Search found 53 matches
- Tue Feb 12, 2019 7:19 pm
- Forum: Phase Changes & Related Calculations
- Topic: 6th edition 9.19
- Replies: 1
- Views: 11
Re: 6th edition 9.19
The system starts at 85C, and since you are given the standard enthalpy at 100C, you have to use 3 different types of deltaS in this problem: the change in entropy when you go from 85C to 100C, the deltaS at 100C, and then the deltaS when you go from 100C to 85C. You have to go through all these ste...
- Tue Feb 12, 2019 3:59 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 6th edition 9.25
- Replies: 1
- Views: 7
6th edition 9.25
“If SO2F2 adopts a positionally disordered arrangement in its crystal form, what might its molar residual entropy be?” I attemoted this problem by first solving for W so I could use it in S = kBlnW, in which there are 6 different microstates possible for the atoms, but got stuck on how many atoms I ...
- Fri Feb 08, 2019 6:33 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What was Avogadro’s favorite sport?
Golf, because he always got a mole-in-one.
Golf, because he always got a mole-in-one.
- Fri Feb 08, 2019 6:32 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What did the chemist say when he found two isotopes of helium?
HeHe
HeHe
- Fri Feb 08, 2019 6:23 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 6th edition 8.25 Calorimeter problem
- Replies: 1
- Views: 18
6th edition 8.25 Calorimeter problem
The question is “A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in .200L of solution in the calorimeter (q = -3.50 kJ), resulting in a temperature rise of 7.32 C. In a subsequent experiment, 100.0 mL of .200 M HBr(aq) and 100.0 mL of KOH(aq) ...
- Sat Feb 02, 2019 8:18 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What is Iron Man's gender?
Fe Male
Fe Male
- Sat Feb 02, 2019 8:16 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Why did chlorine get in trouble for the acid attack?
It was guilt by dissociation.
It was guilt by dissociation.
- Sat Feb 02, 2019 8:15 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What did the pregnant scientist say at the end of her electrolysis experiment?
"My water broke"
"My water broke"
- Sat Feb 02, 2019 8:11 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Review
- Replies: 14
- Views: 87
Re: Midterm Review
Hopefully we will have review sessions this quarter just like we did for Lavelle's 14A classes last quarter. If anything, he will announce it in the next class.
- Mon Jan 28, 2019 7:06 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What is CH2O?
Seawater.
Seawater.
- Mon Jan 28, 2019 7:05 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Whats the molecular formula for coffee?
CoFe2
CoFe2
- Mon Jan 28, 2019 7:04 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Why was the mole of oxygen excited when he left the singles bar?
He got Avogadro's number.
He got Avogadro's number.
- Tue Jan 22, 2019 10:24 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Increasing the pressure (decreasing volume)
- Replies: 2
- Views: 17
Increasing the pressure (decreasing volume)
When the volume is halved for a system at equilibrium that contains 1.85 M H2, 1.36 M N2, and 2.91e-3 M NH3 with an initial Kc at 9.83e-7, how can you determine the new concentrations for N2, H2, and NH3?
- Mon Jan 21, 2019 7:30 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Quadratic Formula
- Replies: 2
- Views: 17
Quadratic Formula
I'm a bit confused on when we need to apply the quadratic formula and use the ICE table. How can we tell when to use this?
- Tue Jan 15, 2019 9:25 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Did you hear about the joke about Cobalt, Radon, and Yttrium? It was so CoRnY.
- Tue Jan 15, 2019 9:25 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
I tried writing a joke about the periodic table, but I wasn't in my element.
- Tue Jan 15, 2019 9:24 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Two chemists walk into a bar. One says, "I'll have an H2O." The second one says "I'll have an H2O too." The second chemist dies.
- Sat Dec 08, 2018 12:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T-shaped vs trigonal planar
- Replies: 1
- Views: 23
T-shaped vs trigonal planar
When do you know whether to place the lone pairs on the equatorial axis instead of the axial axis? For example, for ICL3 which has the VSEPR formula AX3E2, why do we place the two lone pairs on the equatorial axis (resulting in T-shaped molecule) instead of placing them opposite of the other on the ...
- Sat Dec 08, 2018 12:06 pm
- Forum: Naming
- Topic: using prefix "mono"
- Replies: 2
- Views: 26
Re: using prefix "mono"
You don’t need to use the prefix mono-,since the name of the molecule alone should imply that there is only one molecule. For example, if there was a one amine in the coordination complex, you would just say “amine-“ instead of “monoamine-“ as they both mean the same thing.
- Fri Dec 07, 2018 2:33 pm
- Forum: Lewis Acids & Bases
- Topic: How to determine which acid is stronger or weaker?
- Replies: 1
- Views: 26
How to determine which acid is stronger or weaker?
How do you determine which acids are stronger or weaker? For example, between CF3COOH, CH3COOH, and C(CH3)3COOH?
- Fri Dec 07, 2018 2:26 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: determining the strongest acid
- Replies: 2
- Views: 33
Re: determining the strongest acid
Using these rules, does that mean that BrO is a stronger acid than IO as well?
- Fri Dec 07, 2018 2:22 pm
- Forum: Amphoteric Compounds
- Topic: Oxalate bidentate
- Replies: 4
- Views: 33
Re: Oxalate bidentate
Due to the shape of oxalate, it can only bind in two places. Referring to the last image posted, its highly unlikely that the other two oxygens can bend to bind with the TM in the center.
- Fri Dec 07, 2018 2:16 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Compound
- Replies: 2
- Views: 20
Re: Coordination Compound
I believe that a chelate is a coordination compound with a polydentate ligand.
- Thu Dec 06, 2018 10:59 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: Boiling Point
- Replies: 4
- Views: 87
Boiling Point
How can you tell which compound will have a higher boiling point? For example, between the two molecules H2S and H2Se?
- Wed Nov 28, 2018 12:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles Preference
- Replies: 2
- Views: 25
Re: Bond Angles Preference
I think < 109.5 should be used, since its easier to make a mistake when memorizing all of those numbers, but in the end I don't think it actually matters.
- Wed Nov 28, 2018 12:25 pm
- Forum: Dipole Moments
- Topic: Polarizability vs Polarizing power
- Replies: 8
- Views: 70
Re: Polarizability vs Polarizing power
In determining which molecules have higher polarizing power, what is more significant their charge or their size? For example what is the process we take to determine Rb+ has a higher polarizing power than Sr2+? Rb+ actually has a lower polarizing power than Sr2+. Since Sr2+ has a higher charge tha...
- Wed Nov 28, 2018 11:54 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 5
- Views: 53
Re: Bond Angles
You can generally determine the bond angles if you know the shape too. For example if you know the shape is trigonal planar, then you can just divide 360 by 3 and get 120 degrees. This also applies to the trigonal bipyramidal, as that is essentially a trigonal planar shape intersected with a linear ...
- Wed Nov 28, 2018 11:47 am
- Forum: Hybridization
- Topic: pi vs sigma
- Replies: 12
- Views: 84
Re: pi vs sigma
There is less overlap in a pi bond than a sigma bond, since the orbitals are parallel to each other. Since there is more overlap in a sigma bond, sigma bonds are stronger than pi bonds.
- Wed Nov 21, 2018 11:20 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What kind of fish is made up of sodium?
2 Na.
2 Na.
- Wed Nov 21, 2018 11:19 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What kind of dogs do chemists have?
Laboratory Retrievers.
Laboratory Retrievers.
- Tue Nov 20, 2018 3:28 pm
- Forum: Lewis Structures
- Topic: Midterm question
- Replies: 8
- Views: 65
Re: Midterm question
Due to the resonance structures, the average of the bond lengths of the different structures should have blended together, so you estimate the bond length between 120 and 140, and that's how you get around 130.
- Tue Nov 13, 2018 10:35 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: 11
- Views: 127
Re: hydrogen bonding
^Exactly. Higher melting points indicate more stability so this explains the example given in class: GC base pairs in DNA are more stable than AT base pairs. So does this mean GC base pairs have stronger bonds than AT base pairs? Yes, because G-C base pairs have three hydrogen bonds rather than two...
- Tue Nov 13, 2018 10:02 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: hydrogen bonding
- Replies: 2
- Views: 39
Re: hydrogen bonding
For a hydrogen bond to form a hydrogen must have a partial positive charge from being bonded to a atom with higher electronegativity (like N, O, or F). The partially positive hydrogen is then attracted to a partially charged negative atom. For example in the case of water, since H is bonded to O whi...
- Tue Nov 13, 2018 9:55 pm
- Forum: Dipole Moments
- Topic: Induced-dipole
- Replies: 5
- Views: 52
Induced-dipole
What causes an induced-dipole? What is an example of an induced-dipole between two molecules?
- Wed Nov 07, 2018 11:08 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Silver walks up to Gold in a bar and says, “AU, get out of here!”
- Wed Nov 07, 2018 11:07 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Whats the chemical formula for banana?
BaNa2.
BaNa2.
- Mon Nov 05, 2018 1:26 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 23779
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
On the midterm review worksheet, could someone explain how to draw the lewis structure for XeO2F2? Xe should be the center atom, with 2 F's and 2 O's attached to it. The total number of electrons should be 34e-, so there should be one bond between Xe and the F's, and each F should have 3 lone pairs...
- Wed Oct 31, 2018 3:07 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Whats the difference between chemistry and cooking? In chemistry you never lick the spoon.
- Wed Oct 31, 2018 3:05 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Why did the white bear dissolve in water? Because it was polar.
- Wed Oct 31, 2018 3:04 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What is a cation scared of? A dogion.
- Tue Oct 23, 2018 8:29 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Why do we always start with "up" spin?
- Replies: 2
- Views: 26
Re: Why do we always start with "up" spin?
I don't think it matters, it just symbolizes the direction of the electron's spin. The +/- of the 1/2 denotes the direction of the spin of the electron, and has no relation to the energy level of it.
- Tue Oct 23, 2018 8:27 pm
- Forum: Properties of Electrons
- Topic: colombic potential
- Replies: 2
- Views: 96
colombic potential
How do you determine the value for repulsion between the two electrons in the expression for the colombic potential energy of an atom?
- Tue Oct 23, 2018 8:14 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 2.19 (b)
- Replies: 3
- Views: 35
Re: 2.19 (b)
which version of textbook do you have? I have the 6th edition and 2.19b asks for "How many values of m are allowed for an electron in a 6d-subshell?" to which the answer would be m= -2, -1, 0, 1, 2 since l=3 as the electron is in a d-orbital.
- Tue Oct 16, 2018 7:33 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Oxygen, hydrogen, sulfur, sodium, and phosphorous walk into a bar.
"OH SNaP!" said the bartender.
"OH SNaP!" said the bartender.
- Tue Oct 16, 2018 7:30 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
What did the scientist say when she found two isotopes of helium?
HeHe.
HeHe.
- Tue Oct 16, 2018 7:28 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
One guacamole is 6.022x10^23 guaca; also known as Avacado's constant.
- Tue Oct 09, 2018 10:26 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: molar masses on the test
- Replies: 7
- Views: 138
molar masses on the test
Will we be given the molar mass of elements on the exam? or will we have to memorize the molar masses of the elements? I noticed that in the module assessments we were given the molar mass for some of the elements, but not all.
- Tue Oct 09, 2018 7:47 pm
- Forum: Properties of Light
- Topic: chemical principles edition 6 problem 1.13
- Replies: 1
- Views: 13
chemical principles edition 6 problem 1.13
I'm a bit confused on this problem:
Use the Rydberg formula for atomic hydrogen to calculate the wavelength of radiation generated by the transition from n = 4 to n = 2.
In this problem, would 4 be considered n1 and 2 be n2? Or should it be the other way around to avoid any negative values?
Use the Rydberg formula for atomic hydrogen to calculate the wavelength of radiation generated by the transition from n = 4 to n = 2.
In this problem, would 4 be considered n1 and 2 be n2? Or should it be the other way around to avoid any negative values?
- Tue Oct 09, 2018 7:39 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect
- Replies: 6
- Views: 48
Re: Photoelectric Effect
This is the formula for the kinetic energy of an electron. m(e-) is the mass of the electron, and v(e-) stands for the velocity of the electron.
- Tue Oct 09, 2018 6:49 pm
- Forum: Balancing Chemical Reactions
- Topic: Percent Yield
- Replies: 5
- Views: 109
Re: Percent Yield
You might have to, since it appears in some of the homework questions from week 1. Calculating the percent yield is simple, you just need to divide the actual yield over the theoretical yield and multiply that by 100%.
- Thu Oct 04, 2018 7:52 pm
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reactant vs. Reagent??? [ENDORSED]
- Replies: 6
- Views: 95
Re: Limiting Reactant vs. Reagent??? [ENDORSED]
In the textbook it states that reagents are the chemicals available in a laboratory. When a reagent is being used in a particular reaction it is called a reactant.
- Wed Oct 03, 2018 4:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Grading for Chemistry Community [ENDORSED]
- Replies: 6
- Views: 142
Re: Grading for Chemistry Community [ENDORSED]
You need three posts per week, not one post per week.
- Wed Oct 03, 2018 11:32 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 7023
- Views: 771961
Re: Post All Chemistry Jokes Here
Q: What do you call a clown in prison?
A: A silicon.
A: A silicon.