How many moles of FeCl2 can be produced when 74.5 moles of HCl reacts with excess FeS? FeS + 2 HCl → H2S + FeCl2

We can't until we know what we are working with or on

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.

Ithink the answer is 10.576

60.66% is the answer