Tartaric acid, H, C4H406, has two acidic hydrogens. The acid is often present in wines and
precipitates from solution as the wine ages. A
solution containing an unknown concentration of
the acid is titrated with NaOH. It requires 21.65
mL of 0.3000 M NaOH solution to itrate both
acidic protons in 45.00 mL of the tartaric acid
solution.

16- counting by fours

B) movement of materials into and out of the cell

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.