Suppose the half-life of an isotope is 10 years. after how many years will half of this isotope have decayed into its daughter elements?

5 years
10 years
20 years

Calcium hydride (cah2) reacts with water to form hydrogen gas: cah2(s) + 2h2o(l) → ca(oh)2(aq) + 2h2(g) how many grams of cah2 are needed to generate 45.0 l of h2 gas at a pressure of 0.995 atm and a temperature of 32 °c?

Write a paragraph that provides examples of each stage of volcanic activity, a description of the volcano, and facts about each stage.

If you have 5.25 grams of methane (ch4), how many grams of co2 will you produce ?