How many Barium atoms are present in the compound Barium Nitride?

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ

The movement of tectonic plates and in two locations is described below: location a: tectonic played push together location b: tectonic plates push apart