What is the standard notation of the isotope h-2

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

2pos suppose an object in free fall is dropped from a building. its starting velocity is 0 m/s. ignoring the effects of air resistance, what is the speed (in m/s) of the object after falling 3 seconds? give your answer as a positive decimal without units. answer here

What is a metal replacement reaction