A 20.00 mL sample of the standard oxalic acid solution (use the molarity calculated from Q1 above) requires 24.16 mL of your base to reach the endpoint. Calculate the molarity of the base to 4 sig. fig.

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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.