How does chemistry help the environment?

Which of the following signs of a chemical reaction are observed in the reaction of potassium with water? precipitate formed temperature change smell produced gas produced color change

In 2002, the rare earth elements mine in mountain pass, california was closed because

Henry moseley used x-ray experiments to determine the atomic number of elements. how did his discovery contribute to the development of the periodic table? a. it confirmed that elements should be arranged in strict order of increasing atomic mass. b. it led to elements with similar atomic numbers being grouped together. c. it allowed the elements to be placed in strict order of increasing atomic number. d. it showed that the way mendeleev grouped elements together was completely wrong.