How much of one gram of radium-226 will remain unchanged after four half-lives?

If 90.0 grams of ethane reacted with excess chlorine,how many grams of dicarbon hexachloride would form

Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. an industrial chemist studying this reaction fills a 25.0l tank with 4.5 mol of sulfur dioxide gas and 4.5 mol of oxygen gas at 30.°c. he then raises the temperature, and when the mixture has come to equilibrium measures the amount of sulfur trioxide gas to be 1.4 mol. calculate the concentration equilibrium constant for the reaction of sulfur dioxide and oxygen at the final temperature of the mixture. round your answer to 2 significant digits.

Iron (3) oxide will decompose in the presence of hydrogen gas and heater to produced iron and digydrogen monoxide white a balanced chemical equation