ChemBuddy suite - all four calculators!
operating systems:
Windows 9x, 2000, XP, Vista, 7
single user license price:
€99.95 - approximately $127
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ChemBuddy FAQ
I just purchased one of your programs. What do I need to do to use it?
First of all - download the program from our site, from the download page. Install it.
Registration key should have been attached to the order confirmation mail. Save it in the directory where the program is installed, most likely c:\Program Files\ChemBuddy\program name. Alternatively open registration key with Windows notepad, copy content to the clipboad, start the ChemBuddy program, select File/Register from the menu, paste registration key content into edit field and click OK.
In the case of ChemBuddy suite registration key will work for all programs. You may either register each program individually, or save the registration key in the c:\Program Files\ChemBuddy directory.
It seems there is an error in BATE calculations - titration curve for strong base titrated with phosphoric acid has only two end-points, and they are in the wrong places!
That's what we thought at first too. However, everything is OK. Phosphoric acid is rather weak and to some extent behaves as if it had only two dissociations steps, hence only two end points. Strange localisation of these end points is an artefact of the way we have defined titration percentage. Note, that while we could use different definition, it will not help - just strange titration curves will be calculated in other situations. Compare discussion of titration of polyprotic acids at www.titrations.info.
Is it possible for BATE to calculate titration curve for NH4+ ion?
Yes. Just enter it as acid. However, ionic strength calculations are at the moment based on the assumption that undissociated molecules are not charged, so results of the calculated ionic strentgh can be misleading. For ignored or forced ionic strength calculations results will be correct.
What source did you use to obtain the pKb value of NaOH? As a result of this value, the pH of an equi-molar mixture of HCl and NaOH is not 7.00. This is a concern because our texts for general chemistry always teach that the equivalence point for a strong acid - strong base titration will be 7.00!
Good point. We have not seen a book stating what Kb values of strong bases are. But at the same time some books (for example Handbook of Chemical Equilibria in Analytical Chemistry, Kotrly and Sucha, Ellis Horwood Ltd. 1985) give stabilities of hydroxo-complexes of Na+ and K+ ions.
For complexation reaction
stability constant is defined as
At the same time dissociation reaction is
and the dissociation constant is defined as
It is obvious that both reactions are undistinguishable and Kb = K-1.
Logarithms of stability constants for KOH and NaOH are -0.5 and -0.2 respectively so pKb values are 0.5 and 0.2. Both bases - albeit strong - are weaker than it is commonly believed.
Where can I get more information about acid base equilibrium and pH and titration curve calculations?
First of all - try our pH lectures.
If our lectures and questions are not enough, try google. Google for "acid base equilibrium" or "pH calculation". There are many on-line courses that will show up.
If you are too lazy to Google by yourself try great collection of general chemistry resources at General Chemistry Online.
You may also try to ask your questions at one of the forums devoted to chemistry:
- www.chemicalforums.com (really good ones)
- www.physicsforums.com
Where to find information about temperature for CASC density tables?
This information is not given in the program, however, you can compare density for pure water (0 concentration) with this table:
| density | temperature |
|---|---|
| 0.99913 g/mL | 15 deg C |
| 0.99880 g/mL | 17 deg C |
| 0.99862 g/mL | 18 deg C |
| 0.99823 g/mL | 20 deg C |
Does one license cover the installation of your software on my home computer in addition to my office computer?
Yes. Point 1.3 of our End User License Agreement (file BPPEULA.txt installed on your computer together with the program) covers this situation; however it incorrectly defines term "in use". It should read:
1.3. Registered Users are granted a non-exclusive, nontransferable license to use one copy of the Registered Software on only a single computer at any one time. The Registered Software is "in use" when it runs. The Registered Software is not "in use" when it is installed but not running.
BPPEULA.txt files will be modified in next programs releases.
