Search found 12 matches

by HelenMach 1J
Sat Dec 13, 2014 7:40 pm
Forum: *Titrations & Titration Calculations
Topic: Henderson for Titrations
Replies: 1
Views: 249

Re: Henderson for Titrations

"Look at the log part of the HH equation. Suppose that the salt form and the acid form were equal concentrations. That means that the ratio is 1 and the log of 1 is 0. The HH equation then becomes: pH = pKa This is an important (and useful) result. It can be used to determine an uknown Ka by ca...
by HelenMach 1J
Sat Dec 13, 2014 12:49 pm
Forum: Lewis Acids & Bases
Topic: Concentration of hydronium ions
Replies: 2
Views: 453

Re: Concentration of hydronium ions

If these are homework questions, they will most likely refer you to tables 11.1 and 11.2 for the Ka/b and pKa/b values. I am not exactly sure how to solve it myself if you are not allowed to reference these two tables.
by HelenMach 1J
Sat Dec 13, 2014 12:43 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Homework 12.21
Replies: 3
Views: 500

Re: Homework 12.21

The value of pKa2 is given on page 455, Table 11.10. I don't believe you are required to figure this value out yourself, especially since there were no values given to you in order to do so... I believe...
by HelenMach 1J
Sat Dec 13, 2014 12:36 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Significant Figures for Acids and Bases
Replies: 1
Views: 1541

Re: Significant Figures for Acids and Bases

The number of significant figures of a pH/pOH is the same as the number of sig figs in a molar concentration. "Here is the example problem: Calculate the pH of a solution where the [H+] is 0.00100 M. (This could also be a pOH problem. The point being made is the same.) OK, you say, that's prett...
by HelenMach 1J
Fri Dec 12, 2014 8:53 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: how do you know which ion is going to accept/give the proton
Replies: 3
Views: 547

Re: how do you know which ion is going to accept/give the pr

It is an ampholytic compound, both a base Kb = 1.3 x 10−6 AND an acid: Ka = 8 x 10−9... so I am going to assume you're going to have to use your best guess...
by HelenMach 1J
Fri Dec 12, 2014 8:48 pm
Forum: Empirical & Molecular Formulas
Topic: Video: Combustion Analysis
Replies: 2
Views: 372

Re: Video: Combustion Analysis

Thank you so much for the link!
by HelenMach 1J
Tue Dec 09, 2014 12:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis structures that obey the octet rule
Replies: 3
Views: 1467

Re: Lewis structures that obey the octet rule

I am going to assume that it means that the atom in the middle is only allowed 8 valence electrons (besides the few exceptions that do not have eight electrons naturally). So only four bonds, double bonds should be allowed as long as it obeys the eight valence/octet rule...

If someone can confirm....
by HelenMach 1J
Tue Dec 02, 2014 4:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Significant Figures
Replies: 4
Views: 528

Re: Significant Figures

Agreed with Sophie. Remember my T.A. advising us to take a few places over the sig fig amount and just do sig fig at the end. This will give the most accurate answer available.
by HelenMach 1J
Tue Dec 02, 2014 4:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quiz 3 Prep #7, setting up ICE box
Replies: 5
Views: 1211

Re: Quiz 3 Prep #7, setting up ICE box

Kc I believe (talks about equilibrium concentration instead of equilibrium partial pressures)
by HelenMach 1J
Tue Dec 02, 2014 4:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 2012 quiz 3 prep #1
Replies: 5
Views: 1192

Re: 2012 quiz 3 prep #1

Yes! Thank you so much Eduardo!
by HelenMach 1J
Tue Dec 02, 2014 4:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quiz 3 #10
Replies: 8
Views: 1061

Re: Quiz 3 #10

The question does not give you moles... no wait it does in the equation...! I am a bit confused about this question as well. Going to type the question out so people do not have to refer to the book if they answer/understand: Bromine chloride, bromine, and chlorine gases have reached equilibrium in ...
by HelenMach 1J
Sat Nov 29, 2014 5:43 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 2012 quiz 3 prep #1
Replies: 5
Views: 1192

Re: 2012 quiz 3 prep #1

For the water, there was a coefficient two in front of the water molecule, meaning there were two water molecules... and it's written separately, so you know there are for sure two different water molecules. As for the chloride, I am going to assume that it is the same reason? "Since the Cl2 (t...

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