53.9 g of iron oxide is formed during an experiment where 42.3g of iron oxidizes. Fe + O2= Fe2O3
A: which reactant is limiting?

B: what is the theoretical yield (mass) of iron (III) oxide produced in this reaction?

Answerstudying coal cumbustion as an energy source;

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.