How many molecules are in 25.0g of H3PO4?

Asample contains 16.75 g of the radioisotope u-236 and 50.25 g of its daughter isotope, th-232. how long did it take for decay to take place if one half-life of u-236 is 23 million years? 46 million years 69 million years 92 million years 115 million years

Matches the chemical name of each oxide of phosphorus to its chemical formula

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.