The purple crystal shown in the picture above is commonly called amethyst. Select which of the following elements combine in an extended crystal structure to form amethyst.

You encounter a solution that is acidic and you decide to test it by adding a small amount of a strong acid. the ph lowers slightly but is approximately unchanged, and still remains acidic. what can you say about the solution? a. it is a buffer solution. b. it is not a buffer solution it is a strong acid solution. d. the solution has been neutralized. e. the solution has excess acid present

What type of reaction is shown below? check all that apply. 2h2o2 → 2h2o + o2 synthesis decomposition combustion

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.