## Search found 20 matches

Tue Mar 08, 2016 2:45 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2013 Final Question 4A + B Clarifications
Replies: 2
Views: 425

### Re: 2013 Final Question 4A + B Clarifications

Why in part b do you subtract the initial value of O2 instead of adding it?
Sun Feb 28, 2016 3:46 pm
Forum: *Cycloalkanes
Topic: Exercise 1.16 Numbering Carbons in Parent Chain
Replies: 6
Views: 935

### Re: Exercise 1.16 Numbering Carbons in Parent Chain

Would it be wrong to name this 1,1-dimethyl-2-propylcyclopentane? Does there need to be the iso- in front of the propyl or is it sufficient enough to just say propyl since there are 3 carbons on that substituent.
Wed Feb 24, 2016 11:14 pm
Forum: *Alkanes
Topic: Naming Substituents and Carbon Pair
Replies: 1
Views: 268

### Re: Naming Substituents and Carbon Pair

When figuring out which number carbon a substituent is bonded to, you always count so that it will be the lowest number carbon. If there are more than one substituents, the same rule still applies. If you are deciding between, for example, 3, 6, 7 and 2, 6, 9 you would not add them up and see which ...
Tue Feb 16, 2016 12:35 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Homework 15.23 (c)
Replies: 1
Views: 676

### Homework 15.23 (c)

Determine the rate constant for each of the following first-order reactions, in each case expressed for the rate of loss of A: (c) 2A --> B + C, given that [A] 0 =0.153 mol/L and that after 115s the concentration of B rises to 0.035mol/L. Why, in order to find [A] 115s must you subtract the initial ...
Sun Feb 07, 2016 12:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Winter 2015 Midterm Q8C
Replies: 1
Views: 224

### Winter 2015 Midterm Q8C

Assuming the carbon atoms in glucose have 0 oxidation state whereas each H is +1, and each O -2, how many electrons are involved in glucose oxidation? C 6 H 12 O 6 (aq) +O 2 (g) --> H 2 O (l) +CO 2 (g) The answer says that C in CO 2 has a +4 oxidation state Since ther...
Sun Jan 24, 2016 8:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework 8.57
Replies: 2
Views: 373

### Homework 8.57

How do you know that you need to write the balanced equation for each of the reactants and products first instead of just saying that delta H = the sum of the enthalpy of the products - the sum of the enthalpy of the reactants? From doing the second way you get the same answer but positive (312 kJ/m...
Thu Jan 21, 2016 1:41 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.53- Calculating the change in internal energy
Replies: 3
Views: 317

### Re: 8.53- Calculating the change in internal energy

If U = q + w, why is the work=0 for this problem?
Thu Jan 21, 2016 12:13 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Example 8.31
Replies: 1
Views: 272

### Textbook Example 8.31

Example 8.13 Estimate the enthalpy of the reaction between bromine and propene to form 1, 2-dibromopropane. The enthalpy of vaporization is Br 2 is 29.96 kJ/mol, and that of CH 3 CHBrCH 2 Br is 35.61kJ/mol. The reaction is Br 2 + CH 3 CH=CH 2 --> CH 3 CHBrCH 2 Br I understand that you have to find t...
Tue Jan 19, 2016 1:11 am
Forum: Phase Changes & Related Calculations
Topic: Extensive vs. Intensive
Replies: 2
Views: 284

### Extensive vs. Intensive

What does it mean that something is an extensive property of matter versus intensive?
Sun Jan 10, 2016 6:36 pm
Forum: Phase Changes & Related Calculations
Topic: Homework 8.27
Replies: 5
Views: 1218

### Homework 8.27

Calculate the work for each of the following processes beginning with a gas sample in a piston assembly with T=305K, P=1.79atm, and V=4.29L: (a) irreversible expansion against a constant external pressure of 1.00atm to a final volume of 6.52L (b) isothermal, reversible expansion to a final volume of...
Tue Dec 01, 2015 1:26 pm
Forum: Polyprotic Acids & Bases
Topic: HW 12.77 (Calculating pH of alanine)
Replies: 3
Views: 628

### HW 12.77 (Calculating pH of alanine)

12.77 A 3.38 sample of the sodium salt of alanine, NaCH 3 CH(NH 2 )CO 2 is dissolved in water and then the solution is diluted to 50.0mL. For alanine, K a1 =4.57 x 10 -3 , K a2 =1.30 x 10 -10 . What is the pH of the resulting solution? The answer key uses the equation pH = 1/2(pK a1 + pK a2 ) but I ...
Sun Nov 29, 2015 8:58 pm
Forum: Conjugate Acids & Bases
Topic: Fundamentals J.5 (Writing ionic equations)
Replies: 1
Views: 379

### Fundamentals J.5 (Writing ionic equations)

J.5 Complete the overall equation and write the complete ionic equation and the net ionic equation for each of the following acid-base reactions. If the substance is a weak acid or base, leave it in its molecular form in the equations. (b) (CH 3 ) 3 N + HNO 3 --> (CH 3 ) 3 NHNO 3 How do you know tha...
Thu Nov 19, 2015 12:15 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 2013 Quiz 3 Preparation #10
Replies: 10
Views: 1073

### Re: 2013 Quiz 3 Preparation #10

You don't have to convert the bars to any other units. I understand that in order to get the right answer you have to flip the reaction and inverse the K value but I don't understand why that works and why that gets you the right answer as opposed to leaving it the normal way and solving it without ...
Wed Nov 11, 2015 9:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure Calculation?
Replies: 1
Views: 300

### Re: Partial Pressure Calculation?

The equation is like that because K= (PPCl3)(PCl2)/(PPCl5)

and so when you're solving for the partial pressure of PPCl3 you can rearrange the equation to be this:

PPCl3= (K)(PPCl5)/(PCl2)

After plugging in the values you will get PPCl3=(25)(1.18)/(5.43)
Mon Nov 02, 2015 12:09 pm
Forum: Ionic & Covalent Bonds
Topic: How do you know if a compound is ionic?
Replies: 2
Views: 1007

### How do you know if a compound is ionic?

Which compound is more ionic?
(a) Cl2O or Na2O
(b) InCl3 or SbCl3
(c) LiH or HCl
(d) MgCl2 or PCl3

How can you determine which compound is more ionic? Is there a trend we should know?
Wed Oct 28, 2015 4:03 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Valence electron configuration
Replies: 1
Views: 355

### Re: Valence electron configuration

The B2 configuration skipped the third sigma bond because B has a less than 8 electrons. When at least one of the elements has less than 8 electrons the pi bonds and sigma bonds are flipped and the pi bonds will have lower energy. This is also shown on pages 97 & 98 of the course reader if you w...
Sat Oct 24, 2015 6:55 pm
Forum: Hybridization
Topic: 4.39 from Homework
Replies: 1
Views: 314

### Re: 4.39 from Homework

This is due to the fact that the problem stated "each P atom is connected to 3 other P atoms." The only way that this can be possible is if there is a diamond that connects in the middle (like an X). It is different from most other Lewis structures that we see.
Mon Oct 19, 2015 10:48 am
Forum: Ionic & Covalent Bonds
Replies: 1
Views: 327

Can someone explain the difference between an ion being highly polarizable and having high polarizing power?
Mon Oct 05, 2015 10:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 2.43 - Electron configuration
Replies: 2
Views: 351

### Homework 2.43 - Electron configuration

For letter (a) Silver (Ag) why is the electron configuration [Kr] 4d^10 5s^1 versus [Kr] 4d^9 5s^2?

Also, if this is the case, for letter (f) Iodine (I) why is the electron configuration [Kr] 4d^10 5s^2 5p^5 and not [Kr] 4d^10 5s^1 5p^6?
Sun Oct 04, 2015 10:32 pm
Forum: Properties of Light