## Search found 37 matches

- Mon Mar 09, 2015 11:23 am
- Forum: Administrative Questions and Class Announcements
- Topic: QUIZ 1 Solutions
- Replies:
**1** - Views:
**722**

### QUIZ 1 Solutions

Hi- I wanted to review quiz 1 for the final. I am wondering if anyone has the correct solutions to each problem on quiz 1? perhaps someone who got an excellent score would be able to share pictures of their work or a TA has the correct solutions. It would be greatly appreciated. Thank you so much- s...

- Mon Mar 02, 2015 10:16 pm
- Forum: *Nucleophiles
- Topic: determining polarizability!
- Replies:
**2** - Views:
**571**

### determining polarizability!

in Introduction to Organic Chemistry, question 4.1 A self test asks which is more nucleophilic, CI- or I-. I understand the correlation between polarizability and nucleophillic-ness, but I thought a molecule was more polarizable the larger it was? but here I- is smaller and more polarizable! Thank y...

- Wed Feb 11, 2015 12:11 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: CATHODE VS ANODE HALF REACTION HELP!!!!!
- Replies:
**10** - Views:
**1483**

### Re: CATHODE VS ANODE HALF REACTION HELP!!!!!

SO just to clarify.....H+ is always on top when finding kA?

- Wed Feb 11, 2015 10:47 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: CATHODE VS ANODE HALF REACTION HELP!!!!!
- Replies:
**10** - Views:
**1483**

### Re: CATHODE VS ANODE HALF REACTION HELP!!!!!

but you admit gases too?? i thought we could use gases

- Wed Feb 11, 2015 10:45 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: CATHODE VS ANODE HALF REACTION HELP!!!!!
- Replies:
**10** - Views:
**1483**

### Re: CATHODE VS ANODE HALF REACTION HELP!!!!!

also, how come you want HF in the top anyway? why was the equation HF---> H+ + F- written and not H++ F- ---> HF written?

- Wed Feb 11, 2015 10:43 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: CATHODE VS ANODE HALF REACTION HELP!!!!!
- Replies:
**10** - Views:
**1483**

### Re: CATHODE VS ANODE HALF REACTION HELP!!!!!

so we don't follow the "flip the smaller one" rule when finding ka? and does ka only mean aqueous stuff?

- Wed Feb 11, 2015 10:32 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: CATHODE VS ANODE HALF REACTION HELP!!!!!
- Replies:
**10** - Views:
**1483**

### CATHODE VS ANODE HALF REACTION HELP!!!!!

Hi so I have a problem where there are two positive cell potentials and the larger cell potential is actually subtracted from the smaller one creating a negative cell potential. I thought we could either decide which one was the cathode/anode by the oxidation numbers or by flippping the smaller half...

- Wed Feb 11, 2015 10:22 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Determining cathode and anode from two half-reactions...
- Replies:
**3** - Views:
**4882**

### Re: Determining cathode and anode from two half-reactions...

That is helpful. However, I have a problem where there are two positive cell potentials and the larger cell potential is actually subtracted from the smaller one creating a negative cell potential. this kind of contradicts what was said above and I'm really confused why. So this is question 8 in the...

- Tue Feb 10, 2015 5:35 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: What does thermally insulated mean?
- Replies:
**1** - Views:
**1766**

### What does thermally insulated mean?

Hi-

Kind of a general question but in terms of solving problems for thermo, what does it mean to say something is thermally insulated? does that imply isothermal?

Kind of a general question but in terms of solving problems for thermo, what does it mean to say something is thermally insulated? does that imply isothermal?

- Sun Feb 08, 2015 3:44 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: standard cell potentials
- Replies:
**1** - Views:
**220**

### standard cell potentials

on the midterm, how will the standard cell potentials of a half reaction be given to us?

Will it say the whole reaction and then the number of V for that, or will it be for each half reaction?

Will it say the whole reaction and then the number of V for that, or will it be for each half reaction?

- Sun Feb 08, 2015 3:01 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: HW prob 13.11d:Writing the half reactions for galvanic cells
- Replies:
**7** - Views:
**1106**

### Re: HW prob 13.11d:Writing the half reactions for galvanic c

Thank you that is so helpful :) I forgot about that last step!

- Sun Feb 08, 2015 10:00 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: HW prob 13.11d:Writing the half reactions for galvanic cells
- Replies:
**7** - Views:
**1106**

### Re: HW prob 13.11d:Writing the half reactions for galvanic c

In the standard reduction reaction in the acidic solution, how did you get the H+ onto the reactants side with the O2???

- Thu Jan 29, 2015 8:27 am
- Forum: Calculating Work of Expansion
- Topic: isothermal reversible expansion with V and P change
- Replies:
**8** - Views:
**1422**

### Re: isothermal reversible expansion with V and P change

the question reads:

if 2.00 mol of an ideal gas at 300 K and 3.00 atm expands isothermally and reversibly from 6.00 L to 18.00 L and has a final pressure of 1.20 atm, what is w, q, and delta u?

if 2.00 mol of an ideal gas at 300 K and 3.00 atm expands isothermally and reversibly from 6.00 L to 18.00 L and has a final pressure of 1.20 atm, what is w, q, and delta u?

- Wed Jan 28, 2015 11:46 am
- Forum: Calculating Work of Expansion
- Topic: isothermal reversible expansion with V and P change
- Replies:
**8** - Views:
**1422**

### Re: isothermal reversible expansion with V and P change

I understand this, but for number 3 on the workbook quiz that we turn in, the initial pressure is 3.00atm and the final pressure is 1.2atm. the initial volume is 6L and the final volume is 18L. when i plug in the numbers though, -nrTln (v2/v1) does not equal -nrTln (p1/p2) n= 2 mol and T= 300K it ex...

- Tue Jan 27, 2015 11:09 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: When not all bond enthalpies are given
- Replies:
**1** - Views:
**557**

### When not all bond enthalpies are given

Hi- this question is concerning the winter 2014 midterm question 1 & 2 C. So it asks for the enthalpy change for the reaction using the molar bond enthalpies given above. so the equation is CH3OH (g) + NH3 (g) -----> CH3NH2 (g) + H20 (g) but it only gives us the bond enthalpies for C-N, C-O, N-H...

- Tue Jan 27, 2015 12:33 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: what equation to use for q
- Replies:
**2** - Views:
**2283**

### what equation to use for q

how do we know when to use

q=nc delta t

or

q= mc delta t

basically when do we have to use moles or grams and is there a way to easily distinguish between the two?!

thank you SO much for your help its greatly appreciated

q=nc delta t

or

q= mc delta t

basically when do we have to use moles or grams and is there a way to easily distinguish between the two?!

thank you SO much for your help its greatly appreciated

- Thu Jan 08, 2015 4:33 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: energy change due to work
- Replies:
**1** - Views:
**454**

### energy change due to work

in hw question 7.9, the q is given as 5500 kj. the change in internal energy ends up being 5500kj as well, so therefore we can assume that the energy change due to work is negligible. But I am just wondering if we would need to write 0 for this on an exam, or just say that its negligible? thanks for...

- Sat Dec 13, 2014 12:01 am
- Forum: DeBroglie Equation
- Topic: De brogile wavelength of one photoelectron
- Replies:
**1** - Views:
**440**

### De brogile wavelength of one photoelectron

The question asks:

Find the de brogile wavelength of one photoelectron?

Find the de brogile wavelength of one photoelectron?

- Fri Dec 12, 2014 2:43 am
- Forum: Polyprotic Acids & Bases
- Topic: Will we be given the formula equations for polyprotic acids
- Replies:
**1** - Views:
**466**

### Will we be given the formula equations for polyprotic acids

In the Fall 2012 exam question #8: an approximation to finding the pH of a solution containing a polyprotic acid is to treat each step independently and add the [H+] generated at each step. using this approxomation find the pH of a .0037 M solution of H2CO3 using H2co3---> H+ + HCO3- ka=4.3x10^-7 Hc...

- Thu Dec 11, 2014 11:42 pm
- Forum: *Titrations & Titration Calculations
- Topic: Henderson-Hasselbalch Equation
- Replies:
**2** - Views:
**544**

### Re: Henderson-Hasselbalch Equation

well from what I know, you derive the equation to find that the pH =pKa at stoichiometric point. and then we know that the pka=-log[KA] so it makes calculating the pH at stoichiometric point relatively simple because we just take the -log[KA] and since KA is given, its easy!

- Thu Dec 11, 2014 10:34 pm
- Forum: *Titrations & Titration Calculations
- Topic: initial point titrations
- Replies:
**2** - Views:
**472**

### Re: initial point titrations

wow thank you shelby. you are so helpful. sincerely, shelby

ps- i like your name

ps- i like your name

- Thu Dec 11, 2014 9:11 pm
- Forum: *Titrations & Titration Calculations
- Topic: initial point titrations
- Replies:
**2** - Views:
**472**

### initial point titrations

suppose that 25.0 mL of 0.10M cH3cooh (aq) is titrated with .10M NaOH (aq). Assume that the base dissociation constant for CH3C00- is 5.6 x 10 ^ -10.

what type of titration is this?

what is the initial PH of the CH3COOH solution? find the percent dissociation of the CH3COOH. kb= 5.6 x 10^10?

what type of titration is this?

what is the initial PH of the CH3COOH solution? find the percent dissociation of the CH3COOH. kb= 5.6 x 10^10?

- Tue Dec 02, 2014 11:06 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Quiz 3 Preparation Fall 2013 Quiz: #10
- Replies:
**9** - Views:
**1429**

### Re: Quiz 3 Preparation Fall 2013 Quiz: #10

I am stuck on the same problem too. But what equation do we use to find the new equilibrium and how do we calculate the new partial pressure by knowing that the amount of BrCL was halved??

- Tue Nov 25, 2014 12:25 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: HW 10.35
- Replies:
**1** - Views:
**446**

### HW 10.35

Determine K, for each of the following equilibria from the value of K:

a) 2NOCL(g) -----> 2NO (g) + Cl2(g), K= 1.8 x 10^-2 at 500k.

the solution manual shows K = (t/12.027 K) ^deltaN * Kc.

I am wondering where the 12.027 came from and also what t means?

thanks for your help!

a) 2NOCL(g) -----> 2NO (g) + Cl2(g), K= 1.8 x 10^-2 at 500k.

the solution manual shows K = (t/12.027 K) ^deltaN * Kc.

I am wondering where the 12.027 came from and also what t means?

thanks for your help!

- Tue Nov 25, 2014 12:25 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: HW 10.35
- Replies:
**1** - Views:
**372**

### HW 10.35

Determine K, for each of the following equilibria from the value of K:

a) 2NOCL(g) -----> 2NO (g) + Cl2(g), K= 1.8 x 10^-2 at 500k.

the solution manual shows K = (t/12.027 K) ^deltaN * Kc.

I am wondering where the 12.027 came from and also what t means?

thanks for your help!

a) 2NOCL(g) -----> 2NO (g) + Cl2(g), K= 1.8 x 10^-2 at 500k.

the solution manual shows K = (t/12.027 K) ^deltaN * Kc.

I am wondering where the 12.027 came from and also what t means?

thanks for your help!

- Tue Nov 25, 2014 12:07 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: HW 10.35b
- Replies:
**1** - Views:
**401**

### HW 10.35b

Determine K, for each of the following equilibria from the value of K:

a) CaCO3(S) -----> CaO(S) + CO2(g), K= 167 at 1073 K

the answer is just K=pCO2= 167.

is this just because they're solids? so we can just assume that k equals pco2?

a) CaCO3(S) -----> CaO(S) + CO2(g), K= 167 at 1073 K

the answer is just K=pCO2= 167.

is this just because they're solids? so we can just assume that k equals pco2?

- Wed Nov 19, 2014 1:27 pm
- Forum: Naming
- Topic: order of naming
- Replies:
**1** - Views:
**360**

### order of naming

How come the element not in the brackets can either go before or after the brackets?

example:

sodium bisoxalatodiaquaferrate (III)

vs

pentaaminesulfatocobalt (III) chloride

is it because sodium has a positive charge and chloride has a negative charge??

example:

sodium bisoxalatodiaquaferrate (III)

vs

pentaaminesulfatocobalt (III) chloride

is it because sodium has a positive charge and chloride has a negative charge??

- Wed Nov 19, 2014 1:25 pm
- Forum: Naming
- Topic: order of naming
- Replies:
**1** - Views:
**377**

### order of naming

How come the element not in the brackets can either go before or after the brackets?

example:

sodium bisoxalatodiaquaferrate (III)

vs

pentaaminesulfatocobalt (III) chloride

is it because sodium has a positive charge and chloride has a negative charge??

example:

sodium bisoxalatodiaquaferrate (III)

vs

pentaaminesulfatocobalt (III) chloride

is it because sodium has a positive charge and chloride has a negative charge??

- Mon Nov 03, 2014 11:58 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic radius
- Replies:
**2** - Views:
**405**

### Ionic radius

The solution manual answers include the ionic radii, does anyone know if we need to know these will be given to us? and if so, do they need to be included when ranking elements in order of polarizing power?

- Mon Nov 03, 2014 11:30 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2.75
- Replies:
**1** - Views:
**339**

### Re: 2.75

okay i see the table on page 86 now, so now the question is do we get this table on the quiz or no?

- Mon Nov 03, 2014 11:28 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2.75
- Replies:
**1** - Views:
**339**

### 2.75

this problem asks us to determine which compound has bonds with greater ionic character.

first, a is HCl or HI.

So, how do we determine ionic character?

first, a is HCl or HI.

So, how do we determine ionic character?

- Mon Nov 03, 2014 11:26 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2.75
- Replies:
**1** - Views:
**380**

### 2.75

this problem asks us to determine which compound has bonds with greater ionic character.

first, a is HCl or HI.

So, how do we determine ionic character?

first, a is HCl or HI.

So, how do we determine ionic character?

- Mon Nov 03, 2014 11:17 pm
- Forum: Electronegativity
- Topic: problem 2.71
- Replies:
**1** - Views:
**422**

### problem 2.71

This problem asks us to put the elements of increasing electronegativity: antimony, tin, selenium, indium i get that the order goes in, sn, sb, se since electronegativity increases up and to the right, but the solutions manual gives us the rough estimates of electronegativity. I was just wondering i...

- Mon Nov 03, 2014 10:23 pm
- Forum: Resonance Structures
- Topic: 2.57
- Replies:
**1** - Views:
**339**

### 2.57

problem 2.57 asks to draw the lewis structures of these reactive species. ClO is a radical because it has 13 electrons. the solution manual shows a single bond between cl and o and then 5 more electrons around cl and 6 around. I am confused why there isnt a double bond between the 2 and also why cl ...

- Mon Nov 03, 2014 5:19 pm
- Forum: Lewis Structures
- Topic: Expanded octet question
- Replies:
**1** - Views:
**440**

### Expanded octet question

I was working problem 2.55 in the textbook, sulfite had 1 structure with the octet rule and 3 that used the expanded octet rule. I understand that elements in the 3rd period and down can be expanded but i am confused as to how we know when to expand them or not? and how do I know that sulfer only st...

- Thu Oct 30, 2014 5:45 pm
- Forum: Lewis Structures
- Topic: On Hybridization
- Replies:
**1** - Views:
**386**

### On Hybridization

Quiz 2 preperation fall 2012 in workbook what is the hybridization of the central atom in OF2? After drawing the lewis structure I understand that the central atom has 4 total bonds. The answer is sp3. Can someone explain to me why it is sp3? Do certain number of bonds around the central atom correl...

- Mon Oct 27, 2014 9:10 pm
- Forum: Ionic & Covalent Bonds
- Topic: Most likely charge for ions
- Replies:
**4** - Views:
**9800**

### Re: Most likely charge for ions

should we memorize the most likely charges or can we tell by the periodic table?