lodine-131, a radioactive isotope of iodine, has a half-life of 8 days. After 40 days, if 1.5 g of lodine-131 still remains, what is the original amount of iodine-131?

What is the number of moles in 15.0 g ash3?

6what is the importance of water on earth? a) it keeps the top layer of the geosphere cool b) it allows life to exist c) it provides ice at the poles d) it creates earth's blue color from space

Sulfuric acid is a polyprotic acid. write balanced chemical equations for the sequence of reactions that sulfuric acid can undergo when it's dissolved in water.