Martin mixed sulfur (a yellow solid) with iron filings (a black solid) in a ceramic dish called a crucible. Then he separated them using a magnet. What kind of a change is this? somebody help is it A. change in state B. mixing and separation C. replacement D. synthesis

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