Which number completes the balanced chemical equation showing the process of rusting? 4Fe + 3O2 ---> Fe2O3

A. 1

B. 2

C. 4

D. 12

C. chemical changeshope i : )

Do not include the unexpected results

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.