Which one is the scientific evidence?

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

A50.0 ml sample of gas at 20.0 atm of pressure is compressed to 40.0 atm of pressure at constant temperature. what is the new volume? 0.0100 ml 0.325 ml 25.0 ml 100. ml