The half-life of 90Sr is 29 years. What fraction of the atoms in a sample of 90Sr would remain 175 years later

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?

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

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.