## Search found 19 matches

Wed Mar 08, 2017 9:56 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 3 Winter 2017
Replies: 183
Views: 20096

### Re: Quiz 3 Winter 2017

304751905 wrote:for #1, why do we need "iso" in front of propyl? wouldn't the 4- signify the branching?

Its isopropyl because its CH(CH3)2 and not CH3(CH2)2 which would be propyl. as a rule of thumb, the two CH3 indicates iso
Thu Mar 02, 2017 8:49 pm
Forum: *Nucleophiles
Topic: Ambident
Replies: 3
Views: 474

### Re: Ambident

It's a nucleophile thats negative charge is delocalized by resonance over two unlike or unequal atoms
Thu Feb 23, 2017 9:02 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre Equilibria
Replies: 2
Views: 433

### Re: Pre Equilibria

It wasn't included because it acted as the solvent
Mon Feb 13, 2017 8:40 pm
Forum: First Order Reactions
Topic: Reaction Order Graphs
Replies: 1
Views: 356

### Re: Reaction Order Graphs

They would not be a straight line. I believe possibly curved
Thu Feb 09, 2017 6:44 pm
Forum: Balancing Redox Reactions
Topic: Reduction Potential
Replies: 1
Views: 279

### Re: Reduction Potential

Yes I think it is standard to always just get the reduction potential and to know the reverse is the oxidation potential
Thu Feb 02, 2017 5:41 pm
Forum: Phase Changes & Related Calculations
Topic: Practice Quiz 1
Replies: 1
Views: 250

### Re: Practice Quiz 1

1) find moles of PbO (=.22 mol)
2)multiple the moles by the H of reaction for 1 mole (-106.9) to get -23800J which represents the H for reaction consisting of 49.7g of PbO
3)use q=nCT. -23800=n(4.184)(100-25)
4)solve for n and you get 75.9 grams
Mon Jan 23, 2017 5:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.31 HW problem
Replies: 1
Views: 330

### 8.31 HW problem

I don't understand the formula the book used to solve this question... can someone try to explain this one to me?

Calculate the heat released by 5.025 g of Kr(g) at 0.400 atm as it cools from 97.6C to 25.0C at a) a constant pressure and b) a constant volume

Thanks !
Thu Jan 19, 2017 7:40 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: #8.85
Replies: 1
Views: 371

### Re: #8.85

b) PV=nRT , V=5.45L P=1atm, R=0.0821, T=273K.
Solve for "n" and you get 0.243 moles.
multiply this by 180.6KJ/1moleN2 to find out the total KJ for 0.243 moles
(43.9KJ)
Thu Jan 12, 2017 6:25 pm
Forum: Phase Changes & Related Calculations
Replies: 4
Views: 448

Yes. Although the temperature has not increased, heat is still being supplied. And by definition, enthalpy is the amount of heat being released or absorbed at a constant pressure.
Thu Dec 01, 2016 1:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Fall 2014 Final Exam Q5D.
Replies: 1
Views: 322

### Re: Fall 2014 Final Exam Q5D.

They left x out of the numerator because "5.82x10^-3" (the initial concentration of NH3) is very small and would be affected significantly by x. However, in the denominator "2.72" and "3.7" are large numbers in comparison and the difference is great enough that they wou...
Tue Nov 22, 2016 3:15 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Understanding Ka
Replies: 1
Views: 326

### Re: Understanding Ka

A low Ka means that the acid is weak and does not dissociate well. A low Ka means you can disregard the change in molarity of the acid because the change is so negligible (which can streamline your calculations when making an ICE table). A high Ka means the acid is strong and dissociates wells.
Tue Nov 15, 2016 11:46 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination numbers [ENDORSED]
Replies: 1
Views: 311

### Coordination numbers[ENDORSED]

Do molecules outside the brackets contribute to the coordination number? Like in [Co(NH3)4(NO2)Cl]Cl
Would the coordination number be 6 or 7?
Thanks !
Wed Nov 09, 2016 2:15 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Anti-bonding orbital energies
Replies: 1
Views: 235

### Re: Anti-bonding orbital energies

Regardless of whether "z" is greater than or equal to 8 (elements past oxygen) or z is less than 8 (elements from nitrogen and behind), the antibonding remains the same. so antibonding sigma 2p is higher in energy than antibonding pi 2p.
Tue Nov 01, 2016 4:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal pyramidal vs. pyramidal
Replies: 2
Views: 3552

### Re: Trigonal pyramidal vs. pyramidal

There is trigonal pyramidal and trigonal bipyramidal but not a separate "pyramidal." The bond angle is 106 for trigonal pyramidal and 180,90, or 120 for trigonal bipyramidal(:
Tue Oct 25, 2016 2:07 pm
Forum: Lewis Structures
Topic: CO Lewis structure
Replies: 1
Views: 297

### CO Lewis structure

Can someone explain to me why the answer in the book shows CO having a triple bond with one pair of lone electrons on each atom (so that the formal charge of C is -1 and O is +1) rather than a double bond so that O has an extra pair of lone electrons and each atom has a formal charge of 0? Is it bec...
Tue Oct 18, 2016 12:45 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Confusion on which orbitals fill first
Replies: 1
Views: 362

### Confusion on which orbitals fill first

the electron configuration for Ta is [Xe]4f14 5d3 6s2
the electron configuration for Au is {Xe]4f14 5d10 6s1

I was wondering if someone could explain the 6s orbital is full for Ta and not for Au
why isn't Ta [Xe]4f14 5d5?
or why isn't Au [Xe] 4f14 5d9 6s2>

Thanks!
Tue Oct 11, 2016 1:44 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Question 2.29 from the textbook [ENDORSED]
Replies: 2
Views: 496

### Question 2.29 from the textbook[ENDORSED]

How many electrons can have the following quantum numbers in an atom: a)n=2, l=1 b)n=4, l=2, m1=-2 c)n=2 d)n=3, l=2, m1= +1 The answers are: a) six b) two c) eight d) two I needed some help clearing up whether or not I'm interpreting this correctly. Is the answer to "b" and "d" 2...
Tue Oct 04, 2016 11:03 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post-module Question
Replies: 1
Views: 429

### Atomic Spectra Post-module Question

Can molecular spectroscopy be used to identify molecules? If so, why? I know that atomic spectroscopy can be used to identify elements, but I am unclear as to whether the same goes for molecules. I would assume it does not since there are just so many possible molecules. Could someone clarify this f...
Wed Sep 28, 2016 1:26 pm
Forum: Properties of Light
Topic: Photoelectric effect video
Replies: 3
Views: 525

### Re: Photoelectric effect video

Adding on to the previous reply, a shorter wavelength means a higher frequency which is directly proportional to energy. So that's why the shorter wavelengths= more energy... just in case you wanted to look at energy levels in terms of frequency rather than wavelength.