Search found 100 matches

by Hannah_1G
Sat Mar 14, 2020 8:58 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: HCl as anode and cathode in cell diagram
Replies: 3
Views: 29

Re: HCl as anode and cathode in cell diagram

You would take the half reactions: 2H+ (aq,1.0M) + 2e- --> H2 (g,1atm) // E cathode = 0.00V H2 (g,1atm) --> 2H+ (aq,0.075M) + 2e- // E anode = 0.00V Add them together: 2H+ (aq, 1.0M) + H2 (g,1atm) --> 2H+ (aq,0.075M) + H2 (g,1atm) and get Ecell = 0.00V Then use the nernst equation to get: E=E^\circ...
by Hannah_1G
Sat Mar 14, 2020 5:52 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: HCl as anode and cathode in cell diagram
Replies: 3
Views: 29

HCl as anode and cathode in cell diagram

How does this cell diagram work Pt(s)|H 2 (g, 1.0 bar)|HCl(aq, 0.075 mol/L )||HCl(aq, 1.0 mol/L)|H 2 (g, 1.0 bar)|Pt(s)
and how would I balance it to solve for its cell potential?
by Hannah_1G
Sat Mar 14, 2020 4:47 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Redox from cell diagram
Replies: 6
Views: 93

Re: Redox from cell diagram

Similarly with , how do I view the commas in the diagram to write out a half redox reaction?
by Hannah_1G
Sat Mar 14, 2020 4:23 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Redox from cell diagram
Replies: 6
Views: 93

Redox from cell diagram

In the cell diagram:

H and Cl look like they are both oxidized, how would I write the half redox reactions?
by Hannah_1G
Sat Mar 14, 2020 3:12 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Finding k 7B.3
Replies: 1
Views: 45

Finding k 7B.3

How would you go about finding k in part c? 2A B + C, given that [A]0 = 0.153 mol/L and that after 115 s the concentration of B rises to 0.034 mol/L. Would I use 1/2 A= change in concentration of B?
by Hannah_1G
Fri Mar 13, 2020 8:51 pm
Forum: First Order Reactions
Topic: 7B.1 mass of drug left in body
Replies: 2
Views: 48

7B.1 mass of drug left in body

Does the initial mass of the drug replace the concentration in the rate law equation for solving for the left over mass?
Would I use this equation in 7B.1 to solve for how much drug is left?
by Hannah_1G
Fri Mar 13, 2020 8:34 pm
Forum: First Order Reactions
Topic: Rate of reaction and temperature
Replies: 2
Views: 51

Rate of reaction and temperature

If the rate constant and initial molarity are given for a first order reaction and so is a temperature at which the reaction is happening, does the temperature factor in to the rate of the reaction?
by Hannah_1G
Fri Mar 13, 2020 8:05 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic vs Electrolytic cells
Replies: 6
Views: 75

Re: Galvanic vs Electrolytic cells

Kimberly Koo 2I wrote:An electrolytic cell converts electrical energy into chemical energy, while a galvanic cell converts chemical energy into electrical energy.
What exactly would an electrolytic cell do? Is it not generating a voltage charge like a galvanic cell since the energy is turned into chemical?
by Hannah_1G
Fri Mar 13, 2020 7:18 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Order reaction
Replies: 4
Views: 88

Order reaction

How do you tell which order the reaction rate is at? Is it always given? What is it dependent on? I don't very much understand this concept at all, please explain! Thank you!
by Hannah_1G
Fri Mar 13, 2020 7:08 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: rate constant
Replies: 3
Views: 76

rate constant

What is the kr constant? The book just explains it as a proportion of the initial rate of consumption? I am having a hard time understanding this concept.
by Hannah_1G
Fri Mar 13, 2020 2:37 pm
Forum: Balancing Redox Reactions
Topic: redox of chlorine in water 6K.3 d
Replies: 2
Views: 42

redox of chlorine in water 6K.3 d

Cl 2 (g) HClO(aq) + Cl 2 (g). I don't know how to find the reduction half of this problem, it shows Cl going to Cl which isn't a loss or gain of electrons.
by Hannah_1G
Fri Mar 13, 2020 1:52 pm
Forum: Balancing Redox Reactions
Topic: Oxidation number
Replies: 12
Views: 234

Oxidation number

How does oxidation number of an element relate to how many electrons it will lose or gain? I am confused on how to calculate when in acidic or basic solutions it changes the net charges.
by Hannah_1G
Thu Mar 12, 2020 11:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic vs Electrolytic cells
Replies: 6
Views: 75

Galvanic vs Electrolytic cells

Can someone explain the difference between the two? I don't understand what an electrolytic cell is and how it could be different than a galvanic cell.
by Hannah_1G
Thu Mar 12, 2020 7:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry community posts
Replies: 3
Views: 53

Chemistry community posts

Hi, is there a way to separate and count posts made in 14A from 14B as to see how many you've done for each class rather than in total?
by Hannah_1G
Thu Mar 05, 2020 2:36 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: finding n in G=-nFE
Replies: 15
Views: 229

finding n in G=-nFE

How do you find n?
by Hannah_1G
Thu Mar 05, 2020 2:32 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs free energy and balancing redox reactions
Replies: 2
Views: 47

Gibbs free energy and balancing redox reactions

Should we check and balance each redox half reaction before trying to calculate gibbs free energy? For example 6L.1: 2 Ce4+ (aq) + 3 I- (aq) 2Ce3+ (aq) + I3- (aq), E cell ° = +1.08 V. Before calculating gibbs, would I need to balance the reaction?
by Hannah_1G
Thu Mar 05, 2020 2:19 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G and Delta G naught
Replies: 2
Views: 34

Delta G and Delta G naught

What is the difference between ? Why can +RTlnQ = [tex]\Delta G?
by Hannah_1G
Thu Mar 05, 2020 12:02 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 11.15
Replies: 12
Views: 1000

Re: 11.15

How do we know this reaction is at equilibrium? Shouldn't only Q be used?
by Hannah_1G
Tue Feb 11, 2020 10:24 pm
Forum: Phase Changes & Related Calculations
Topic: Heat required for sublimation
Replies: 2
Views: 116

Heat required for sublimation

When calculating the heat required for ice to change into water vapor, do the steps need to be broken down into ice to liquid and liquid to water vapor and taking the sum of that since the heat capacities are different at different phases?
by Hannah_1G
Tue Feb 11, 2020 9:30 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4D.15 Sum of enthalpy in equation is positive, but answer is negative
Replies: 1
Views: 25

4D.15 Sum of enthalpy in equation is positive, but answer is negative

Subtracting the enthalpy of formation of the product from the reactants generates a positive number, but the answer is negative. Can someone please explain why this is the case?
by Hannah_1G
Mon Feb 10, 2020 10:11 pm
Forum: Phase Changes & Related Calculations
Topic: 4C.7 vaporization enthalpy
Replies: 2
Views: 38

4C.7 vaporization enthalpy

How do you go about solving this? The moles of liquid methane are given and the heat required. The only equation I know for enthalpy of vaporization is Hvap= Hm(vapor) - Hm(liquid).
by Hannah_1G
Mon Feb 10, 2020 10:08 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4C.3 finding temperature of ideal gas
Replies: 1
Views: 21

Re: 4C.3 finding temperature of ideal gas

The book only has partial answer to the question, the temperature it gives is for constant volume not the pressure. I think I did it correctly.
by Hannah_1G
Mon Feb 10, 2020 9:49 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4C.3 finding temperature of ideal gas
Replies: 1
Views: 21

4C.3 finding temperature of ideal gas

I tried to solve the first part of this problem using Cp,m= 5/2 R and q= 765J and finding the change in temperature with q/(moles)(Cp,m) but I keep getting the final temperature as 343K when the book says 373 K.
by Hannah_1G
Mon Feb 10, 2020 8:24 pm
Forum: Calculating Work of Expansion
Topic: 4B.13 B finding moles
Replies: 1
Views: 21

4B.13 B finding moles

How do you find moles for the equation when temperature, pressure, and volume are given?
by Hannah_1G
Mon Feb 10, 2020 8:13 pm
Forum: Calculating Work of Expansion
Topic: Initial pressure of gas [ENDORSED]
Replies: 1
Views: 53

Initial pressure of gas [ENDORSED]

If the system has a given pressure and another pressure is acting on it doing work, do you ignore the systems initial pressure to solve for work? For reference, 4B.13 says calculate the work for a gas sample in a piston assembly with T=305 K, P=1.79 atm, and V=4.29 L: (a) irreversible expansion agai...
by Hannah_1G
Mon Feb 10, 2020 1:48 am
Forum: Polyprotic Acids & Bases
Topic: 6E.3 Ignoring second deprotonation
Replies: 1
Views: 149

6E.3 Ignoring second deprotonation

The question tells to calculate the pH of the diprotic acids and to ignore the second deprotonation if approximation is justified, how would you know to ignore or not?
by Hannah_1G
Sun Feb 09, 2020 7:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Finding concentration of H30 and OH from Kw
Replies: 2
Views: 59

Finding concentration of H30 and OH from Kw

Are Ka and Kb always equal when Kw is given? I don't know how else to solve for the concentration of H30+ and OH- when only the value of Kw was given. For reference, homework problem 6A.21
by Hannah_1G
Sun Feb 09, 2020 7:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: finding pH from concentration of H30+
Replies: 2
Views: 46

finding pH from concentration of H30+

If the log[H30+], without the negative sign, is already positive, is it wrong? For example, a concentration of 3.1 M results in a pH= -.49, using -log(3.1).
by Hannah_1G
Sun Feb 09, 2020 7:32 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Volume decrease
Replies: 7
Views: 100

Volume decrease

I thought the rule for volume decrease is that the side with less moles will be favored; however, in 5.39 the volume was halved and the reactant which has more moles in equation, I calculated it to have increased in concentration.
by Hannah_1G
Sun Feb 09, 2020 7:30 pm
Forum: Ideal Gases
Topic: Partial pressure plot
Replies: 1
Views: 105

Partial pressure plot

In 5.35 theres a partial pressure/ Kpa vs time graph and you have to figure out how to balance the equation as well as calculate K from it. How are we supposed to read this?
by Hannah_1G
Sun Feb 09, 2020 7:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Halogen equilibrium reaction
Replies: 1
Views: 31

Halogen equilibrium reaction

How is X2(g) 2X(g), where X is a halogen, affected by temperature? Does it favor reactant or product?
by Hannah_1G
Sun Feb 09, 2020 7:23 pm
Forum: Ideal Gases
Topic: Change in pressure
Replies: 7
Views: 133

Change in pressure

What is the rule for increasing or decreasing pressure and its affect on shifting the reaction?
by Hannah_1G
Sun Feb 09, 2020 7:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Change in concentration
Replies: 2
Views: 28

Change in concentration

Does increasing or decreasing the concentration of a product affect the concentration of another product? For example, for the reaction 4NH3(g) + 5O2(g) 4NO(g) + 6H20(g), does increasing the concentration of NO affect the concentration of H20?
by Hannah_1G
Sun Feb 09, 2020 7:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pressure change
Replies: 3
Views: 49

Pressure change

How does pressure increasing or decreasing change the concentration of products or reactants in equilibrium? Does a change in pressure for a reactant affect another reactant in the reaction?
by Hannah_1G
Sun Feb 09, 2020 7:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Hw 5I.23
Replies: 1
Views: 32

Hw 5I.23

Not sure what I am doing wrong, but in solving the concentrations using an ice table I am getting a larger change in concentration than what was initially there.
by Hannah_1G
Tue Feb 04, 2020 7:54 pm
Forum: Calculating Work of Expansion
Topic: Reversible and irreversible process
Replies: 2
Views: 46

Reversible and irreversible process

Can someone explain what this means in terms of expansion? How can work be irreversible?
by Hannah_1G
Wed Jan 29, 2020 11:11 pm
Forum: Calculating Work of Expansion
Topic: 4A.3
Replies: 2
Views: 26

4A.3

I cannot get the correct answer. I am using the area of a cylinder with .15 m as radius and .2 m as height times the height to get the volume times 2 atm as the pressure.
by Hannah_1G
Wed Jan 29, 2020 11:06 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 4a.9
Replies: 3
Views: 38

4a.9

What formula is used to calculate the change in temperature from copper at 100 degrees C placed in water at 22 degrees C? I don't know how to begin this problem
by Hannah_1G
Wed Jan 22, 2020 9:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Hw I.15 ICE table
Replies: 1
Views: 26

Hw I.15 ICE table

How do you calculate the change in concentration when only the products are used in the reaction and the equilibrium concentration is given? Initial concentration of .2 M of NH3 with H2S and K= 1.6 x 10-4
by Hannah_1G
Wed Jan 22, 2020 6:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 5H.1
Replies: 1
Views: 19

Homework 5H.1

How does K= 41 go to K= 1.7 x103 when the reaction has twice as many moles in reactants and products? For reference the original reaction is N2 + 3H2 = 2NH3 and K= 41 and the reaction is changed to 2N2 + 6H2 = 4NH3.
by Hannah_1G
Tue Jan 14, 2020 5:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: equilibrium concentration with gases
Replies: 7
Views: 71

equilibrium concentration with gases

If the reaction is homogeneous with gas phase but the question is in terms of concentration and gives the moles of the reactants and products, is pressure ignored?
by Hannah_1G
Sat Dec 07, 2019 9:03 pm
Forum: Lewis Acids & Bases
Topic: Lewis structure of acids and bases
Replies: 2
Views: 104

Re: Lewis structure of acids and bases

The filling of the octets is the most important aspect - double and triple bonds come in later. Double bonds should be used when both the central and attached atom has an extra lone pair each, and if the formal charge conditions are most favorable. I am not sure what you are talking about regarding...
by Hannah_1G
Sat Dec 07, 2019 8:42 pm
Forum: Lewis Acids & Bases
Topic: Lewis structure of acids and bases
Replies: 2
Views: 104

Lewis structure of acids and bases

When figuring out the lewis structure of an acid or base, should you stay away from double or triple bonds even if it stabilizes the molecule? Do the bonds make it have less acid/base characteristic. In all of the examples I've seen of finding if a molecule is an acid or base from the lewis structur...
by Hannah_1G
Sat Dec 07, 2019 8:27 pm
Forum: Lewis Acids & Bases
Topic: SO3 molecule as lewis acid
Replies: 1
Views: 86

SO3 molecule as lewis acid

The book draws SO3 (hw 6.5) with one double bond and two single bonds, but it is more unstable than SO3 having three double bonds. Does it have to do with SO3 acting as an acid or base?
by Hannah_1G
Sat Dec 07, 2019 5:01 pm
Forum: Conjugate Acids & Bases
Topic: Reaction arrows
Replies: 3
Views: 104

Reaction arrows

Do we need a reverse arrow in all acid and base chemical equations?
by Hannah_1G
Sat Dec 07, 2019 4:07 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: CO3 2-
Replies: 1
Views: 33

CO3 2-

CO3 with a -2 charge is either a mono or bidentate ligand, according to the book. Is it possibly monodentate because the molecule is small?
by Hannah_1G
Sat Dec 07, 2019 3:56 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand polydentate
Replies: 4
Views: 132

Ligand polydentate

How do you figure out how many sites a ligand can bind to on a metal?
by Hannah_1G
Sat Dec 07, 2019 2:31 pm
Forum: Dipole Moments
Topic: Lone pairs
Replies: 5
Views: 144

Re: Lone pairs

If the lone pairs are on opposite sides then they cancel out. An example of this would be XeF4 since it is square planar and all the dipole movements from the Fs and electron pairs are negated. So you need to know the molecular shape before figuring out if the lone pairs align to create a dipole mo...
by Hannah_1G
Sat Dec 07, 2019 2:29 pm
Forum: Conjugate Acids & Bases
Topic: Strength
Replies: 2
Views: 106

Strength

Will a strong acid have a strong conjugate base and the same for the opposite?
by Hannah_1G
Fri Dec 06, 2019 10:19 pm
Forum: Bronsted Acids & Bases
Topic: Strong vs. Weak
Replies: 2
Views: 59

Strong vs. Weak

If the product of an acidic reaction still has hydrogens in its molecule is it commonly a weak acid? Like acetic acid, CH3COOH after dissolving in water its left as CH3CO2-, whereas HCl is left as Cl-.
by Hannah_1G
Fri Dec 06, 2019 8:41 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: what is a ligand?
Replies: 7
Views: 84

Re: what is a ligand?

In lecture, I'm pretty sure Lavelle said that CO was a ligand and I'm confused as to how that is so.
by Hannah_1G
Fri Dec 06, 2019 12:10 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: what is a ligand?
Replies: 7
Views: 84

what is a ligand?

Can someone explain what a ligand is and what it does?
by Hannah_1G
Fri Dec 06, 2019 12:08 am
Forum: Resonance Structures
Topic: localization
Replies: 1
Views: 103

localization

are all resonance structures delocalized electrons?
by Hannah_1G
Fri Dec 06, 2019 12:08 am
Forum: Bond Lengths & Energies
Topic: single bonds and s bonds [ENDORSED]
Replies: 1
Views: 130

single bonds and s bonds [ENDORSED]

How do you total in the strength in a bond when factoring how many bonds and the s- orbital characteristic of it? If I'm not mistaken having a hybridized orbital sp is stronger than sp2 but is a double bond stronger than a single bond of 2p-2p?
by Hannah_1G
Fri Dec 06, 2019 12:05 am
Forum: Dipole Moments
Topic: Lone pairs
Replies: 5
Views: 144

Lone pairs

How do you figure out if lone pairs align to create a dipole moment?
by Hannah_1G
Fri Dec 06, 2019 12:03 am
Forum: Determining Molecular Shape (VSEPR)
Topic: lone pairs
Replies: 2
Views: 51

lone pairs

How would you determine where the lone pairs on a central atom would be in a molecular shape? How would you know if they align to create a dipole moment or cancel eachother out?
by Hannah_1G
Thu Dec 05, 2019 11:59 pm
Forum: Hybridization
Topic: Determining Hybridization
Replies: 4
Views: 45

Re: Determining Hybridization

If the electrons are localized, then it's how many electron density regions it has. So like CH4, the carbon has 4 electron density regions, so it has sp3.
by Hannah_1G
Thu Dec 05, 2019 11:57 pm
Forum: Hybridization
Topic: Hybridization & Sigma and Pi Bonds
Replies: 4
Views: 59

Re: Hybridization & Sigma and Pi Bonds

Unhybridized orbitals are used to make pi bonds
by Hannah_1G
Thu Dec 05, 2019 11:56 pm
Forum: Hybridization
Topic: resonance structures
Replies: 1
Views: 49

resonance structures

Is it correct that resonance structures have unhybridized orbitals since the electrons are delocalized?
by Hannah_1G
Thu Dec 05, 2019 11:54 pm
Forum: Hybridization
Topic: s orbital [ENDORSED]
Replies: 1
Views: 107

s orbital [ENDORSED]

why is having a sp hybridization stronger than sp2?
by Hannah_1G
Thu Dec 05, 2019 11:53 pm
Forum: Hybridization
Topic: unhybridized orbitals
Replies: 1
Views: 27

unhybridized orbitals

Is it possible for a sigma bond to be unhybridized?
by Hannah_1G
Thu Dec 05, 2019 11:16 pm
Forum: Hybridization
Topic: Simple explanation
Replies: 1
Views: 42

Simple explanation

Can someone simply explain hybridization for me? Can't understand what it means and the 4 different hybrid orbitals.
by Hannah_1G
Wed Dec 04, 2019 9:58 pm
Forum: Lewis Acids & Bases
Topic: Ionic and compounds
Replies: 1
Views: 579

Ionic and compounds

How do you know when an acid and base reaction forms ions or compounds of eachother? Like Ca(OH)2 + 2HCN forms Ca(CN)2 + 2H2O but 2Na + 2OH- + H2S forms 2H2O + 2NA+ + S2-
by Hannah_1G
Wed Nov 20, 2019 11:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Name confusion
Replies: 4
Views: 55

Name confusion

How do you know when the shape is being asked for, for instance, seesaw or its asking for tetrahedral? What are the differences between those two different categories of naming the molecule shape? Sorry if this isn't clear, I just don't know if I should be predicting the molecule as t-shaped or trig...
by Hannah_1G
Wed Nov 20, 2019 10:53 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: Dipole-Dipole and induced dipole
Replies: 4
Views: 52

Re: Dipole-Dipole and induced dipole

You should look at the OVERALL characteristic. This molecule is polar overall because of the electronegativity difference between the C and Cl. Assuming that this molecule is interacting with only itself, dipole induced-dipole is not possible because it requires a non polar molecule which ClCH3 is ...
by Hannah_1G
Wed Nov 20, 2019 10:46 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: Strengths of forces
Replies: 4
Views: 56

Re: Strengths of forces

If you are referring to diethyl ether to having dipole-dipole intermolecular forces and water to have hydrogen bonding, then water (hydrogen bonding) would have a stronger intermolecular force because hydrogen bonds are stronger than dipole-dipole bonds. Thank you this is what I was asking! Do you ...
by Hannah_1G
Wed Nov 20, 2019 10:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: tetrahedral vs. trigonal pyramidal
Replies: 4
Views: 42

tetrahedral vs. trigonal pyramidal

Are tetrahedral and trigonal pyramidal the same?
by Hannah_1G
Wed Nov 20, 2019 10:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 6
Views: 76

Bond Angles

Lone pairs on central atom cause the expected bond angles to be slightly less?
by Hannah_1G
Wed Nov 20, 2019 10:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs
Replies: 13
Views: 155

Lone pairs

Do lone pairs not on the center atom account for shape? For example HCN
by Hannah_1G
Wed Nov 20, 2019 9:47 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: Strengths of forces
Replies: 4
Views: 56

Strengths of forces

Would hydrogen bonding (in water) be stronger than one dipole moment (diethyl ether)?
by Hannah_1G
Wed Nov 20, 2019 9:30 pm
Forum: Dipole Moments
Topic: Melting points
Replies: 15
Views: 393

Melting points

Would a double bond create a higher melting point than a dipole moment?
by Hannah_1G
Wed Nov 20, 2019 9:10 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: 3F.5
Replies: 4
Views: 65

3F.5

How does butanol have a higher melting point than diethyl ether when they have the same atoms?
by Hannah_1G
Wed Nov 20, 2019 8:43 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: 2
Views: 57

Hydrogen Bonding

Are possible hydrogen bonding sites on every H and O,N,F electron lone pairs in a molecule? And the amount of lone pairs also tells how many hydrogen bonds could happen on an atom in a molecule?
by Hannah_1G
Tue Nov 19, 2019 8:02 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: Dipole-Dipole and induced dipole
Replies: 4
Views: 52

Dipole-Dipole and induced dipole

How do you separate the two different forces? How does ClCH3 have dipole-dipole interactions rather than dipole-induced dipole?
by Hannah_1G
Tue Nov 19, 2019 7:52 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: 3
Views: 49

Hydrogen bonding

Is hydrogen bonding only possible in a molecule with hydrogen already in it? Is it impossible for that type of interaction to occur on molecules containing O,N, or F with lone pairs that aren't already bonding to hydrogen?
by Hannah_1G
Tue Nov 05, 2019 6:50 pm
Forum: Administrative Questions and Class Announcements
Topic: DINO NUGGETS Review Session! Download Problems HERE [ENDORSED]
Replies: 52
Views: 4958

Re: DINO NUGGETS Review Session! Download Problems HERE [ENDORSED]

In the answer key for the mini dino nuggets, the dipole moments in question 2a are going towards the negative partial charge when in the textbook it says to go towards the positive charge. What would be correct?
by Hannah_1G
Sun Nov 03, 2019 6:40 pm
Forum: Photoelectric Effect
Topic: Photons emitted in a time interval
Replies: 2
Views: 50

Re: Photons emitted in a time interval

I forgot to times it by Avogadro's constant to find amount of photons. But this number should be multiplied by two?
by Hannah_1G
Sun Nov 03, 2019 6:38 pm
Forum: Photoelectric Effect
Topic: Photons emitted in a time interval
Replies: 2
Views: 50

Photons emitted in a time interval

For reference, I am doing 1B.9, which gives the wavelength of the light and watts of the light and I am stumped on how many photons are being emitted in 2 seconds. I used E=hv to find the energy of a singular photon and then I divided that by the watts which gave me the answer in the back of the boo...
by Hannah_1G
Sun Nov 03, 2019 6:13 pm
Forum: Photoelectric Effect
Topic: Energy per Photon
Replies: 4
Views: 90

Re: Energy per Photon

If the question is asking this but in a 2 second interval would you do the same but times it by 2?
by Hannah_1G
Sun Nov 03, 2019 5:42 pm
Forum: Photoelectric Effect
Topic: Energy of electron
Replies: 2
Views: 53

Energy of electron

1B.7 is asking for the energy emitted by a sodium atom when it generates a photon and for the energy of 5.00 mg of sodium emitting light. Do I think of the excited sodium atom as a photon in this problem? As in the formula E=hv applies to this question, not the kinetic energy of an electron. Then, I...
by Hannah_1G
Sun Nov 03, 2019 5:17 pm
Forum: Photoelectric Effect
Topic: Work function of an atom
Replies: 4
Views: 63

Re: Work function of an atom

Brittney Hun 1K wrote:So I used two different equations to derive the energy because it's not asking for the energy of an electron, which is what the kinetic energy formula finds. I used E=hv, but found v first using v=c/lamda for part a.
What is the question asking for?
by Hannah_1G
Sun Nov 03, 2019 5:16 pm
Forum: Photoelectric Effect
Topic: Work function of an atom
Replies: 4
Views: 63

Re: Work function of an atom

Never mind I know that doesn't work because the v in that formula is for the speed of the electron. Is the work function of the atom supposed to be given to find this if only wavelength of light is provided? I should be using (hc)/ - = Ek
by Hannah_1G
Sun Nov 03, 2019 5:02 pm
Forum: Photoelectric Effect
Topic: Work function of an atom
Replies: 4
Views: 63

Work function of an atom

If a problem (1B.7) is asking for the energy emitted by an atom when it generates a photon and the wavelength of the photon ejected is given, would I use the Ek= 1/2 me x v2 formula?
by Hannah_1G
Sat Nov 02, 2019 9:31 pm
Forum: Empirical & Molecular Formulas
Topic: Formula Units
Replies: 2
Views: 152

Formula Units

What is being asked by finding the formula units and number of molecules from moles of a molecule? For reference Fundamentals E.21 asks to calculate the amount of moles, amount of molecules and formula units from 10 g of Al2O3.
by Hannah_1G
Sat Nov 02, 2019 8:45 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Atoms to Moles
Replies: 7
Views: 240

Atoms to Moles

Is it correct to divide the amount of atoms in a sample by the molar constant to find the amount of moles?
by Hannah_1G
Tue Oct 29, 2019 2:59 pm
Forum: Ionic & Covalent Bonds
Topic: Homework 2A.9
Replies: 2
Views: 46

Re: Homework 2A.9

Thank you! So this question is asking for what possible ions follow those configurations and have a 2+ charge?
by Hannah_1G
Mon Oct 28, 2019 7:28 pm
Forum: Ionic & Covalent Bonds
Topic: Homework 2A.9
Replies: 2
Views: 46

Homework 2A.9

The question asks which M2+ ions are expected to have the following ground-state electron configurations: a) [Ar]3d7 b) [Ar]3d6
I'm confused by what the question is asking and how the electron configuration can change for this ion?
by Hannah_1G
Mon Oct 21, 2019 10:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 4 homework problems
Replies: 5
Views: 64

Re: Week 4 homework problems

205296774 wrote:Our homework and units aren't broken up by week. The quantum unit is multiple weeks long so the page with the key concepts and hw problems apply to this week, too.

Hope this helps!

Did Lavelle say that we can use chemical bond problems for this weeks homework?
by Hannah_1G
Mon Oct 21, 2019 10:11 pm
Forum: Lewis Structures
Topic: Octet
Replies: 2
Views: 690

Re: Octet

The octet rule is violated in compounds with more than eight electrons assigned to their valence shell. These are called expanded valence shell molecules. Such compounds are formed only by central atoms in the third row of the periodic table and beyond that have empty d orbitals in their valence sh...
by Hannah_1G
Mon Oct 21, 2019 10:09 pm
Forum: Lewis Structures
Topic: Homework 2B.3 d
Replies: 2
Views: 45

Homework 2B.3 d

How do you figure out the lewis structure of BrF3 when they share 24 valence electrons?
by Hannah_1G
Mon Oct 21, 2019 9:54 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground state electron configuration of ions
Replies: 4
Views: 52

Ground state electron configuration of ions

In the homework it asks for the ground state electron configuration of ions, does ground state mean that the ions need to be changed to a neutral atom?
by Hannah_1G
Wed Oct 09, 2019 9:23 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G
Replies: 4
Views: 269

Fundamentals G

In the second part of G.17 it asks for the mass of CuSO4 5H20 that must be used to prepare 250 mL of .2 M CuSO4(aq). I am very confused by what to do with the water molecule in this problem, I don't know how to start solving this.
by Hannah_1G
Wed Oct 09, 2019 9:14 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G13
Replies: 6
Views: 1496

Re: Fundamentals G13

I am having trouble with this concept as well, the amount of individual moles in a molecule has the same ratio as moles of the molecule? So 2 nitrogen moles are always in 1 mole of NH4NO3?
by Hannah_1G
Wed Oct 09, 2019 7:38 pm
Forum: Molarity, Solutions, Dilutions
Topic: Mole ratios/ G.5 hw
Replies: 2
Views: 183

Mole ratios/ G.5 hw

In homework problem G.5 the question says there is 2.111 g of sodium carbonate (Na 2 CO 3 ) and you have to find the molarity in a solution, is it possible to find the mole ratio of the molecule and apply it to the elements? The molar mass of sodium carbonate is 105.81 gmol -1 , so in a sample of 2....
by Hannah_1G
Wed Oct 02, 2019 9:45 pm
Forum: SI Units, Unit Conversions
Topic: Sig figs
Replies: 18
Views: 323

Re: Sig figs

No, the number of sig figs can vary because it is based on the least amount of sig figs present in the problem. However, any conversion factors do not count when determining the number of sig figs. Thank you this helped a lot. I was looking for the homework question to mention how many sig figs to ...
by Hannah_1G
Wed Oct 02, 2019 9:40 pm
Forum: Limiting Reactant Calculations
Topic: L1 homework
Replies: 2
Views: 31

L1 homework

The question asks how much can Br2 can be produced from .30 moles of ClO2 when the balanced reaction is given. Is it simple enough to assume that 6 moles of ClO2 produces one mole of Br2 so .30/6 would be the amount of Br2 in moles produced?
by Hannah_1G
Wed Oct 02, 2019 8:20 pm
Forum: SI Units, Unit Conversions
Topic: Sig figs
Replies: 18
Views: 323

Re: Sig figs

If the question doesn't mention sig figs, should I not worry about the precision of the answer then?
by Hannah_1G
Wed Oct 02, 2019 7:58 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E.7 calculate atoms in moles
Replies: 4
Views: 75

E.7 calculate atoms in moles

The question gives how many carbon atoms are in a molecule of DNA and to calculate in moles how many atoms of carbon there are. Is this asking to divide the number of atoms by moles to be in terms of mole or to multiple the amount of carbon by Avogadro's constant to find the true amount of atoms? So...
by Hannah_1G
Wed Oct 02, 2019 7:47 pm
Forum: SI Units, Unit Conversions
Topic: Sig figs
Replies: 18
Views: 323

Sig figs

For the homework are we supposed to be using a set significant figure number?

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