How many moles of aluminum oxide (al2o3) are in a sample with a mass of 204.0 g?

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

What effect might melting sea ice have for people who live in coastal areas?

If a solution had a ph of 7 what is the solution