## Search found 41 matches

Wed Jun 13, 2018 9:52 pm
Forum: Conjugate Acids & Bases
Topic: No Proton Transferred? HW Problem
Replies: 4
Views: 381

### Re: No Proton Transferred? HW Problem

ramayyala1G wrote:I'm pretty sure a proton was transferred around since the hydrogen's are being moved around. What problem is this?

12.9C!
Wed Jun 13, 2018 1:55 pm
Forum: Conjugate Acids & Bases
Topic: No Proton Transferred? HW Problem
Replies: 4
Views: 381

### No Proton Transferred? HW Problem

How do I know there's no proton transferred in this equation? I'm lost because I thought there were protons moving around to different components of the equation?

CH3COOH(aq)  + NH3(aq) --> CH3CONH2(aq) + H2O(l)
Wed Jun 13, 2018 1:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair=Polar?
Replies: 3
Views: 295

### Re: Lone Pair=Polar?

Chem_Mod wrote:No, for example square planar has 4 atoms attached and 2 lone pairs, but it is nonpolar if all the attachments are the same.

Ah, makes sense! Thank you!
Wed Jun 13, 2018 1:26 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Final Topic Question- Acids/Bases [ENDORSED]
Replies: 1
Views: 196

### Final Topic Question- Acids/Bases[ENDORSED]

Will we have to do any calculation problems regarding ACIDS/BASES on the final? Such as calculating pH?
Tue Jun 12, 2018 8:42 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation State
Replies: 3
Views: 240

### Oxidation State

How do you determine the oxidation state of a coordinate complex?

EX: Na2(PtBr4)
Tue Jun 12, 2018 6:44 pm
Forum: Hybridization
Topic: S-Character and Bond Angle Relationship
Replies: 3
Views: 880

### S-Character and Bond Angle Relationship

What does "as the s-character of a hybrid orbital increases, the bond angle increases" mean? Because sp2 = trigonal planar so bond angle is 120, and then when you go up to sp3= tetrahedral so bond angle decreases to 109.5 So my question is what does s-character mean exactly?? Does s-charac...
Tue Jun 12, 2018 5:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair=Polar?
Replies: 3
Views: 295

### Lone Pair=Polar?

If a lewis structure has a lone pair on central atom, does that automatically make the structure polar?
Sun Jun 10, 2018 8:26 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge
Replies: 5
Views: 248

### Re: Formal charge

Lone pairs are counted as 2 electrons, while a single bond is counted as one valence electron when determining formal charge.
Sun Jun 10, 2018 12:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal planar vs Bent
Replies: 1
Views: 261

### Trigonal planar vs Bent

For Hw question 4.5 when drawing the lewis structure for ClO2+ the answer says the arrangement is trigonal planar, but I thought it would be bent because their are 3 "things" connected to the central atom of Cl, one being a lone pair and 2 bonds. So I am confused to how the solution says i...
Sat Jun 09, 2018 10:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing Tetrahedral Structures
Replies: 4
Views: 165

### Drawing Tetrahedral Structures

When drawing the tetrahedral structure do we have to draw the black triangle or a dashed triangle to represent hydrogen bonds to a central atom for example as showed in some of the solutions in the solutions book (EX: 4.3) or can I just normally draw a straight line as the bond?
Sun Jun 03, 2018 10:03 pm
Forum: Bond Lengths & Energies
Topic: Test 3 Q 8 [ENDORSED]
Replies: 9
Views: 501

### Re: Test 3 Q 8[ENDORSED]

remember, the smaller the atom, the shorter the bond, the stronger the bond.
Sun Jun 03, 2018 9:59 pm
Forum: Biological Examples
Topic: Biological Function on Final?
Replies: 3
Views: 271

### Re: Biological Function on Final?

According to a UA session, the UA said to know

Cisplatin
- chemotherapy drugs: stops cancer/cell growth
- forms coordination compounds with DNA to stop cell division

Hemoglobin
- transports oxygen in blood
- 4 Myoglobins to bind 4 Oxygen molecules
Sun Jun 03, 2018 9:48 pm
Forum: Hybridization
Topic: basics of hybridization
Replies: 18
Views: 815

### Re: basics of hybridization

Basically, hybridization results from orbital overlap. To figure out the hybridization of an atom, you basically count the "things" (atoms and lone pairs only) surrounding an atom-- not including the central atom. So if there are 2 things surrounding a central atom then its sp. 3 things- s...
Wed May 23, 2018 3:53 pm
Forum: Lewis Structures
Topic: Writing Chemical Formulas- HW Question 3.25
Replies: 2
Views: 141

### Writing Chemical Formulas- HW Question 3.25

For example, 3.25 A asks to write the chemical formula for magensium arsenide.

For this, how exactly does one go about solving it. Do I look at the individual elements charge separately at first and then balance them? I'm pretty confused.
Sun May 20, 2018 9:07 pm
Forum: Dipole Moments
Topic: London Dispersion, Induced dipole- Induced dipole, Van Der Waals
Replies: 5
Views: 234

### Re: London Dispersion, Induced dipole- Induced dipole, Van Der Waals

Yes, all three of those names can be interchanged with one another since they mean the same thing.
Sun May 20, 2018 9:06 pm
Forum: Electronegativity
Topic: Isoelectronic [ENDORSED]
Replies: 11
Views: 673

### Re: Isoelectronic[ENDORSED]

Isoelectronic means that two or more elements have the same numbers of electrons or the same electronic structure.
Sun May 20, 2018 9:03 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge purpose
Replies: 40
Views: 1780

### Re: Formal charge purpose

This is because you are trying to find the most stable lewis structure for a molecular formula, and to do this you need to determine the formal charges of each resonance.
Mon May 14, 2018 12:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions [ENDORSED]
Replies: 3
Views: 163

### Re: Exceptions[ENDORSED]

Exactly what the above comment said. Half full and full shells are more stable than ones that are not. Thus, Cr and Cu since they are one away from being half full or full, we go ahead and put their d shell as 3d5 and 3d10 and then take away an electron from their 4s2 to make it 4s1.
Mon May 14, 2018 12:03 pm
Forum: General Science Questions
Topic: Conceptual Questions
Replies: 4
Views: 273

### Re: Conceptual Questions

I too like to explain the concepts to people or find pneumonics that can help me try to remember trends for example and why those trends exist
Sat May 05, 2018 9:20 pm
Forum: Trends in The Periodic Table
Topic: 2.67 part C (electron affinity)
Replies: 3
Views: 103

### 2.67 part C (electron affinity)

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? Are the trends for electron affinity the same as ionization energy? Decreases down a group, increases across a period (from l...
Sat May 05, 2018 8:54 pm
Forum: Trends in The Periodic Table
Topic: Determining Smaller First Ionization Energy
Replies: 1
Views: 80

### Determining Smaller First Ionization Energy

Which member of each pair has the smaller first ionization energy: (a) Ca or Mg; (b) Mg or Na; (c) Al or Na? Is this determined by simply looking at the ionization trends? Which is that ionization energy decreases down a group, and increases across a period, so for ... a) because Ca is below Mg, Cal...
Sat May 05, 2018 7:04 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations Exceptions
Replies: 3
Views: 97

### Electron Configurations Exceptions

What are all of the electron configuration exceptions we need to be familiar with?

Cu, Cr, and Ag? Are there anymore?

Also, I'm still a little confused on how to do these exceptions, do we just memorize the way they are supposed to be written?
Sat May 05, 2018 4:45 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.19
Replies: 3
Views: 139

### Re: 2.19

How do we know how many subshells there are when we are given an n value? For example, "How many subshells are there in the shell with n=4?" Hi, I use this method: subshells are the L (orbital angular momentum), to figure out the L: look at them as levels. Start at 0 and continue writing ...
Wed May 02, 2018 12:25 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Post Module Question #8/9 [ENDORSED]
Replies: 3
Views: 556

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

Try using the equation KE=1/2 mv^2 You should get the kinetic energy for one hydrogen atom. From there you can use dimensional analysis to calculate the kinetic energy per mole of electrons/hydrogen atoms. How do we "calculate the kinetic energy per mole of electrons/hydrogen atoms" becau...
Wed May 02, 2018 12:08 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Online Assessment Question
Replies: 1
Views: 121

### Heisenberg Online Assessment Question

I also had a question on how to go about solving this Heisenberg Uncertainty problem. The problem reads... The hydrogen atom has a radius of approximately 0.05 nm. Assume that we know the position of an electron to an accuracy of 1 % of the hydrogen radius, calculate the uncertainty in the speed of ...
Tue May 01, 2018 11:59 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg (Calculating Uncertainty in Speed)
Replies: 1
Views: 123

### Heisenberg (Calculating Uncertainty in Speed)

I have a question which might be really simple but I am making it more confusing I guess. Under the Heisenberg Uncertainty Online Assessments, if it says the uncertainty in speed is one hundredth the speed of light, what does that look like? (1/100)(3 x 10^8)?
Tue May 01, 2018 9:37 pm
Forum: Molarity, Solutions, Dilutions
Topic: Key for Test #1
Replies: 4
Views: 228

### Re: Key for Test #1

Was wondering the same thing! ^^^
Sun Apr 29, 2018 2:53 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: HW question 2.17 [ENDORSED]
Replies: 2
Views: 132

### Re: HW question 2.17[ENDORSED]

^ I have this same question as well.
Sun Apr 29, 2018 2:52 pm
Forum: Properties of Light
Topic: Test #2: Q6 [ENDORSED]
Replies: 10
Views: 599

### Re: Test #2: Q6[ENDORSED]

When I did this problem to find wavelength I used wavelength= ch/E instead.
Sun Apr 29, 2018 2:50 pm
Forum: DeBroglie Equation
Topic: homework problems [ENDORSED]
Replies: 5
Views: 267

### Re: homework problems[ENDORSED]

Can someone explain this?

Which of the following increase when the electron in a
hydrogen atom undergoes a transition from the 2s-orbital to a
2p-orbital? (a) Energy of the electron. (b) Value of n. (c) Value
of l. (d) Radius of the atom.
Mon Apr 23, 2018 11:38 am
Forum: Photoelectric Effect
Topic: What is work function? [ENDORSED]
Replies: 15
Views: 2111

### Re: What is work function?[ENDORSED]

It is the minimum threshold needed to eject an electron from the metal.
Mon Apr 23, 2018 11:37 am
Forum: Administrative Questions and Class Announcements
Topic: Test Time
Replies: 6
Views: 351

### Re: Test Time

Yeah, just try practicing 8 problems in 40 minutes so you can get a feel for it.
Mon Apr 23, 2018 11:36 am
Forum: SI Units, Unit Conversions
Topic: Chemical Formulas [ENDORSED]
Replies: 11
Views: 440

### Re: Chemical Formulas[ENDORSED]

Yes, that is correct!
Mon Apr 16, 2018 3:27 pm
Forum: Photoelectric Effect
Topic: Higher Frequency and Kinetic Energy [ENDORSED]
Replies: 5
Views: 361

### Re: Higher Frequency and Kinetic Energy[ENDORSED]

How do you solve this question in the Photoelectric Module? What exactly is the Work function? 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. Answer the following three questions. What is the kinetic ene...
Sun Apr 15, 2018 5:37 pm
Forum: SI Units, Unit Conversions
Topic: Chemical Formulas [ENDORSED]
Replies: 11
Views: 440

### Re: Chemical Formulas[ENDORSED]

Kuldeep Gill 1H wrote:Hi, I was just wanted to know... to what extent should we know chemical formulas?

For the first test, I am sure he will give us the formula itself so we shouldn't worry too much about that!
Sun Apr 15, 2018 5:36 pm
Forum: Properties of Light
Topic: wavelength description [ENDORSED]
Replies: 11
Views: 432

### Re: wavelength description[ENDORSED]

Alondra Juarez section 1E wrote:In Mondays lecture Dr. Lavelle demonstrated the figure of the electric field and described what a wavelength was considered however, I am still confused as to what does amplitude mean in this context is it the height of the wavelength or...?

Amplitude is the height of the wave!
Sun Apr 15, 2018 5:35 pm
Forum: Properties of Light
Topic: hw chapter 1 question 11
Replies: 3
Views: 140

### Re: hw chapter 1 question 11

Had another question regarding question 5 in chapter 1 as well.

Arrange the following types of photons of electromagnetic
radiation in order of increasing energy: -rays, visible light,

How are we supposed to know this? just from the readings?
Sun Apr 15, 2018 5:32 pm
Forum: Properties of Light
Topic: HW 1.7 (using nm vs pm)
Replies: 8
Views: 308

### Re: HW 1.7 (using nm vs pm)

Had a question regarding example 3 in chapter 1 as well? Which of the following happens when the frequency of electromagnetic radiation decreases? Explain your reasoning. (a) The speed of the radiation decreases. (b) The wavelength of the radiation decreases. (c) The extent of the change in the elec...
Sat Apr 14, 2018 11:38 pm
Forum: Balancing Chemical Reactions
Topic: How to Balance [ENDORSED]
Replies: 5
Views: 198

### Re: How to Balance[ENDORSED]

Does someone have any tips how to balance complicated chemical equations? Some of the ones on the test were not ones you could figure out the numbers for right away. So I was wondering if someone has a helpful method to solve equations like those ones. I would start with looking at the element that...
Sat Apr 14, 2018 8:06 pm
Forum: SI Units, Unit Conversions
Topic: Moles mols mol? [ENDORSED]
Replies: 21
Views: 1472

### Re: Moles mols mol?[ENDORSED]

Naqiyah Qadir 1I wrote:They are all the same but M (molarity) is given in moles/Liter, correct?

Yes, that is correct!
Wed Apr 11, 2018 9:46 pm
Forum: SI Units, Unit Conversions
Topic: Moles mols mol? [ENDORSED]
Replies: 21
Views: 1472

### Re: Moles mols mol?[ENDORSED]

Hello! I had a quick question for L1 in the fundamentals section outline.

Without using a calculator, estimate what amount of Br2
(in moles) can be obtained from 0.30 mol ClO2 in the reaction
6 ClO21g2  2 BrF31l2 S 6 ClO2F1s2  Br21l2.