PARADOX
Video..    Paradox.wmv

Tutorial... PDoxTut.html


PARADOX-1
CONSERVATION of MASS

The weight of a bottle and balloon, sealed together, decreases as vinegar and baking soda generate carbon dioxide and inflate the balloon.
Mass is conserved but the weight decreases due to buoyancy.
Buoyancy  equals the mass of the air displaced by the inflating balloon.

 


PARADOX-2
pH of 0.05 M HCl
C.G.McCarty and E. Vitz, J. Chem. Ed. 83 752 (2006)

4 M CaCl2 is weakly acidic due to hydrolysis
0.05 M HCl gives a pH reading of 1.7 (1.3 theoretical)
The mixture of 10 mL of each of the above gives a pH of 0.8
This despite the common ion and dilution effects
From where does all that hydrogen ion suddenly appear (or does it)
Color of solutions due to addition of Methyl Violet indicator
 


STUDENT PARADOX

While vinegar does not clean copper efficiently,
a mixture of salt and vinegar does.
Make measurements and explain this conundrum.

    R W Kluiber 10/23/2006  (Mole Day)