The isotope chromium-51 has a half-life of 28 days. if the original sample had a mass of 28.0 grams, what mass of the chromium-51 sample remains after 84 days?

Write a paragraph that provides examples of each stage of volcanic activity, a description of the volcano, and facts about each stage.

What are the three major branches of natural science? • earth and space science, life science, physical science •earth and space science, physical science, chemistry •physical science, life science, chemistry •life science, chemistry, physics

What is the chemical name of the compound na2co3? use the list of polyatomic ions and the periodic table to you answer. a. sodium carbon oxide b. sodium carbonate c. sodium(ll) carbonate d. sodium oxalate