How many different kinds of particles are there in the world?

Find the mass in grams of 1.37x1020 particles of h3po4

Which of the following molecules is polar? c3h7oh c2h5cooh

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