If the half-life of a radioisotope is 20,000 years, then a sample in which three-quarters of that radioisotope has decayed is years old

Which of these properties, used alone, would be least useful in identifying most minerals? a. color b. luster c. streak d. density

If an area has high air pressure and low humidity, what type of weather will it most likely have? plz !

In vapor-liquid equilibrium in a binary mixture, both components are generally present in both phases. how many degrees of freedom are there for such a system? the reaction between nitrogen and hydrogen to form ammonia occurs in the gas phase. how many degrees of freedom are there for this system? steam and coal react at high temperatures to form hydrogen, carbon monoxide, carbon dioxide, and methane. the following reactions have been suggested as being involved in the chemical transformation: