895 Liters of Hydrogen gas is reacted with 89.95 grams of Oxygen gas at STP (standard temperature and pressure). This synthesis reaction produced warer. Treat Hydrogen and Oxygen as ideal gasses.

It must be measured in k.hope my answer is to you : )

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.