One element isotope has exactly the same mass number and atomic mass. It was used as the definition of the atomic mass unit (amu). Which element isotope is it and what is its atomic mass?

Sulfuric acid (a component of acid rain) reacts with limestone (calcium carbonate) to produce calcium sulfate and carbon dioxide. this damages buildings and statues made of limestone. which solution of sulfuric acid will damage these structures more quickly? a. 0.001% b. 0.005% c. 0.010% d. 0.015%

Describe the interaction that occurs between two objects with the same electrical charge.

Which of the following are sources of revenue for media companies? a. direct sales to producers b.advertising and subscriptions c. online purchase d. capital investments