Search found 17 matches

by Feng Ming Li 2K
Thu Feb 11, 2016 12:57 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8017
Views: 1403030

Re: Chemistry Jokes

Since Valentine's day is coming up, this would be appropriate to ask someone you have been wanting to talk to! Good luck~

Are you a Carbon sample? Because I want to date you.
by Feng Ming Li 2K
Sat Feb 06, 2016 12:33 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Monatomic vs Diatomic
Replies: 1
Views: 407

Monatomic vs Diatomic

The entropy change for a monatomic molecule is greater than that of a diatomic molecule because it has a larger number of particles. Shouldn't the diatomic molecule have a larger number of particles since there would be two molecules? Why is the entropy change bigger for the monatomic molecule?
by Feng Ming Li 2K
Sat Feb 06, 2016 12:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Winter 2011 Midterm Q2A
Replies: 1
Views: 335

Winter 2011 Midterm Q2A

When calculating the standard reaction enthalpy, why can't I just ignore HCl (g)-> HCl(aq)? The 6HCl (aq) from 2Al(s) + 6Hcl(aq)-> A AlCl3 (aq) +3H2(g) can be cancelled from H2 (g) +Cl2 (g)-> 2HCl(g) by multiplying the whole equation by 3. Also, why is the final answer -704 when the sum of everythin...
by Feng Ming Li 2K
Sun Jan 31, 2016 1:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: General Cell Reaction Question
Replies: 1
Views: 314

General Cell Reaction Question

Cu(s)|Cu^{2+}||Ce^{4+}, Ce^{3+}|Pt(s) Hi, so when I was doing the Standard cell potential problems, I noticed that Platinum is sometimes in the beginning or end of the equation set. How come Platinum is not taken into account when we calculate the standard cell potentials? Also, why is there a comma...
by Feng Ming Li 2K
Mon Jan 18, 2016 10:26 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework 8.55
Replies: 1
Views: 379

Homework 8.55

The second equation: 2Al (s) + O2 (g) --> Al2O3 (s) is turned into 2Al (s) + 3/2 O2 (g) ---> Al2O3 (s). How did the O2 changed into 3/2 O2 without changing the other elements in the balanced equation?
by Feng Ming Li 2K
Sun Jan 10, 2016 9:43 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant P and Constant V Calorimetry
Replies: 2
Views: 476

Re: Constant P and Constant V Calorimetry

Hi, a Constant P Calorimetry stands for constant pressure calorimetry and it measures the change in enthalpy of a reaction at constant pressure. A Constant V calorimetry, constant volume calorimetry, measures the heat of combustion of a reaction.
by Feng Ming Li 2K
Sat Dec 05, 2015 8:55 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: strength of acids/ bases
Replies: 3
Views: 658

strength of acids/ bases

How do you determine if it is a strong acid or base or if it is a weak acid or base? Do you just memorize the strength from a chart?

Thanks
by Feng Ming Li 2K
Sun Nov 29, 2015 9:55 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Determining weak bases
Replies: 3
Views: 988

Re: Determining weak bases

There are several other criterion to determine if it is a strong or weak base: - Water-soluble ionic compounds that contain hydroxide ions (OH-) are strong bases. -Anions in ionic compounds with except OH-, Cl-, HSO4-, NO3-, ClO4-, HSO4-, and H2PO4- are weak bases. These should be with group 1 or 2 ...
by Feng Ming Li 2K
Sun Nov 22, 2015 10:21 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Bronsted acids or bases Vs Lewis acids and bases
Replies: 1
Views: 419

Bronsted acids or bases Vs Lewis acids and bases

What is the most obvious way to tell the difference between Bronsted acids or bases and Lewis acids and bases? How do you label compounds with the correct classification? Thanks!
by Feng Ming Li 2K
Mon Nov 16, 2015 4:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 11.89 balanced equation
Replies: 1
Views: 319

Homework 11.89 balanced equation

For the balanced equation of part A, the answer is 2A -> B+ 2C. How come it's not just A-> B+C ? Thanks!!
by Feng Ming Li 2K
Sat Nov 14, 2015 10:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 11.13 Reaction Quotient Q
Replies: 1
Views: 512

Homework 11.13 Reaction Quotient Q

Write the reaction quotient Q for (a) 2 BCl3(g) + 2 Hg(l) ---> B2Cl4(s) + Hg2Cl2(s) (b) P4S10(s) + 16 H2O(l) ---> 4 H3PO4(aq) + 10 H2S(aq) (c) Br2(g) + 3 F2(g) ---> 2 BrF3(g) If I use the formula in the book which is Q= [Products]/[Reactants]. I would get a different answer from what is shown in the...
by Feng Ming Li 2K
Sun Nov 08, 2015 1:46 pm
Forum: Naming
Topic: Naming Complexes and coordination compounds
Replies: 1
Views: 419

Re: Naming Complexes and coordination compounds

According to the compound, there are two [Co(NH3)3(OH2)3] because there is a subscript, which is 2, outside of the bracket. Based on that information, you can tell that there are two complex ions, which are [Co(NH3)3(OH2)3]2. Since (SO4)3 is outside of the bracket, it is its own ion. Sulfate, (SO4)3...
by Feng Ming Li 2K
Sun Nov 01, 2015 10:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Distinct DIfference between Linear and Bent
Replies: 2
Views: 5270

Distinct DIfference between Linear and Bent

I understand that for bent, there is at least one lone pair, however, is there an easy way to figure out the molecule is linear or bent, or do I have to memorize VSEPR. For example, I3- is linear while SO2 is bent.
by Feng Ming Li 2K
Wed Oct 28, 2015 12:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarization of a molecule with loose electrons
Replies: 1
Views: 369

Re: Polarization of a molecule with loose electrons

For O3, there is a dipole moment because if you calculate the formal charges of the oxygen molecules, you would get 0, +1, and -1. The central oxygen molecule would have a charge of +1, making the two other oxygen molecules more negative. Therefore, the dipole would be pointing away from the central...
by Feng Ming Li 2K
Wed Oct 28, 2015 12:05 pm
Forum: Lewis Structures
Topic: Drawing a reduced anion
Replies: 2
Views: 493

Re: Problem 3.103

since there are 6 carbons, you have to bond the carbons first and then attach the hydrogen and the oxygen molecules to each carbon. After that, you can focus on the double bonds and the formal charges to ensure that it is the correct lewis structure.
by Feng Ming Li 2K
Wed Oct 21, 2015 8:20 pm
Forum: Lewis Structures
Topic: Homework 3.49 part c
Replies: 1
Views: 246

Homework 3.49 part c

The question is: Draw the Lewis structure and determine the formal charge on each atom in (c) CO.

Since oxygen can only form two bonds, how come in this problem, oxygen can form a triple bond with carbon?
by Feng Ming Li 2K
Sun Oct 11, 2015 9:32 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Fundamentals E.3
Replies: 1
Views: 489

Fundamentals E.3

Here is the question: In a nanotechnology lab you might have the capability to manipulate individual atoms. The atoms on the left are gallium atoms (molar mass 70 g*mol^-1), those on the right are atoms of astatine (molar mass 210 g*mol^-1). How many astatine atoms would the pan on the right have to...

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