertainty in the location or speed of a particle

HW Question 1B.5
How would you go about answering the following question? I'm having trouble beginning it.

The y-ray photons emitted by the nuclear decay of a technetium-99 atom used in radiopharmaceuticals have an energy of 140.511 keV. Calculate the wavelength of these y-rays.
Sun Oct 13, 2019 4:16 pm
Forum: Photoelectric Effect
Topic: HW Question 1B.3
Replies: 2
Views: 29

### HW Question 1B.3

The answer to the following question is The Photoelectric effect but I am having trouble understanding why. Could someone please explain? From the following list of observations, select the one that best supports the idea that electromagnetic radiation has the properties of particles. Explain your r...
Sun Oct 13, 2019 4:13 pm
Forum: Properties of Light
Topic: HW Question 1A.11
Replies: 2
Views: 40

### HW Question 1A.11

In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series, Lyman series, Paschen series), as shown in Figs. 1.10 and 2.1. What is common to the lines within a series that makes the grouping them together logical? I am con...
Sun Oct 13, 2019 4:10 pm
Forum: Properties of Light
Topic: Homework Question 1A.7
Replies: 2
Views: 32

### Homework Question 1A.7

The frequency of violet light is 7.1 1014 Hz. What is the wavelength (in nanometers) of violet light? (b) When an electron beam strikes a block of copper, x-rays with a frequency of 2.0 1018 Hz are emitted. What is the wavelength (in picometers) of these x-rays?" What would be the steps for con...
Wed Oct 02, 2019 9:46 pm
Forum: Balancing Chemical Reactions
Topic: Tips on Balancing
Replies: 4
Views: 69

### Tips on Balancing

In one stage in the commercial production of iron metal in a blast furnace, the iron(III) oxide, Fe2O3, reacts with carbon monoxide to form Fe3O4 and carbon dioxide. In a second stage, the Fe3O4 reacts further with carbon monoxide, to produce elemental iron and carbon dioxide. Write the balanced equ...
Wed Oct 02, 2019 9:42 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity
Replies: 4
Views: 38

### Re: Molarity

Thank you, everyone, for your help!
Wed Oct 02, 2019 9:40 pm
Forum: Limiting Reactant Calculations
Topic: limiting reactant
Replies: 5
Views: 85

### limiting reactant

When limestone, which is principally CaCO3, is heated, carbon dioxide and quicklime, CaO, are produced by the reaction CaCO3(s)-->CaO(s)+CO2(g). If 17.5 g of CO2 is produced from the thermal decomposition of 42.73 g of CaCO3, what is the percentage yield of the reaction? I'm having a little trouble ...
Wed Oct 02, 2019 9:37 pm
Forum: Limiting Reactant Calculations
Topic: L3
Replies: 3
Views: 32

### L3

Compounds that can be used to store hydrogen in vehicles are being actively sought. One reaction being studied for hydrogen storage is Li3N + 2 H2 ---> LiNH2 + 2 LiH. (a) What amount (in moles) of H2 is needed to react with 1.5 mg of Li3N? (b) Calculate the mass of Li3N that will produce 0.650 mol L...